View source for Astronomy:MAVEN

{{Short description|NASA Mars orbiter}}
{{Infobox spaceflight
| name              = Mars Atmosphere and Volatile Evolution
| names_list        = {{plainlist|
* MAVEN
* Mars Atmosphere and Volatile Evolution
}}
| image             = MAVEN spacecraft model.png
| image_caption     = Artist's rendering of the MAVEN spacecraft bus
| image_size        = 300px

| mission_type      = Mars atmospheric research
| operator          = [[Organization:NASA|NASA]]
| COSPAR_ID         = 2013-063A
| SATCAT            = 39378
| website           = {{oweb|https://www.nasa.gov/mission_pages/maven/main/index.html}}
| mission_duration  = 2 years (planned)<br/>Science phase extended indefinitely<br/>{{time interval|23 September 2014|show=ymd|sep=,}} (in progress)
| manufacturer      = [[Company:Lockheed Martin Space|Lockheed Martin Space Systems]]
| dry_mass          = {{cvt|809|kg}}
| launch_mass       = {{cvt|2454|kg}}<ref>{{cite web|url=https://solarsystem.nasa.gov/missions/maven/in-depth/ |title=MAVEN |publisher=NASA's Solar System Exploration website |access-date=December 1, 2022}}</ref>
| payload_mass      = {{cvt|65|kg}}
| dimensions        = 2.3 m × 2.3 m × 2 m
| power             = 1135 watts<ref name="MAVEN">[http://mars.jpl.nasa.gov/files/resources/MAVENPresentation2013.pdf 'MAVEN' Mission PowerPoint] {{PD-notice}}</ref>

| launch_date       = 18 November 2013, 18:28:00 [[Physics:Coordinated Universal Time|UTC]]
| launch_rocket     = [[Engineering:Atlas V|Atlas V]] 401 (AV-038)
| launch_site       = Cape Canaveral, SLC-41
| launch_contractor = [[Company:United Launch Alliance|United Launch Alliance]]

| last_contact      = 
| decay_date        = 

| orbit_reference   = [[Astronomy:Areocentric orbit|Areocentric orbit]]
| orbit_regime      = [[Astronomy:Elliptic orbit|Elliptic orbit]]
| orbit_periapsis   = {{cvt|150|km}}
| orbit_apoapsis    = {{cvt|6200|km}}
| orbit_inclination = 75°
| orbit_period      = 4.5 hours
| apsis             = areon

| interplanetary = {{Infobox spaceflight/IP
  | type            = orbiter
  | object          = [[Astronomy:Mars|Mars]]
  | orbits          = 
  | arrival_date    = 22 September 2014, 02:24 UTC <ref name="NASA-20140921">{{cite web|last1=Brown|first1=Dwayne|last2=Neal-Jones|first2=Nancy|last3=Zubritsky|first3=Elizabeth|title=NASA's Newest Mars Mission Spacecraft Enters Orbit around Red Planet|url=http://www.jpl.nasa.gov/news/news.php?release=2014-318|date=September 21, 2014|publisher=NASA|access-date=September 22, 2014}} {{PD-notice}}</ref><br/><small>[[Astronomy:Timekeeping on Mars|MSD]] 50025 08:07 [[Astronomy:Timekeeping on Mars|AMT]]</small>
}}

| instruments       = 

| insignia          = MAVEN Mission Logo.png
| insignia_caption  = Maven mission logo
| insignia_size     = 200px

| programme         = '''[[Astronomy:Mars Scout Program|Mars Scout Program]]'''
| previous_mission  = ''[[Engineering:Phoenix (spacecraft)|Phoenix]]''
| next_mission      = [[Physics:Mars Exploration Ice Mapper|International-Mars Ice Mapper]]
}}
'''MAVEN''' is a [[Organization:NASA|NASA]] spacecraft orbiting [[Astronomy:Mars|Mars]] to study the loss of that planet's atmospheric gases to space, providing insight into the history of the planet's climate and water.<ref name="factsheet">{{cite web|title=MAVEN Fact Sheet|url=https://mars.nasa.gov/files/mep/MAVEN-Fact-Sheet.pdf}} {{PD-notice}}</ref> The name is an acronym for "'''Mars Atmosphere and Volatile Evolution'''" while the word ''maven''  also denotes "a person who has special knowledge or experience; an expert".<ref>{{cite tweet |user=maven2mars |number=394917251918618624 |date=October 28, 2013 |title=Fittingly, from #Hebrew, via #Yiddish, a "maven" is a trusted expert who understands and seeks to pass knowledge on to others. #MAVEN #Mars |access-date=7 March 2015}}</ref><ref>{{cite book|url=https://archive.org/details/americanheritage0000unse_a1o7/page/1082|title=American Heritage Dictionary of the English Language|date=2000 |publisher=Houghton Mifflin|isbn=0-395-82517-2|edition=4th|location=Boston|page=[https://archive.org/details/americanheritage0000unse_a1o7/page/1082 1082]|quote=A person who has special knowledge or experience; an expert.|access-date=7 March 2015|url-access=registration}}</ref> MAVEN was launched on an [[Engineering:Atlas V|Atlas V]] rocket from {{wipe|Cape Canaveral Air Force Station}}, Florida, on 18 November 2013 [[UTC]] and went into orbit around Mars on 22 September 2014 [[UTC]]. The mission is the first by [[Organization:NASA|NASA]] to study the Mars atmosphere. The probe is analyzing the planet's upper atmosphere and ionosphere to examine how and at what rate the [[Astronomy:Solar wind|solar wind]] is stripping away volatile compounds.

The [[Principal investigator|principal investigator]] for the mission is [[Biography:Shannon Curry|Shannon Curry]] at the [[Organization:University of California, Berkeley|University of California, Berkeley]]. She took over from [[Biography:Bruce Jakosky|Bruce Jakosky]] of the Laboratory for Atmospheric and Space Physics at the [[Organization:University of Colorado Boulder|University of Colorado Boulder]], who proposed and led the mission until 2021.<ref name="factsheet"/> The project cost $582.5 million to build, launch, and operate through its two-year prime mission.<ref name="maven-co">{{cite web|title=The Planetary Exploration Budget Dataset |url=https://docs.google.com/spreadsheets/d/12frTU01gfT1CXGWFimN3whf4348F_r3XolTqBt02OyM/edit#gid=1774841387|website=planetary.org|publisher=The Planetary Society|access-date=November 2, 2020}}</ref>

== Pre-launch ==
[[File:MAVEN Launch2-full.jpg|thumb|upright=1.2|left|MAVEN – Atlas V ignition (18 November 2013)]]

Proposed in 2006, the mission was the second of [[Organization:NASA|NASA]]'s [[Astronomy:Mars Scout Program|Mars Scout Program]], which had previously yielded [[Engineering:Phoenix (spacecraft)|Phoenix]]. It was selected for development for flight in 2008.<ref name=":1">{{cite journal|last1=Jakosky|first1=B. M.|last2=Lin|first2=R. P.|last3=Grebowsky|first3=J. M.|last4=Luhmann|first4=J. G.|last5=Mitchell|first5=D. F.|last6=Beutelschies|first6=G.|last7=Priser|first7=T. |last8=Acuna|first8=M.|last9=Andersson|first9=L.|last10=Baird|first10=D.|last11=Baker|first11=D.|date=December 2015|title=The Mars Atmosphere and Volatile Evolution (MAVEN) Mission |url=http://link.springer.com/10.1007/s11214-015-0139-x|journal=Space Science Reviews|volume=195|issue=1–4|pages=3–48|doi=10.1007/s11214-015-0139-x|bibcode=2015SSRv..195....3J|s2cid=18698391|issn=0038-6308}}</ref>

On 2 August 2013, the MAVEN spacecraft arrived at Kennedy Space Center, in Florida to begin launch preparations.<ref>{{cite web|url=http://www.nasa.gov/press/2013/august/nasa-begins-launch-preparations-for-next-mars-mission/index.html|title=NASA Begins Launch Preparations for Next Mars Mission|access-date=August 6, 2013|date=August 5, 2013|publisher=NASA}} {{PD-notice}}</ref>

On 1 October 2013, only seven weeks before launch, a government shutdown caused suspension of work for two days and initially threatened to force a 26-month postponement of the mission. With the spacecraft nominally scheduled to launch on 18 November 2013, a delay beyond 7 December 2013 would have caused MAVEN to miss the launch window as [[Astronomy:Mars|Mars]] moved too far out of alignment with the [[Astronomy:Earth|Earth]].<ref>{{cite web|title=A Government Shutdown Could Delay MAVEN's Launch to Mars|url=https://www.planetary.org/articles/20130930-a-government-shutdown-could-delay-maven|first=Casey |last=Dreier |date=September 30, 2013|publisher=The Planetary Society|access-date=December 11, 2022}}</ref>

However, two days later, on 3 October 2013, a public announcement was made that NASA had deemed the 2013 MAVEN launch so essential to ensuring future communication with current NASA assets on Mars — the rovers ''[[Engineering:Opportunity (rover)|Opportunity]]'' and ''[[Engineering:Curiosity (rover)|Curiosity]]'' — that emergency funding was authorized to restart spacecraft processing in preparation for an on-time launch.<ref>{{cite web |last=Jakosky|first=Bruce|url=http://lasp.colorado.edu/home/maven/2013/10/03/maven-reactivation-status-update/|title=MAVEN reactivation status update|publisher=Laboratory of Atmospheric and Space Physics |date=September 20, 2013|access-date=October 4, 2013}}</ref>

== Objectives ==
[[File:Targeting Mars.ogg|thumb|upright=1.3|right|alt=MAVEN's interplanetary journey to Mars|MAVEN's interplanetary journey to Mars]]

Features on Mars that resemble dry [[Earth:Stream bed|riverbeds]] and the discovery of [[Earth:Mineral|mineral]]s that form in the [[Astronomy:Water on Mars|presence of water]] indicate that Mars once had a [[Astronomy:Atmosphere of Mars|dense enough atmosphere]] and was warm enough for [[Astronomy:Water on Mars|liquid water]] to flow on the surface. However, that thick atmosphere was somehow lost to space. Scientists suspect that over millions of years, Mars lost 99% of its atmosphere as the [[Astronomy:Planetary core|planet's core]] cooled and its magnetic field decayed, allowing the [[Astronomy:Solar wind|solar wind]] to sweep away most of the water and volatile compounds that the atmosphere once contained.<ref name=sun-steals>[http://www.nasa.gov/mission_pages/maven/news/confirmation.html MAVEN Mission to Investigate How Sun Steals Martian Atmosphere] By Bill Steigerwald (October 5, 2010) {{PD-notice}}</ref>
<!-- [[File:MarsMaven-Orbit-Insertion-142540-20140917.png|thumb|upright=1.2|right|Artist's concept of the insertion of the MAVEN orbiter around the planet Mars (17 September 2014)]] -->

The goal of MAVEN is to determine the history of the loss of atmospheric gases to space, providing answers about [[Astronomy:Climate of Mars|Martian climate]] evolution. By measuring the rate with which the atmosphere is currently escaping to space and gathering enough information about the relevant processes, scientists will be able to infer how [[Astronomy:Atmosphere of Mars|the planet's atmosphere]] evolved over time. The MAVEN mission's primary scientific objectives are:

* Measure the composition and structure of the upper atmosphere and ionosphere today, and determine the processes responsible for controlling them
* Measure the rate of loss of gas from the top of the atmosphere to space, and determine the processes responsible for controlling them
* Determine properties and characteristics that will allow us to extrapolate backwards in time to determine the integrated loss to space over the four-billion-year history recorded in the geological record.<ref name=":1"/>

== Timeline ==
MAVEN launched from the Cape Canaveral Air Force Station (CCAFS) on 18 November 2013, using an [[Engineering:Atlas V|Atlas V]] 401 [[Engineering:Launch vehicle|launch vehicle]].<ref>{{cite web|title=MAVEN PressKit |url=https://lasp.colorado.edu/home/maven/files/2011/02/MAVEN_PressKit_Final.pdf}}</ref><ref name=":2"/> It reached Mars on 22 September 2014, and was inserted into an [[Astronomy:Elliptic orbit|elliptic orbit]] approximately {{cvt|6200|km}} by {{cvt|150|km}} [[Astronomy:Areocentric orbit|above the planet's surface]].<ref name=":2">{{cite web|title=MAVEN Science Orbit|url=https://lasp.colorado.edu/home/maven/science/science-orbit/|access-date=2020-09-18}}</ref>

In October 2014, as the spacecraft was being fine-tuned to start its primary science mission, the comet Siding Spring was also performing a close flyby of Mars. The researchers had to maneuver the craft to mitigate harmful effects of the comet, but while doing so, were able to observe the comet and perform measurements on the composition of expelled gases and dust.<ref>{{cite web |last=mars.nasa.gov|title=NASA's MAVEN Studies Passing Comet and Its Effects|url=https://mars.nasa.gov/news/nasas-maven-studies-passing-comet-and-its-effects|access-date=2020-09-18|publisher=NASA's Mars Exploration Program}} {{PD-notice}}</ref>

On 16 November 2014, investigators completed MAVEN's commissioning activities and began its primary science mission, scheduled to last one year.<ref>{{cite web|last=mars.nasa.gov|title=MAVEN Completes Commissioning And Begins Its Primary Science Mission|url=https://mars.nasa.gov/news/maven-completes-commissioning-and-begins-its-primary-science-mission|access-date=2020-09-18|website=NASA's Mars Exploration Program}} {{PD-notice}}</ref> During that time, MAVEN had observed a nearby comet, measured how volatile gases are swept away by solar wind, and performed four "deep dips" down to the border of the upper and lower atmospheres to better characterize the planet's entire upper atmosphere.<ref>{{cite web|last=mars.nasa.gov|title=NASA's MAVEN Celebrates One Year at Mars|url=https://mars.nasa.gov/news/nasas-maven-celebrates-one-year-at-mars|access-date=2020-09-18|website=NASA's Mars Exploration Program}} {{PD-notice}}</ref> In June 2015, the science phase was extended through September 2016, allowing MAVEN to observe the Martian atmosphere through the entirety of the planet's seasons.<ref name=":0"/>

On 3 October 2016, MAVEN completed one full Martian year of scientific observations. It had been approved for an additional 2-year extended mission through September 2018. All spacecraft systems were still operating as expected.<ref>{{cite web|title=MAVEN Celebrates One Mars Year of Science|date=3 October 2016 |url=https://lasp.colorado.edu/home/maven/2016/10/03/maven-celebrates-one-mars-year-of-science/|access-date=2020-09-25}}</ref>

In March 2017, MAVEN's investigators had to perform a previously unscheduled maneuver to avoid colliding with [[Astronomy:Phobos (moon)|Phobos]] the following week.<ref>{{cite web|title=MAVEN Steers Clear of Mars Moon Phobos|date=2 March 2017 |url=https://lasp.colorado.edu/home/maven/2017/03/02/maven-steers-clear-of-mars-moon-phobos/|access-date=2020-09-25}}</ref>

On 5 April 2019, the navigation team completed a two-month [[Astronomy:Aerobraking|aerobraking]] maneuver to lower MAVEN's orbit and enable it to better serve as a communications relay for current landers as well as the rover ''[[Engineering:Perseverance (rover)|Perseverance]]''. This new elliptic orbit is approximately {{cvt|4500|km}} by {{cvt|130|km}}. With 6.6 orbits per Earth day, the lower orbit allows more frequent communication with rovers.<ref name=":3">{{cite web|title=MAVEN Uses Red Planet's Atmosphere to Change Orbit|date=5 April 2019 |url=https://lasp.colorado.edu/home/maven/2019/04/05/maven-uses-red-planets-atmosphere-to-change-orbit/|access-date=2020-09-25}}</ref>

As of September 2020, the spacecraft is continuing its science mission as well, with all instruments still operating and with enough fuel to last at least until 2030.<ref name=":3"/>

On August 31, 2021, Shannon Curry became the Principal Investigator of the mission.<ref>{{Cite web|last=Gran|first=Rani|date=September 9, 2021|title=NASA Mars Mission Begins a New Chapter of Science With a New Leader|url=https://www.nasa.gov/feature/goddard/2021/nasa-mars-mission-begins-a-new-chapter-of-science-with-a-new-leader}}</ref>

NASA became aware of failures in the MAVEN's inertia measurement units (IMU) in late 2021, necessary for the probe to maintain its orbit; having already moved from the main IMU to the backup one in 2017, they saw the backup ones showing signs of failure. In February 2022, both IMUs had appeared to lost the ability to perform its measurement properly. After doing a heartbeat termination to restore the use of the backup IMU, NASA engineers set to reprogram MAVEN to use an "all stellar" mode using star positions to maintain its altitude, eliminating the reliance on the IMUs. This was put into place in April 2022 and completed by May 28, 2022, but during this period, MAVEN could not be used for scientific observations or to relay communications to Earth from the rovers ''Curiosity'' and ''Perseverance'' and the ''Insight'' lander. Reduced communication was handled by other Mars orbiters.<ref>{{cite web |url=https://www.space.com/nasa-mars-spacecraft-maven-nearly-lost |title=NASA's Mars MAVEN spacecraft spent 3 months on the brink of disaster |first=Meghan |last=Bartels |date=June 1, 2022 |accessdate=June 2, 2022 |work=Space.com }}</ref>

[[File:Animation of MAVEN trajectory around Sun.gif|300px|thumb|left|Animation of MAVEN's trajectory around the Sun<br>{{legend2|magenta| MAVEN}}{{·}}{{legend2| Lime|Mars}}{{·}}{{legend2| RoyalBlue|Earth}}{{·}}{{legend2| Yellow|Sun}}]]
{|
|-
||[[File:Animation of MAVEN trajectory around Mars.gif |300px|thumb |center|Animation of MAVEN{{'s}} trajectory around Mars from September 22, 2014 to September 22, 2016<br />{{legend2|magenta| MAVEN}}{{·}}{{legend2| Lime|Mars}}]]
||[[File:MavenAerobrakingDiagram-20190211.jpg|thumb|upright=1.6|center|<div style="text-align:center">MAVEN aerobraking to a lower orbit – in preparation for the Mars 2020 mission (February 2019)</div>]]
|}
{{clear}}

== Spacecraft overview ==
MAVEN was built and tested by [[Company:Lockheed Martin Space|Lockheed Martin Space Systems]]. Its design is based on those of ''[[Astronomy:Mars Reconnaissance Orbiter|Mars Reconnaissance Orbiter]]'' and ''[[Astronomy:2001 Mars Odyssey|2001 Mars Odyssey]]''. The orbiter has a cubical shape of about {{cvt|2.3|×|2.3|×|2|m}} high,<ref>[http://www.nasa.gov/mission_pages/maven/news/maven-structure.html MAVEN Mission Primary Structure Complete] ''NASA'' (26 September 2011) {{PD-notice}}</ref> with two [[Physics:Solar panels on spacecraft|solar arrays]] that hold the [[Physics:Magnetometer|magnetometer]]s on both ends. The total length is {{cvt|11.4|m}}.<ref>[http://www.nasa.gov/sites/default/files/files/MAVENFactSheet_Final20130610.pdf MAVEN – Facts] {{PD-notice}}</ref>

=== Relay telecommunications ===
[[File:Pia17952 electra transceiver dsc09326 0.jpg|thumb|upright=1.2|right|MAVEN's Electra UHF radio transceiver]]

NASA's [[Organization:Jet Propulsion Laboratory|Jet Propulsion Laboratory]] provided an [[Engineering:Electra (radio)|Electra]] ultra high frequency ([[Physics:Ultra high frequency|UHF]]) relay radio payload which has a data return rate of up to 2048 kbit/s.<ref>{{cite web|url=http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/7832/1/03-2150.pdf|title=The Electra Proximity Link Payload for Mars Relay Telecommunications and Navigation|access-date=January 11, 2013|date=September 29, 2003 |publisher=NASA|url-status=dead|archive-url=https://web.archive.org/web/20130502170707/http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/7832/1/03-2150.pdf|archive-date=May 2, 2013}} {{PD-notice}}</ref> The highly elliptical orbit of the MAVEN spacecraft may limit its usefulness as a relay for operating landers on the surface, although the long view periods of MAVEN's orbit have afforded some of the largest relay data returns to date of any Mars orbiter.<ref>[http://www.jpl.nasa.gov/news/news.php?feature=4370 Newest NASA Mars Orbiter Demonstrates Relay Prowess] NASA 10 November 2014 {{PD-notice}}</ref> During the mission's first year of operations at Mars — the primary science phase — MAVEN served as a backup relay orbiter. In the extended mission period of up to ten years, MAVEN will provide UHF relay service for present and future Mars rovers and landers.<ref name=":0">[http://lasp.colorado.edu/home/maven/about/faqs/ MAVEN – FAQ]</ref>

=== Scientific instruments ===
[[File:Main swea5 full.jpg|thumb|upright=1.2|right|Solar Wind Electron Analyzer (SWEA) measures solar wind and ionosphere electrons.]]
[[File:MAVEN — Magnetometer.jpg|thumb|upright=1.2|right|Magnetometer of MAVEN]]
[[File:Solar Energetic Particles.jpg|thumb|upright=1.2|right|SEP instrument of MAVEN]]

The [[Organization:University of Colorado Boulder|University of Colorado Boulder]], [[Organization:University of California, Berkeley|University of California, Berkeley]], and [[Organization:Goddard Space Flight Center|Goddard Space Flight Center]] each built a suite of instruments for the spacecraft, and they include:<ref>{{cite web |url=http://lasp.colorado.edu/home/maven/science/instrument-package/|title=MAVEN – Instruments|access-date=October 25, 2012|year=2012|publisher=University of Colorado Boulder}}</ref>

Built by the University of California, Berkeley Space Sciences Laboratory:

* Solar Wind Electron Analyzer (SWEA)<ref>{{cite journal|last1=Mitchell|first1=D. L.|last2=Mazelle|first2=C.|last3=Sauvaud|first3=J.-A.|last4=Thocaven|first4=J.-J.|last5=Rouzaud|first5=J.|last6=Fedorov|first6=A. |last7=Rouger|first7=P.|last8=Toublanc|first8=D.|last9=Taylor|first9=E.|last10=Gordon|first10=D.|last11=Robinson|first11=M.|date=2016-04-01|title=Solar Wind Electron Analyzer for MAVEN |url=https://doi.org/10.1007/s11214-015-0232-1|journal=Space Science Reviews|volume=200|issue=1|pages=495–528|doi=10.1007/s11214-015-0232-1|s2cid=14670274|issn=1572-9672}}</ref> – measures [[Astronomy:Solar wind|solar wind]] and ionosphere [[Physics:Electron|electron]]s. The goals of SWEA with respect to MAVEN are to deduce magneto-plasma topology in and above the ionosphere, and to measure atmospheric electron impact ionization effects.<ref>{{cite web |title=Solar Wind Electron Analyzer (SWEA)|url=https://lasp.colorado.edu/home/maven/science/instrument-package/swea/|access-date=2020-10-02}}</ref>
* Solar Wind Ion Analyzer (SWIA)<ref>{{cite journal|last1=Halekas|first1=J. S.|last2=Taylor|first2=E. R.|last3=Dalton|first3=G.|last4=Johnson|first4=G.|last5=Curtis|first5=D. W.|last6=McFadden|first6=J. P. |last7=Mitchell|first7=D. L.|last8=Lin|first8=R. P.|last9=Jakosky|first9=B. M.|date=2015-12-01|title=Solar Wind Ion Analyzer for MAVEN|url=https://doi.org/10.1007/s11214-013-0029-z|journal=Space Science Reviews |volume=195|issue=1|pages=125–151|doi=10.1007/s11214-013-0029-z|bibcode=2015SSRv..195..125H|s2cid=16917187|issn=1572-9672}}</ref> – measures solar wind and [[Astronomy:Magnetosheath|magnetosheath]] ion density and velocity. The SWIA therefore characterizes the nature of solar wind interactions within the upper atmosphere.
* SupraThermal And Thermal Ion Composition (STATIC)<ref>{{cite journal|last1=McFadden|first1=J. P.|last2=Kortmann|first2=O.|last3=Curtis|first3=D.|last4=Dalton|first4=G.|last5=Johnson|first5=G.|last6=Abiad |first6=R.|last7=Sterling|first7=R.|last8=Hatch|first8=K.|last9=Berg|first9=P.|last10=Tiu|first10=C.|last11=Gordon|first11=D.|date=2015-12-01|title=SupraThermal and Thermal Ion Composition (STATIC) Instrument for MAVEN|journal=Space Science Reviews|volume=195|issue=1|pages=199–256|doi=10.1007/s11214-015-0175-6|issn=1572-9672|doi-access=free}}</ref> – measures thermal ions to moderate-energy escaping ions. This provides information on the current ion escape rates from the atmosphere and how rates change during various atmospheric events.
* Solar Energetic Particle (SEP)<ref>{{cite journal|last1=Larson|first1=Davin E.|last2=Lillis|first2=Robert J.|last3=Lee|first3=Christina O.|last4=Dunn|first4=Patrick A.|last5=Hatch|first5=Kenneth|last6=Robinson |first6=Miles|last7=Glaser|first7=David|last8=Chen|first8=Jianxin|last9=Curtis|first9=David|last10=Tiu|first10=Christopher|last11=Lin|first11=Robert P.|date=2015-12-01|title=Solar Energetic Particle Investigation for MAVEN|url=https://doi.org/10.1007/s11214-015-0218-z|journal=Space Science Reviews|volume=195|issue=1|pages=153–172|doi=10.1007/s11214-015-0218-z|s2cid=122683322|issn=1572-9672}}</ref> – determines the impact of [[Astronomy:Solar energetic particles|SEPs]] on the upper atmosphere. In context with the rest of this suite, it evaluates how SEP events affect upper atmospheric structure, temperature, dynamics and escape rates.

Built by the [[Organization:University of Colorado Boulder|University of Colorado Boulder]] Laboratory for Atmospheric and Space Physics:

* Imaging Ultraviolet Spectrometer (IUVS)<ref>{{cite journal|last1=McClintock|first1=William E.|last2=Schneider|first2=Nicholas M.|last3=Holsclaw|first3=Gregory M.|last4=Clarke|first4=John T.|last5=Hoskins |first5=Alan C.|last6=Stewart|first6=Ian|last7=Montmessin|first7=Franck|last8=Yelle|first8=Roger V.|last9=Deighan|first9=Justin|date=2015-12-01|title=Imaging Ultraviolet Spectrograph (IUVS) for MAVEN |url=https://doi.org/10.1007/s11214-014-0098-7|journal=Space Science Reviews|volume=195|issue=1|pages=75–124|doi=10.1007/s11214-014-0098-7|s2cid=18008947|issn=1572-9672}}</ref> – measures global characteristics of the upper atmosphere and ionosphere. The IUVS has separate far-UV and mid-UV channels, a high resolution mode to distinguish [[Physics:Deuterium|deuterium]] from [[Chemistry:Hydrogen|hydrogen]], optimization for [[Astronomy:Airglow|airglow]] studies, and capabilities that allow complete mapping and nearly continuous operation.<ref>{{cite web|title=IUVS for MAVEN |url=https://lasp.colorado.edu/home/maven/science/instrument-package/iuvs/iuvs-imaging-highlights/|access-date=2020-10-12}}</ref>
* Langmuir Probe and Waves (LPW)<ref>{{cite journal|last1=Andersson|first1=L.|last2=Ergun|first2=R. E.|last3=Delory|first3=G. T.|last4=Eriksson|first4=A.|last5=Westfall|first5=J.|last6=Reed|first6=H. |last7=McCauly|first7=J.|last8=Summers|first8=D.|last9=Meyers|first9=D.|date=2015-12-01|title=Langmuir Probe and Waves (LPW) instrument for MAVEN|url=https://doi.org/10.1007/s11214-015-0194-3|journal=Space Science Reviews|volume=195|issue=1|pages=173–198|doi=10.1007/s11214-015-0194-3|bibcode=2015SSRv..195..173A|s2cid=119556488|issn=1572-9672}}</ref> – determines ionosphere properties and wave heating of escaping ions and solar [[Physics:Extreme ultraviolet|extreme ultraviolet]] (EUV) input to atmosphere. This instrument provides better characterization of the basic state of the ionosphere and can evaluate the effects of the solar wind on the ionosphere.

Built by [[Organization:Goddard Space Flight Center|Goddard Space Flight Center]]:

* Magnetometer (MAG)<ref>{{cite journal|last1=Connerney|first1=J. E. P.|last2=Espley|first2=J.|last3=Lawton|first3=P.|last4=Murphy|first4=S.|last5=Odom|first5=J.|last6=Oliversen|first6=R.|last7=Sheppard |first7=D.|date=2015-12-01|title=MAVEN Magnetic Field Investigation|journal=Space Science Reviews|volume=195|issue=1|pages=257–291|doi=10.1007/s11214-015-0169-4 |bibcode=2015SSRv..195..257C|issn=1572-9672|doi-access=free}}</ref> – measures interplanetary solar wind and ionosphere [[Astronomy:Magnetosphere|magnetic fields]].
* Neutral Gas and Ion Mass Spectrometer (NGIMS)<ref>{{cite journal|last1=Mahaffy|first1=Paul R.|last2=Benna|first2=Mehdi|last3=King|first3=Todd|last4=Harpold|first4=Daniel N.|last5=Arvey|first5=Robert |last6=Barciniak|first6=Michael|last7=Bendt|first7=Mirl|last8=Carrigan|first8=Daniel|last9=Errigo|first9=Therese|last10=Holmes|first10=Vincent|last11=Johnson|first11=Christopher S.|date=2015-12-01|title=Neutral Gas and Ion Mass Spectrometer for MARVEN|journal=Space Science Reviews|volume=195|issue=1|pages=49–73|doi=10.1007/s11214-014-0091-1|issn=1572-9672|doi-access=free}}</ref> – measures the composition and [[Physics:Isotope|isotope]]s of [[Astronomy:Critical ionization velocity|neutral gases]] and [[Physics:Ion|ion]]s. This instrument evaluates how the lower atmosphere can affect higher altitudes while also better characterizing the structure of the upper atmosphere from the homopause to the [[Earth:Thermopause|exobase]].

SWEA, SWIA, STATIC, SEP, LPW, and MAG are part of the Particles and Fields instrument suite, IUVS is the Remote Sensing instrument suite, and NGIMS is its own eponymous suite.

== Cost ==
[[File:MAVEN Development and Prime Mission Costs.svg|thumb|upright=1.2|left|MAVEN Development and Prime Mission Costs]]

MAVEN cost US$582.5 million to build, launch, and operate for its prime mission, nearly US$100 million less than originally estimated. Of this total, US$366.8 million was for development, US$187 million for launch services, and US$35 million was for the 2-year prime mission. On average, NASA spends US$20 million annually on MAVEN's extended operations.<ref name="maven-co" />

== Results ==
=== Atmospheric loss ===
Mars loses water into its thin atmosphere by evaporation. There, solar radiation can split the water molecules into their components, [[Chemistry:Hydrogen|hydrogen]] and [[Chemistry:Oxygen|oxygen]]. The hydrogen, as the lightest element, then tends to rise far up to the highest levels of the [[Astronomy:Atmosphere of Mars|Martian atmosphere]], where several processes can strip it away into space, to be forever lost to the planet. This loss was thought to proceed at a fairly constant rate, but MAVEN's observations of Mars's atmospheric hydrogen through a full Martian year (almost two Earth years) show that the escape rate is highest when Mars's orbit brings it closest to the [[Astronomy:Sun|Sun]], and only one-tenth as great when it is at its farthest.<ref>{{cite journal|last1=Jakosky|first1=Bruce M.|last2=Grebowsky|first2=Joseph M.|last3=Luhmann|first3=Janet G.|last4=Brain |first4=David A.|date=2015|title=Initial results from the MAVEN mission to Mars|journal=Geophysical Research Letters|volume=42|issue=21 |pages=8791–8802|doi=10.1002/2015GL065271|bibcode=2015GeoRL..42.8791J|issn=1944-8007|doi-access=free}}</ref>

On 5 November 2015, [[Organization:NASA|NASA]] announced that data from MAVEN shows that the deterioration of Mars's atmosphere increases significantly during [[Astronomy:Solar flare|solar storms]]. That loss of atmosphere to space likely played a key role in Mars's gradual shift from its [[Chemistry:Carbon dioxide|carbon dioxide]]–dominated atmosphere – which had kept Mars relatively warm and allowed the planet to support liquid surface water – to the cold, arid planet seen today. This shift took place between about 4.2 and 3.7 billion years ago.<ref name="NASA-15217">{{cite web|last=Northon|first=Karen|date=November 5, 2015|title=NASA Mission Reveals Speed of Solar Wind Stripping Martian Atmosphere|url=http://www.nasa.gov/press-release/nasa-mission-reveals-speed-of-solar-wind-stripping-martian-atmosphere|access-date=November 5, 2015|publisher=NASA}} {{PD-notice}}</ref> Atmospheric loss was especially notable during an interplanetary [[Astronomy:Coronal mass ejection|coronal mass ejection]] in March 2015.<ref>{{cite journal|last1=Jakosky|first1=B. M.|last2=Grebowsky|first2=J. M.|last3=Luhmann|first3=J. G. |last4=Connerney|first4=J.|last5=Eparvier|first5=F.|last6=Ergun|first6=R.|last7=Halekas|first7=J.|last8=Larson|first8=D.|last9=Mahaffy|first9=P.|last10=McFadden|first10=J.|last11=Mitchell|first11=D. L. |date=2015-11-06|title=MAVEN observations of the response of Mars to an interplanetary coronal mass ejection|url=https://www.science.org/doi/10.1126/science.aad0210|journal=Science|volume=350 |issue=6261|pages=aad0210|doi=10.1126/science.aad0210|pmid=26542576|bibcode=2015Sci...350.0210J|s2cid=2876558|issn=0036-8075}}</ref>

{{wide image|PIA18613-MarsMAVEN-Atmosphere-3UV-Views-20141014.jpg|600px|align-cap=center|Mars – [[Astronomy:Atmosphere of Mars|escaping atmosphere]] – [[Chemistry:Carbon|carbon]], [[Chemistry:Oxygen|oxygen]], [[Chemistry:Hydrogen|hydrogen]] (MAVEN – [[Ultraviolet–visible spectroscopy|UV]] – 14 October 2014).<ref name="NASA-20141014-NJ">{{cite web|last1=Jones|first1=Nancy|last2=Steigerwald|first2=Bill|last3=Brown|first3=Dwayne|last4=Webster|first4=Guy |title=NASA Mission Provides Its First Look at Martian Upper Atmosphere|url=http://www.jpl.nasa.gov/news/news.php?release=2014-351|date=October 14, 2014|publisher=NASA|access-date=October 15, 2014}} {{PD-notice}}</ref>}}

=== Different types of aurora ===
In 2014, MAVEN researchers detected widespread [[Astronomy:Aurora|aurora]] throughout the planet, even close to the equator. Given the localized magnetic fields on Mars (as opposed to Earth's global magnetic field), aurora appear to form and distribute in different ways on Mars, creating what scientists call diffuse aurora. Researchers determined that the source of the particles causing the aurorae were a huge surge of electrons originating from the Sun. These highly energetic particles were able to penetrate far deeper into Mars's atmosphere than they would have on Earth, creating aurora much closer to the surface of the planet (~60&nbsp;km as opposed to 100–500&nbsp;km on Earth).<ref>{{cite journal|last1=Schneider|first1=N. M.|last2=Deighan|first2=J. I.|last3=Jain|first3=S. K.|last4=Stiepen|first4=A.|last5=Stewart|first5=A. I. F.|last6=Larson|first6=D. |last7=Mitchell|first7=D. L.|last8=Mazelle|first8=C.|last9=Lee|first9=C. O.|last10=Lillis|first10=R. J.|last11=Evans|first11=J. S.|date=2015-11-06|title=Discovery of diffuse aurora on Mars |url=https://www.science.org/doi/10.1126/science.aad0313|journal=Science|volume=350|issue=6261|pages=aad0313|doi=10.1126/science.aad0313|pmid=26542577|bibcode=2015Sci...350.0313S|hdl=2268/180453|s2cid=7043426|issn=0036-8075}}</ref>

Scientists also discovered proton aurora, different from the so-called typical aurora which is produced by electrons. Proton aurora were previously only detected on Earth.<ref>{{cite journal|last1=Deighan |first1=J.|last2=Jain|first2=S. K.|last3=Chaffin|first3=M. S.|last4=Fang|first4=X.|last5=Halekas|first5=J. S.|last6=Clarke|first6=J. T.|last7=Schneider|first7=N. M.|last8=Stewart|first8=A. I. F.|last9=Chaufray |first9=J.-Y.|last10=Evans|first10=J. S.|last11=Stevens|first11=M. H.|date=October 2018|title=Discovery of a proton aurora at Mars|url=http://www.nature.com/articles/s41550-018-0538-5|journal=Nature|volume=2 |issue=10|pages=802–807|doi=10.1038/s41550-018-0538-5|bibcode=2018NatAs...2..802D|s2cid=105560692|issn=2397-3366}}</ref>

=== Interaction with a comet ===
The fortuitous arrival of MAVEN just before a flyby of the comet Siding Spring gave researchers a unique opportunity to observe both the comet itself as well as its interactions with the Martian atmosphere.  The spacecraft's IUVS instrument detected intense ultraviolet emissions from magnesium and iron ions, a result from the comet's meteor shower, which were much stronger than anything ever detected on Earth.<ref>{{cite journal|last1=Schneider|first1=N. M.|last2=Deighan|first2=J. I.|last3=Stewart|first3=A. I. F.|last4=McClintock|first4=W. E.|last5=Jain|first5=S. K.|last6=Chaffin|first6=M. S.|last7=Stiepen|first7=A. |last8=Crismani|first8=M.|last9=Plane|first9=J. M. C.|author9-link=John Plane|last10=Carrillo‐Sánchez|first10=J. D.|last11=Evans|first11=J. S.|date=2015|title=MAVEN IUVS observations of the aftermath of the Comet Siding Spring meteor shower on Mars|journal=Geophysical Research Letters|volume=42|issue=12|pages=4755–4761|doi=10.1002/2015GL063863|bibcode=2015GeoRL..42.4755S|issn=1944-8007|doi-access=free}}</ref> The NGIMS instrument was able to directly sample dust from this [[Astronomy:Oort cloud|Oort Cloud]] comet, detecting at least eight different types of metal ions.<ref>{{cite journal|last1=Benna |first1=M.|last2=Mahaffy|first2=P. R.|last3=Grebowsky|first3=J. M.|last4=Plane|first4=J. M. C.|author4-link=John Plane|last5=Yelle|first5=R. V.|last6=Jakosky|first6=B. M.|date=2015|title=Metallic ions in the upper atmosphere of Mars from the passage of comet C/2013 A1 (Siding Spring)|journal=Geophysical Research Letters|volume=42|issue=12|pages=4670–4675 |doi=10.1002/2015GL064159|bibcode=2015GeoRL..42.4670B|issn=1944-8007|doi-access=free}}</ref>

=== Detection of metal ions ===
In 2017, results were published detailing the detection of metal ions in Mars's ionosphere. This is the first time metal ions have been detected in any planet's atmosphere other than Earth's. It was also noted that these ions behave and are distributed differently in the atmosphere of Mars given that the red planet has a much weaker magnetic field than our own.<ref>{{cite journal|last1=Grebowsky|first1=J. M. |last2=Benna|first2=M.|last3=Plane|first3=J. M. C.|last4=Collinson|first4=G. A.|last5=Mahaffy|first5=P. R.|last6=Jakosky|first6=B. M.|date=2017|title=Unique, non-Earthlike, meteoritic ion behavior in upper atmosphere of Mars|journal=Geophysical Research Letters|volume=44|issue=7|pages=3066–3072|doi=10.1002/2017GL072635|bibcode=2017GeoRL..44.3066G |issn=1944-8007|doi-access=free}}</ref>

=== Impacts on future exploration ===
In September 2017, NASA reported a temporary doubling of [[Physics:Radiation|radiation levels]] on the surface of Mars, as well as an [[Astronomy:Aurora|aurora]] 25 times brighter than any observed earlier. This occurred due to a massive, and unexpected, [[Astronomy:Coronal mass ejection|solar storm]].<ref name="PHYS-20170930">{{cite web|last=Scott|first=Jim|title=Large solar storm sparks global aurora and doubles radiation levels on the martian surface|url=https://phys.org/news/2017-09-large-solar-storm-global-aurora.html|date=September 30, 2017|website=phys.org|access-date=September 30, 2017}}</ref> The observation provided insight into how changes in radiation levels might impact the planet's habitability, helping NASA researchers understand how to predict as well as mitigate effects on future human Mars explorers.

== See also ==
{{div col|colwidth=30em}}
* {{Annotated link|Atmosphere of Mars}}
* {{Annotated link|Trace Gas Orbiter}}
* {{Annotated link|Exploration of Mars}}
* {{Annotated link|List of Mars orbiters}}
* {{Annotated link|List of missions to Mars}}
* {{Annotated link|Mars Express}}
* {{Annotated link|Mars Global Surveyor}}
* {{Annotated link|Mars MetNet}}
* {{Annotated link|Mars Exploration Program}}
* {{Annotated link|Mars Orbiter Mission}}
* {{Annotated link|New Frontiers program}}
* {{Annotated link|Sandra Cauffman}}
* {{Annotated link|Space weather}}
{{div col end}}

== References ==
{{Reflist}}

== External links ==
{{Commons}}
* [https://science.nasa.gov/mission/maven/ MAVEN – NASA]
* [http://mars.jpl.nasa.gov/programmissions/missions/present/maven/ MAVEN – JPL]
* [http://lasp.colorado.edu/home/maven/ MAVEN – University of Colorado Boulder]
* [http://www.nasa.gov/mission_pages/maven/news/propellant-tank.html Integration of MAVEN Propellant Tank – NASA]
* [http://www.spaceflightnow.com/mars/maven/status.html SpaceflightNow MAVEN mission status center]
* [http://lasp.colorado.edu/home/maven/science/released-results/ Released results from MAVEN]

{{Mars spacecraft}}
{{Solar System probes}}
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{{2013 in space}}
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[[Category:Mars Exploration Program]]
[[Category:Lockheed Martin satellites and probes]]
[[Category:Mars Scout Program]]
[[Category:Missions to Mars]]
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{{Sourceattribution|MAVEN}}