View source for Astronomy:Timeline of Opportunity

{{short description|Robotic rover that was active on the planet Mars from 2004 to 2018}}
{{Italic title|string=Opportunity}}
[[File:PIA21494-MarsRoverOpportunity-LandingSite-20150408.jpg|thumb|500px|''Opportunity'' rover's landing site (HiRISE; MRO; April 8, 2015).]]
[[File:Opportunity in Endurance Crater.jpg|thumb|Artist generated view of ''Opportunity'', in a real image taken by said rover of a crater]]
[[File:PIA07372-MarsOpportunityRover-SelfPortrait-20041220-crop-rotate-sm.jpg|thumb|Selfie looking down on its panels, December 2004]]

''[[Engineering:Opportunity (rover)|Opportunity]]'' is a robotic [[Astronomy:Rover (space exploration)|rover]] that was active on the planet [[Astronomy:Mars|Mars]] from 2004 to 2018.<ref name="NASA-Opportunity">{{cite web | last=Nelson | first=Jon | title=Mars Exploration Rover - Opportunity | url=http://www.jpl.nasa.gov/missions/mars-exploration-rover-opportunity-mer/ | date= | work=[[Organization:NASA|NASA]] | access-date=February 2, 2014 }}</ref>  Launched on July 7, 2003, ''Opportunity'' landed on Mars' [[Astronomy:Meridiani Planum|Meridiani Planum]] on January 25, 2004, at 05:05 Ground UTC (about 13:15 [[Astronomy:Timekeeping on Mars|Mars local time]]), three weeks after its twin ''Spirit'' (MER-A), also part of [[Organization:NASA|NASA]]'s Mars Exploration Rover Mission, touched down on the other side of the planet.<ref name="january">"Spirit" landed on January 4, 2004.</ref> While ''Spirit'' became immobile in 2009 and ceased communications in 2010, ''Opportunity'' exceeded its planned 90 [[Astronomy:Sol (day on Mars)|sol]] (Martian days) duration of activity by 14 years 46 days (in Earth time). ''Opportunity'' continued to move, gather scientific observations, and report back to Earth until 2018. What follows is a summary of events during its continuing mission.

''Opportunity'' started in Eagle crater in 2004, literally landing inside on the crater basin, then it travelled outward making its way to Endurance crater. After this it went to Victoria crater, all the way making many panoramas, measurements, studying rocks and smaller craters, even what are thought to be meteorites. It then traveled to Endeavour crater, where it has been making its way south along the Western rim. On June 10, 2018, contact was lost when a global dust storm blotted out the Sun, thus depriving the rover of enough power for operations and communication with Earth. In September 2018, after the storm subsided, NASA began making various efforts to contact and listen to the rover if it endured the storm. NASA officials declared that the ''Opportunity'' mission was complete on February 13, 2019, after it failed to wake from over 1,000 repeated signals sent since August 2018.<ref>{{Cite web|url=https://mars.nasa.gov/mer/mission/rover-status/opportunity/recent/all/index.cfm?y=2018|title=Rover Update: All|last=mars.nasa.gov|website=mars.nasa.gov|access-date=2019-02-13}}</ref>

== Mission timeline ==

===Summary===
[[File:Opportunity rover lifetime progress map.jpg|thumb|center|1000px|Lifetime progress map with Washington, D.C. overlay for size and distance comparison.]]

====Landing site context====
{{Multiple image
| align = center
| total_width = 1000
| image1 = 226782main 5296.jpg
| caption1 = Overall location of ''Opportunity'' on the planet Mars
| image2 = MOLA opportunity.jpg
| caption2 = ''Opportunity''{{'}}s landing site (denoted with a star)
| image3 = PIA05154.jpg
| caption3 = Landing ellipse of ''Opportunity''; with Bopulu on the left, and the Endeavour, Iazu, unnamed on the right, below the ellipse
| image4 = Meridianicropped.png
| caption4 = Annotated elevation map of ''Opportunity'' landing site and some surrounding craters including Endeavour and Miyamato
}}

=== 2004 ===

==== Landing site: "Eagle" crater ====
{{Multiple image
| total_width = 1000
| image1 = Merbfirst.jpg
| caption1 = ''Opportunity's'' first 360-degree [[Grayscale|grayscale]] panorama, taken by the navcam on Sol 1 of the mission, showing interior of Eagle crater at Meridiani Planum
| image2 = Opportunity - PIA05152.jpg
| caption2 = First color panorama taken by ''Opportunity'', showing the Martian landscape at Meridiani Planum
| align = center
}}

''Opportunity'' landed in [[Astronomy:Meridiani Planum|Meridiani Planum]] at {{Coord|1.95|S|354.47|E|globe:mars_type:landmark}}, about {{convert|25|km|mi|sp=us}} downrange (east) of its intended target on January 25, 2004, at 05:05.<ref name="MERFacts">{{cite news |title=NASA Facts: Mars Exploration Rover |publisher=NASA/JPL |url=http://www.jpl.nasa.gov/missions/mer/merfactsheet.pdf |date=October 24, 2004 |access-date=March 25, 2014 |archive-date=March 27, 2009 |archive-url=https://web.archive.org/web/20090327135047/http://www.jpl.nasa.gov/missions/mer/merfactsheet.pdf |url-status=dead }}</ref> Although Meridiani is a flat [[Earth:Plain|plain]], without the rock fields seen at previous Mars landing sites, ''Opportunity'' rolled into an [[Astronomy:Impact crater|impact crater]] 22 meters in [[Diameter|diameter]], with the rim of the crater approximately {{convert|10|m|ft|sp=us}} from the rover.<ref name="MERFacts" /> NASA Scientists were so excited about landing in a crater that they called the landing a "hole in one"; however, they were not aiming for the crater (and did not know it existed). Later, the crater was named ''Eagle crater'' and the landing site designated "[[Engineering:Space Shuttle Challenger disaster|''Challenger'']] Memorial Station".<ref name="ChallengerMemorial">{{cite web| url=http://marsrovers.nasa.gov/newsroom/pressreleases/20040128a.html | archive-url=https://web.archive.org/web/20040216050919/http://marsrovers.nasa.gov/newsroom/pressreleases/20040128a.html | url-status=dead | archive-date=February 16, 2004 | title=Space Shuttle Challenger Crew Memorialized on Mars | publisher=NASA | date= | access-date=July 24, 2008}}</ref> This was the darkest landing site ever visited by a spacecraft on Mars. It would be two weeks before ''Opportunity'' was able to get a better look at its surroundings.

Scientists were intrigued by the abundance of rock outcrops dispersed throughout the crater, as well as the crater's soil, which appeared to be a [[Physics:Mixture|mixture]] of coarse gray grains and fine reddish grains. This sweeping look at the unusual rock outcropping near ''Opportunity'' was captured by the rover's panoramic camera. Scientists believe the seemingly layered rocks are either volcanic ash deposits or sediments laid down by wind or water. It was given the name ''Opportunity Ledge''.

Geologists said that the layers—some no thicker than a finger—indicate the rocks likely originated either from sediments carried by water or wind, or from falling volcanic ash. "We should be able to distinguish between those two hypotheses", said Dr. Andrew Knoll of Harvard University, Cambridge, a member of the science team for ''Opportunity'' and its twin, ''Spirit''. If the rocks are sedimentary, water is a more likely source than wind, he said.<ref name="nasa_20040127a">{{cite web | url=http://marsrovers.nasa.gov/newsroom/pressreleases/20040127a.html | archive-url=https://web.archive.org/web/20040216050228/http://marsrovers.nasa.gov/newsroom/pressreleases/20040127a.html | url-status=dead | archive-date=February 16, 2004 | title=Scientists Thrilled To See Layers in Mars Rocks Near Opportunity | date= | access-date=July 8, 2006 }}</ref>

These layered rocks measure only {{convert|10|cm|in|sp=us}} tall and are thought to be either volcanic ash deposits or sediments carried by water or wind. The layers are very thin measuring just a few millimeters thick in some cases.

<!--{{Wide image|Pancam Sol1 Postcard part th361.jpg|800px|First color panorama taken by ''Opportunity'', showing the Martian landscape at Meridiani Planum, shortly after it touched down in 2004}}-->
{{clear}}

[[File:PIA05229 label.jpg|thumb|500px|center|Mars Global Surveyor [[Engineering:Orbiter|orbiter]]'s photograph of landing site showing "hole in one." (See also: simulation of ''Opportunity''{{'s}} trajectory on arrival at Mars in January 2004).]]

{{clear}}

==== "Opportunity Ledge" outcroppings ====
{{Wide image|MERB outcrop map 01-mw-01-labels-B041R1 br.jpg|1600px|This panoramic image, showing the locations of rocks and outcrops at the northwestern rim of Eagle crater, was taken with ''Opportunity'' still on its lander. These layered rocks measure only {{convert|10|cm|in|abbr=off}} tall and were thought at that time to be either volcanic ash deposits or sediments carried by water or wind. See also [[:File:Eagle crater on the Mars PIA05163.jpg|a version of this image without annotations.]] (Courtesy NASA/JPL-Caltech)}}

On Sol 15, ''Opportunity'' took a close up of the rock "Stone Mountain" in the outcrop area of the crater, raising speculation that the rock consisted of very fine grain or dust, in contrast to Earth [[Earth:Sandstone|sandstone]], which is compacted sand with rather large grains. The [[Earth:Weathering|weathering]] agent [[Earth:Erosion|eroding]] away layers of this rock seemed to be visible as dark spots.<ref name="nasa2">{{cite web | quote=Embedded in it like blueberries in a muffin are these little spherical grains", said Dr. [[Biography:Steve Squyres|Steve Squyres]] of [[Organization:Cornell University|Cornell University]], Ithaca, N.Y., principal investigator for the rovers' scientific instruments. He also said: "One other treasure, a clue that just popped up, not gonna quote any numbers yet, but we have now completed an APXS measurement on the outcrop and it has got a lot of [[Chemistry:Sulfur|sulfur]] in it. Maybe a few times more sulfur than we've seen on any other location on Mars. | url=http://www.jpl.nasa.gov/releases/2004/54.cfm | title=Mars Rover Pictures Raise 'Blueberry Muffin' Questions | last1=Webster | first1=Guy | last2=Savage | first2=Donald | work=News | publisher=JPL | date=February 9, 2004 | url-status=dead | archive-date=2004-02-10 | archive-url=https://web.archive.org/web/20040210124137/http://www.jpl.nasa.gov/releases/2004/54.cfm }}</ref>

A picture received on February 10 (taken on Sol 16) showed that the thin layers in the bedrock converge and diverge at low angles, suggesting that some "moving current" such as volcanic flow, wind, or water formed these rocks. The discovery of these layers was significant for scientists who had planned this mission to test the "water hypothesis" rigorously.

==== El Capitan outcropping ====
[[File:El Capitan sol27 pancam.jpg|thumb|Section of El Capitan.]]
{{main|Astronomy:El Capitan (Mars)}}
On February 19 the survey of "Opportunity Ledge" was declared successful. A specific target in the outcrop (dubbed "El Capitan"), whose upper and lower portions appeared to differ in layering and weathering characteristics, was selected for further investigation. El Capitan, about {{convert|10|cm|in|sp=us}} high, was named after a mountain in Texas.<ref name="El Capitan Is That A Rock Or What">{{cite web|url=http://www.spacedaily.com/news/mars-mers-04zzl.html|title=El Capitan Is That A Rock Or What|author=Moffett field|publisher=Space Daily|date=February 25, 2004}}</ref> ''Opportunity'' reached El Capitan on Sol 27, and took a first picture of the rocks with its panoramic camera.

On Sol 30, ''Opportunity'' used its [[Engineering:Rock Abrasion Tool|Rock Abrasion Tool]] (RAT) for the first time to investigate the rocks around El Capitan. The image on the right-hand side shows a close-up view taken after the drilling and cleaning process was complete. Due to chance, two [[Astronomy:Martian spherules|spherules]] were also cut partially, and seem to show scratches and other marks made by the diamond-crusted grind tool. The black areas are artifacts of the imaging process, when parts of the picture are missing.

During a press conference on  {{age in sols|2004|01|25|2004|03|02}} March 2, 2004, mission scientists discussed their conclusions about the bedrock and the evidence for the presence of liquid water during their formation. They presented the following reasoning to explain the small, elongated voids in the rock visible on the surface and after grinding into it (see last two images below).<ref name="Meridiani Planum Evidence" >{{cite web|url=http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20040302a.html | title=Opportunity Rover Finds Strong Evidence Meridiani Planum Was Wet | date= | access-date=July 8, 2006 }}</ref>

These voids are consistent with features known to geologists as "[[Earth:Vug|vug]]s". These are formed when crystals form inside a rock matrix and are later removed through erosive processes, leaving behind voids. Some of the features in this picture are "disk-like", which is consistent with certain types of crystals, notably sulfate minerals.

Additionally, mission members presented first data from the [[Astronomy:MIMOS II|MIMOS II]] Mössbauer spectrometer taken at the bedrock site. The iron spectrum obtained from the rock El Capitan shows strong evidence for the mineral [[Chemistry:Jarosite|jarosite]]. This mineral contains [[Chemistry:Hydroxide|hydroxide]] ions, which indicates the presence of water when the minerals were formed. Mini-TES data from the same rock showed that it consists of a considerable amount of sulfates.

<gallery class="center">
Image:Opportunity photo of Mars outcrop rock.jpg|Close up of a rock outcrop.
Image:Opp layered sol17-B017R1 br.jpg|Thin rock layers, not all parallel to each other.
Image:Xpe First Opp RAT-B032R1 br.jpg|Section of hole created by RAT.
Image:17-jg-03-mi2-B035R1_br.jpg|Voids or "vugs" inside the rock.
</gallery>

==== Analyzing soil through digging a trench ====
{{Multiple image
| image1 = The Mystery of the Sparkling Spheres.jpg
| caption1 = This image, taken by the microscopic imager, reveals shiny, spherical objects embedded within the trench wall
| image2 = Opportunity from orbit.gif
| caption2 = Mapping out of various aspects of ''Opportunity''{{'}}s mission up to April 2004 as seen from orbit
| align = center
| total_width = 800
}}

In order to analyze the soil inside the crater it was decided to try to dig a trench with the wheels. The rover alternately pushed soil forward and backward out of the trench with its right front wheel while other wheels held the rover in place. The rover turned slightly between bouts of digging to widen the hole. The process lasted 22 minutes. The resulting trench — the first dug by either Mars Exploration Rover — is about {{convert|50|cm|in|sp=us}} long and {{convert|10|cm|in|sp=us}} deep.<ref name="Opportunity Digs; Spirit Advances">{{cite web| url=http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20040217a.html | title=Opportunity Digs; Spirit Advances | date= | access-date=July 8, 2006}}</ref>
Two features that caught scientists' attention were the clotty texture of soil in the upper wall of the trench and the brightness of soil on the trench floor.

By inspecting the sides and floor of a hole it dug, ''Opportunity'' found some things it had not imaged beforehand, including shiny round pebbles and soil so fine-grained that the rover's microscope could not make out individual particles.

What is underneath is different from what is at the immediate surface.<ref name="Opportunity Examines Trench As Spirit Prepares To Dig One">{{cite web | url=http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20040219a.html | title=Opportunity Examines Trench As Spirit Prepares To Dig One | date= | access-date=August 7, 2006}}</ref> The soils consist of fine-grained basaltic sand and a surface lag of hematite-rich spherules, spherule fragments, and other granules. Underlying the thin soil layer, are flat-lying sedimentary rocks. These rocks are finely laminated, are rich in sulfur, and contain abundant sulfate salts.<ref name="investigation">S. Squyres, ''et al.'', "The Opportunity Rover's Athena Science Investigation At Meridiani Planum, Mars," ''Science, Vol. 306'', Issue 5702, 1698–1703 (December 3, 2004).</ref>

==== Endurance crater ====
On sol  {{age in sols|2004|01|25|2004|04|20}} April 20, 2004, the rover reached Endurance crater, which was known to have many layers of rocks.<ref name="Opportunity Arrives at 'Endurance Crater'">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2004.html#sol94 | title=Opportunity Arrives at 'Endurance Crater' | date= | access-date=August 9, 2011 }}</ref>  In May the rover circumnavigated the crater, and made observations with Mini-TES and the panoramic camera. The rock "Lion Stone" was investigated on Sol 107<ref name="Opportunity Digs, Scuffs, and Cruises.">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2004.html#sol107 | title=Opportunity Digs, Scuffs, and Cruises. | date= | access-date=August 9, 2011}}</ref> and found to be similar in composition to the layers found in Eagle crater.

{{Multiple image
| image1 = Fram Crater in color.jpg
| caption1 = Fram crater on Sol {{age in sols|2004|01|25|2004|04|24}}, April 24, 2004
| image2 = Burns cliff.jpg
| caption2 = The view of Burns Cliff inside Endurance Crater.
| align = center
| total_width = 800
}}

On sol  {{age in sols|2004|01|25|2004|06|04}} June 4, 2004 mission members announced their intention to drive ''Opportunity'' into Endurance, even if it should turn out to be impossible to get back out, targeting the various rock layers that were identified in the pictures from the crater rim. "This is a crucial and careful decision for the Mars Exploration Rovers' extended mission", said Dr. Edward Weiler, NASA's associate administrator for space science. Steve Squyres, principal investigator from Cornell University said: "Answering the question of what came before the evaporites is the most significant scientific issue we can address with ''Opportunity'' at this time."<ref name="endurance1">{{cite web|url=http://marsrovers.nasa.gov/newsroom/pressreleases/20040604a.html|archive-url=https://web.archive.org/web/20041027222107/http://marsrovers.nasa.gov/newsroom/pressreleases/20040604a.html|url-status=dead|archive-date=October 27, 2004|title=Mars Rover Opportunity Gets Green Light To Enter Crater| date= | access-date=July 7, 2006}}</ref>

A first drive into the crater was executed on sol {{age in sols|2004|01|25|2004|06|08}} June 8, and ''Opportunity'' backed out again the same day.<ref name="Opportunity Dip">{{cite web|url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2004.html#sol133 | title=Opportunity Takes A Dip | date= | access-date=August 9, 2011}}</ref> 
It was found that the angle of the surface was well inside the safety margin (about 18 degrees), and the full excursion toward the rock layer of interest was started. During Sols 134 (June 12), 135, and 137 the rover drove deeper and deeper into the crater. Although some wheel slip was observed, driving was discovered to be possible even at slope angles up to 30 degrees.

Wispy clouds, similar to Earth's [[Earth:Cirrus cloud|cirrus cloud]]s, were spotted.

''Opportunity'' spent roughly 180 sols inside the crater, before backing out of it again in mid December 2004, on Sol 315.<ref name="Out of 'Endurance'">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2004.html#sol306 | title=Out of 'Endurance' | publisher=NASA | date= | access-date=August 9, 2011}}</ref> Scientific results of the sedimentary geology of the crater were published in the journal ''[[Earth:Earth and Planetary Science Letters|Earth and Planetary Science Letters]]''<ref name="sedimentary">{{cite book | first1=S. W. | last1=Squyres | first2=A. H. | last2=Knoll | title=Sedimentary Geology at Meridiani Planum, Mars | publisher=Elsevier | location=Amsterdam | isbn=978-0-444-52250-4 | year=2005 | quote=reprinted from ''Earth and Planetary Science Letters, Vol. 240'', No. 1 (2005). }}</ref>  In December 2004, daily power output varied from 840 watt-hours while inside Endurance Crater to 730 watt-hours on the plains.<ref name="Status Updates 2004">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2004.html | date=December 21, 2004 | access-date=April 29, 2014 | title=Opportunity Status Updates 2004 | publisher=NASA}}</ref>
{{clear}}
{{wide image|MarsEndurance.jpg|1000px|Endurance Crater panorama (approximate true color)}}

=== 2005 ===

==== Heat Shield Rock and stuck in sand ====
[[File:MERB 528 2.jpg|thumb|Traverse map released July 2005, from about Sol 405 to Sol 528]]
After exiting Endurance crater, in January 2005 ''Opportunity'' was driven to examine its own discarded [[Astronomy:Heat shield|heat shield]]. While in the vicinity of the heat shield, on Sol 345 it came upon an object that was immediately suspected and soon confirmed to be a [[Astronomy:Meteorite|meteorite]]. The meteorite was promptly named [[Astronomy:Heat Shield Rock|Heat Shield Rock]],<ref name="Hovering Near Heat Shield and a Holey Rock">{{cite web|url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2005.html#sol341| title=Hovering Near Heat Shield and a Holey Rock | date= | access-date=August 9, 2011}}</ref> and is the first meteorite identified on another planet (although the [[Astronomy:Bench Crater meteorite|Bench Crater]] and Hadley Rille meteorites were found earlier on the [[Astronomy:Moon|Moon]]).

After about 25&nbsp;sols of observations ''Opportunity'' headed south for a crater named Argo, nearly {{convert|300|m|ft|sp=us}} from the heat shield.<ref name="Opportunity Continues on the Plains After Marking One Year on Mars">{{cite web| url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2005.html#sol353 | title=Opportunity Continues on the Plains After Marking One Year on Mars | date= | access-date=August 9, 2011}}</ref>

The rover was commanded to dig another trench on the vast plains of Meridiani Planum, on Sol 366, and observations continued until Sol 373 (February 10, 2005). The rover then passed the craters "Alvin" and "Jason", and by Sol 387, approached a "crater triplet" on its way to Vostok Crater. Along the way, ''Opportunity'' set a distance record for one-day travel by either rover: {{convert|177.5|m|ft|sp=us}}, on sol  {{age in sols|2004|01|25|2005|02|19}} February 19, 2005. On Sol  {{age in sols|2004|01|25|2005|02|26}} (February 26, 2005), the rover approached one of the three craters, dubbed Naturaliste. A rock target named "Normandy" was chosen for investigation on Sol 392, and ''Opportunity'' remained there until Sol 395.

''Opportunity'' reached Vostok Crater on Sol 399, finding it mostly filled with sand and lined by outcrops. It was then ordered south into what has been called "etched terrain", to search for more bedrock.

On March 20, 2005 (Sol 410) ''Opportunity'' set a new Martian record for the longest single day drive when it drove {{convert|220|m|ft|sp=us}}.<ref name="Update20050331">{{cite web|url=http://marsrover.nasa.gov/mission/status_opportunityAll_2005.html#sol408 |archive-url=https://web.archive.org/web/20090322044019/http://marsrover.nasa.gov/mission/status_opportunityAll_2005.html#sol408 |url-status=dead |archive-date=March 22, 2009 |title=Opportunity Continues to Set Martian Records |publisher=NASA/JPL |date=March 31, 2005}}</ref><ref name="Durable Mars Rovers Sent Into Third Overtime Period">{{cite web|url=http://www.nasa.gov/vision/universe/solarsystem/mer-040505.html |title=Durable Mars Rovers Sent Into Third Overtime Period |publisher=NASA/JPL |date=April 5, 2005 }}</ref><ref name="Mars rover mission extended">{{cite news|url=http://www.cnn.com/2005/TECH/space/04/07/mars.rovers/index.html |title=Mars rover mission extended |work=CNN|date=2005-04-07 }}</ref>

By Sol 415, ''Opportunity'' stopped by some soil [[Earth:Ripple marks|ripples]] to investigate the differences between soil in the trough of a ripple and its crest. Various soil targets included "Mobarak" in the trough, named in honor of Persian New Year, and "Norooz" and "Mayberooz" on the crest. By Sol 421, the rover left the ripple for "Viking" crater.

Between April 26, 2005 (Sol 446) and June 4, 2005 (Sol 484) ''Opportunity'' was stuck in a Martian sand dune. The problem began on sol {{age in sols|2004|01|25|2005|04|26}} (April 26, 2005) when ''Opportunity'' inadvertently dug itself into a sand dune: Mission scientists reported that images indicated all four corner wheels were dug in by more than a wheel radius, just as the rover attempted to climb over a dune about {{convert|30|cm|in|sp=us}} tall. The sand dune was designated "Purgatory Dune" by mission planners.

The rover's condition was simulated on Earth prior to any attempt to move, out of concern that the rover might become permanently immobilized. After various simulations intended to mimic the properties and behavior of Martian sand were completed, the rover executed its first wheel movements on sol {{age in sols|2004|01|25|2005|05|13}} (May 13, 2005), intentionally advancing only a few centimeters, after which mission members evaluated the results.

During Sol 465 and 466 more drive commands were executed, and with each trial the rover moved another couple of centimeters. At the end of each movement, panoramic images were acquired to investigate the atmosphere and the surrounding dune field. The sand dune escape maneuver was successfully completed on sol {{age in sols|2004|01|25|2005|06|04}} (June 4, 2005), and all six wheels of ''Opportunity'' were on firmer ground. After studying "Purgatory" from Sol 498 to Sol 510, ''Opportunity'' proceeded southward toward "Erebus crater".
{{Wide image |Opportunity Heat Shield.jpg|800px|Area around the heat shield, including the resulting shield impact crater. The heat shield was released before the rover landed and impacted the surface on its own}}
{{Gallery|align=center|Image:PIA07269-Mars Rover Opportunity-Iron Meteorite.jpg|Heat Shield Rock was the first meteorite ever identified on another planet.
|Image:Opportunity heat shield Sol335B P2364 L456-B339R1.jpg|Heat shield, with Heat Shield Rock just above and to the left in the background.
|Image:Opportunity Sol468 HazCam.JPG|Dug in back wheels on Sol 468.
}}

==== Erebus crater ====
''Opportunity '' studied [[Astronomy:Erebus (crater)|Erebus crater]], a large, shallow, partially buried crater and a stopover on the way south toward Victoria crater, between October 2005 and March 2006.

New programming to measure the percentage of slip in the wheels was successful in preventing the rover from getting stuck again. Another "Purgatory"-like incident was averted on Sol 603, when onboard slip check software stopped a drive after slip reached 44.5%.<ref name="Opportunity_20051011">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2005.html#sol599 | title=Opportunity Update: Opportunity Backs Out of Potentially Sticky Situation (October 11, 2005) | access-date=June 3, 2006}}</ref> It proceeded over many [[Earth:Ripple marks|ripples]] and 'half-pipes', taking photographs after each sol's journey.

On Sol  {{age in sols|2004|01|25|2005|11|03}} (November 3, 2005) ''Opportunity'' woke up in the midst of a mild dust storm that lasted three days. The rover was able to drive in self-protective auto-mode during the storm, but it could not take any post-drive images. Less than three weeks later, another cleaning event cleared the dust off of the solar array so as to produce around 720 watt-hours (80% of max). On Sol {{age in sols|2004|01|25|2005|12|01}} (December 1, 2005), it was discovered the motor used to stow the robotic arm for travel was stalling. This problem took nearly two weeks to fix. Initially, the arm was stowed only for travel and was extended at night to prevent the arm from getting stuck. However, further stalling convinced engineers to leave the arm extended at all times to avoid the arm becoming stuck in the stowed position and becoming unusable.

''Opportunity'' observed numerous outcroppings around Erebus crater.

It also collaborated with [[Organization:European Space Agency|ESA]]'s [[Astronomy:Mars Express|Mars Express]] by using the miniature [[Physics:Thermal Emission Spectrometer|Thermal Emission Spectrometer]] and panoramic camera (Pancam), and took images of a transit across the Sun by Phobos. On Sol {{age in sols|2004|01|25|2006|03|22}} (March 22, 2006), ''Opportunity'' began the journey to its next destination, Victoria crater, which it would reach in September 2006 (Sol 951).<ref name="NASA_Photojournal_PIA08813">{{cite web|url=http://photojournal.jpl.nasa.gov/catalog/PIA08813|title=PIA08813: 'Victoria Crater' at Meridiani Planum| date= | access-date=June 28, 2010}}</ref> It would stay at Victoria crater until August 2008 (Sol 1630–1634).<ref name="NASA_Photojournal_PIA13088">{{cite web|url=http://photojournal.jpl.nasa.gov/catalog/PIA13088|title=PIA13088: Opportunity's Wheel Tracks at Victoria Crater| date= | access-date=June 28, 2010}}</ref>

{{wide image|Payson Ridge, Erebus Crater, Mars Opportunity Rover.jpg|1000px|An outcrop named "Payson", on the western edge of Erebus.}}
{{wide image|PIA03621-Opportunity Rover-Olympia Panorama.jpg|1000px| Erebus Olympia rock outcrop in Erebus}}

==== Shoulder troubles ====
The "shoulder" joint of ''Opportunity''{{'}}s arm has had troubles since Sol 2 (January 25, 2004), the rover's second day on Mars. Engineers discovered that the heater on the shoulder azimuth joint, which controls side-to-side motion of the robotic arm, was stuck in the "on" position. Closer investigation revealed that the on-off switch had probably failed during assembly, test, and launch operations on Earth. Fortunately for ''Opportunity'', the rover was equipped with a built-in safety mechanism called a "T-stat box" (thermostatic switch) that provided protection against overheating. When the shoulder azimuth joint, also known as Joint 1, got too hot, the T-stat switch automatically opened and temporarily disabled the heater. When the joint got cold again, the T-stat closed. As a result, the heater stayed on all night but not all day.

[[File:Heat Shield Rock2.jpg|thumb|''Opportunity'' extends its arm to analyze Heat Shield Rock on Sol 349 (early 2005).]]

The safety mechanism worked until ''Opportunity'' approached the first winter on Mars. As the Sun began to retreat lower in the sky and solar power levels dropped, it became clear that ''Opportunity'' would not be able to keep the batteries charged with a heater draining power all night long. On Sol {{age in sols|2004|01|25|2004|05|28}} (May 28, 2004), rover operators began using a procedure known as "deep sleep," during which ''Opportunity'' disconnected the batteries at night. Deep sleep prevented the stuck heater (and everything else on the rover except the clock and the battery heaters) from drawing power. When the Sun came up the next morning and sunlight began hitting the solar arrays, the batteries automatically reconnected, the robotic arm became operational, the shoulder joint warmed up, and the thermostatic switch opened, disabling the heater. As a result, the shoulder joint was extremely hot during the day and extremely cold at night. Such huge temperature swings, which tend to make electric motors wear out faster, were taking place every sol.

This strategy worked for ''Opportunity'' until Sol 654 (November 25, 2005), when the Joint-1 azimuth motor stalled because of increased electrical resistance. Rover operators responded by delivering higher-than-normal current to the motor. This approach also worked, though Joint 1 continued to stall periodically. Typically, the rover's handlers simply tried again the next sol and the joint worked. They determined that the Joint-1 motor stalls were most likely due to damage caused by the extreme temperature cycles the joint experienced during deep sleep. As a precaution, they started keeping the robotic arm out in front of the rover overnight, rather than stowing it underneath the rover deck, where it would be virtually unusable in the event of a Joint-1 motor failure. They stowed the arm only while driving and unstowed it immediately at the end of each drive.

=== 2006 ===

==== Journey to Victoria crater ====
On March 22, 2006 (Sol 760), ''Opportunity'' left Erebus crater and began the journey to Victoria crater, which it reached in September 2006 (Sol 951<ref name="NASA_Photojournal_PIA08813" />). It would stay at Victoria crater until August 2008 (Sol 1630–1634).<ref name="NASA_Photojournal_PIA13088" />

[[File:MERB 878.jpg|thumb|700px|center|The rover's journey up to Sol 878 (July 2006) on the way to Victoria crater]]
{{Clear}}

==== Arrival at Victoria crater ====
{{main|Astronomy:Victoria (crater)}}

[[Astronomy:Victoria (crater)|Victoria crater]] is a massive impact crater approximately {{convert|7|km|mi|sp=us}} from the original landing site. Victoria's diameter is six times larger than [[Astronomy:Endurance (crater)|Endurance crater]]. Scientists believed that rock outcrops along the walls of Victoria would yield more information about the geologic history of Mars, if the rover survived long enough to investigate them.

On Sol {{age in sols|2004|01|25|2006|09|26}} (September 26, 2006) Opportunity reached the rim of Victoria Crater<ref name="NASA Mars Rover Arrives at Dramatic Vista on Red Planet">{{cite web|url=http://www.jpl.nasa.gov/news/news.cfm?release=2006-116|title=NASA Mars Rover Arrives at Dramatic Vista on Red Planet|website=[[Organization:Jet Propulsion Laboratory|Jet Propulsion Laboratory]]|access-date=September 30, 2006|archive-date=July 11, 2015|archive-url=https://web.archive.org/web/20150711152731/http://www.jpl.nasa.gov/news/news.php?release=2006-116|url-status=dead}}</ref> and transmitted the first substantial views of Victoria, including the dune field at the bottom of the crater. The [[Astronomy:Mars Reconnaissance Orbiter|Mars Reconnaissance Orbiter]] photographed Opportunity at the rim of the crater.<ref name="Mars orbiter looks down on rover">{{cite news |url=http://news.bbc.co.uk/1/hi/sci/tech/5413754.stm |title=Mars orbiter looks down on rover |publisher=BBC News | date=October 6, 2006}}</ref>

{{wide image|Victoria Crater, Cape Verde-Mars.jpg|1500px|Victoria Crater as seen by the NASA ''Opportunity'' (MER-B) in 2006 using its Pancam instrument}}

=== 2007 ===

==== Moving around Victoria's rim ====

On January 4, 2007, both rovers received new flight software for their computers. The update was received just in time for the third anniversary of their landing. The new systems let the rovers decide whether to transmit an image, and whether to extend their arms to examine rocks, which would save much time for scientists, as they would not have to sift through hundreds of images to find the one they want, or examine the surroundings to decide to extend the arms and examine the rocks.<ref name="Old rovers learn new tricks">{{cite news | url=http://www.cbc.ca/technology/story/2007/01/04/tech-mars.html | work=CBC News | title=Old rovers learn new tricks | date=January 4, 2007}}</ref>

The APXS instrument was now for the first time used to determine the amount of the [[Chemistry:Noble gas|noble gas]] [[Chemistry:Argon|argon]] in the atmosphere of Mars. The same measurements were done on the other side of the planet by its rover twin Spirit. The purpose of this experiment was to determine the atmospheric mixing processes and track their changes with time.<ref name="sol_1057">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2007.html#sol1057 | title=Sol 1057 | publisher=NASA | date= }}</ref>

In January the rover drove along the north side of the crater rim and imaged the cliffs from different viewpoints. While driving another meteorite was found: ''Santa Caterina''.<ref name="sol_1049">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2007.html#sol1049 | title=Sol 1049 | publisher=NASA | date= }}</ref>
In March the ''Valley without peril'' was reached. This point had thought to be a possible entry point into the crater. But it turned out that this point had a too steep slope to drive carefully downside. After two additional cliffs where inspected it was decided to drive the whole way back to the point, where ''Opportunity'' arrived at Victoria crater. On June 15, 2007, the rover arrived at Duck Bay and prepared for entering the crater.

A series of cleaning events beginning on Sol {{age in sols|2004|01|25|2007|04|20}} (April 20, 2007) allowed ''Opportunity''{{'}}s [[Physics:Solar energy|solar energy]] production to rise to above 800 watt-hours per Sol. By Sol {{age in sols|2004|01|25|2007|05|04}} (May 4, 2007) the solar array current was peaking above 4.0 [[Ampere|ampere]]s, values not seen since Sol {{age in sols|2004|01|25|2004|02|10}} (February 10, 2004).<ref name="Status Updates">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol1164 | date= | access-date=May 7, 2007 | title=Opportunity Status Updates: Sols 1152–1156, 1157–1163, and 1164–1170 | publisher=NASA | archive-date=June 20, 2014 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol1164 | url-status=dead }}</ref> However, the advent of extensive dust storms on Mars starting in mid-2007 (in-line with Mars' six Earth-year global dust storm cycle), dropped energy production levels to 280 watt-hours per day.<ref name="'Scary Storm' on Mars Could Doom Rovers">{{cite web|url=http://www.space.com/news/070705_dusty_rovers.html| date= 5 July 2007| access-date=July 15, 2007|title='Scary Storm' on Mars Could Doom Rovers| website= Space.com}}</ref>

==== Dust storms ====
[[File:Mars dust opacities MER-B Sol 1205 to 1235.jpg|thumb|Time-lapse composite of the Martian horizon during Sols 1205 (0.94), 1220 (2.9), 1225 (4.1), 1233 (3.8), 1235 (4.7) shows how much sunlight the dust storms blocked; Tau of 4.7 indicates 99% blocked. credit:NASA/JPL-Caltech/Cornell.]]

Toward the end of June 2007, a series of dust storms began clouding the Martian atmosphere with dust. The storms intensified and by July 20, both ''Opportunity'' and ''Spirit'' were facing the real possibility of system failure due to lack of power. NASA released a statement to the press that said (in part) "We're rooting for our rovers to survive these storms, but they were never designed for conditions this intense".<ref name="nasa4">{{cite web | url=http://www.jpl.nasa.gov/news/news.cfm?release=2007-080 | publisher=JPL | title=News Releases | date= | access-date=2014-03-25 | archive-date=2012-01-17 | archive-url=https://web.archive.org/web/20120117024242/http://www.jpl.nasa.gov/news/news.cfm?release=2007-080 | url-status=dead }}</ref> The key problem caused by the dust storm was a dramatic reduction in solar power. There was so much dust in the atmosphere that it blocked 99 percent of direct sunlight to the rover. The ''Spirit'' rover, on the other side of the planet, was getting slightly more sunlight than ''Opportunity''.

Normally the solar arrays are able to generate about 700 watt-hours of energy per day. During the storms, the power generated is greatly reduced. If the rovers get less than 150 watt-hours per day they have to start draining their batteries. If the batteries run dry, key electrical elements are likely to fail due to the intense cold. On July 18, 2007, the rover's solar-panel only generated 128 watt-hours, the lowest level ever. NASA responded by commanding Opportunity to only communicate with Earth once every three days, the first time that this had happened since the start of the mission.

The dust storms continued through July and at the end of the month, NASA announced that the rovers, even under their very-low-power mode were barely getting enough energy to survive. If the temperature of the ''Opportunity''{{'}}s electronics module continued to drop, according to the announcement, "there is a real risk that Opportunity will trip a low-power fault. When a low-power fault is tripped, the rover's systems take the batteries off-line, putting the rover to sleep and then checking each sol to see if there is sufficient available energy to wake up and perform daily fault communications. If there is not sufficient energy, Opportunity will stay asleep. Depending on the weather conditions, Opportunity could stay asleep for days, weeks or even months, all the while trying to charge its batteries with whatever available sunlight there might be."<ref name="nasa5">{{cite web | url=http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20070731a.html | title=Mars Exploration Rover Mission: Press Releases | publisher=NASA | date= }}</ref> It was quite possible that the rover would never wake up from a low-power fault.

By sol {{age in sols|2004|01|25|2007|08|07}} August 7, 2007 the storms appeared to be weakening, and although power levels were still low they were sufficient for ''Opportunity'' to begin taking and returning images.<ref name="Martian Skies Brighten Slightly">{{cite web|url=http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20070807a.html|title=Martian Skies Brighten Slightly| date= | access-date=August 8, 2007}}</ref> By August 21 dust levels were still improving, the batteries were fully charged and ''Opportunity'' was able to make its first drive since the dust storms began.<ref name="Mars Exploration Rover Status Report: Rovers Resume Driving">{{cite web|url=http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20070824a.html|title=Mars Exploration Rover Status Report: Rovers Resume Driving| date= | access-date=September 13, 2007}}</ref>

''Opportunity'' made a short drive into Duck Bay on sol {{age in sols|2004|01|25|2007|09|11}} September 11, 2007 and then reversed out again to test traction on the initial slope into Victoria Crater.<ref name="victoria1">{{cite web | url=http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20070911a.html | title=Opportunity Takes A Dip Into Victoria Crater | date= | access-date=September 13, 2007 }}</ref> On sol {{age in sols|2004|01|25|2007|09|13}}  September 13, 2007 it returned
to begin a more thorough exploration of the inner slope, examining a series of layers of pale-coloured rock in the upper parts of Duck Bay and the face of the promontory [[Astronomy:Cape Verde (Mars)|Cape Verde]] in detail.

<gallery class="center">
File:Victoria crater from HiRise.jpg|Victoria crater (HiRise).
Image:Opportunity at Victoria Crater from Mars reconnaissance orbiter.jpg|''Opportunity'' at the rim of Victoria Crater, as imaged by [[Astronomy:Mars Reconnaissance Orbiter|MRO]] (October 3, 2006).
Image:Oppland01.jpg|''Opportunity'' at the rim of Victoria Crater, as imaged by [[Astronomy:Mars Reconnaissance Orbiter|MRO]] (November 29, 2006).
Image:Opportunity Tracks.jpg|''Opportunity'' tracks, as seen by HiRISE. The white dots are places where rover stopped to perform scientific observations or turned (6/2007).
</gallery>

=== 2008 ===
Rover daily power output averaged 580 watt-hours in the first days of 2008, with atmospheric opacity (tau) caused by dust at about 0.71, and solar array dust factor averaging 0.787.<ref name="Status Updates 2008">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2008.html | date=January 2, 2008 | access-date=April 29, 2014 | title=Opportunity Status Updates 2008 | publisher=NASA}}</ref>

==== Inspecting Victoria crater ====
On Sol 1502 (April 15, 2008) the motor stalled at the beginning of an unstowing operation at the end of a drive, when the arm was still tucked underneath the rover. The motor continued to stall on all subsequent attempts, sol after sol. Engineers performed tests at various times of day to measure electrical resistance. They found that the resistance was lowest (essentially normal) when the joint was at its warmest—in the morning, following deep sleep, after the heater had been on for several hours, and just before the T-stat opened. They decided to try to unstow the arm one more time under these conditions.

At 08:30 local Mars time on Sol {{age in sols|2004|01|25|2008|05|14}} (May 14, 2008), they allowed ''Opportunity'' to direct as much current as possible to the warm, joint-1 azimuth motor in order to get the robotic arm into a usable position, in front of the rover. It worked.

Because ''Opportunity'' will likely never again stow the robotic arm, engineers devised a strategy for driving the rover safely with the arm deployed in front.<ref name="nasa3">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2008.html#sol1525 | title=Mars Exploration Rover Mission: All Opportunity Updates | publisher= | date= }}</ref>

==== Departing Victoria crater ====
[[File:Looking Back at Arena of Exploration.jpg|thumb|Departing Victoria crater]]
The rover exited Victoria crater's Duck Bay on August 24–28, 2008 (sol 1630–1634).<ref name="NASA_Photojournal_PIA13088" /> Before exiting the crater the rover experienced a current spike similar to the one that preceded the malfunction of the right front wheel of its twin ''Spirit''. After Victoria crater and during its journey to Endeavour crater the rover investigated sets of "dark cobbles" on the Meridiani plains.<ref name="PlanetaryAug2008">{{cite web | url=http://www.planetary.org/news/2008/0831_The_Mars_Exploration_Rovers_Update.html | title=Opportunity Exits Victoria Crater, Spirit Picks Up Pace on Panorama | first=A.J.S | last=Rahl | publisher=Planetary Society | date=August 31, 2008 | url-status=dead | archive-url=https://web.archive.org/web/20080907212950/http://www.planetary.org/news/2008/0831_The_Mars_Exploration_Rovers_Update.html | archive-date=2008-09-07 }}</ref>

[[Astronomy:Endeavour (crater)|Endeavour]] is {{convert|22|km|mi|sp=us|abbr=on}} in diameter and is {{convert|12|km|mi|sp=us}} south-east of Victoria.<ref name="2008HeadingTowardsCrater">{{cite web|url=http://www.jpl.nasa.gov/news/news.cfm?release=2008-176|title=Mars Exploration Rover to head toward bigger crater|website=[[Organization:Jet Propulsion Laboratory|Jet Propulsion Laboratory]]|access-date=September 22, 2008|archive-date=June 5, 2011|archive-url=https://web.archive.org/web/20110605031248/http://www.jpl.nasa.gov/news/news.cfm?release=2008-176|url-status=dead}}</ref> Rover drivers estimated that this distance could be traversed in about two years.<ref name="2008HeadingTowardsCrater" /> Scientists expected to see a much deeper stack of rock layers at the crater than those examined by ''Opportunity'' in Victoria.<ref name="2008HeadingTowardsCrater" /> The discovery of phyllosilicate clay-bearing rock on the Endeavour crater rim promised exposure to a rock-type that is even more hospitable to life than types previously analyzed.<ref name="New life-related geology beckons Opportunity rover">{{cite web | url=http://www.spaceflightnow.com/news/n0907/19opportunity/ | title=New life-related geology beckons Opportunity rover | date= | access-date=August 2, 2009}}</ref>

The [[Astronomy:Solar conjunction|solar conjunction]], where the Sun is between Earth and Mars, started on sol {{age in sols|2004|01|25|2007|11|29}} November 29, 2008 and communication with the rovers was not possible until December 13, 2008. During this time the rover team planned to have ''Opportunity'' use the Mössbauer spectrometer to examine a rock outcrop named "Santorini".<ref name="Opportunity Prepares for Two Weeks of Independent Study">{{cite web | date= | access-date=November 30, 2008 | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol1709 | title=Opportunity Prepares for Two Weeks of Independent Study | publisher=NASA/JPL | archive-date=June 20, 2014 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol1709 | url-status=dead }}</ref>

=== 2009 ===

==== Driving through Meridiani plains ====
On sol {{age in sols|2004|01|25|2009|03|07}} (March 7, 2009) ''Opportunity'' first saw the rim of Endeavour after driving about {{convert|3.2|km|mi|sp=us|abbr=on}} since it left Victoria in August 2008.<ref name="NASA20090318PressRelease">{{cite news|title=One Mars Rover Sees A Distant Goal; The Other Takes A New Route |publisher=NASA/JPL |url=http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20090318a.html |date=March 18, 2009}}</ref><ref name="NASA20090318gallery">{{cite news |title=One Mars Rover Sees A Distant Goal; The Other Takes A New Route - Endeavour Crater in Context|publisher=NASA/JPL |url=http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20090318a.html |date=March 18, 2009 }}</ref> ''Opportunity'' also saw Iazu crater that was about {{convert|38|km|mi|sp=us}} away and is about {{convert|7|km|mi|sp=us}} in diameter.<ref name="NASA20090318gallery" />

On sol {{age in sols|2004|01|25|2009|04|07}} (April 7, 2009) ''Opportunity'' generated 515 watt-hours after a cleaning event of the solar arrays increased energy production by about 40%.<ref name="Update20090408">{{cite web |url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol1844 |title=Cleaning Event Boosts Energy |publisher=NASA/JPL |date=April 8, 2009 |access-date=March 25, 2014 |archive-date=June 20, 2014 |archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol1844 |url-status=dead }}</ref> From April 16 to 22 (sol 1859 to 1865) ''Opportunity'' made a series of drives and during that week traveled a total distance of {{convert|478|m|ft|sp=us}}.<ref name="Update20090422">{{cite web|url=http://marsrovers.nasa.gov/mission/status_opportunityAll.html#sol1859 |archive-url=https://archive.today/20121212093250/http://marsrovers.nasa.gov/mission/status_opportunityAll.html#sol1859 |archive-date=2012-12-12 |title=Five Long Drives |website=NASA/JPL |date=April 22, 2009}}</ref> The drive actuator for the right front wheel, which had been rested while ''Opportunity'' studied a rock outcrop called "Penrhyn", had motor currents very close to normal levels.<ref name="Update20090408" /><ref name="Update20090422" /><ref name="Update20090319">{{cite web |url=http://marsrovers.nasa.gov/mission/status_opportunityAll.html#sol1824 |archive-url=https://web.archive.org/web/20040226194228/http://marsrovers.nasa.gov/mission/status_opportunityAll.html#sol1824 |url-status=dead |archive-date=February 26, 2004 |title=At Outcrop with Endeavour in Sight |publisher=NASA/JPL |date=March 19, 2009 }}</ref><ref name="Update20090325">{{cite web |url=http://marsrovers.nasa.gov/mission/status_opportunityAll.html#sol1831 |archive-url=https://web.archive.org/web/20040226194228/http://marsrovers.nasa.gov/mission/status_opportunityAll.html#sol1831 |url-status=dead |archive-date=February 26, 2004 |title=Brushing and Examining an Outcrop |publisher=NASA/JPL |date=March 25, 2009 }}</ref><ref name="Update20090331">{{cite web |url=http://marsrovers.nasa.gov/mission/status_opportunityAll.html#sol1838 |archive-url=https://web.archive.org/web/20040226194228/http://marsrovers.nasa.gov/mission/status_opportunityAll.html#sol1838 |url-status=dead |archive-date=February 26, 2004 |title=Examining Rock's Interior |publisher=NASA/JPL |date=March 31, 2009 }}</ref><ref name="Update20090415">{{cite web|url=http://marsrovers.nasa.gov/mission/status_opportunityAll.html#sol1852 |archive-url=https://web.archive.org/web/20040226194228/http://marsrovers.nasa.gov/mission/status_opportunityAll.html#sol1852 |url-status=dead |archive-date=February 26, 2004 |title=Five Long Drives |publisher=NASA/JPL |date=April 15, 2009 }}</ref>

==== More meteorite findings ====
On sol {{age in sols|2004|01|25|2009|07|18}} (July 18, 2009) a large dark rock was noted in the opposite direction from which ''Opportunity'' was traveling and so the rover headed toward it, reaching it on sol {{age in sols|2004|01|25|2009|07|28}} (July 28).<ref name="Heading Toward 'Block Island' Cobble">{{cite web |url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2009.html#sol1947 |title=Heading Toward 'Block Island' Cobble |publisher=NASA/JPL |access-date=August 9, 2011 |archive-date=July 25, 2011 |archive-url=https://web.archive.org/web/20110725054958/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2009.html#sol1947 |url-status=dead }}</ref>  The rock turned out to be a meteorite and was named Block Island. ''Opportunity'' spent until September 12, 2009 (Sol 2004) investigating the meteorite, before returning to its journey toward Endeavour Crater.<ref name="Departing Block Island">{{cite web |url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2009.html#sol2001 |title=Departing Block Island |publisher=NASA/JPL |access-date=August 9, 2011 |archive-date=July 25, 2011 |archive-url=https://web.archive.org/web/20110725054958/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2009.html#sol2001 |url-status=dead }}</ref>

Its journey was interrupted on Sol 2022 by the find of another meteorite, a {{convert|0.5|m|ft|sp=us}} specimen dubbed 'Shelter Island',<ref name="Another Meteorite Find">{{cite web| url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2009.html#sol2021 | title=Opportunity Knocks with Another Meteorite Find | publisher=NASA/JPL | date= | access-date=August 9, 2011 | archive-date=July 25, 2011 | archive-url=https://web.archive.org/web/20110725054958/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2009.html#sol2021 | url-status=dead}}</ref> which the rover investigated until Sol 2034. It then headed for another meteorite, 'Mackinac Island', which it reached four sols later on sol {{age in sols|2004|01|25|2009|10|17}} (October 17, 2009). The rover conducted a drive-by imaging sequence but otherwise did not investigate this meteorite, resuming its journey to Endeavour.<ref name="A Meteorite Called 'Mackinac'">{{cite web |url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2009.html#sol2036 |title=A Meteorite Called 'Mackinac' |publisher=NASA/JPL |access-date=August 9, 2011 |archive-date=July 25, 2011 |archive-url=https://web.archive.org/web/20110725054958/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2009.html#sol2036 |url-status=dead }}</ref>

On sol {{age in sols|2004|01|25|2009|11|10}} (November 10, 2009) the rover reached a rock target of interest, named 'Marquette Island'.<ref name="nasa6">{{cite web |url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2009.html#sol2057 |title=Approaching "Marquette Island" |publisher=NASA/JPL |access-date=August 9, 2011 |archive-date=July 25, 2011 |archive-url=https://web.archive.org/web/20110725054958/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2009.html#sol2057 |url-status=dead }}</ref>  Prolonged study until sol {{age in sols|2004|01|25|2010|01|12}} January 12, 2010<ref name="Leaving Marquette Behind">{{cite web| url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2010.html#sol2118 |title=Leaving Marquette Behind |publisher=NASA/JPL | date= | access-date=August 9, 2011 }}</ref> ensued, as it was uncertain what type of rock this represented, but the eventual conclusion was that it was rock ejecta from deep within the surface of Mars rather than a meteorite.<ref name="Preparing to Grind">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2009.html#sol2091 | title=Preparing to Grind | publisher=NASA/JPL | date= | access-date=August 9, 2011 | archive-date=July 25, 2011 | archive-url=https://web.archive.org/web/20110725054958/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll_2009.html#sol2091 | url-status=dead }}</ref>

<gallery class="center">
Image:Endeavour Crater Annotated 2009-03-07.jpg|Annotated image showing the position of Opportunity on March 7, 2009, and names for the craters Iazu, Endeavour, and Victoria.
Image:Opportunity Eyes Block Island.jpg|On July 18, 2009 ''Opportunity'' imaged an oddly shaped, dark rock, which was found to be a meteorite.
Image:Block Island Meteorite on Mars.jpg|''Opportunity'' prepares to inspect the unusual rock, now dubbed Block Island. It is the largest meteorite found by a Martian rover so far.
Image:Opportunity Rover Approaches Marquette Island.jpg|''Opportunity'' took this picture of a rock informally named 'Marquette Island' as it approached the rock for investigations that have suggested the rock is a stony meteorite.
</gallery>

=== 2010 ===

==== Concepción ====
{{Multiple image
| total_width = 1000
| align = center
| image1 = Rim of Bopolu Crater 2010.jpg
| caption1 = After rover left Concepcion crater, it took this view southward spotting the rim of Bopulu crater {{convert|65|km|mi|abbr=off|sp=us}} away.
| image2 = Context mapmerbsol2239.jpg
| caption2 = Map of the region around ''Opportunity'' shows the relative locations of several craters and the rover in May 2010.
| image3 = Pancam super res sol 2239 Endeavour.jpg
| caption3 = The view from the rover's perspective from the location noted in the above top-down view. The white lines in the above view indicate the rover's [[Physics:Field of view|field of view]] in this image.
}}

On January 28, 2010 (Sol 2138) ''Opportunity'' arrived at Concepcion crater.<ref name="Update20100120">{{cite web | url=http://marsrover.nasa.gov/mission/status_opportunityAll.html#sol2125 | archive-url=https://web.archive.org/web/20040301043746/http://marsrover.nasa.gov/mission/status_opportunityAll.html#sol2125 | url-status=dead | archive-date=March 1, 2004 | title=Driving to 'Concepcion' Crater | publisher=NASA/JPL | date=January 20, 2010 }}</ref> ''Opportunity'' successfully circumnavigated the {{convert|10|m|ft|sp=us|adj=on}} diameter crater before continuing on towards Endeavour. Energy production varied from about 305 watt-hours to about 270 Wh during this period.<ref name="Update20100120" />

On sol {{age in sols|2004|01|25|2010|05|05}} (May 5, 2010), due to potentially hazardous dune fields along the direct path between Victoria and Endeavour, a new route was charted that extended the distance to travel between the two craters to {{convert|19|km|mi|sp=us}}.<ref name="Universe_Today_May_5_2010">{{cite web| url=http://www.universetoday.com/63858/opportunitys-long-and-winding-road-to-endeavour-crater/ | title=Opportunity's Long and Winding Road to Endeavour Crater | publisher=Universe Today | date=May 5, 2010}}</ref>

On (May 19, 2010), ''Opportunity'' reached {{age in sols|2004|01|25|2010|05|19}} sols of operation, making it the longest Mars surface mission in history, breaking the record of 2245 sols set by ''[[Astronomy:Viking 1|Viking 1]]''.<ref name="Opportunity breaks record">{{cite web | url=https://www.theregister.co.uk/2010/05/20/opportunity_record/ | title=Opportunity rover breaks Mars longevity record | publisher=The Register | date= | access-date=August 4, 2010}}</ref>

==== Santa Maria crater ====
In July 2010, it was announced that the ''Opportunity'' team would use the theme of names given to places visited
by British Royal Navy Captain, Lieutenant James Cook, in his 1769–1771 Pacific Ocean voyage in command of [[Engineering:HMS Endeavour|HMS ''Endeavour'']], for informal names of sites at [[Astronomy:Endeavour (crater)|Endeavour Crater]]. These would include "Cape Tribulation" and "Cape Dromedary", "Cape Byron" (the most easterly point of the Australian mainland), and "Point Hicks" (the part of the Australian mainland first sighted by the ''Endeavour'' in 1770).<ref name="More Detail">{{cite web | url=http://www.marsdaily.com/reports/Opportunity_To_See_More_Detail_At_Crater_Destination_999.html | title=Opportunity To See More Detail At Crater Destination | publisher=Marsdaily.com | date=June 30, 2010 }}</ref>

On sol {{age in sols|2004|01|25|2010|09|08}} (September 8, 2010), the halfway point of the {{convert|19|km|mi|sp=us}} journey between Victoria crater and Endeavour crater was reached.<ref name="NASA20100908PressRelease">{{cite news|title=Opportunity Rover Reaches Halfway Point of Long Trek |publisher=NASA/JPL |url=http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20100908a.html |date=September 8, 2010}}</ref>

In November the rover spent a few days imaging a {{convert|20|m|ft|sp=us}} crater called Intrepid while navigating through a field of small impact craters. On sol {{age in sols|2004|01|25|2010|11|14}}  November 14, 2010 total odometry passed the {{convert|25|km|mi|sp=us}} mark. Average solar array energy production in October and November was about 600 watt-hours.<ref name="nasa7">{{cite web| url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol2418 | title=sols 2418–2423, November 12–17, 2010 | publisher=NASA/JPL | date=November 17, 2010 | access-date=March 25, 2014 | archive-date=June 20, 2014 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol2418 | url-status=dead}}</ref>

<!--[[File:Santa Maria Crater (Mars).jpg|thumb|left|Santa Maria crater.]]-->
On sol {{age in sols|2004|01|25|2010|12|15}} (December 15, 2010) the rover arrived at [[Astronomy:Santa Maria (crater)|Santa Maria]] and spent several weeks investigating the {{convert|90|m|ft|sp=us}} wide crater.<ref name="tips">{{cite web| url=http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20101216a.html | title=Spacecraft Provides Travel Tips for Mars Rover | publisher=NASA/JPL | date=December 16, 2010}}</ref> The results from ''Opportunity'' were compared to data taken from orbit by the CRISM instrument, a spectrometer, on the ''[[Astronomy:Mars Reconnaissance Orbiter|Mars Reconnaissance Orbiter]]''.<ref name=tips/> CRISM had detected water-bearing minerals at Santa Maria crater, and the rover helped further analyze this.<ref name=tips/> ''Opportunity'' drove farther in that Martian year (that is about 2 Earth years), than in any previous year.<ref name=tips/>

{{wide image|Santa Maria Crater (Mars).jpg|1100px|Santa Maria Crater panorama}}

===2011===
====Heading to Endeavour crater====
After its arrival at the edge of Santa Maria crater, the team positioned the rover at its southeastern rim and collected data.<ref name="jpl2011">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol2600 | publisher=NASA/JPL | title=Opportunity Updates: 2011 | work=Opportunity Rover Update Archive | date= | access-date=2014-03-25 | archive-date=2014-06-20 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol2600 | url-status=dead }}</ref> They also prepared for the two-week [[Astronomy:Solar conjunction|solar conjunction]] of late January, when the Sun was between Earth and Mars and communication was blocked. In late March ''Opportunity'' began the {{convert|6.5|km|mi|sp=us}} journey between Santa Maria and Endeavour, and on June 1, the rover passed the {{convert|30|km|mi|sp=us}} traverse milestone (over 50 times its designed distance).<ref name="jpl2011" /><ref name="Big Milestone">{{cite web|url=http://www.nasa.gov/mission_pages/mer/news/mer20110602.html|title=NASA - Opportunity Passes Small Crater and Big Milestone |publisher=Nasa.gov |access-date=July 15, 2012}}</ref> Two weeks later, on sol {{age in sols|2004|01|25|2011|07|17}}  (July 17, 2011), ''Opportunity'' had driven {{convert|20|mi|km|order=flip|abbr=on}} on Mars.<ref name="twenty">{{cite web| url=http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20110719a.html | title=NASA's Opportunity Tops 20 Miles of Mars Driving | publisher=Jet Propulsion Laboratory | date=July 19, 2011}}</ref>

By sol {{age in sols|2004|01|25|2011|08|29}}  (August 29, 2011), ''Opportunity'' had continued to function effectively 30 times longer than its planned 90-[[Astronomy:Timekeeping on Mars#Sols|sol]] mission, aided by solar cell cleaning events, and performed extensive geological analysis of Martian rocks and planetary surface features with its instruments.<ref name="Opportunity Mission Manager Update">{{cite web | url=http://www.nasa.gov/mission_pages/mer/opportunity-update.html | title=Opportunity Mission Manager Update | date= | access-date=September 12, 2011 }}</ref>

{{Multiple image
| total_width = 1000
| image1 = MERB Sol2592 1.jpg
| caption1 = A infographic showing the traverse from Victoria to Endeavour, Sol 2592
| image2 = MERB Sol2710 1merbarrives.jpg
| caption2 = ''Opportunity'' arrives at Endeavour crater, Sol 2710
| align = center
}}

==== Endeavour crater arrival ====
''Opportunity'' arrived at [[Astronomy:Endeavour (crater)|Endeavour crater]] on sol {{age in sols|2004|01|25|2011|09|08}} (August 9, 2011), at a landmark called ''Spirit Point'' named after its rover twin, after traversing {{convert|13|mi|km|order=flip|abbr=on}} from Victoria crater, over a three-year period.<ref name="nasa8">{{cite web| url=http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20110810a.html | title=NASA Mars Rover Arrives at New Site on Martian Surface | publisher=Jet Propulsion Laboratory | date=August 10, 2011}}</ref> Endeavour is {{convert|14|mi|km|order=flip|abbr=on}} wide and offers scientists new terrain to explore, including older rocks than encountered heretofore, and clay minerals that may have formed in the presence of water. The rover's deputy principal investigator, Ray Arvidson, said it will probably not enter Endeavour crater as it appears to contain material observed previously. The rocks on the rim are older than any previously studied by ''Opportunity''. "I think there's much more interest in driving around the perimeter of the rim," said Arvidson.<ref name="space">{{cite web| url=http://www.space.com/12594-nasa-mars-rover-opportunity-arrives-huge-crater.html | title=NASA Rover Arrives at Huge Mars Crater After 3-Year Trek | publisher=Space.com | date=August 10, 2011}}</ref> The rover survived so long this goal was accomplished, and by 2016 it was decided to not only enter Endevaour crater but also explore, for the first time in history what is thought to be a water carved gully on Mars (update:2016).<ref>{{cite web|url=http://www.jpl.nasa.gov/news/news.php?release=2016-259|title=NASA's Opportunity Rover to Explore Mars Gully|website=NASA/JPL|access-date=7 September 2018}}</ref>

Upon arriving at Endeavour, ''Opportunity'' almost immediately began discovering Martian phenomena not previously observed. On sol {{age in sols|2004|01|25|2011|08|22}} (August 22, 2011) the rover began examining Tisdale 2, a large ejecta block. "This is different from any rock ever seen on Mars," said [[Biography:Steve Squyres|Steve Squyres]], principal investigator for ''Opportunity'' at Cornell University in Ithaca, New York. "It has a composition similar to some volcanic rocks, but there's much more zinc and bromine than we've typically seen. We are getting confirmation that reaching Endeavour really has given us the equivalent of a second landing site for Opportunity."<ref name="wustl">{{cite web | url=http://news.wustl.edu/news/Pages/22660.aspx | first=Tony | last=Fitzpatrick | title=Opportunity on verge of new discovery | publisher= | date= }}</ref><ref name="NASA's Mars Rover Opportunity begins study of Martian crater">{{cite web|url=http://www.defenceweb.co.za/index.php?option=com_content&view=article&id=18729:nasas-mars-rover-opportunity-begins-study-of-martian-crater&catid=90:science-a-technology&Itemid=204 |title=NASA's Mars Rover Opportunity begins study of Martian crater |publisher=DefenceWeb |date=September 6, 2011 }}</ref> (See also [[Astronomy:Cape York (Mars)|Cape York (Mars)]])

{{Gallery
| width  = 200
| height = 120
| align  = center
|File:PIA14508 - West Rim of Endeavour Crater on Mars.jpg|West Rim of Endeavour Crater
|File:PIA14509_-_Arrival_at_'Spirit_Point'_by_Mars_Rover_Opportunity.jpg|Spirit Point at Endeavour Crater
|File:Opportunity Rover Examines Tisdale 2.jpg|''Opportunity'' examines Tisdale 2
|File:PIA15033 Pancam sol2769 L456atc.tif|"Homestake" formation <!-- File:PIA15034 Pancam sol2769 L257F.tif -->
}}

In December the ''Homestake'' formation was analyzed, which was concluded to be formed of [[Chemistry:Gypsum|gypsum]]. Using three of the rover's instruments - the Microscopic Imager, the Alpha Particle X-Ray Spectrometer and the Panoramic Camera's filters - researchers determined the deposit to be hydrated calcium sulfate, or gypsum, a mineral that does not occur except in the presence of water. This discovery was called "slam dunk" evidence that "water flowed through underground fractures in the rock."<ref name="cnn">{{cite web | url=http://lightyears.blogs.cnn.com/2011/12/08/opportunity-finds-more-evidence-of-water-on-mars/?hpt=hp_t3 | title=Opportunity finds more evidence of water on Mars | website=Lightyears.blogs.cnn.com | date= | access-date=2014-03-25 | archive-date=2016-02-05 | archive-url=https://web.archive.org/web/20160205071231/http://lightyears.blogs.cnn.com/2011/12/08/opportunity-finds-more-evidence-of-water-on-mars/?hpt=hp_t3 | url-status=dead }}</ref>

''Opportunity'' had driven more than {{convert|34|km|mi|abbr=on}} by November 22, 2011 (sol 2783), as preparations were made for the coming Martian winter.<ref name="NASA Opportunity rover updates">{{cite web|url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol2778|title=NASA Opportunity rover updates|publisher=NASA|date=November 22, 2011|access-date=March 25, 2014|archive-date=June 20, 2014|archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol2778|url-status=dead}}</ref> It moved to terrain that positioned it about 15 degrees to the north, an angle more favorable for [[Physics:Solar energy|solar energy]] production during the [[Astronomy:Mars|Martian]] winter.<ref name="Jan 2012">{{Cite web|url=http://www.nasa.gov/mission_pages/mer/news/mer20120124.html |title=NASA - Durable NASA Rover Beginning Ninth Year of Mars Work|website=Nasa.gov |date=January 24, 2012}}</ref>

===2012===
{{Multiple image
| align = center
| total_width = 1000
| image1 = PIA14506 Opportunity's View Approaching Rim of Endeavour.jpg
| caption1 = Looking south along Western rim of Endeavour crater, August 2011
| image2 = MERB Sol3348 1.jpg
| caption2 = Rover's arrival and subsequent path around Cape York, and its departure as it headed south into Botany Bay towards [[Astronomy:Solander Point|Solander Point]] between 2012 and 2013
| image3 = PIA15276 Locator Map for 'Greeley Haven' on Endeavour Rim.jpg
| caption3 = Traverse map showing location of Greely and the rover's track in 2012
}}

====Greeley Haven====
[[File:Late Afternoon Shadows at Endeavour Crater on Mars.jpg|thumb|View over the Endeavour crater, imaged by ''Opportunity'' in March 2012. (False-color image)]]
In January 2012 the rover returned data from Greeley Haven, named after the geologist [[Biography:Ronald Greeley|Ronald Greeley]], while enduring its fifth Martian winter.<ref name="Jan 2012" /> It studied the Martian wind, which has been described as "the most active process on Mars today", and conducted a radio science experiment.<ref name="Jan 2012" /> By carefully measuring radio signals, wobbles in Martian rotation may show whether the planet has a solid or liquid interior.<ref name="Jan 2012" /> The winter worksite sits on the Cape York segment of the rim of Endeavour Crater. ''Opportunity'' reached the edge of this {{convert|14|mi|km|order=flip|abbr=on}} crater in August after three years of driving from smaller Victoria Crater, which it studied for two years.<ref name="NASA 9">{{cite web| url=http://www.nasa.gov/mission_pages/mer/news/mer20120105.html | title='Greeley Haven' is Winter Workplace for Mars Rover | publisher=NASA | date=January 5, 2012}}</ref>

On Sol 2852 (February 1, 2012) the energy production from the solar array was 270 watt-hours, with a Mars atmospheric opacity (Tau) of 0.679, a solar array dust factor of 0.469, with total [[Engineering:Odometry|odometry]] at {{convert|21.35|mi|km|order=flip|abbr=on}}.<ref name="nasa10">{{cite web | url=http://www.jpl.nasa.gov/missions/mer/daily.cfm#Opportunity | publisher=JPL | title=Opportunity daily | date= | access-date=2014-03-25 | archive-date=2008-07-13 | archive-url=https://web.archive.org/web/20080713085838/http://www.jpl.nasa.gov/missions/mer/daily.cfm#Opportunity | url-status=dead }}</ref> By March (around Sol 2890), 'Amboy' rock was studied with the [[Astronomy:MIMOS II|MIMOS II]] Mössbauer spectrometer and the Microscopic Imager, and the amount of [[Chemistry:Argon|Argon]] gas in the Martian air was measured.<ref name="nasa11">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol2887 | title=Opportunity Status Sol 2887 | publisher=NASA | date= | access-date=2014-03-25 | archive-date=2014-06-20 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol2887 | url-status=dead }}</ref> The Mars [[Astronomy:Winter solstice|winter solstice]] passed on March 30, 2012 (Sol 2909) and on April 1 there was a small cleaning event.<ref name="March April">{{Cite web|url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol2907|title=NASA Sol 2907|website=Marsrovers.jpl.nasa.gov|access-date=7 September 2018|archive-date=20 June 2014|archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol2907|url-status=dead}}</ref> On Sol 2913 (April 3, 2012) solar array energy production was 321 watt-hours.<ref name="March April" />

The mission of Mars rover ''Opportunity'' continued, and by May 1, 2012 (Sol 2940), energy production had increased to 365 watt-hours, with the solar array dust factor at 0.534.<ref name="Sol 2935">{{Cite web|url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol2935|title=NASA Sol 2935|website=Marsrovers.jpl.nasa.gov|access-date=7 September 2018|archive-date=20 June 2014|archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol2935|url-status=dead}}</ref> The team prepared the rover for movement and finished up collecting data on Amboy rock.<ref name="Sol 2935" /> 60 Doppler radio passes were completed over the winter.<ref name="sol2969">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol2969 | publisher=NASA | title=Robotic Arm Gets to Work on Veins of Gypsum | date= | access-date=2014-03-25 | archive-date=2014-06-20 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol2969 | url-status=dead }}</ref>

On May 8, 2012 (Sol 2947), the rover moved {{convert|12|ft|m|order=flip}}.<ref name="sol2947">{{cite web| url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol2941 | title=Opportunity on the Road Again! | date= | access-date=May 11, 2012 | archive-date=June 20, 2014 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol2941 | url-status=dead}}</ref> On that day the Solar energy production was 357 watt-hours with a solar array dust factor of 0.536.<ref name=sol2947/> ''Opportunity'' had been stationary on Greeley Haven for 130 Sols (Mars' days), with a 15 degrees tilt to the North to help survive the winter; after the drive the northerly tilt decreased to 8 degrees.<ref name=sol2947/> The drive marked the end of the [[Earth:Geodynamics|geodynamics]] science experiment, which used radio Doppler measurements while the rover was stationary.<ref name=sol2947/> By June 2012, it studied Mars dust and a nearby rock vein christened "Monte Cristo" as it headed North.<ref name="sol2969" />

====Exploring Matijevic hill at Cape York====
On July 2, 2012 ''Opportunity''{{'}}s 3000 Sols on Mars were celebrated.<ref name="sol3035" /> 
By July 5, 2012, NASA published a new panorama (seen below) showing the surroundings of ''Opportunity'' at the Greeley Haven position at [[Astronomy:Cape York (Mars)|Cape York]].<ref name="PIA15689">{{cite web|url=http://photojournal.jpl.nasa.gov/catalog/PIA15689 |title='Greeley Panorama' from Opportunity's Fifth Martian Winter (False Color)| date= | access-date=July 7, 2012}}</ref> Also, the other end of the Endeavour crater is seen in the right half of the scene, a crater that spans {{convert|22|km|mi|sp=us}} in diameter. On July 12, 2012 (Sol 3010), solar arrays produced 523 watt-hours and {{convert|21.49|mi|m|order=flip|abbr=on}} was the total distance traveled from landing.<ref name="sol3009">{{cite web| url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3009 | publisher=NASA | title=Slow-Going for Opportunity This Week | date= | access-date=2014-03-25 | archive-date=2014-06-20 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3009 | url-status=dead}}</ref> That month, [[Astronomy:Mars Reconnaissance Orbiter|Mars Reconnaissance Orbiter]] spotted a dust storm and water ice clouds near the rover.<ref name=sol3009/>

{{Multiple image
| align = center
| total_width = 1000
| image1 = PIA15689-4619.jpg
| caption1 = ''Greeley Haven'' panorama – a view of Cape York and the Endeavour crater – was taken while overwintering at the Greeley Haven position at Cape York in the first half of 2012. This false-color panoramic view was combined from 817 individual images taken in the near-infrared, green and violet spectral bands.
| image2 = PIA16139 Puzzling Little Martian Spheres That Don't Taste Like 'Blueberries'.tif
| caption2 = Spheres at Kirkwood, each are about 3 mm across
}}

Before ''[[Engineering:Curiosity (rover)|Curiosity]]'' landed on August 6, 2012, ''Opportunity'' sent special Ultra High Frequency radio signals to simulate ''Curiosity'' for a radio observatory in Australia.<ref name="sol3035">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#3035 | publisher=NASA | title=With Curiosity on the Surface Opportunity Will Resume Driving Soon | date= | access-date=2014-03-25 | archive-date=2014-06-20 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#3035 | url-status=dead }}</ref> August activities for ''Opportunity'' included collecting data on atmospheric opacity,<ref name="sol3035" /> visiting ''Sao Rafael'' and ''Berrio'' craters,<ref name="status_3042">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#3042 | title=Opportunity is on the Move Again! | publisher=NASA | date= | access-date=2014-03-25 | archive-date=2014-06-20 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#3042 | url-status=dead }}</ref> and achieving {{convert|35|km|mi|sp=us}} of driving on Sol 3056 (August 28, 2012).<ref name=sol3118/> Also, on August 19, 2012 [[Astronomy:Mars Express|Mars Express]] orbiter automatically exchanged data with both ''Curiosity''  and ''Opportunity'' in one orbit, its first double contact.<ref name="esa_20120818">{{cite web| url=http://blogs.esa.int/mex/2012/08/18/mars-express-rocking-and-rolling-with-nasas-curiosity-opportunity/ | title=Mars Express - ''Mars Express rocking and rolling with NASA's Curiosity & Opportunity'' | first=T. | last=Ormston | year=2012 | publisher=ESA}}</ref>

In the fall ''Opportunity'' headed south, exploring Matijevic hill and searching for phyllosilicate minerals.<ref name=sol3118>{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#3118 | title=More Driving And Imaging At 'Matijevic Hill' | publisher=NASA | date= | access-date=2014-03-25 | archive-date=2014-06-20 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#3118 | url-status=dead }}</ref> Some data was sent to Earth directly using X-Band radio signals, as opposed to orbiter relays.<ref name=sol3118/> Finally, the number of power cycles on the rover's Inertial Measurement Unit were reduced.<ref name=sol3118/> Science work included testing various hypotheses about the newly discovered spherules.<ref name="jpl_2012-306">{{cite web | url=http://www.jpl.nasa.gov/news/news.php?release=2012-306 | publisher=NASA | title=Mars Rover Opportunity Working at 'Matijevic Hill' | date=September 28, 2012 }}</ref>

{{blockquote|A small dust cleaning event occurred on Sol 3175 (Dec. 29, 2012), improving the energy production by about 40 watt-hours per sol. As of Sol 3180 (Jan. 3, 2013), the solar array energy production was 542 watt-hours with an atmospheric opacity (Tau) of 0.961 and an improved solar array dust factor of 0.633.|NASA<ref name=sol3174>{{cite web | url=http://marsrover.nasa.gov/mission/status_opportunityAll.html#sol3174 | archive-url=https://web.archive.org/web/20040301043746/http://marsrover.nasa.gov/mission/status_opportunityAll.html#sol3174 | url-status=dead | archive-date=2004-03-01 | publisher=NASA | title=Sol 3174 | date= }}</ref>}}

===2013===

====Leaving Cape York====
[[File:PIA17074-MarsOpportunityRover-EsperanceRock-20130223-fig1.jpg|thumb|left|150px|"Esperance" rock on Mars – viewed by the ''Opportunity'' Rover (February 23, 2013).]] 
Opportunity began the year at the edge of Endeavour Crater's Cape York,<ref name=sol3174/> and the total distance travelled since landing on Mars was {{convert|35|km |mi |abbr=on}}.<ref name=sol3174/><ref name="mars_999">{{cite web | url=http://www.marsdaily.com/reports/Opportunity_Scores_Another_Dust_Cleaning_Event_At_Vermillion_999.html | author=Mars Daily Staff | title=Opportunity Scores Another Dust Cleaning Event At Vermillion | publisher= | date=}}</ref> After completing work at Matijevic Hill the ''Opportunity'' rover headed south to the rim of Endeavour Crater. Next, the rover headed south across a gap in the rim to a place the researchers called Botany Bay, then up onto the next rim segment to the south. There are two hills to the south of it, one called Solander Point and farther south is Cape Tribulation.<ref name="SFN-20130125">{{cite web |last=Harwood |first=William |title=Opportunity rover moves into 10th year of Mars operations |url=http://www.spaceflightnow.com/news/n1301/25opportunity/ |date=January 25, 2013 |publisher=Space Flight Now }}</ref> The current aim is for ''Opportunity'' to reach Solander Point before winter reaches the Martian southern hemisphere as the area has ground tilted to the north allowing the rover to stay active during the winter months. In addition Solander Point has a large geological stack for Opportunity to explore.<ref name="mer20130607">{{cite web | url=http://www.nasa.gov/mission_pages/mer/news/mer20130607.html | publisher=[[Organization:NASA|NASA]] | title=Mars Rover Opportunity Trekking Toward More Layers | date= }}</ref>
In April 2013, the rover passed through a three-week-long solar conjunction, when communication with Earth was blocked because of the Sun.<ref name=nasa3291>{{cite web | url=http://marsrover.nasa.gov/mission/status_opportunityAll.html#sol3291 | archive-url=https://web.archive.org/web/20040301043746/http://marsrover.nasa.gov/mission/status_opportunityAll.html#sol3291 | url-status=dead | archive-date=2004-03-01 | publisher=NASA | title=Sol 3291 | date= }}</ref> The rover arm was positioned on a rock during that time so the APXS could collect data.<ref name=nasa3291/>

On May 16, 2013, NASA announced that ''Opportunity'' had driven further than any other NASA vehicle on a world other than Earth.<ref name="40YearRecordNASA20130516">{{cite news |title=Nine-Year-Old Mars Rover Passes 40-Year-Old Record |publisher=NASA/JPL |url=http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20130516a.html |date=May 16, 2013 }}</ref> After ''Opportunity''{{'}}s total odometry went over {{convert|35.744|km|mi|sp=us}} it surpassed the total distance driven by the [[Engineering:Apollo 17|Apollo 17]] [[Astronomy:Lunar Roving Vehicle|Lunar Roving Vehicle]].<ref name="40YearRecordNASA20130516" /> The record for longest distance driven by a vehicle on another world was as of 2013 held by the [[Astronomy:Lunokhod 2|Lunokhod 2]] [[Astronomy:Lunar rover|lunar rover]].<ref name="40YearRecordNASA20130516" /> Based on wheel rotations Lunokhod 2 was thought to have covered {{convert|37|km|mi|sp=us}}, but Russian scientists have revised that to an estimated distance of about {{convert|42|km|mi|sp=us}} based on orbital images of the lunar surface.<ref name="plan_06211627">{{cite web|url=http://www.planetary.org/blogs/emily-lakdawalla/2013/06211627-opportunity-lunokhod-record.html |title=Is Opportunity near Lunokhod's distance record? Not as close as we used to think! |publisher=The Planetary Society |last1=Lakdawalla |first1=Emily |date=June 21, 2013}}</ref><ref name="nature_13229">{{cite journal |last1=Witze |first1=Alexandra |title=Space rovers in record race |journal=Nature  |date=June 19, 2013 |volume=498 |issue=7454 |pages=284–5 |doi=10.1038/498284a |pmid=23783609 |bibcode=2013Natur.498..284W |doi-access=free }}</ref>

On May 17, 2013, NASA announced that a preliminary analysis of one of the rock targets, named "[[Astronomy:List of rocks on Mars#Opportunity|Esperance]]", suggested that water in the past may have had a [[Chemistry:PH|neutral pH]].<ref name="NASA-20130517">{{cite web |last1=Webster |first1=Guy |last2=Brown |first2=Dwayne |title=Mars Rover Opportunity Examines Clay Clues in Rock |url=http://www.nasa.gov/mission_pages/mer/news/mer20130517.html  |date=May 17, 2013 |work=[[Organization:NASA|NASA]] }}</ref>  This was later confirmed in further studies, supporting the notion that ancient Mars was a "water-rich world with conditions amenable for life".<ref name="NYT-20130607">{{cite news |last=Chang |first=Kenneth |title=Martian Rock Another Clue to a Once Water-Rich Planet|url=https://www.nytimes.com/2013/06/08/science/space/martian-rock-another-clue-to-a-once-water-rich-planet.html |date=June 7, 2013 |work={{wipe|The New York Times}} }}</ref> As of June 20, 2013 (Sol 3344), ''Opportunity''{{'}}s total odometry was reported at {{convert|22.89|mi|km|order=flip|abbr=on}}, while en route to 'Solander Point.'<ref name="sol3340-3344">{{cite news| title=sols 3340-3344, Jun. 16, 2013-Jun. 20, 2013: Opportunity is Healthy and Driving to 'Solander Point' | publisher=NASA/JPL | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3340 | date=June 20, 2013 | access-date=March 25, 2014 | archive-date=June 20, 2014 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3340 | url-status=dead}}</ref>  June 21, 2013 marked five Martian years on the 'red planet'.<ref name="nasa3340">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3340 | publisher=NASA | title=Sol 3340 | date= | access-date=2014-03-25 | archive-date=2014-06-20 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3340 | url-status=dead }}</ref> The project manager, noting the harsh conditions of the planet, has said each day is "a gift".<ref name="ut_102744">{{cite web | url=http://www.universetoday.com/102744/opportunity-rover-discovers-martian-habitable-zone-favorable-for-pre-biotic-chemistry/ | publisher=Universe Today | title=Opportunity Rover Discovers Martian Habitable Zone Favorable for Pre-biotic Chemistry | date= | first=K. | last=Kremer }}</ref>

[[File:PIA17076 fig1-SolanderPoint.tif|thumb|600px|center|The rover on its way to Solander point, with a traverse line up to July 2013]]
{{clear}}

====Solander Point====
[[File:PIA17078 - Opportunity's view of 'Solander Point'.jpg|thumb|right|Solander point as seen overlooking Botany bay; Pancam image at 753, 535, and 432 nanometers light wavelengths (i.e. approximately true color).<ref name="jpl_pia7078">{{cite web | url=http://photojournal.jpl.nasa.gov/catalog/PIA17078 | title=PIA17078: Opportunity's view of 'Solander Point' | publisher=NASA | date= }}</ref>]]
<!-- Deleted image removed: [[File:PIA17586solander.jpg|thumb|500px|Looking south on Solander Point with the crater floor to the left]] -->
By early July 2013 ''Opportunity'' was approaching [[Astronomy:Solander Point|Solander Point]], with daily drives ranging from dozens of meters (yards) to over a hundred.<ref name="jpl_sol3351">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3351 | publisher=NASA | title=Sol 3351 | date= | access-date=2014-03-25 | archive-date=2014-06-20 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3351 | url-status=dead }}</ref> It arrived at its base in early August 2013, after investigating a curious terrain patch along the way.<ref name=sol3391/> Solander could provide a northward facing slope to aid in sunlight collection, as the Martian winter was approaching (as the season changes, the angle of the Sun is shifting).<ref name=sol3391/> On Sol 3390 (August 6, 2013) energy intake was 385 watt-hours, down from 395 on Sol 3384 (July 31, 2013), and 431 on Sol 3376 (July 23, 2013).<ref name=sol3391/> In May 2013 it had been as high as 546 watt-hours.<ref name=sol3391/> Other factors that impact collection include the atmospheric opacity (i.e. "Tau") and "solar array dust factor"{{mdash}}dust that collects on the panels.<ref name=sol3391/> Although the rover cannot clean the dust off, such systems were considered for the rover during its development.<ref name="ns_200811">{{cite web | url=https://www.newscientist.com/blogs/shortsharpscience/2008/11/why-dont-the-mars-rovers-have.html | title=Why don't the Mars rovers have dust wipers? | work=New Scientist | year=2008 }}</ref>

In September, numerous surface targets and rocks around Solander were examined by the rover.<ref name=sol3391>{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3391 | publisher=NASA | title=Sol 3391 | date= | access-date=2014-03-25 | archive-date=2014-06-20 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3391 | url-status=dead }}</ref> Solar array energy production dropped to 346 watt-hours by Sol 3430 (September 16, 2013),<ref name=sol3391/> and 325 watt-hours by Sol 3452 (October 9, 2013).<ref name="jpl_sol3445">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3445 | publisher=NASA | title=Mars Sol 3445 | date= | access-date=2014-03-25 | archive-date=2014-06-20 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3445 | url-status=dead }}</ref> By traveling to locations with favorable tilt, dubbed "lily pads", ''Opportunity'' managed to receive over about 300 watt-hours per day even as the heart of the Mars winter approached.<ref name=sol3473>{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3473 | publisher=NASA | title=Sol 3473 | date= | access-date=2014-03-25 | archive-date=2014-06-20 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3473 | url-status=dead }}</ref> The Martian winter minimum was predicted for February 2014, but by making use of the northward slopes the rover had enough power to remain mobile during the Martian winter.<ref name=solander>{{cite web | url=http://www.nasa.gov/mission_pages/mer/news/working-at-edge-of-solander/ | publisher=NASA | title=Mars Rover Opportunity Working at Edge of 'Solander' | date= }}</ref> By the end of October the rover was climbing up Solander point, where it was hoped some of the oldest rocks yet seen would be examined.<ref name=nasauphill/> The rocks were believed to date to Mars's [[Astronomy:Noachian|Noachian]] Period about four billion years ago, and could have provided some science surprises by Christmas.<ref name="rayl">{{cite web | url=http://www.planetary.org/explore/space-topics/space-missions/mer-updates/2013/10-mer-update-opportunity-gets-back-to-the-past-at-winter-site.html | work=TPS | first=A.J.S. | last=Rayl | title=Mars Exploration Rovers Update: Opportunity Gets Back to the Past at Winter Site : Sols 3444 - 3473 | publisher= | date= }}</ref> The team was hunting for "juicy" slopes of 5 to 20 degrees for more power.<ref name="rayl" />

As it ascended, it doglegged in early November to avoid an area of dusty ripples.<ref name=sol3473/> It continued to collect data on Martian rocks and dust in the area.<ref name=sol3473/> Total odometry by November 5, 2013 (or in Mars days since the landing, Sol 3478) was {{convert|38.53|km|abbr=on}}.<ref name=sol3473/> Energy production from the Sun on that date was 311 watt-hours, with Tau at 0.536 and the dust factor at 0.491.<ref name=sol3473/>
{{Bar graph
| title       = 
| float       = none
| bar_width   = 30
| width_units = em
| data_max    = 800
| label_type  = Date
| data_type   = Watt-hours
| label1      = Sol&nbsp;3376&nbsp;(July&nbsp;23,&nbsp;2013)
| data1       = 431
| label2      = Sol 3384 (July 31, 2013) 
| data2       = 395
| label3      = Sol&nbsp;3390&nbsp;(August&nbsp;6,&nbsp;2013) 
| data3       = 385
| label4      = Sol&nbsp;3430&nbsp;(September&nbsp;16,&nbsp;2013)
| data4       = 346
| label5      = Sol 3452 (October 9, 2013)
| data5       = 325 
| label6      = Sol 3472 (October 30, 2013)
| data6       = 299 
| label7      = Sol 3478 (November 5, 2013)
| data7       = 311
| label8      = Sol 3494 (November 21, 2013)
| data8       = 302 
| label9      = Sol 3507 (Dec. 5, 2013)
| data9       = 270
}}
Before ''Spirit'' rover stopped responding in 2010, it reported 134 watt-hours as temperatures plunged below minus 41.5 degrees Celsius (minus 42.7 degrees Fahrenheit).<ref name="jpl_2204">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_spiritAll_2010.html#sol2204 | publisher=NASA | title=Spirit Sol 2204 | date= }}</ref>

By early December power levels had hit 270 watt-hours per day, even as it climbed higher up the ridge.<ref name="autogenerated1">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3499 | publisher=NASA | title=Sol 3499 | date= | access-date=2014-03-25 | archive-date=2014-06-20 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3499 | url-status=dead }}</ref> It maintained a northerly tilt to increase energy production on Solander point.<ref name=nasa3508>{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3508 | publisher=NASA | title=Sol 3508 | date= | access-date=2014-03-25 | archive-date=2014-06-20 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3508 | url-status=dead }}</ref> In early December one of the communication relay satellites at Mars, Odyssey, had some difficulties so the rover sent its telemetry directly to Earth.<ref name=nasa3508/> The orbiter returned to operation after December 10, 2013, and the rover prepared for additional drives.<ref name=nasa3508/> On Sol 3521 (Dec. 19, 2013) the rover took micro-images and used the Alpha Particle X-ray Spectrometer.<ref name=nasa3520>{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3520 | publisher=NASA | title=Sol 3520 | date= | access-date=2014-03-25 | archive-date=2014-06-20 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3520 | url-status=dead }}</ref> Between December 31 and New Year's Day cleaning events removed dust, improving the Solar Array Dust Factor to 0.566 (where higher is better and 1.0 is totally clean).<ref name=nasa3520/> Energy production increased 35 watt-hours/day after this cleaning, to 371 watt-hours/day.<ref name=nasa3520/>

[[File:MERB Sol3492 1.jpg|thumb|800px|left|Sol 3492 traverse map for MER-B, dated November 2013]]
{{clear}}
{{Wide image|Pia17366 sol-3463-navcam 1.jpg|700px|This is a southward uphill view as the rover ascended the mountain in October 2013. It is assembled from NavCam images.<ref name=nasauphill>{{cite web | url=http://www.nasa.gov/mission_pages/mer/news/mer20131023.html | publisher=NASA | title=Mars Rover Opportunity Heads Uphill | date= }}</ref>}}

===2014===

{{Multiple image
| align = center
| total_width = 1000
| image1 = PIA07372-MarsOpportunityRover-SelfPortrait-20041220-crop-rotate-sm.jpg
| caption1 = Self-portrait of ''Opportunity'' taken early in the mission (December 19–20, 2004)
| image2 = PIA17759-MarsOpportunityRover-SelfPortrait-20140106.jpg
| caption2 = Self-portrait of ''Opportunity'' near [[Astronomy:Endeavour (crater)|Endeavour Crater]] (January 6, 2014). Note the change in appearance in relation to the photo nine years earlier (left).
| image3 = MERB Sol3555 1.jpg
| caption3 = ''Opportunity''{{'}}s path at Solander Point and along Murray Ridge up to February 2014 (Sol 3555)
}}

''Opportunity'' started off 2014 on the western ridge of Endeavour crater, providing elevated panoramas of the surrounding region.<ref name=nasa3520/> Research on data from Mars orbiters identified interesting minerals on the outcrop.<ref name=nasa3520/> Some communication and difficulties the previous month delayed investigating these rocks, but on the positive side, the wait, along with a cleaning event over January 1, allowed for more electrical power to be available.<ref name=nasa3520/> The rover is tilted towards the Sun to help it get more power, and it is expected that it can remain active during the Martian winter.<ref name=solander/>

==== Pinnacle Island ====

On January 17, NASA reported that a [[Astronomy:List of rocks on Mars|rock]], named "[[Astronomy:List of rocks on Mars#Opportunity|Pinnacle Island]]", that was not in a rover image taken on Sol 3528, "mysteriously" appeared 13 days later in a similar image taken on Sol 3540. One possible explanation, presented by Steven Squyres, [[Principal investigator|principal investigator]] of the Mars Exploration Rover Mission, was that the rover, in one of its turning motions, flicked the rock from a few meters away and into the new location.<ref name="SPACE-20140117">{{cite web |last=O'Neill |first=Ian |title=Mystery Rock 'Appears' in Front of Mars Rover |url=http://www.space.com/24330-mars-rover-mystery-rock-appears.html
|date=January 17, 2014 |work=Space.com }}</ref><ref name="NYT-20140124">{{cite news|last=Chang |first=Kenneth |title=Mars Rover Marks an Unexpected Anniversary With a Mysterious Discovery| url=https://www.nytimes.com/2014/01/24/science/space/mars-rover-marks-an-unexpected-anniversary-with-a-mysterious-discovery.html |date=January 24, 2014 |work={{wipe|The New York Times}} }}</ref>

In response, Rhawn Joseph [[Astronomy:Journal of Cosmology#NASA lawsuit|published an article]] in the fringe journal ''[[Astronomy:Journal of Cosmology|Journal of Cosmology]]''<!--fringe= not-peer reviewed, non-scientific language, did not use scientific process, no data no evidence.--> on January 17, 2014,<ref name="cos_20140117">{{cite journal | title=Apothecia on Mars? Life Discovered on the Red Planet | journal=Journal of Cosmology |volume=17| date=17 January 2014 | first=Rhawn Gabriel | last=Joseph | url=http://cosmology.com/ApotheciaOnMars.html }}</ref> and filed a writ of mandamus on January 27, 2014, in San Francisco Federal Court, stating that the object is a living entity and demanded that NASA re-examine the rock more closely.<ref name="PS-20140128">{{cite web |last=Lecher |first=Colin |title=Lawsuit Alleges NASA Is Failing To Investigate Alien Life|url=http://www.popsci.com/article/science/lawsuit-alleges-nasa-failing-investigate-alien-life |work=Popular Science |date=January 28, 2014 }}</ref><ref name="ABA-20140129">{{cite web|last=Weiss |first=Debra Cassens |title=Suit says NASA was 'recklessly negligent and bizarre' for failing to investigate Mars rock|url=http://www.abajournal.com/news/article/suit_says_nasa_was_recklessly_negligent_and_bizarre_for_failing_to_take_clo|work=[[Organization:American Bar Association|American Bar Association]] |date=January 29, 2014 }}</ref><ref name="CHN-20140129">{{cite web |last=Bailey |first=Lorraine |url=http://www.courthousenews.com/2014/01/29/64918.htm | title=Is Mysterious Mars Rock a Fungus? |work=Courthouse News Service |date=January 29, 2014 }}</ref> However, NASA already had examined the rock with the rover's [[Engineering:Microscope|microscope]]<ref name="CHN-20140129"/> and analyzers, and confirmed it was a rock with a high sulphur, manganese, and magnesium content.<ref name="TT-20140124">{{cite web |author=<!--Not stated--> |title=Scientist closer to solving Mars rock mystery, says NASA exper |url=https://www.telegraph.co.uk/science/space/10594511/Scientists-closer-to-solving-Mars-rock-mystery-says-Nasa-expert.html |archive-url=https://web.archive.org/web/20140125204219/http://www.telegraph.co.uk/science/space/10594511/Scientists-closer-to-solving-Mars-rock-mystery-says-Nasa-expert.html |url-status=dead |archive-date=January 25, 2014 |work=The Telegraph |date=January 24, 2014 }}</ref> According to Steven Squyres, "We have looked at it with our microscope. It is clearly a rock."<ref name="CHN-20140129" /> On February 14, 2014, NASA released [[:File:PIA17942-MarsOpportunityRover-PinnacleIslandRockMysterySolved-20140204.jpg|an image]] showing the location from where the "[[Astronomy:List of rocks on Mars#Opportunity|Pinnacle Island]]" rock was dislodged by the ''Opportunity'' rover.

{{Multiple image
|align=center
|total_width=800
|image1=PIA17761-MarsOpportunityRover-MysteryRock-Sol3528-Sol3540-color.jpg
|image2=Mars Pinnacle Rock.png
|image3=PIA17942-MarsOpportunityRover-PinnacleIslandRockMysterySolved-20140204.jpg
|caption1="Mysterious" appearance of a rock shaped as a "jelly doughnut" - sol 3528 & 3540<ref name="SPACE-20140117" /><ref name="NYT-20140124" /> ([[:File:MarsOpportunityRover-MysteryRock-Sol3528-Sol3540.jpg|b/w]]).
|caption2=Closeup - Rock contains [[Chemistry:Sulfur|sulfur]], [[Chemistry:Magnesium|magnesium]] and [[Chemistry:Manganese|manganese]].<ref name="TT-20140124" /> 
|caption3=Location where "[[Astronomy:List of rocks on Mars#Opportunity|Pinnacle Island]]" rock was dislodged by rover; mystery solved (February 4, 2014).}}
{{clear}}

==== Renewed focus ====
On January 23, 2014, NASA celebrated the tenth anniversary (officially, January 25, 2014) of the rover's landing on Mars by sharing a self-portrait of the rover from above.<ref name="MERFacts" /> They also reported on the latest discoveries of [[Astronomy:List of rocks on Mars#Opportunity|some Martian rocks]] and stated, "These rocks are older than any we examined earlier in the mission, and they reveal more favorable conditions for microbial life than any evidence previously examined by investigations with ''Opportunity''."<ref name="NASA-20140124">{{cite web |last1=Brown |first1=Dwayne |last2=Webster |first2=Guy |title=NASA's Opportunity at 10: New Findings from Old Rover |url=http://www.jpl.nasa.gov/news/news.php?release=2014-022 |date=January 23, 2014 |work=[[Organization:NASA|NASA]] }}</ref><ref name="SCI-20140124b">{{cite journal |author=Arvidson, R.E. |title=Ancient Aqueous Environments at Endeavour Crater, Mars |date=January 24, 2014 |journal=Science |volume=343 |number=6169 |doi=10.1126/science.1248097 |display-authors=0 |pages=1248097 |pmid=24458648|bibcode=2014Sci...343G.386A |s2cid=17718415 |url=http://nrs.harvard.edu/urn-3:HUL.InstRepos:12330889 }}</ref><ref name="SCI-20140124">{{cite journal |title=Special Collection - Curiosity - Exploring Martian Habitability |url=https://www.science.org/action/doSearch?AllField=Curiosity+Mars |date=January 24, 2014 |journal=Science }}</ref>

{{wide image|PIA19109-MarsOpportunityRover-EndeavourCrater-CapeTribulation-20150122.jpg|800px|MER-B eventually reached Cape Tribulation, and took a panorama from its top: ''[[Engineering:Opportunity (rover)|Opportunity]]''{{'s}} view from Cape Tribulation on the rim of Endeavour Crater, January 22, 2015. This was the highest elevation point yet achieved by MER-B<ref name="planetary.org">{{cite web|url=http://www.planetary.org/multimedia/space-images/mars/MER-B-Opportunity-Cape-Tribulation-Summit-Panorama.html|title=MER-B Opportunity Cape Tribulation Summit Panorama|website=Pplanetary.org|access-date=7 September 2018}}</ref>}}
{{Clear}}

On January 24, 2014, NASA reported that [[Organization:Timeline of Mars Science Laboratory#Current status|current studies]] on the planet [[Astronomy:Mars|Mars]] by the [[Engineering:Curiosity (rover)|''Curiosity'']] and ''Opportunity'' [[Astronomy:Mars rover|rovers]] will now be searching for evidence of ancient life, including a [[Biology:Biosphere|biosphere]] based on [[Biology:Autotroph|autotroph]]ic, [[Biology:Chemotroph|chemotroph]]ic and/or [[Biology:Lithotroph#Chemolithotrophs|chemolithoautotrophic]] [[Biology:Microorganism|microorganism]]s, as well as ancient water, including [[Earth:Lacustrine plain|fluvio-lacustrine environments]] ([[Earth:Plain|plain]]s related to ancient [[Earth:River|river]]s or [[Earth:Lake|lake]]s) that may have been [[Astronomy:Planetary habitability|habitable]].<ref name="SCI-20140124" /><ref name="SCI-20140124a">{{cite journal |last=Grotzinger |first=John P. |title=Introduction to Special Issue - Habitability, Taphonomy, and the Search for Organic Carbon on Mars |journal=Science |date=January 24, 2014 |volume=343 |number=6169 |pages=386–387 |doi=10.1126/science.1249944 |pmid=24458635|bibcode=2014Sci...343..386G |doi-access=free }}</ref><ref name="SCI-20140124special">{{cite journal |title=Special Issue - Table of Contents - Exploring Martian Habitability |url=https://www.science.org/toc/science/343/6169 |date=January 24, 2014|journal=Science |volume=343 |number=6169 |pages=345–452 }}</ref><ref name="SCI-20140124c">{{cite journal |author=Grotzinger, J.P. |title=A Habitable Fluvio-Lacustrine Environment at Yellowknife Bay, Gale Crater, Mars |date=January 24, 2014 |journal=Science |volume=343 |number=6169 |doi=10.1126/science.1242777 |display-authors=0 |pmid=24324272 |pages=1242777 |bibcode=2014Sci...343A.386G |s2cid=52836398 |doi-access=free |hdl=2060/20150008374 |hdl-access=free }}</ref> The search for evidence of [[Astronomy:Planetary habitability|habitability]], [[Earth:Taphonomy|taphonomy]] (related to fossils), and organic carbon on the planet [[Astronomy:Mars|Mars]] is now a primary [[Organization:NASA|NASA]] objective.<ref name="SCI-20140124a" />

Among many activities in March 2014, the rover studied the rock "Augustine," and on Sol 3602 (March 12, 2014), produced 498 watt-hours from sunlight.<ref name="sol_3596">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3596 | publisher=NASA | title=Mars Sol 3596 | date= | access-date=2014-03-25 | archive-date=2014-06-20 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3596 | url-status=dead }}</ref> Two cleaning events in March 2014 significantly boosted available power.<ref name="nasa3603">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3603 | publisher=NASA | title=Mars Sol 3603 | date= | access-date=2014-03-25 | archive-date=2014-06-20 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3603 | url-status=dead }}</ref>  Since January 2013, the solar array dust factor (one of the determinants of solar power production) varied from a relatively dusty 0.467 on December 5, 2013 (sol 3507) to a relatively clean 0.964 on May 13, 2014 (sol 3662).<ref name="Opportunity Updates (All)">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html | publisher=NASA | title=Opportunity Updates | access-date=21 May 2014 | date= | archive-date=20 June 2014 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html | url-status=dead }}</ref>

{{Bar graph
| title       = 
| float       = none
| bar_width   = 30
| width_units = em
| data_max    = 800
| label_type  = Date
| data_type   = Watt-hours
| label1      = Sol&nbsp;3534&nbsp;(Jan.&nbsp;1,&nbsp;2014)
| data1       = 371
| label2      = Sol&nbsp;3602&nbsp;(March&nbsp;12,&nbsp;2014)
| data2       = 498
| label3      = Sol 3606 (March 16, 2014)
| data3       = 615
| label4      = Sol 3621 (April 1, 2014)
| data4       = 661
| label5      = Sol 3676 (May 27, 2014)
| data5       = 764
| label6      = Sol 3703 (Jun 24, 2014)
| data6       = 743
| label7      = Sol 3751 (Aug 12, 2014)
| data7       = 679 
| label8      = Sol 3812 (Oct 14, 2014)
| data8       = 605
| label9      = Sol 3867 (Dec 9, 2014)
| data9       = 500
}}
On July 28, 2014, NASA announced that ''Opportunity'', after having traveled over {{convert|25|mi|km|order=flip|abbr=on}} on the planet [[Astronomy:Mars|Mars]], has set a new "off-world" record as the [[Astronomy:Rover (space exploration)|rover]] having driven the greatest distance, surpassing the previous record held by the Soviet Union's [[Astronomy:Lunokhod 2|Lunokhod 2 rover]] that had traveled {{convert|39|km|mi|abbr=on}}.<ref name="NASA-20140728a">{{cite web|last1=Webster |first1=Guy |last2=Brown |first2=Dwayne |title=NASA Long-Lived Mars Opportunity Rover Sets Off-World Driving Record |url=http://www.jpl.nasa.gov/news/news.php?release=2014-245 |date=July 28, 2014 |work=[[Organization:NASA|NASA]] |access-date=July 29, 2014}}</ref><ref name="FRB-20140729">{{cite web |last=Knapp |first=Alex |title=NASA's Opportunity Rover Sets A Record For Off-World Driving |url=https://www.forbes.com/sites/alexknapp/2014/07/29/nasas-opportunity-rover-sets-a-record-for-off-world-driving |date=July 29, 2014  |work={{wipe|Forbes}} |access-date=July 29, 2014}}</ref>

After a series of "resets" pointed to problems with flash memory, the rover stopped driving from late August to early September, 2014, in order to reformat its flash memory.<ref name="sol_3773">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3773 | publisher=NASA | title=Mars Sol 3773 | date=September 9, 2014 | access-date=March 25, 2014 | archive-date=June 20, 2014 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3773 | url-status=dead }}</ref>  Though minor memory problems persisted in the immediate aftermath of reformatting, they did not hinder the rover's continued operation; ''Opportunity'' resumed driving towards "Ulysses" crater and "Marathon Valley," exceeding total odometry of 41 kilometers by November 11, 2014.<ref name="sol_3835">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3835 | publisher=NASA | title=Mars Sols 3835-3839 | date=November 11, 2014 | access-date=November 20, 2014 | archive-date=June 20, 2014 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3835 | url-status=dead }}</ref>

[[File:PIA18614.jpg|thumb|900px|center|Wdowiak Ridge on the North-Western rim of Endeavour crater.MER-B recorded this panorama on Sept. 17, 2014 (Sol 3,786)<ref>{{cite web|url=https://photojournal.jpl.nasa.gov/catalog/PIA18614|title=Catalog Page for PIA18614|website=photojournal.jpl.nasa.gov|access-date=7 September 2018}}</ref>]]

{{Multiple image
| align = center
| total_width = 1000
| image1 = MERB Sol3689 1.jpg
| caption1 = Traverse as of June 2014 from roughly sol 3500 to 3689
| image2 = MERB Sol3757 1.jpg
| caption2 = Traverse as of August 2014 from roughly sol 3728 to 3757
| image3 = MERB Sol3868 1.jpg
| caption3 = Traverse as of December 2014 from roughly sol 3750 to 3868
}}

=== 2015 ===
2015 was a year of superlative achievements for the MER-B mission, starting off with summiting [[Astronomy:Cape Tribulation (Mars)|Cape Tribulation]] in January 2015, which was the highest elevation achieved yet on its mission.<ref name="planetary.org"/> Then in March 2016 it accomplished the distance of a classic [[Engineering:Marathon|marathon]].<ref>{{cite web|url=https://www.nasa.gov/press/2015/march/nasas-opportunity-mars-rover-finishes-marathon-clocks-in-at-just-over-11-years|title=Opportunity Mars Rover Finishes Marathon in Just Over 11 Years|first=Karen|last=Northon|date=25 March 2015|website=Nasa.gov|access-date=7 September 2018}}</ref> Also in March 2016 it achieved the steepest slope traverse (32 degree) yet of its mission, surpassing the slope it took on at Burns Cliff in 2004.<ref>{{cite web|url=http://www.nasa.gov/feature/jpl/rover-takes-on-steepest-slope-ever-tried-on-mars|title=Rover Takes on Steepest Slope Ever Tried on Mars|first=Tony|last=Greicius|date=31 March 2016|website=Nasa.gov|access-date=7 September 2018}}</ref> MER-B was trying to reach a target on Knudsen Ridge, on the south side of Marathon Valley, which meant attempting a steep grade which can cause wheel slippage.<ref name="ReferenceA">{{cite web|url=http://mars.nasa.gov/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1901|title=Rover Takes on Steepest Slope Ever Tried on Mars – NASA's Mars Exploration Program|website=Nasa.gov|access-date=7 September 2018}}</ref>  Another effect of this angle was that sand and dust that had collected on the rover flowed in streaks over the back of the rover, such was the incline.<ref name="ReferenceA"/>

In 2015 MER-B entered Marathon Valley and would study it until September 2016.<ref name="ReferenceB">{{cite web|url=http://mars.nasa.gov/multimedia/images/?ImageID=8100&NewsInfo=59C884BFF2B8E0EFC0DB03B94F94BA55AC4A8F96030077DDCA4C50F3A9DED997CB89D4DAF6D1C35FCB409EE2D7F68B01CBCFCF00A11252E4995A898E|title=From 'Marathon Valley' to Gully on Endeavour Rim – NASA's Mars Exploration Program|website=Nasa.gov|access-date=7 September 2018}}</ref>

{{Multiple image
| image1 = PIA19141.jpg
| caption1 = ''Opportunity''{{'}}s traverse up to February 2015 as it approached Spirit of Saint Louis Crater and Marathon Valley, and came close to traveling the distance of a traditional [[Engineering:Marathon|marathon]] (about 26 miles or 42 km)
| image2 = Spirit-st-louis-mars-crater-opportunity-rover-labeled-false-color-PIA19394wiki.jpg
| caption2 = In May 2015 the rover visited Spirit of St. Louis Crater, a shallow crater about {{convert|110|ft|m|abbr=off|sp=us}} long and {{convert|80|ft|m|abbr=off|sp=us}} across. In its center is Lindbergh Mound, about 2-3 meters (yards) high. This version of the panorma is annotated and in [[False color|false color]]<ref>{{cite web|url=http://mars.nasa.gov/mer/gallery/press/opportunity/20150521a.html|title=Mars Exploration Rover|last=mars.nasa.gov|website=mars.nasa.gov|access-date=7 September 2018}}</ref>
| align = center
| total_width = 1000
}}

On March 23, 2015, NASA reported ''Opportunity''{{'s}} flash memory was successfully reformatted.<ref name="NASA-20150323">{{cite web |last=Webster |first=Guy |title=NASA Reformats Memory of Longest-Running Mars Rover |url=http://www.jpl.nasa.gov/news/news.php?feature=4517 |date=March 23, 2015 |work=[[Organization:NASA|NASA]] |access-date=March 23, 2015 }}</ref> After completing analysis of the flash memory issues, engineers concluded that some of the problems stemmed from a single memory bank, one of  ''Opportunity''{{'s}} seven "banks" of onboard flash memory. A software upgrade was sent which allows the rover to bypass this bank, known as Bank 7.<ref name="Mars Rover Opportunity Gets Memory Fix Ahead of Marathon Milestone">{{cite web |title=Mars Rover Opportunity Gets Memory Fix Ahead of Marathon Milestone |website=Space.com |url=http://www.space.com/28911-opportunity-mars-rover-memory-fix.html |date=March 24, 2015 |access-date=March 25, 2015 }}</ref>  By February 2015, total odometry exceeded 42 kilometers.<ref name="sol_3922">{{cite web | url=http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3922 | publisher=NASA | title=Mars Sols 3835-3839 | date=February 9, 2015 | access-date=September 18, 2015 | archive-date=June 20, 2014 | archive-url=https://web.archive.org/web/20140620024319/http://marsrovers.jpl.nasa.gov/mission/status_opportunityAll.html#sol3922 | url-status=dead }}</ref> From July to September, the rover mostly operated using a RAM-only mode, to avoid ongoing flash memory issues. In September, a series of tests were performed to better understand the volatility of the device.<ref>[https://d2cj35nmzi9erd.cloudfront.net/mer/mission/status_opportunityAll.html#sol4126] {{dead link|date=September 2018}}</ref>

{{Bar graph
| title       = 
| float       = none
| bar_width   = 30
| width_units = em
| data_max    = 800
| label_type  = Date
| data_type   = Watt-hours
| label1      = Sol&nbsp;3894&nbsp;(Jan.&nbsp;6,&nbsp;2015)
| data1       = 438
| label2      = Sol&nbsp;3936&nbsp;(Feb&nbsp;18,&nbsp;2015)
| data2       = 559
| label3      = Sol&nbsp;4003&nbsp;(April&nbsp;28,&nbsp;2015)
| data3       = 526
| label4      = Sol&nbsp;4042&nbsp;(June&nbsp;7,&nbsp;2015)
| data4       = 490
| label5      = Sol&nbsp;4098&nbsp;(Aug&nbsp;4,&nbsp;2015)
| data5       = 431
| label6      = Sol&nbsp;4161&nbsp;(Oct&nbsp;7,&nbsp;2015)
| data6       = 327
| label7      = Sol&nbsp;4221&nbsp;(Dec&nbsp;8,&nbsp;2015)
| data7       = 407
| label8      = 
| data8       = 
| label9      = 
| data9       = 
}}

During the beginning of October 2015, ''Opportunity'' began its drive to north-tilted slopes in Marathon Valley of the west rim of Endeavour crater in preparation for the Martian winter. By November 2, after attempting to use the rover's flash memory, ''Opportunity'' again suffered an "amnesia" event.<ref name="sol_4186">{{cite web | url=http://mars.nasa.gov/mer/mission/status_opportunityAll.html#sol4181| publisher=NASA | title=Mars Sols 4181-4187 | date= }}</ref> and the decision was made to switch back to use RAM on November 11 (Sol 4195).<ref name="sol_4195">{{cite web | url=http://mars.nasa.gov/mer/mission/status_opportunityAll.html#sol4194| publisher=NASA | title=Mars Sols 4194-4201 | date= }}</ref>

{{Multiple image
| image1 = PIA19151-MarsOpportunityRover-MarathonValley-20150323.jpg
| caption1 = Marathon Valley as viewed by the ''Opportunity'' rover ([http://photojournal.jpl.nasa.gov/jpeg/PIA19152.jpg false color]; [http://photojournal.jpl.nasa.gov/jpeg/PIA19153.jpg stereo]; March 13, 2015).
| image2 = MERB Sol4227 1.jpg
| caption2 = Color sat-view of MER-B's track along the Western edge of the crater up to December 2015
| align = center
| total_width = 1000
}}

=== 2016 ===
On January 3, 2016 (Sol 4246), ''Opportunity'' went through the winter solstice on Mars with already improved [[Astronomy:Solar irradiance|solar insolation]], with the rover producing 449 watt-hours from its solar panels.<ref name="sol_4246">{{cite web | url=http://mars.nasa.gov/mer/mission/status_opportunityAll.html#sol4229| publisher=NASA | title=Mars Sols 4229-4246 | date= }}</ref> On January 25, 2016, ''Opportunity'' had marked twelve years since landing on Mars and continued its scientific investigation of Marathon Valley.<ref name="sol_4268">{{cite web | url=http://mars.nasa.gov/mer/mission/status_opportunityAll.html#sol4263| publisher=NASA | title=Mars Sols 4263-4268 | date= }}</ref>

{{Multiple image
| image1 = Mars-rover-opportunity-solar-panel-PIA20329.jpg
| caption1 = On March 21, 2016, while trying to reach target on the slope of Marathon Valley in Cape Tribulation, the Mars rover attained a slope of 32 degrees, the highest angle yet for the rover since its mission began. This was so steep that dust that had accumulated on its top panels began to flow downward.<ref>{{cite web|url=https://mars.nasa.gov/resources/7782/|title=Streaks on Opportunity Solar Panel After Uphill Drive – NASA's Mars Exploration Program|website=Mars.nasa.gov|access-date=7 September 2018}}</ref>
| image2 = Opportunity-devilish-view-ridge-PIA20012-br2.jpg
| caption2 = ''Opportunity'' images a Martian whirlwind (April 2016)
| align = center
| total_width = 1000
}}

On March 31, 2016, ''Opportunity'' captured an image of a dust devil inside Endeavour crater.<ref name="sol_4331">{{cite web | url=http://mars.nasa.gov/mer/mission/status_opportunityAll.html#sol4331| publisher=NASA | title=Mars Sols 4331-4337 | date=April 5, 2016 |access-date=May 28, 2016}}</ref>  Although the [[Engineering:Spirit (rover)|''Spirit'']] rover saw dust devils frequently, they have been less common in the area that ''Opportunity'' is exploring.<ref name="mashable20160402">{{cite web |last=Kramer |first=Miriam |title=NASA rover snaps photo of a dust devil swirling on Mars |url=http://mashable.com/2016/04/02/mars-rover-opportunity-dust-devil-photo/ |date=April 2, 2016 |work=Mashable |access-date=May 28, 2016}}</ref>

====Marathon Valley Panorama====
In June 2016, MER-B took a special panoramic image called the ''Sacagawea Panorama'' in honor of Sacagawea, the Lemhi Shoshone woman that helped the Lewis and Clark Expedition on their journey of exploration across America in 1804 to 1806.<ref name="photojournal.jpl.nasa.gov">{{cite web|url=http://photojournal.jpl.nasa.gov/catalog/PIA20749|title=Catalog Page for PIA20749|website=photojournal.jpl.nasa.gov|access-date=7 September 2018}}</ref> The image was taken of Marathon Valley at Endeavour Crater on the planet Mars.<ref name="photojournal.jpl.nasa.gov"/>
{{wide image|PIA20749marathonvalley.jpg|1000px|align-cap=center|''Sacagawea Panorama'' by ''Opportunity'', 2016}}
On the right side of this image is "Knudsen Ridge", and beyond Marathon valley is the floor of Endeavor crater.<ref name="photojournal.jpl.nasa.gov"/> In the distance is the rim of crater on the other side.<ref name="photojournal.jpl.nasa.gov"/>

====Marathon Valley departure====
In September 2016, ''Opportunity'' departed from Marathon Valley which it traversed through over the previous Earth year.<ref name="mars.nasa.gov">{{Cite web|url=http://mars.nasa.gov/mer/mission/status_opportunityAll.html|title=Mars Exploration Rover Mission: All Opportunity Updates|website=mars.nasa.gov|access-date=2018-02-15}}</ref> As it continued to explore the Western rim of Endeavor crater, it was directed out of Lewis and Clark gap in Marathon valley, and made its way towards Spirit mound.<ref name="mars.nasa.gov"/> By early October 2016, the rover had reached Spirit mound by passing through Bitterroot valley, where it began to collect data on a science target.<ref name="mars.nasa.gov"/>

Starting in October 2016, the three new mission goals include driving down into Endeavour Crater along what is thought to be a water-carved gully, compare the material on the plains to the interior of the crater, and to find pre-impact rocks (rocks that pre-date the impact that presumably formed Endeavour crater).<ref>{{Cite web |url=https://thespacereporter.com/2016/10/opportunity-rover-explore-martian-gully/ |title=Opportunity rover to explore Martian gully - |access-date=2016-10-14 |archive-url=https://web.archive.org/web/20161012153142/https://thespacereporter.com/2016/10/opportunity-rover-explore-martian-gully/ |archive-date=2016-10-12 |url-status=dead }}</ref><ref>{{cite web|url=http://www.jpl.nasa.gov/news/news.php?feature=6642|title=NASA's Opportunity Rover to Explore Mars Gully|website=NASA/JPL|access-date=7 September 2018}}</ref>

By October 4, 2016, the rover had traveled {{convert|26.99|mi|km}}, and generated 472 watt-hours of electricity.<ref name="mars.nasa.gov"/> This date was mission time of Sol (Mars days) 4514.<ref name="mars.nasa.gov"/>

{{Multiple image
| image1 = MERB Sol4505 1.jpg
| caption1 = A detailed-class rover traverse map by the mission, released on September 28, 2016 showing the track of the rover up to Sol 4500 as it heads deeper in Endeavor crater
| image2 = Pia20854 gully map.jpg
| caption2 = Annotated version of MER-B traverse to Spirit Mound from Marathon Valley in late 2016
| align = center
| total_width = 1000
}}

The gully in the above annotated picture is a few hundred meters from the rover, and is the location of the suspected fluid-carved, possibly water, gullies that have never been investigated from the surface before.<ref name="ReferenceB"/> One of the MER-B goals is to drive down to this gully and examine it.<ref name="ReferenceB"/>

====Imaging ''Schiaparelli''{{'}}s descent====
In October 2016 the ESA [[Engineering:Schiaparelli EDM lander|''Schiaparelli'' lander]] attempted to land near Endeavour crater, and the two teams worked together for ''Opportunity'' to possibly image the lander during its descent.<ref>{{Cite web |url=http://www.skyandtelescope.com/astronomy-blogs/astronomy-space-david-dickinson/schiaparelli-lander-mars/ |title=Schiaparelli Lander Set to Touch Down on Mars |first=David |last=Dickinson |date=October 16, 2016 |work=Sky and Telescope}}</ref> ''Opportunity'' did take pictures of the area of the sky the lander was coming down in although the lander was not identified at that time; the nature of MER-B's cameras, the terrain, and the uncertainty of the lander's location, meant imaging was not a certainty.<ref>{{Cite web |url=http://www.planetary.org/blogs/emily-lakdawalla/2016/10191525-brief-update-opportunitys.html |title=Brief update: Opportunity's attempt to image Schiaparelli unsuccessful |first=Emily |last=Lakdawalla |date=2016-10-19 |work=The Planetary Society}}</ref> By late October 2016 it was confirmed Schiaparelli had crashed into the surface rather than achieving a soft touchdown.<ref>{{Cite web |url=http://www.astronomy.com/news/2016/10/schiaparelli-computer-glitch |title=Schiaparelli may have crashed due to computer glitch |date=October 25, 2016 |first=Nicole |last=Kiefert |work=Astronomy.com <!-- original source: https://www.theverge.com/2016/10/25/13407096/exomars-schiaparelli-lander-crash-mars-cause-software-esa -->}}</ref>

====Moving on====
The rover headed south from Spirit point after the events of ExoMars, continuing its mission on the edge of Endeavour crater.<ref name="ReferenceC">{{cite web|url=http://mars.nasa.gov/mer/mission/status_opportunityAll.html#sol4542|title=Mars Exploration Rover Mission: All Opportunity Updates|website=mars.nasa.gov|access-date=7 September 2018}}</ref> On Sol 4541 (Nov. 1, 2016), the solar array energy production is 390 watt-hours and on Sol 4548 (Nov. 8, 2016), the solar array energy production is 445 watt-hours.<ref name="ReferenceC"/> A readout from the EEPROM was returned to Earth, this is used in the test-bed rovers on Earth.<ref name="ReferenceC"/>

===2017===
On Sol 4623 (January 24, 2017 PST) the team celebrated 13 years operating ''Opportunity'' on the surface of Mars.<ref>{{Cite web|url=http://mars.nasa.gov/mer/mission/status_opportunityAll.html#sol4617|title=Mars Exploration Rover Mission: All Opportunity Updates|website=mars.nasa.gov|access-date=2017-02-14}}</ref> By February 7, 2017 (Sol 4636) the rover had traveled {{convert|44|km|mi|abbr=off|sp=us}} on the surface of Mars.<ref name="auto">{{Cite web|url=http://mars.nasa.gov/mer/mission/status_opportunityAll.html#sol4631|title=Mars Exploration Rover Mission: All Opportunity Updates|website=mars.nasa.gov|access-date=2017-02-14}}</ref> Power collection from the Sun on that date was 414 watt-hours.<ref name="auto"/> The long-term goal at the time was a gully south of the rover on the Western rim of Endeavour crater.<ref>{{Cite web|url=http://www.planetary.org/explore/space-topics/space-missions/mer-updates/2017/01-mer-update-opportunity-celebrates-13-years-on-mars.html|title=Mars Exploration Rovers Update: Opportunity Celebrates the Big 1-3, Begins 14th Year of Ops!|website=Planetary.org|language=en|access-date=2017-02-14}}</ref> Science operations also continued including microscopic imaging of select rocks, APXS operation, and atmospheric [[Chemistry:Argon|argon]] gas measurements.<ref>{{Cite web|url=http://mars.nasa.gov/mer/mission/status_opportunityAll.html#sol4624|title=Mars Exploration Rover Mission: All Opportunity Updates|website=mars.nasa.gov|access-date=2017-02-14}}</ref>

Throughout 2017, ''Opportunity'' worked its way south along the Western rim as it moved towards the gully, which the team named ''Perseverance Valley'' in April 2017.<ref>{{Cite web|url=http://www.planetary.org/explore/space-topics/space-missions/mer-updates/2017/04-mer-update-opportunity-perseverance-valley.html|title=The Mars Exploration Rovers Update: Opportunity Closes in on Perseverance Valley|website=Planetary.org|language=en|access-date=2018-02-08}}</ref><ref name="auto1">{{Cite web|url=http://www.planetary.org/explore/space-topics/space-missions/mer-updates/2017/03-mer-update-opportunity-dodges-dust-storm.html|title=Mars Exploration Rovers Update: Opportunity Dodges Dust Storms, Makes Tracks to Perseverance Valley|website=Planetary.org|language=en|access-date=2018-02-08}}</ref> Some other names considered for this feature were Perseverance Gulch, Perseverance Ravine, and Perseverance Gorge.<ref name="auto1"/> It is a valley network that runs downslope in the Cape Bryon section of Western rim of Endeavour crater.<ref name="auto1"/>

The Martian winter reached its hardest time for the rover this year, with reduced sunlight and colder temperatures.<ref>{{Cite web|url=https://www.jpl.nasa.gov/news/news.php?feature=7018|title=NASA Mars Rover Team's Tilted Winter Strategy Works|website=NASA/JPL|access-date=2018-02-09}}</ref> One strategy the Rover team uses is to position the Rover on northward faced slopes to get more sunlight, and because the gully runs east–west, they were often able to use the southern edge of the gully channel of Perseverance Valley to tilt the rover this way.<ref>{{cite web|url=https://www.jpl.nasa.gov/news/news.php?feature=7018|title=NASA Mars Rover Team's Tilted Winter Strategy Works|website=NASA/JPL|access-date=7 September 2018}}</ref> The Martian winter solstice was in November 2017, and it is the 8th one that MER-B has passed through.<ref>{{cite web|url=https://mars.nasa.gov/news/nasa-mars-rover-teams-tilted-winter-strategy-works/|title=NASA Mars Rover Team's Tilted Winter Strategy Works – NASA's Mars Exploration Program|website=Mars.nasa.gov|access-date=7 September 2018}}</ref>

Some energy production readings from 2017:<ref name="nasa.gov1">{{cite web|url=https://mars.nasa.gov/mer/mission/status_opportunityAll.html|title=Mars Exploration Rover Mission: All Opportunity Updates|website=Mars.nasa.gov|access-date=7 September 2018}}</ref>
{{Bar graph
| title       = ''Opportunity'' solar array energy production (2017)
| float       = left
| bar_width   = 30
| width_units = em
| data_max    = 800
| label_type  = Date
| data_type   = Watt-hours
| label1     = Sol 4602 (January 3, 2017)
| data1      = 520
| label2     = Sol 4636 (February 7, 2017)
| data2      = 414
| label3     = Sol 4663 (March 6, 2017)
| data3      = 441
| label4     = Sol 4691 (April 4, 2017)
| data4      = 415
| label5     = Sol 4718 (May. 2, 2017)
| data5      = 405
| label6     = Sol 4752 (June 6, 2017)
| data6      = 362
| label7     = Sol 4786 (July 11, 2017)
| data7      = 352
| label8     = Sol 4814 (August 8, 2017)
| data8      = 319 
| label9     =Sol 4841 (Sept. 5, 2017)
| data9     = 285
| label10     =Sol 4875 (Oct. 10, 2017)
| data10    = 339
| label11     =4909 (Nov. 14, 2017)
| data11    = 393
| label12     =Sol 4934 (Dec. 10, 2017)
| data12    = 408
}}
{{clear}}
{{wide image|PIA21707-Mars-OpportunityRover-OrionCrater-April2017.jpg|1000px|Panorama of Orion Crater (enhanced color; April 26, 2017).<ref name="NASA-20170616"/>}}
[[File:PIA21723-MarsOpportunityRover-PerseveranceValley-20170619.jpg|thumb|center|1000px|{{center|''Above Perseverance Valley, July 2017''}}]]
{{clear}}

{{Multiple image
| align = center
| total_width = 1000
| image1 = MERB Sol4625 1.jpg
| caption1 = Traverse map to January 27, 2017 (Sol 4625)
| image2 = MERB Sol4695 1.jpg
| caption2 = Traverse map to April 11, 2017 (Sol 4695)<ref>{{cite web|url=https://mars.nasa.gov/mer/mission/tm-opportunity/opportunity-sol4695.html|title=Mars Exploration Rover|last=mars.nasa.gov|website=mars.nasa.gov|access-date=7 September 2018}}</ref>
| image3 = Oppymap4836sept17.png
| caption3 = Traverse map to September 12, 2017 (Sol 4836)<ref>{{cite web|url=https://mars.nasa.gov/mer/mission/tm-opportunity/opportunity-sol4836.html|title=Mars Exploration Rover|last=mars.nasa.gov|website=mars.nasa.gov|access-date=7 September 2018}}</ref>
}}

[[File:PIA21497capetrib.jpg|thumb|1000px|center|''Opportunity'' looks north as it departs Cape Tribulation, its southern end shown here (April 2017)<ref>{{cite web|url=https://photojournal.jpl.nasa.gov/catalog/PIA21497|title=Catalog Page for PIA21497|website=photojournal.jpl.nasa.gov|access-date=7 September 2018}}</ref>]]
{{Clear}}

====Up to 4836 (September 2017)====
Rover arrives at the Gully (Perseverance Valley) and heads into it, taking measurements and pictures, but also had to survive the Mars winter (November Winter Solstice).

===2018===
In 2018 the rover continued to explore the area called Perseverance Valley,<ref name="auto2">{{Cite news|url=https://mars.nasa.gov/news/nasa-mars-rover-teams-tilted-winter-strategy-works/|title=NASA Mars Rover Team's Tilted Winter Strategy Works|last=mars.nasa.gov|work=Mars planet facts news & images {{!}} NASA Mars rover + mission info|access-date=2018-01-23|language=en}}</ref> which is on the western rim of Endeavor Crater. The feature was previously called "Gully" and it was named by the rover team in early 2017.<ref>{{Cite web|url=http://www.planetary.org/explore/space-topics/space-missions/mer-updates/2017/03-mer-update-opportunity-dodges-dust-storm.html|title=Mars Exploration Rovers Update: Opportunity Dodges Dust Storms, Makes Tracks to Perseverance Valley|website=Planetary.org|language=en|access-date=2018-02-12}}</ref> The rover reached Perseverance Valley (the gully) in 2017 and spent the rest of the year exploring this area. In 2018 this in-depth study continued.<ref name="auto2"/>

The Valley may have a previously unknown type of rock.<ref>{{cite web|url=http://www.planetary.org/explore/space-topics/space-missions/mer-updates/2018/01-mer-update-opportunity-completes-14-years-of-exploring.html|title=The Mars Exploration Rovers Update: Mission Completes 14 Years of Exploring, Opportunity Roves into Year 15!|website=Planetary.org|access-date=7 September 2018}}</ref> It is thought to be a fluid-carved channel, a spillway from the surrounding planes down to the crater floor.<ref name="Space.com">{{Cite news|url=https://www.space.com/37601-opportunity-mars-rover-perseverance-valley-panorama.html|title=Aging Mars Rover Captures Gorgeous 'Sprained Ankle' Panorama (Photos)|work=Space.com|access-date=2018-02-12}}</ref> Among the candidates for what carved the channels are water, but also ice or wind currents.<ref name="Space.com"/> One of the ongoing questions is the idea of ancient water on Mars, and how it may have impacted the modern Mars environment.<ref name="Space.com"/> In the 2010s NASA has been on the hunt for ancient fossils left by tiny living organisms especially when they make large colonies, such as [[Earth:Stromatolite|Stromatolite]]s, which look like mushroom shaped rocks but are made by colonies of bacteria.<ref name="news.nationalgeographic.com">{{Cite news|url=https://news.nationalgeographic.com/2016/10/alien-fossils-nasa-exploring-mars-2020-space-science/|archive-url=https://web.archive.org/web/20161020014235/http://news.nationalgeographic.com/2016/10/alien-fossils-nasa-exploring-mars-2020-space-science/|url-status=dead|archive-date=October 20, 2016|title=NASA's Bold Plan to Hunt for Fossils on Mars|date=2016-10-17|access-date=2018-02-12}}</ref> The question of ancient bacteria on Mars was raised in the 1990s, when a scientist thought he had found microscopic bacterial fossils on a meteorite that came from Mars (see ALH84001) but was found on Earth.<ref name="news.nationalgeographic.com"/> Future missions, such as [[Astronomy:Mars 2020|Mars 2020]], will carry more advanced chemical and geological detectors to Mars with them; some images taken by ''Opportunity'' have led to speculation about whether the images contain evidence of [[Astronomy:Extraterrestrial life|extraterrestrial life]]. One example, as reported by ''National Geographic'', appears to show a [[Biology:Cauliflower|cauliflower]]-shaped rock in an image taken by the ''Spirit'' rover in 2007, which, to some scientists, resembled fossils of microscopic stromatolites, which are ubiquitous on Earth, and represent the earliest widely accepted example of life in Earth's biosphere.<ref name="news.nationalgeographic.com"/> Stromatolites, thought to be signs of some of the earliest life discovered on Earth, almost 4 billion years ago, are on Earth today.<ref name="Newsweek">{{Cite news|url=http://www.newsweek.com/ancient-organism-life-earth-tasmania-stromatolites-715024|title=Stromatolites have been on Earth for 3.7 billion years, and scientists just found some in a Tasmanian swamp|date=2017-11-17|work=Newsweek|access-date=2018-02-12|language=en}}</ref> Another candidate are cynobacteria which are also determined to be among the oldest life on Earth.<ref name="Newsweek"/> Because of the large impacts that eject matter into space Mars has exchanged material with over long time scales, leading some to suggest life could make the journey between Earth and Mars.<ref>{{Cite news|url=https://www.space.com/22577-earth-life-from-mars-theory.html|title=Earth Life Likely Came from Mars, Study Suggests|work=Space.com|access-date=2018-02-12}}</ref> Indeed, cynobacteria survived for almost two-years in space (Aboard ISS) and could still come alive again when put in life conditions after being in zero-g, zero-air, high radiation conditions common to outer space.<ref>{{Cite news|url=https://www.popsci.com/technology/article/2010-08/bacteria-survive-553-day-exposure-exterior-iss|title=Earth Bacteria Survive a 553-Day Space Exposure on the Exterior of the ISS|work=Popular Science|access-date=2018-02-12|language=en}}</ref> On the colonization side, cyanobacteria like [[Biology:Nostoc pruniforme|nostoc]] colonies that have been studied for terraforming are known to survive on [[Astronomy:Martian regolith simulant|Mars regolith simulant]] and lower pressures.<ref>{{Cite journal|last1=Arai|first1=Mayumi|last2=Tomita-Yokotani|first2=Kaori|last3=Sato|first3=Seigo|last4=Hashimoto|first4=Hirofumi|last5=Ohmori|first5=Masayuki|last6=Yamashita|first6=Masamichi|date=2008|title=Growth of terrestrial cyanobacterium, Nostoc sp., on Martian Regolith Simulant and its vacuum tolerance|journal=Biological Sciences in Space|language=en|volume=22|issue=1|pages=8–17|doi=10.2187/bss.22.8|issn=0914-9201|doi-access=free}}</ref> Some the evidence for ancient water include the discovery of minerals that form in the presence of water, such as [[Chemistry:Jarosite|Jarosite]], discovered by ''Opportunity'' at Eagle Crater in 2004.<ref name="auto3">{{Cite web|url=http://www.planetary.org/explore/space-topics/space-missions/mer-updates/2018/01-mer-update-opportunity-completes-14-years-of-exploring.html|title=The Mars Exploration Rovers Update: Mission Completes 14 Years of Exploring, Opportunity Roves into Year 15!|website=Planetary.org|language=en|access-date=2018-02-12}}</ref> (see also [[Astronomy:Martian spherules|Martian spherules]])

''Opportunity'' studied the rock target Jornada del Muerto in Perseverance Valley, using its surviving suite of instruments including the Microscopic Imager (MI), APXS, and the color cameras.<ref name="auto3"/> At this time rocks from the Matijevic Formation have not been found, and the valley is proving to have some complicated natures<ref name="auto3"/> One area being studied is how the dust flows through channel and makes deposits.<ref name="auto3"/>

On Sol 4977 (Jan. 23, 2018), the stored backup flight software was updated to the latest version.<ref name="nasa.gov1"/> On that day electrical production was 644 watt-hours, and total distance traveled on Mars since landing was {{convert|28.02|mi|km|abbr=off|sp=us}}.<ref name="nasa.gov1"/>

[[File:Navigation Camera Sol 4959 of the MER-B Opportunity rover on Mars.jpg|thumb|500px|left|MER-B NavCam image Sol 4959<ref>{{cite web|url=https://mars.nasa.gov/mer/gallery/all/1/n/4959/1N568428036EFFD0J8P1826R0M1.HTML|title=Mars Exploration Rover|last=mars.nasa.gov|website=mars.nasa.gov|access-date=7 September 2018}}</ref> Start of January 2018, looking along rim of Endeavour crater]]
{{clear}}

On Sol 4999 (Feb. 15, 2018) MER-B took a Pancam of the Martian sunrise.<ref>{{cite web|url=https://mars.jpl.nasa.gov/mer/mission/status_opportunityAll.html|title=Mars Exploration Rover Mission: All Opportunity Updates|website=mars.jpl.nasa.gov|access-date=7 September 2018}}</ref>

====5000 sols on Mars====
{{Multiple image
| align = center
| total_width = 800
| image1 = PIA22222-Mars-OpportunityRover-FirstSelfie-20180220.jpg
| caption1 = ''Opportunity''{{'}}s first self-portrait including the camera mast on Mars<br />(February 14−20, 2018 / sols 4998−5004)
| image2 = View looking west on to Perseverance Valley on the western rim of Endeavour crater laid over 3-D topographic map of the terrain with 5-fold vertical exaggeration.jpg
| caption2 = HiRise image from MRO, was laid over 3-D topographic map of the terrain, with 5-fold vertical exaggeration; view looking west on to Perseverance Valley on the western rim of Endeavour crater (February 15, 2018)<ref>{{cite web|url=https://mars.nasa.gov/resources/21497/|title=Martian 'Perseverance Valley' in Perspective (Vertical Exaggeration) – NASA's Mars Exploration Program|website=Mars.nasa.gov|access-date=7 September 2018}}</ref>
}}

On February 16, 2018, MER-B achieved 5000 sols (Martian Days) on Mars since landing on the planet in January 2004.<ref name="auto4">{{Cite news|url=https://mars.nasa.gov/resources/21497/|title=Martian 'Perseverance Valley' in Perspective (Vertical Exaggeration)|last=mars.nasa.gov|work=Mars planet facts news & images {{!}} NASA Mars rover + mission info|access-date=2018-02-16|language=en}}</ref> At the time it was making its way down Perseverance Valley (aka the Gully) on the western rim of Endeavour crater, which it has been exploring in since 2011.<ref name="auto4"/> The interior rim of the crater where ''Opportunity'' is exploring is sloped at about 15 to 20 degrees on average.<ref name="auto4"/>

=====Sol 5,000 (Feb. 16, 2018)<ref name="auto4"/>=====
On Sol 5000 the team used the rover to take a self-portrait including the Pancam mast, by using the microscopic imager on the end of the robotic arm.<ref>{{cite web|url=http://www.planetary.org/multimedia/space-images/spacecraft/opportunitys-sol-5000-self-portrait.html|title=Opportunity's sol 5000 self-portrait|website=Planetary.org|access-date=7 September 2018}}</ref>

Power production on Sol 5004 (Feb. 20, 2018) was 653 watt-hours.<ref>{{cite web|url=https://mars.jpl.nasa.gov/mer/mission/status_opportunityAll.html|title=Mars Exploration Rover Mission: All Opportunity Updates|website=Mars.jpl.nasa.gov|access-date=7 September 2018}}</ref>

====Dust storm====
[[File:PIA22487-Mars-BeforeAfterDust-20180719.gif|thumb|left|200px|{{center|Mars (before/after) dust storm<br />(July 2018)}}]]
[[File:PIA22519-Mars-DustStorm-Animated-20180611.gif|thumb|right|220px|{{center|This animation of Mars shows a growing dust storm from May 31 to June 11, 2018. The images were taken by the Mars Color Imager (MARCI) camera on the Mars Reconnaissance Orbiter (MRO). Locations of ''Opportunity'' and ''Curiosity'' are noted.}}]]thumb|right|220px|{{center|Mars ''Opportunity'' rover – diminishing visibility (simulated) due to dust storm (June 2018).}}thumb|Values of the energy production (in Watthours), tau (atmosphere opacity) and the dust factor for the rover ''Opportunity'' since landing in 2004.<!---Highlighted are the minimum energy levels in the dust storm of 2007, in the winter time 2010 and at the beginning of the dust storm of 2018. In the second diagram the values of tau are displayed. Highlighted are the max tau in the dust storm of 2007 (4.12) and of the dust storm of 2018 (10.8). The third diagram shows the dust factor.--->thumb|right|220px|<div align="center">''Opportunity'' rover ‒ last image<ref name="FRBS-20190218" /><br />(of 228,771 images; 10 June 2018)<ref name="NASA-20190219" /></div><!---[[File:PIA22329-Mars-DustStorm-20180606.jpg|thumb|right|300px|{{center|This map of Mars shows the growing storm on June 6, 2018. The map was taken with photographs of the Mars Color Imager (MARCI) camera on the Mars Reconnaissance Orbiter (MRO). The blue dot marks the location of ''Opportunity''}}]]--->
In June 2018, a local dust storm began to develop near ''Opportunity''.<ref name="NASA-20180613ag">{{cite web |last=Good |first=Andrew |title=NASA Encounters the Perfect Storm for Science |url=https://www.jpl.nasa.gov/news/news.php?feature=7160 |date=June 13, 2018 |work=[[Organization:NASA|NASA]] |access-date=June 14, 2018 }}</ref><ref name="NYT-20180613">{{cite news |last=Chokshi |first=Niraj |title=Huge Dust Storm on Mars Threatens NASA's Opportunity Rover |url=https://www.nytimes.com/2018/06/13/science/mars-dust-storm-martian.html |date=June 13, 2018 |work={{wipe|The New York Times}} |access-date=June 13, 2018 }}</ref> The first signs of the {{convert|1000|km|mi|abbr=on}} distant storm were discovered on June 1, 2018, in photographs by the [[Astronomy:Mars Reconnaissance Orbiter#MARCI (camera)|Mars Color Imager]] (MARCI) camera on the [[Astronomy:Mars Reconnaissance Orbiter|Mars Reconnaissance Orbiter]] (MRO). More weather reports from the MRO and the MARCI team indicated a prolonged storm. Although this was, at that time, still far away from the rover, it began to influence the atmospheric opacity at the rover's location.

Within days, the storm had spread globally. As a result, plans were developed on June 4 and 5 to prepare for the anticipated lower power supply. Since then, the atmosphere over the rover had worsened further. On June 3, the 5105th Sol, ''Opportunity''{{'s}} solar panels still generated 468 watt-hours. The atmospheric opacity (called tau value) was about 1.0.

The power supply dropped to 345 watt hours on June 4 at a tau of 2.1. On June 6, only 133 watt hours were generated, the tau value was estimated at 3.0. ''Opportunity'' has not experienced such high tau levels since the last dust storm in 2007, which had an estimated tau value of 5.5. The 2018 storm had an estimated tau value of 10.8 on June 10 and the storm spanned an area of {{convert|41|e6km2|e6sqmi|abbr=unit}} - the approximate area of both North America and Russia combined.<ref name="NASA-20180612">{{cite web|last1=Good |first1=Andrew |last2=Brown |first2=Dwayne |last3=Wendell |first3=JoAnna |title=NASA to Hold Media Teleconference on Martian Dust Storm, Mars Opportunity Rover |url=https://www.jpl.nasa.gov/news/news.php?feature=7158 |date=June 12, 2018 |work=[[Organization:NASA|NASA]] |access-date=June 12, 2018}}</ref>

The rover team made another plan, in which the rover gets only the latest commands at the first sol in the morning and sleeps until the next morning. The rover then wakes up in the afternoon to conduct atmospheric measurements with the Pancam and conduct a brief communication session with the [[Astronomy:Mars Reconnaissance Orbiter|MRO orbiter]]. However, scientific investigations were discontinued, and the rover entered continuous hibernation on June 12. Although ''Opportunity'' rover requires the power generated by solar panels to keep the central electrical components warm, it features a small [[Engineering:Radioisotope heater unit|radioisotope heater unit]] (RPU) that does not require sunlight to function,<ref name=hopeful>[https://www.bbc.com/news/science-environment-44477502 Mars Opportunity: Rover 'should ride out storm']. Jonathan Amos, ''BBC News''. 14 June 2018.</ref> and the relatively warm summer weather was not expected to damage the electronic components at night.<ref name="NASA-20180613"/> The winter cold is likely the reason that ''Opportunity''{{'s}} twin rover [[Engineering:Spirit (rover)#2010|''Spirit'']] stopped working in 2010.

Although such dust storms are not surprising, they rarely occur. They can arise within a short time and then persist for weeks to months. During the southern season of summer, the sunlight heats dust particles and brings them higher into the atmosphere. This creates wind, which in turn stirs up more dust. This results in a feedback loop that scientists are still trying to understand, so they are taking an opportunity to study this storm from orbit using the various visible and infrared instruments on the MRO orbiter.<ref name="NASA-20180613"/>

As of June 10, 2018 the mission for ''Opportunity'' was able to extend its 92-day (Earth) mission to over 5250 days.<ref name="https">{{cite web|url=https://mars.nasa.gov/resources/8249/spirit-and-opportunity-by-the-numbers/|title=Spirit And Opportunity By The Numbers – NASA's Mars Exploration Program|website=Mars.nasa.gov|access-date=7 September 2018}}</ref> ''Opportunity'' took its [[:File:NASA-MarsOpportunityRover-LastImage-PanCam-Sol5111-20180610.jpg|last image]] (of an overall total of 228,771 raw images) on June 10, 2018.<ref name="FRBS-20190218">{{cite news |last=O'Callaghan |first=Jonathan |title=This Was The Last Photo Taken By NASA's Opportunity Rover On Mars |url=https://www.forbes.com/sites/jonathanocallaghan/2019/02/18/this-was-the-last-photo-taken-by-nasas-opportunity-rover-on-mars/ |date=18 February 2019 |work={{wipe|Forbes}} |access-date=19 February 2019 }}</ref><ref name="NASA-20190219">{{cite web |author=<!--Not stated--> |title=Opportunity: All 228,771 Raw Images |url=https://mars.nasa.gov/mer/gallery/all/opportunity.html |date=19 February 2019 |work=[[Organization:NASA|NASA]] |access-date=19 February 2019 }}</ref>

On June 12, 2018, ''Opportunity'' entered [[Engineering:Safe mode (spacecraft)|safe mode]] as evidenced by its lack of communication.<ref name="SA-20180613">{{cite web |last=Malik |first=Tariq |title=As Massive Storm Rages on Mars, Opportunity Rover Falls Silent - Dust clouds blotting out the sun could be the end of the solar-powered probe |url=https://www.scientificamerican.com/article/as-massive-storm-rages-on-mars-opportunity-rover-falls-silent/ |date=June 13, 2018 |work=Scientific American |access-date=June 13, 2018 }}</ref><ref name=hopeful/> A NASA teleconference about the [[Engineering:Opportunity mission timeline#Dust storm|dust storm]] was presented on June 13, 2018.<ref>{{cite web|url=https://www.youtube.com/watch?v=fIKxdRFx2Wo|title=Mars Dust Storm News|date=13 June 2018|access-date=7 September 2018|publisher=[[Company:YouTube|YouTube]]}}</ref><ref name="NASA-20180612" /><ref name="SPC-20180612">{{cite web |last=Wall |first=Mike |title=NASA's Curiosity Rover Is Tracking a Huge Dust Storm on Mars (Photo) |url=https://www.space.com/40867-nasa-curiosity-rover-mars-dust-storm.html |date=12 June 2018 |work=Space.com |access-date=13 June 2018 }}</ref><ref name="NASA-20180613">{{cite web |author=NASA Staff |title=Mars Dust Storm News - Teleconference - audio (065:22) |url=https://www.youtube.com/watch?v=fIKxdRFx2Wo |date=13 June 2018 |work=[[Organization:NASA|NASA]] |access-date=13 June 2018 }}</ref> ''Opportunity''{{'s}} team implemented additional communication times from NASA's Deep Space Network to receive up-to-date data from Mars. The data obtained showed that the temperature of the rover had fallen to {{convert|-29|C}}. An advantage of the dust storm is that the temperature differences are not as extreme as they are on the surface of Mars. In addition, the swirled-up dust absorbs heat, thereby increasing the ambient temperature at the location of ''Opportunity''.<ref name='Official updates'>{{Cite web|url=https://mars.nasa.gov/mer/mission/status_opportunityAll.html|title=Mars Exploration Rover Mission: All Opportunity Updates|website=mars.nasa.gov|access-date=2018-02-10}}</ref><ref name='hunkers down'>[https://www.nasa.gov/feature/jpl/opportunity-hunkers-down-during-dust-storm Opportunity Hunkers Down During Dust Storm]. NASA. 12 June 2018.</ref> NASA reported on June 20, 2018, that the dust storm had grown to completely cover the entire planet.<ref name="NASA-20180620">{{cite web|last1=Shekhtman |first1=Lonnie |last2=Good |first2=Andrew |title=Martian Dust Storm Grows Global; Curiosity Captures Photos of Thickening Haze |url=https://www.jpl.nasa.gov/news/news.php?feature=7164 |date=June 20, 2018 |work=[[Organization:NASA|NASA]] |access-date=June 21, 2018}}</ref><ref name="SPC-20180621">{{cite web |last=Malik |first=Tariq |title=Epic Dust Storm on Mars Now Completely Covers the Red Planet |url=https://www.space.com/40952-mars-dust-storm-2018-covers-entire-planet.html |date=June 21, 2018 |work=Space.com |access-date=June 21, 2018 }}</ref>

NASA stated they did not expect to resume communication until after the global dust storm subsided.<ref name=hopeful/><ref name='hunkers down'/><ref name="NASA-20180613"/><ref name='Official updates'/>
{{Bar graph
| title       = ''Opportunity'' solar array energy production during the 2018 dust storm
| float       = left
| bar_width   = 30
| width_units = em
| data_max    = 700
| label_type  = Date
| data_type   = Watt-hours<ref name="nasa.gov1"/>
| label1     =Sol 5079 (May 8, 2018)
| data1    = 667
| label2    =Sol 5100 (May 29, 2018)
| data2    = 652
| label3    =Sol 5105 (June 3, 2018)
| data3    = 468
| label4    =Sol 5106 (June 4, 2018)
| data4   = 345
| label5    =Sol 5107 (June 6, 2018)
| data5   =  133 
| label6    =Sol 5111 (June 10, 2018)
| data6   =  22
}}

====After the storm====
At the beginning of September 2018, the atmospheric opacity (tau) over the rover site was estimated to be below 1.5. This started a 45-day window that was expected to be the best time to re-establish contact with the rover.<ref name='Official updates'/> After more than three months without contact, NASA expected ''Opportunity'' to have most of its timers in fault state. To take this into account, as of September 19, 2018, "sweep and beep" commands are sent throughout the available transmission time.<ref name='NASA mission updates'>{{cite web|url=https://mars.nasa.gov/mer/mission/status_opportunityAll.html#sols-5196|title=Mars Exploration Rover Mission: All Opportunity Updates|website=mars.nasa.gov|access-date=1 October 2018}}</ref>

By early October, the storm subsided and the atmosphere cleared up, but the rover kept silent,<ref name='Official updates'/> suggesting either a catastrophic failure or a layer of dust covered its solar panels.<ref name='covered panels'>[https://www.space.com/42115-mars-rover-opportunity-still-silent-4-months-later.html Opportunity Rover Still Silent on Mars, 4 Months After Epic Dust Storm Began]. Mike Wall, ''Space.com''. 12 October 2018.</ref> By November 27, 2018, NASA had attempted to contact ''Opportunity'' 359 times.<ref>{{Cite web|url=https://www.spaceflightinsider.com/space-centers/jet-propulsion-laboratory/opportunity-alls-quiet-on-the-martian-front/|title=Opportunity: All's quiet on the Martian front...|date=2018-12-04|website=SpaceFlight Insider|language=en-US|access-date=2018-12-28}}</ref> The team remained hopeful that a windy period between November 2018 and January 2019 would clear the dust from its solar panels, as had happened before.<ref name='covered panels'/>

===2019===
On February 12, 2019, NASA announced it made its final attempt to contact the rover before declaring the rover dead.<ref>{{Cite web|url=https://www.space.com/mars-rover-opportunity-last-nasa-call.html|title=NASA Has Made Its Last Attempt to Call Opportunity Rover on Mars|last1=Science|first1=Mike Wall 2019-02-12T12:15:00Z|last2=Astronomy|website=Space.com|date=12 February 2019 |language=en|access-date=2019-02-13}}</ref>

==Sol milestones==
*Sol 3,000 (July 2, 2012)<ref>{{cite web|url=https://www.nasa.gov/mission_pages/mer/multimedia/pia16122.html|title=NASA - Opportunity's Surroundings on 3,000th Sol|website=Nasa.gov|access-date=7 September 2018}}</ref>
*Sol 4,000 (April 26, 2015)<ref>{{cite web|url=http://www.planetary.org/explore/space-topics/space-missions/mer-updates/2015/04-mer-update-opportunity-logs-sol-4000.html|title=Mars Exploration Rovers Update: Opportunity Logs Sol 4000, Digs Spirit of St. Louis Crater|website=Planetary.org|access-date=7 September 2018}}</ref>
*Sol 5,000 (Feb. 16, 2018)<ref name="auto4"/>
*Sol 5,111 (June 10, 2018) – Contact lost.<ref name="https"/>
*Sol 5,352 (Feb 12, 2019) – Mission officially declared dead.<ref>{{Cite web|url=https://www.theverge.com/2019/2/13/18223144/nasa-mars-opportunity-rover-radio-silence-dust-storm-end-of-mission|title=NASA is saying goodbye to its Opportunity rover on Mars after eight months of radio silence|last=Grush|first=Loren|date=2019-02-13|website=The Verge|access-date=2019-02-13}}</ref>

== Solar array energy production ==
[[File:PIA22737-Mars-2018DustStorm-MCS-MRO-Animation-20181030.webm|thumb|left|575px|{{center|[[Astronomy:Atmosphere of Mars|Mars dust storm]] – optical depth tau – May to September 2018<br />(Mars Climate Sounder; Mars Reconnaissance Orbiter)<br />(1:38; animation; October 30, 2018; file description}}]]
{{Bar graph
| title       = ''Opportunity'' solar array energy production per sol (2018 dust storm)
| float       = left
| bar_width   = 30
| width_units = em
| data_max    = 800
| label_type  = Date
| data_type   = Watt-hours<ref name="Official updates"/>
| label1      = Sol 5079 (May 8, 2018)
| data1       = 667
| label2      = Sol 5100 (May 29, 2018)
| data2       = 652
| label3      = Sol 5105 (June 3, 2018)
| data3       = 468
| label4      = Sol 5106 (June 4, 2018)
| data4       = 345
| label5      = Sol 5107 (June 6, 2018)
| data5       = 133
| label6      = Sol 5111 (June 10, 2018)
| data6       = 22
}}
{{Clear}}

=== Examples ===
Examples of watt-hours per sol collected by the rover:<ref name="OpportunityStatusUpdates">{{cite web|url=http://mars.nasa.gov/mer/mission/status_opportunityAll.html|title=All Opportunity Status Updates|access-date=July 1, 2015|archive-url=https://archive.today/20150830191319/http://mars.nasa.gov/mer/mission/status_opportunityAll_2011.html|archive-date=August 30, 2015|url-status=live}}</ref>

{| class="wikitable mw-collapsible mw-collapsed"
|-
! Solar array energy production throughout mission graphs
|-
|
{{Bar graph
| title       = ''Opportunity'' solar array energy production (2013–2014)
| float       = left
| bar_width   = 30
| width_units = em
| data_max    = 800
| label_type  = Date
| data_type   = Watt-hours
| label1      = Sol 3376 (July 23, 2013)
| data1       = 431
| label2      = Sol 3384 (July 31, 2013)
| data2       = 395
| label3      = Sol 3390 (August 6, 2013)
| data3       = 385
| label4      = Sol 3430 (September 16, 2013)
| data4       = 346
| label5      = Sol 3452 (October 9, 2013)
| data5       = 325
| label6      = Sol 3472 (October 30, 2013)
| data6       = 299
| label7      = Sol 3478 (November 5, 2013)
| data7       = 311
| label8      = Sol 3494 (November 21, 2013)
| data8       = 302
| label9      = Sol 3507 (December 5, 2013)
| data9       = 270
| label10     = Sol 3534 (January 1, 2014)
| data10      = 371
| label11     = Sol 3602 (March 12, 2014)
| data11      = 498
| label12     = Sol 3606 (March 16, 2014)
| data12      = 615
| label13     = Sol 3621 (April 1, 2014)
| data13      = 661
| label14     = Sol 3676 (May 27, 2014)
| data14      = 764
| label15     = Sol 3710 (July 1, 2014)
| data15      = 745
| label16     = Sol 3744 (August 5, 2014)
| data16      = 686
| label17     = Sol 3771 (September 2, 2014)
| data17      = 713
| label18     = Sol 3805 (October 7, 2014)
| data18      = 640
| label19     = Sol 3834 (November 6, 2014)
| data19      = 505
| label20     = Sol 3859 (December 1, 2014)
| data20      = 468
}}

{{Bar graph
| title       = ''Opportunity'' solar array energy production (2015–2016)
| float       = left
| bar_width   = 30
| width_units = em
| data_max    = 800
| label_type  = Date
| data_type   = Watt-hours
| label1      = Sol 3894 (January 6, 2015)
| data1       = 438
| label2      = Sol 3921 (February 3, 2015)
| data2       = 484
| label3      = Sol 3948 (March 3, 2015)
| data3       = 545
| label4      = Sol 3982 (April 7, 2015)
| data4       = 559
| label5      = Sol 4010 (May 5, 2015)
| data5       = 508
| label6      = Sol 4055 (June 21, 2015)
| data6       = 477
| label7      = Sol 4084 (July 20, 2015)
| data7       = 432
| label8      = Sol 4119 (August 25, 2015)
| data8       = 404
| label9      = Sol 4153 (September 29, 2015)
| data9       = 352
| label10     = Sol 4180 (October 27, 2015)
| data10      = 332
| label11     = Sol 4201 (November 18, 2015)
| data11      = 376
| label12     = Sol 4221 (December 8, 2015)
| data12      = 407
| label13     = Sol 4246 (January 3, 2016)
| data13      = 449
| label14     = Sol 4275 (February 2, 2016)
| data14      = 498
| label15     = Sol 4303 (March 1, 2016)
| data15      = 585
| label16     = Sol 4337 (April 5, 2016)
| data16      = 650
| label17     = Sol 4377 (May. 16, 2016)
| data17      = 672
| label18     = Sol 4398 (June 7, 2016)
| data18      = 637
| label19     = Sol 4425 (July 5, 2016)
| data19      = 644
| label20     = Sol 4457 (August 7, 2016)
| data20      = 607
| label21     = Sol 4486 (September 5, 2016)
| data21      = 476
| label22     = Sol 4514 (October 4, 2016)
| data22      = 472
| label23     = Sol 4541 (November 1, 2016)
| data23      = 390
| label24     = Sol 4575 (December 6, 2016)
| data24      = 372
}}
{{clear}}

{{Bar graph
| title       = ''Opportunity'' solar array energy production (2017–2018)
| float       = left
| bar_width   = 30
| width_units = em
| data_max    = 800
| label_type  = Date
| data_type   = Watt-hours
| label1      = Sol 4602 (January 3, 2017)
| data1       = 520
| label2      = Sol 4636 (February 7, 2017)
| data2       = 414
| label3      = Sol 4663 (March 6, 2017)
| data3       = 441
| label4      = Sol 4691 (April 4, 2017)
| data4       = 415
| label5      = Sol 4718 (May. 2, 2017)
| data5       = 405
| label6      = Sol 4752 (June 6, 2017)
| data6       = 362
| label7      = Sol 4786 (July 11, 2017)
| data7       = 352
| label8      = Sol 4814 (August 8, 2017)
| data8       = 319
| label9      = Sol 4841 (September 5, 2017)
| data9       = 285
| label10     = Sol 4875 (October 10, 2017)
| data10      = 339
| label11     = Sol 4909 (November 14, 2017)
| data11      = 393
| label12     = Sol 4934 (December 10, 2017)
| data12      = 408
| label13     = Sol 4970 (January 16, 2018)
| data13      = 525
| label14     = Sol 4991 (February 8, 2018)
| data14      = 628
| label15     = Sol 5025 (March 13, 2018)
| data15      = 679
| label16     = Sol 5052 (April 10, 2018)
| data16      = 694
| label17     = Sol 5079 (May 8, 2018)
| data17      = 667
| label18     = Sol 5100 (May 29, 2018)
| data18      = 652
| label19     = Sol 5105 (June 3, 2018)
| data19      = 468
| label20     = Sol 5106 (June 4, 2018)
| data20      = 345
| label21     = Sol 5107 (June 6, 2018)
| data21      = 133
| label22     = Sol 5111 (June 10, 2018)
| data22      = 22

}}
|}
{{clear}}

==Craters, rocks, etc.==
[[File:Burns cliff.jpg|thumb|400px|Burns cliff in Endurance crater]]
[[File:PIA08809 Layers of 'Cape Verde' in 'Victoria Crater'.jpg|thumb|400px|Victoria Crater's Cape Verde]]
Some of the craters MER-B has investigated
*[[Astronomy:Eagle (Meridiani Planum crater)|Eagle crater]], visited 2004, {{convert|72|ft|m|abbr=off|sp=us}} across (diameter)<ref>{{Cite web|url=https://marsmobile.jpl.nasa.gov/multimedia/images/2017/landing-hardware-at-eagle-crater-mars-annotated|title=Mars Mobile|last=NASA|first=JPL|website=marsmobile.jpl.nasa.gov|language=en|access-date=2018-02-15}}{{dead link|date=June 2021|bot=medic}}{{cbignore|bot=medic}}</ref>
*[[Astronomy:Endurance (crater)|Endurance crater]], 2004, {{convert|130|m|ft|abbr=off|sp=us}}  across<ref>{{Cite web|url=https://mars.nasa.gov/mer/gallery/press/opportunity/20040506a.html|title=Mars Exploration Rover|last=mars.nasa.gov|website=mars.nasa.gov|access-date=2018-02-15}}</ref>
**Burn's Cliff<ref name="mars.jpl.nasa.gov">{{Cite web|url=https://mars.jpl.nasa.gov/mer/gallery/press/opportunity/20040506a.html|title=Mars Exploration Rover|last=mars.nasa.gov|website=mars.jpl.nasa.gov|access-date=2018-02-15}}</ref>
*[[Astronomy:Victoria (crater)|Victoria crater]], 2006–9, 800 meters (half a mile) across.<ref name="nasa.gov">{{Cite web|url=https://www.nasa.gov/mission_pages/MRO/multimedia/pia08813.html|title=NASA - 'Victoria Crater' at Meridiani Planum|website=Nasa.gov|language=en|access-date=2018-02-15}}</ref>
**[[Astronomy:Cape Verde (Mars)|Cape Verde]]<ref name="nasa.gov"/>
*[[Astronomy:Endeavour (crater)|Endeavour crater]], since 2011, {{convert|22|km|mi|abbr=on}}<ref name="mars.jpl.nasa.gov"/>
**[[Astronomy:Cape York (Mars)|Cape York]]
**[[Astronomy:Solander Point|Solander Point]], 2013<ref>{{Cite news|url=https://phys.org/news/2013-08-mars-rover-opportunity-edge-solander.html|title=Mars rover Opportunity working at edge of 'Solander'|access-date=2018-02-15}}</ref>
**[[Astronomy:Cape Tribulation (Mars)|Cape Tribulation]]
***Marathon Valley, 2015-2016<ref>{{Cite news|url=https://www.nasa.gov/jpl/pia19151/mars-marathon-valley-overlook|title=Mars 'Marathon Valley' Overlook|last=Perez|first=Martin|date=2015-03-24|work=NASA|access-date=2018-02-15|language=en}}</ref><ref name="mars.nasa.gov2">{{cite web|url=http://mars.nasa.gov/mer/mission/status_opportunityAll.html|title=Mars Exploration Rover Mission: All Opportunity Updates|website=mars.nasa.gov|access-date=7 September 2018}}</ref> 
**Perseverance Valley (aka the Gully), 2017-2018<ref>{{Cite web|url=http://redplanet.asu.edu/?tag=perseverance-valley|title=Perseverance Valley {{!}} Red Planet Report|website=redplanet.asu.edu|language=en-US|access-date=2018-02-15}}</ref>

===Rocks===
[[File:PIA07269-Mars Rover Opportunity-Iron Meteorite.jpg|thumb|200px|The first meteorite found on another planet, the Meridiani Planum Meteorite (aka Heat Shield Rock)<ref>{{cite web|url=https://photojournal.jpl.nasa.gov/catalog/PIA07269|title=Catalog Page for PIA07269|website=photojournal.jpl.nasa.gov|access-date=7 September 2018}}</ref>]]
Some excitement from finding meteorites, new types of rock or signatures detected from orbit, and speculations on ancient alien fossils which as of yet lean towards geological processes.

''Examples''
* [[Astronomy:Block Island meteorite|Block Island]]
* [[Astronomy:Bounce Rock|Bounce Rock]]
* [[Astronomy:El Capitan (Mars)|El Capitan]]
* [[Astronomy:Heat Shield Rock|Heat Shield Rock]] (formally the Meridiani Planum meteorite)<ref>{{Cite web|url=https://www.lpi.usra.edu/meteor/metbull.php?code=32789|title=Meteoritical Bulletin: Entry for Meridiani Planum|website=Lpi.usra.edu|access-date=2018-02-16}}</ref>
* [[Astronomy:Last Chance (Mars)|Last Chance]]
* [[Astronomy:Mackinac Island meteorite|Mackinac Island]]
* [[Astronomy:Oileán Ruaidh (Mars rock)|Oileán Ruaidh]]
* [[Astronomy:Shelter Island meteorite|Shelter Island]]
*Jelly Doughnut (aka Pinnacle Island)<ref>{{cite web|url=https://www.nasa.gov/press/2014/february/mars-rover-heads-uphill-after-solving-doughnut-riddle|title=Mars Rover Heads Uphill After Solving 'Doughnut' Riddle|first=Karen|last=Northon|date=14 February 2014|website=Nasa.gov|access-date=7 September 2018}}</ref>

Some other famous targets are the "blueberries" (2004) and "newberries", aka Kirkwood spheres (2012)<ref>{{Cite news|url=https://mars.nasa.gov/resources/6944/|title=Martian 'Blueberries'|last=mars.nasa.gov|work=Mars planet facts news & images {{!}} NASA Mars rover + mission info|access-date=2018-02-16|language=en}}</ref><ref>{{Cite news|url=http://www.scpr.org/blogs/news/2012/12/04/11389/nasa-opportunity-rover-clay-curiosity-mars-life/|title=Photos: NASA's Opportunity rover finds 'newberries' on Mars, may contain clay|date=2012-12-04|work=Southern California Public Radio|access-date=2018-02-16}}</ref>

See also [[Astronomy:List of rocks on Mars#Opportunity|List of rocks on Mars]] and List of surface features of Mars imaged by ''Opportunity''
{{clear}}

== Images ==
The rover could take pictures with its different cameras, but only the PanCam camera had the ability to photograph a scene with different color filters. The panorama views are usually built up from PanCam images. By February 3, 2018, ''Opportunity'' had returned 224,642 pictures.<ref>{{cite web|url=http://marsrovers.jpl.nasa.gov/gallery/all/opportunity.html|title=Mars Exploration Rover|first=Brian|last=Truong|work=nasa.gov|access-date=November 20, 2013|archive-url=https://web.archive.org/web/20131110232401/http://marsrovers.jpl.nasa.gov/gallery/all/opportunity.html|archive-date=November 10, 2013|url-status=live}}</ref><ref>{{cite web|url=https://www.space.com/39728-mars-rover-opportunity-5000-martian-days.html|title=Opportunity Rover Celebrates 5,000 Days on Mars|website=Space.com|date=February 16, 2018|access-date=February 17, 2018|archive-url=https://web.archive.org/web/20180217012443/https://www.space.com/39728-mars-rover-opportunity-5000-martian-days.html|archive-date=February 17, 2018|url-status=live}}</ref>

=== Views ===
{{Clear}}
{{Gallery|align=center|Challenger Memorial Station At Meridiani Planum.jpg|''Opportunity'' images the empty lander, the ''Challenger Memorial Station''
|Pia16128-640-MatijevicHill-EnduranceCrater-20120928.jpg|Pancam view from August 2012 (Sol 3058)
|Pia17271 sol3355-rearhaz 3.jpg|Solander Point is visible on the horizon; foreground shows Botany Bay<!---there is about {{convert|3.3|ft|m|order=flip|abbr=on}} between the wheels---><ref>{{cite web|url=http://www.nasa.gov/mission_pages/mer/multimedia/pia17271.html|title=Opportunity's View in 'Botany Bay' Toward 'Solander Point'|work=NASA|date=July 2, 2013|access-date=August 14, 2013|archive-url=https://web.archive.org/web/20130806045414/http://www.nasa.gov/mission_pages/mer/multimedia/pia17271.html|archive-date=August 6, 2013|url-status=live}}</ref>
|Opportunity in Endurance Crater (cropped).jpg|''Opportunity'' in [[Astronomy:Endurance (crater)|Endurance crater]] (simulated view based on actual imagery)
|PIA22928-MarsOpportunityRover-BackTrackView-20100804.jpg|BackTrack view (August 2010)
}}

=== Panoramas ===
A selection of panoramas from the mission:
{{wide image|Fram Crater in color.jpg|800px|Panorama of Fram crater (Sol {{age in sols|2004|01|25|2004|04|24}}, April 23, 2004)}}
{{wide image|Naturaliste crater site A47 cyl-med.jpg|800px|Panorama of [[Astronomy:Naturaliste (crater)|Naturaliste crater]], in foreground (March 1, 2005)}}
{{wide image|Erebus 360 L257atc-B652R1.jpg|800px|Panorama taken on the rim of Erebus crater. The rover's solar panels are seen on the lower half (December 5, 2005).}}
{{wide image|PIA19109-MarsOpportunityRover-EndeavourCrater-CapeTribulation-20150122.jpg|800px|Panorama of the rim of [[Astronomy:Endeavour (crater)|Endeavour crater]] from Cape Tribulation (January 22, 2015)}}
{{wide image|Spirit-st-louis-mars-crater-opportunity-rover-labeled-false-color-PIA19394wiki.jpg|800px|Panorama of Spirit of St. Louis crater, a shallow crater about {{convert|110|ft|order=flip|sp=us}} long and {{convert|80|ft|order=flip|sp=us}} across. In its center is Lindbergh Mound, about 2 to 3 meters (6 to 10 ft) high. (annotated; [[False color|false color]]; May 2015).<ref>{{cite web|url=http://mars.nasa.gov/mer/gallery/press/opportunity/20150521a.html|title=Mars Exploration Rover Mission: Press Release Images: Opportunity|last=mars.nasa.gov|work=nasa.gov|access-date=January 5, 2017|archive-url=https://web.archive.org/web/20161202044216/http://mars.nasa.gov/mer/gallery/press/opportunity/20150521a.html|archive-date=December 2, 2016|url-status=live}}</ref>}}
{{wide image|PIA21707-Mars-OpportunityRover-OrionCrater-April2017.jpg|800px|Panorama of Orion crater (enhanced color; April 26, 2017)<ref name="NASA-20170616">{{cite web |last1=Webster |first1=Guy |last2=Cantillo |first2=Laurie |last3=Brown |first3=Dwayne |title=Martian Crater Provides Reminder of Apollo Moonwalk |url=https://www.jpl.nasa.gov/news/news.php?feature=6873 |date=June 16, 2017 |work=[[Organization:NASA|NASA]] |access-date=June 16, 2017 |archive-url=https://web.archive.org/web/20170617203639/https://www.jpl.nasa.gov/news/news.php?feature=6873 |archive-date=June 17, 2017 |url-status=live |df=mdy-all }}</ref>}}
{{wide image|PIA21497capetrib.jpg|800px|''Opportunity'' looks north as it departs Cape Tribulation, its southern end shown here (April 2017)<ref>{{cite web|url=https://photojournal.jpl.nasa.gov/catalog/PIA21497|title=Catalog Page for PIA21497|website=photojournal.jpl.nasa.gov|access-date=September 7, 2018|archive-url=https://web.archive.org/web/20180819055225/https://photojournal.jpl.nasa.gov/catalog/PIA21497|archive-date=August 19, 2018|url-status=live}}</ref>}}
{{clear}}
{{wide image|PIA21723-MarsOpportunityRover-PerseveranceValley-20170619.jpg|800px|Panorama above Perseverance Valley (June 19, 2017)}}
{{wide image|22341_PIA22908-MarsOpportunityRover-LastPanorama-Spring2018-20190312.jpg|800px|Final panorama image taken by ''Opportunity'' between May and June 2018 prior to being disabled by the dust storms.}}
{{wide image|PIA23247-TestOpportunityRoverOnEarth-Dusty-20180906.jpg|800px|Panorama of the ''Opportunity'' rover team by "Dusty" – a testing replica of the rover on Earth (September 6, 2018).}}

=== Close-up images ===
{{Clear}}
{{Gallery|align=center|File:Blueberries eagle.gif|[[Astronomy:List of rocks on Mars#2004 – Opportunity rover (MER-B)|"Blueberries"]] (hematite spheres) on a rocky outcrop at Eagle Crater. Note the merged triplet in the upper left.
|File:PIA16139 Puzzling Little Martian Spheres That Don't Taste Like 'Blueberries'.tif|[[Astronomy:List of rocks on Mars#2004 – Opportunity rover (MER-B)|"Blueberries"]]: This view displays an area about 6 centimeters across. It was taken at an outcrop named "Kirkwood" at the Cape York on the rim of Endeavour crater on Mars. The spheres seen here are about 3 millimeters in diameter. The Microscopic Imager took this image at 3064 sol.
|File:PIA23245-MarsOpportunityRover-Rock-JornadaDelMuerto-20190604.jpg|[[Astronomy:List of rocks on Mars#2004 – Opportunity rover (MER-B)|"Jornada del Muerto"]] - rock found in Perseverance Valley<br />(posted June 4, 2019)
}}

=== From orbit ===
{{Clear}}
{{Gallery|align=center|File:Oppland02a.jpg|''Opportunity'' landing site, lander, as imaged by [[Astronomy:Mars Reconnaissance Orbiter|MRO]]<br /> (November 29, 2006)
|File:Opportunity landing site4.jpg|''Opportunity'' landing site, parachute and backshell, as imaged by [[Astronomy:Mars Reconnaissance Orbiter|MRO]] (November 29, 2006)
|File:Oppland03a.jpg|''Opportunity'' landing site, heat shield, as imaged by [[Astronomy:Mars Reconnaissance Orbiter|MRO]]<br /> (November 29, 2006)
|File:Opportunity Rover by HiRISE.jpg|''Opportunity'' (circled) as seen by HiRISE on January 29, 2009. Endeavour Crater is {{convert|17|km|mi|abbr=on}} away.
|File:Opportunity at Victoria Crater from Mars reconnaissance orbiter.jpg|The Mars Exploration Rover ''Opportunity'' at the rim of Victoria crater as photographed from the ''[[Astronomy:Mars Reconnaissance Orbiter|Mars Reconnaissance Orbiter]]'''s HiRISE camera.<ref>{{Cite web|url=https://www.nasa.gov/mission_pages/MRO/multimedia/pia08812.html|title=NASA - The Opportunity Rover at 'Victoria Crater'|website=www.nasa.gov}}</ref>
}}

=== Area maps ===

{{Gallery|align=center|File:Opportunity rover's landing site.jpg|''Opportunity'' landing ellipse in [[Astronomy:Meridiani Planum|Meridiani Planum]], near Endeavour crater
|File:PIA13708westernrimgeo.jpg|This geological map created from MRO's CRISM instrument data from orbit gives an overview of some of the geology in the area MER-B is exploring
|File:Meridiani Planum PIA13704.jpg|This map, color-coded for minerals (CRISM) and annotated, shows the rover's traverse up to about 2010 with some nearby features noted.
}}

=== Traverse maps ===
An example of a rover traverse map featuring a line showing path of the rover, and mission sols, which are Mars days counted from its landing and typical of Mars surface mission time reporting. Topographic lines and various feature names are also common.

{{Gallery|align=center|File:MERB Sol2710 1merbarrives.jpg|''Opportunity'' arrives at Endeavour crater, Sol 2710
|File:MERB 528 2.jpg|''Opportunity'' traverse map, from Sol 405 to 528 (2005)
|Image:MERB Sol2055 1.jpg|''Opportunity'' traverse map, from sol 1 (2004) through sol 2055 (2009)
|Image:MERB Sol2442 PIA13598 br.jpg|Annotated ''Opportunity'' traverse map as of December 8, 2010 (Sol 2442)
|Image:Sol3689.jpg|Annotated ''Opportunity'' traverse map as of June 11, 2014 (Sol 3689)
|Image:CapeYork-Map-2014.png|''Opportunity''{{'}}s traverse on Cape York from Sol 2678 to Sol 3317 with some additional annotations of the main features.
|Image:Oppymap4836sept17.png|Traverse map up to 4836 (September 12, 2017)<ref>{{cite web|url=https://mars.nasa.gov/mer/mission/tm-opportunity/opportunity-sol4836.html|title=Mars Exploration Rover|website=mars.nasa.gov}}</ref>
}}
{{clear}}
{{Features and artificial objects on Mars}}

==See also==
{{div col|colwidth=30em}}
* ''Curiosity'' rover timeline
* ''[[Astronomy:InSight|InSight]]''
* ''[[Astronomy:Mars Express|Mars Express]]''
* [[Astronomy:Timeline of Mars 2020|''Perseverance'' rover timeline]]
* [[Engineering:Sojourner (rover)|''Sojourner'' rover timeline]]
* [[Engineering:Spirit (rover)#Mission timeline|''Spirit'' rover timeline]]
{{div col end}}

==References==
{{Reflist}}

==External links==
* [http://mars.nasa.gov/mer/home/index.html NASA/JPL Mission page]
* [https://mars.nasa.gov/mer/gallery/all/opportunity.html MER-B Gallery]

{{Features visited by Opportunity}}
{{NASAMER}}
{{NASA space program}}
{{Mars spacecraft}}

[[Category:Spaceflight timelines|Opportunity]]
[[Category:Exploration of Mars]]

{{Sourceattribution|Timeline of Opportunity}}