View source for Astronomy:International Cometary Explorer

{{Short description|NASA satellite of the Explorer program}}
{{Infobox spaceflight
| name              = International Cometary Explorer
| names_list        = ISEE-3<br/>International Sun-Earth Explorer-C<br/>Explorer 59
| image             = ISEE3-ICE.jpg
| image_caption     = ICE satellite
| image_size        = 300px

| mission_type      = Magnetospheric research<br/>ISEE-3: [[Astronomy:Sun|Sun]]/[[Astronomy:Earth|Earth]] {{L1}} orbiter<br/>ICE: 21P/G-Z and [[Astronomy:Halley's Comet|Halley]] fly-by
| operator          = [[Organization:NASA|NASA]]
| COSPAR_ID         = 1978-079A
| SATCAT            = 11004
| mission_duration  = Launch to last routine contact:<br/>{{time interval|12 August 1978 15:12|5 May 1997|show=ymd|sep=,}}<br/>Launch to last contact:<br/>{{time interval|12 August 1978 15:12|16 September 2014 |show=ymd|sep=,}}

| spacecraft        = Explorer LIX
| spacecraft_type   = International Sun-Earth Explorer
| spacecraft_bus    = ISEE
| manufacturer      = Fairchild Industries
| launch_mass       = {{cvt|479|kg}}<ref>{{cite web|url=https://solarsystem.nasa.gov/missions/isee-3-ice/in-depth/ |title=ISEE-3/ICE |publisher=NASA's Solar System Exploration website |access-date=November 30, 2022}}</ref>
| dry_mass          = {{cvt|390|kg}}
| dimensions        = {{cvt|1.77|xx|1.58|m}}
| power             = 173 [[Watt|watt]]s

| launch_date       = 12 August 1978, 15:12 [[Physics:Coordinated Universal Time|UTC]]
| launch_rocket     = [[Engineering:Delta (rocket family)|Thor-Delta 2914]] (Thor 633 / Delta 144)
| launch_site       = Cape Canaveral, SLC-17B
| launch_contractor = [[Company:Douglas Aircraft Company|Douglas Aircraft Company]]

| entered_service   = 12 August 1978
| deactivated       = 5 May 1997
| last_contact      = 16 September 2014
| decay_date        = 

| orbit_reference   = [[Astronomy:Heliocentric orbit|Heliocentric orbit]]
| orbit_periapsis   = {{cvt|0.93|AU}}
| orbit_apoapsis    = {{cvt|1.03|AU}}
| orbit_inclination = 0.10°
| orbit_period      = 355 days
| apsis             = helion

| instruments_list  = {{Infobox spaceflight/Instruments
  | name1  = Solar Wind Plasma Experiment
  | name2  = Helium Vector Magnetometer
  | name3  = Low Energy Cosmic Ray Experiment
  | name4  = Medium Energy Cosmic Ray Experiment
  | name5  = High Energy Cosmic Ray Experiment
  | name6  = Plasma Wave Instrument
  | name7  = Low Energy Proton Experiment
  | name8  = Cosmic Ray Electrons and Nuclei
  | name9  = X-Rays and Electrons Instrument
  | name10 = Radio Mapping Experiment
  | name11 = Plasma Composition Experiment
  | name12 = Heavy Isotope Spectrometer Telescope
  | name13 = Ground Based Solar studies Experiment
 }}

| programme         = '''Explorer program'''
| previous_mission  = [[Astronomy:Heat Capacity Mapping Mission|Heat Capacity Mapping Mission]]
| next_mission      = [[Astronomy:Explorer 60|Explorer 60]]
}}

The '''International Cometary Explorer''' (ICE) spacecraft (designed and launched as the '''International Sun-Earth Explorer-3''' (ISEE-3) satellite), was launched 12 August 1978, into a [[Astronomy:Heliocentric orbit|heliocentric orbit]]. It was one of three spacecraft, along with the mother/daughter pair of [[Astronomy:ISEE-1|ISEE-1]] and [[Engineering:ISEE-2|ISEE-2]], built for the International Sun-Earth Explorer (ISEE) program, a joint effort by [[Organization:NASA|NASA]] and [[Organization:European Space Research Organisation|ESRO]]/[[Organization:European Space Agency|ESA]] to study the interaction between the [[Earth:Earth's magnetic field|Earth's magnetic field]] and the [[Astronomy:Solar wind|solar wind]].

ISEE-3 was the first spacecraft to be placed in a [[Astronomy:Halo orbit|halo orbit]] at the {{L1|nolink=yes}} Earth-Sun [[Astronomy:Lagrange point|Lagrange point]].<ref name="nasa_sse">{{cite web|url=http://solarsystem.nasa.gov/missions/profile.cfm?MCode=ISEEICE|archive-url=https://web.archive.org/web/20150610112432/http://solarsystem.nasa.gov/missions/profile.cfm?MCode=ISEEICE|title=ISEE-3/ICE|work=Solar System Exploration|publisher=NASA|url-status=dead |archive-date=June 10, 2015}} {{PD-notice}}</ref> Renamed ICE, it became the first spacecraft to visit a [[Astronomy:Comet|comet]],<ref>{{cite book|url=https://www.nasa.gov/sites/default/files/atoms/files/beyond-earth-tagged.pdf|title=Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016|page=2|last1=Siddiqi|first1=Asif A.|lccn=2017059404|isbn=9781626830424|publisher=NASA History Program Office|edition=second |year=2018|id=SP2018-4041|series=The NASA history series|location=Washington, D.C.}} {{PD-notice}}</ref> passing through the plasma tail of comet Giacobini-Zinner within about {{cvt|7800|km}} of the nucleus on 11 September 1985.<ref>{{cite report|url=http://ipnpr.jpl.nasa.gov/progress_report/42-87/87X.PDF|title=Halley Comet Missions|publisher=NASA|first1=C.|last1=Stelzried|first2=L. |last2=Efron|first3=J.|last3=Ellis|pages=241–242|date=July–September 1986|id=TDA Progress Report 42-87}} {{PD-notice}}</ref>

NASA suspended routine contact with ISEE-3 in 1997, and made brief status checks in 1999 and 2008.<ref name="verge20140523">{{cite news|url=https://www.theverge.com/2014/5/23/5745326/spaceship-come-home-isee-3-reboot-project|title=Spaceship come home: can citizen scientists rescue an abandoned space probe?|publisher=The Verge|first=Adi|last=Robertson|date=May 23, 2014|access-date=June 26, 2014}}</ref><ref name="io9-20140415">{{cite news|url=http://space.io9.com/can-this-1970s-spacecraft-explore-again-1563432452|title=Can This 1970s Spacecraft Explore Again?|website=space.io9.com|first=Mika|last=McKinnon|date=April 15, 2014|access-date=June 26, 2014}}</ref>

On 29 May 2014, two-way communication with the spacecraft was reestablished by the '''ISEE-3 Reboot Project''', an unofficial group,<ref>{{cite web|url=https://twitter.com/ISEE3Reboot/status/481658765893070848 |title=We do NOT like...|publisher=Twitter.com|date=June 25, 2014|access-date=June 25, 2014}}</ref> with support from the Skycorp company and SpaceRef Interactive.<ref name=ars20140529>{{cite news |url=https://arstechnica.com/science/2014/05/isee-3-spacecraft-makes-first-earth-contact-in-16-years/|title=ISEE-3 spacecraft makes first Earth contact in 16 years|publisher=Ars Technica|first=Megan|last=Geuss |date=May 29, 2014|access-date=May 31, 2014}}</ref><ref>{{cite news|url=http://www.ctvnews.ca/video?clipId=373599&playlistId=1.1846763&binId=1.810401&playlistPageNum=1|title=Citizen-scientists look to reboot 35-year-old spacecraft|publisher=CTV News|first=Dan|last=Matheson|date=May 2014|access-date=May 31, 2014}}</ref><ref name="NYT-20140615">{{cite news |url=https://www.nytimes.com/2014/06/15/science/space/calling-back-a-zombie-ship-from-the-graveyard-of-space.html|title=Calling Back a Zombie Ship From the Graveyard of Space|newspaper=The New York Times |first=Kenneth|last=Chang|date=June 15, 2014|access-date=June 15, 2014}}</ref>  On 2 July 2014, they fired the thrusters for the first time since 1987. However, later firings of the thrusters failed, apparently due to a lack of nitrogen pressurant in the fuel tanks.<ref name="ISEE3-20140710">{{cite news|url=http://space.io9.com/distributed-rocket-science-is-a-thing-now-1603240054/all|title=Distributed Rocket Science is a Thing Now|website=space.io9.com|first=Mika|last=McKinnon|date=July 10, 2014|access-date=July 12, 2014}}</ref><ref name="NYT-20140718">{{cite news|url=https://www.nytimes.com/2014/07/19/opinion/Rebooting-ISEE-3-Space-for-All.html|title=Lost and Found in Space|newspaper=The New York Times|series=The Opinion Pages|last=Cowing|first=Keith|date=July 18, 2014|access-date=July 18, 2014}}</ref> The project team initiated an alternative plan to use the spacecraft to "collect scientific data and send it back to Earth",<ref name="NYT-20140709">{{cite news|url=https://www.nytimes.com/2014/07/10/science/space/space-probe-might-lack-nitrogen-to-push-it-home.html|title=Space Probe Might Lack Nitrogen to Push It Home|newspaper=The New York Times|last=Chang|first=Kenneth|date=July 9, 2014|access-date=July 10, 2014}}</ref> but on 16 September 2014, contact with the probe was lost.<ref name=lost>{{cite web|url=http://spacecollege.org/isee3/isee-3-is-in-safe-mode.html|title=ISEE-3 is in Safe Mode|publisher=Space College|first=Keith |last=Cowing|date=September 25, 2014|access-date=October 7, 2014|quote=The ground stations listening to ISEE-3 have not been able to obtain a signal since the 16 September 2014}}</ref>

== Original mission: International Sun/Earth Explorer 3 (ISEE-3) ==
[[File:ISEE Orbits.gif|thumb|upright=1.0|right|International Sun/Earth Explorer's orbits]]
[[File:ISEE3-ICE-trajectory.gif|thumb|upright=1.0|right|ICE mission]]
[[File:ISEE-3 (ICE) Revisits Earth.ogg|thumb|upright=1.0|Top-down view of the orbit of ICE relative to the inner Solar System in and after 2009.]]

ISEE-3 carries no cameras; instead, its instruments measure energetic particles, waves, [[Physics:Plasma|plasmas]], and fields.

ISEE-3 originally operated in a [[Astronomy:Halo orbit|halo orbit]] about the {{L1}} Sun-Earth [[Astronomy:Lagrange point|Lagrange point]], 235 Earth radii above the surface (about {{cvt|1500000|km}}. It was the first artificial object placed at a so-called "libration point",<ref>{{cite book|url=https://www.nasa.gov/sites/default/files/atoms/files/beyond-earth-tagged.pdf|title=Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016|page=2 |last1=Siddiqi|first1=Asif A.|lccn=2017059404|isbn=9781626830424|publisher=NASA History Program Office|edition=second|year=2018|id=SP2018-4041|series=The NASA history series|location=Washington, D.C.}} {{PD-notice}}</ref> entering orbit there on 20 November 1978,<ref name="nasa_sse"/> proving that such a suspension between gravitational fields was possible. It rotates at 19.76 rpm about an axis perpendicular to the [[Astronomy:Ecliptic|ecliptic]], to keep it oriented for its experiments, to generate solar power and to communicate with Earth.

The purposes of the mission were:
* to investigate solar-terrestrial relationships at the outermost boundaries of the Earth's magnetosphere;
* to examine in detail the structure of the solar wind near the Earth and the shock wave that forms the interface between the solar wind and Earth's magnetosphere;
* to investigate motions of and mechanisms operating in the [[Astronomy:Plasma sheet|plasma sheet]]s; and,
* to continue the investigation of cosmic rays and solar flare emissions in the interplanetary region near 1 AU.

== Second mission: International Cometary Explorer ==
After completing its original mission, ISEE-3 was re-tasked to study the interaction between the solar wind and a cometary atmosphere. On 10 June 1982, the spacecraft performed a maneuver which removed it from its halo orbit around the {{L1|nolink=yes}} point and placed it in a [[Astronomy:Hohmann transfer orbit|transfer orbit]]. This involved a series of passages between Earth and the Sun-Earth {{L2}} Lagrange point, through the Earth's magnetotail.<ref name="nssdc-isee3">{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1978-079A|title=ISEE 3|publisher=NASA|access-date=August 8, 2015}} {{PD-notice}}</ref> Fifteen propulsive maneuvers and five lunar gravity assists resulted in the spacecraft being ejected from the Earth-Moon system and into a [[Astronomy:Heliocentric orbit|heliocentric orbit]]. Its last and closest pass over the Moon, on December 22, 1983, was only {{cvt|119.4|km}} above the lunar surface; following this pass, the spacecraft was re-designated as the International Cometary Explorer (ICE).<ref name="eoportal-isee3">{{cite web |url=https://directory.eoportal.org/web/eoportal/satellite-missions/i/isee-3|title=ISEE-3 / ICE (International Cometary Explorer) mission|publisher=ESA eoPortal Directory|access-date=August 8, 2015}}</ref>

=== Giacobini-Zinner encounter ===
Its new orbit put it ahead of the Earth on a trajectory to intercept comet Giacobini-Zinner. On 11 September 1985, the craft passed through the comet's plasma tail.<ref name="eoportal-isee3"/> ICE did a [[Engineering:Flyby (spaceflight)|flyby]] of the comet nucleus at a distance of {{cvt|7800|km}} of the nucleus on 11 September 1985.<ref>{{cite report|url=http://ipnpr.jpl.nasa.gov/progress_report/42-87/87X.PDF|title=Halley Comet Missions|publisher=NASA|first1=C.|last1=Stelzried|first2=L.|last2=Efron|first3=J.|last3=Ellis|pages=241–242|date=July–September 1986|id=TDA Progress Report 42-87}} {{PD-notice}}</ref>

=== Halley encounter ===
ICE transited between the Sun and Comet Halley in late March 1986, when other spacecraft  were near the comet on their early-March comet rendezvous missions. (This "[[Astronomy:Halley Armada|Halley Armada]]" included [[Engineering:Giotto (spacecraft)|Giotto]], [[Astronomy:Vega program|Vega 1 and 2]], [[Engineering:Suisei (spacecraft)|Suisei]] and [[Astronomy:Sakigake|Sakigake]].) ICE flew through the tail; its minimum distance to the comet nucleus was {{cvt|28|e6km}}.<ref>{{cite encyclopedia|chapter=International Cometary Explorer (ICE)|encyclopedia=Encyclopedia of Astronomy and Astrophysics|publisher=IOP Science|editor-first=Paul|editor-last=Murdin|date=November 2000 |doi=10.1888/0333750888/4650|bibcode=2000eaa..bookE4650.|isbn=0333750888|hdl=2060/19920003890|hdl-access=free }}</ref> For comparison, Earth's minimum distance to Comet Halley in 1910 was {{cvt|20.8|e6km}}.<ref>{{cite web|url=http://www.astronomy.com/asy/default.aspx?c=a&id=2295|title=Comets|website=astronomy.com|first=Francis|last=Reddy|archive-url=https://web.archive.org/web/20100607084217/http://www.astronomy.com/asy/default.aspx?c=a&id=2295|archive-date=June 7, 2010}}</ref>

=== Heliospheric mission ===
An update to the ICE mission was approved by NASA in 1991. It defines a [[Astronomy:Heliosphere|heliospheric]] mission for ICE consisting of investigations of [[Astronomy:Coronal mass ejection|coronal mass ejection]]s in coordination with ground-based observations, continued [[Astronomy:Cosmic ray|cosmic ray]] studies, and the [[Engineering:Ulysses (spacecraft)|Ulysses]] probe. By May 1995, ICE was being operated under a low duty cycle, with some data-analysis support from the Ulysses project.

=== End of mission ===
On 5 May 1997, NASA ended the ICE mission, leaving only a carrier signal operating. The ISEE-3/ICE downlink bit rate was nominally 2048 bits per second during the early part of the mission, and 1024 bit/s during the 21P/Giacobini–Zinner comet encounter. The bit rate then successively dropped to 512 bit/s (on 9 December 1985), 256 bit/s (on 5 January 1987), 128 bit/s (on 24 January 1989) and finally to 64 bit/s (on 27 December 1991). Though still in space, NASA donated the craft to the Smithsonian Museum.<ref name=Privateers>{{cite news |url=https://www.theregister.co.uk/2014/04/25/privateers_race_to_capture_forgotten_nasa_space_probe_using_crowdsourced_cash/|title=Privateers race to capture forgotten NASA space probe using crowdsourced cash |newspaper=The Register|first=Iain|last=Thomson|date=April 24, 2014|access-date=May 20, 2014}}</ref>

By January 1990, ICE was in a 355-day [[Astronomy:Heliocentric orbit|heliocentric orbit]] with an aphelion of 1.03 AU, a perihelion of 0.93 AU and an inclination of 0.1°.

=== Further contact ===
In 1999, NASA made brief contact with ICE to verify its carrier signal. On 18 September 2008, NASA, with the help of [[Company:KinetX|KinetX]], located ICE using the [[Astronomy:NASA Deep Space Network|NASA Deep Space Network]] after discovering that it had not been powered off after the 1999 contact. A status check revealed that 12 of its 13 experiments were still functioning, and it still had enough propellant for {{cvt|150|m/s}} of [[Astronomy:Delta-v|Δv]]. It was determined to be possible to reactivate the spacecraft in 2014,<ref name=autogenerated1>{{cite web|url=http://space.about.com/od/spacemissions/p/iseeiceinfo.htm|title=International Sun-Earth Explorer 3 - International Cometary Explorer|publisher=About.com|first=Nick|last=Greene|access-date=June 26, 2014|url-status=dead|archive-url=https://web.archive.org/web/20140712202824/http://space.about.com/od/spacemissions/p/iseeiceinfo.htm|archive-date=July 12, 2014}}</ref> when it again made a close approach to Earth, and scientists discussed reusing the probe to observe more comets in 2017 or 2018.<ref>{{cite web|url=http://www.planetary.org/blog/article/00001673/|title=It's Alive!|publisher=The Planetary Society|first=Emily|last=Lakdawalla|date=October 3, 2008|access-date=3 October 2008|archive-date=20 February 2012|archive-url=https://web.archive.org/web/20120220052909/http://www.planetary.org/blog/article/00001673/|url-status=dead}}</ref>

== ISEE-3 Reboot Project ==
Sometime after NASA's interest in the ICE waned, others realized that the spacecraft might be steered to pass close to another comet. A team of engineers, programmers, and scientists began to study the feasibility and challenges involved.<ref name="NYT-20140615"/>

In April 2014, its members formally announced their intentions to "recapture" the spacecraft for use, calling the effort the ISEE-3 Reboot Project. A team webpage said, "We intend to contact the ISEE-3 (International Sun-Earth Explorer) spacecraft, command it to fire its engine and enter an orbit near Earth, and then resume its original mission... If we are successful we intend to facilitate the sharing and interpretation of all of the new data ISEE-3 sends back via crowd sourcing".<ref>{{cite web|url=http://spacecollege.org/isee3/isee-3.html|title=ISEE-3 Reboot Project (IRP)|publisher=Space College|first=Keith |last=Cowing|date=April 14, 2014}}</ref>

On 15 May 2014, the project reached its [[Crowdfunding|crowdfunding]] goal of US$125,000 on RocketHub, which was expected to cover the costs of writing the software to communicate with the probe, searching through the NASA archives for the information needed to control the spacecraft, and buying time on the dish antennas.<ref>{{cite web|url=http://spacecollege.org/isee3/isee-3-reboot-project-passes-funding-goal.html |title=ISEE-3 Reboot Project Passes Funding Goal|publisher=Space College|first=Keith|last=Cowing|date=May 15, 2014}}</ref> The project then set a "stretch goal" of US$150,000, which it also met with a final total of US$159,502 raised.<ref>{{cite web|url=http://spacecollege.org/isee3/isee-3-reboot-project-completes-crowdfunding-drive.html|title=ISEE-3 Reboot Project Completes Crowdfunding Drive|publisher=Space College|first=Keith|last=Cowing|date=May 23, 2014}}</ref>

The project members were working on deadline: if they got the spacecraft to change its orbit by late May or early June 2014, or in early July by using more fuel, it could use the Moon's gravity to get back into a useful [[Astronomy:Halo orbit|halo orbit]].<ref>{{cite news|url=https://www.npr.org/2014/03/18/289628696/space-thief-or-hero-one-mans-quest-to-reawaken-an-old-friend|title=Space Thief Or Hero? One Man's Quest To Reawaken An Old Friend|publisher=National Public Radio|first=Nell|last=Greenfieldboyce|date=March 18, 2014}}</ref><ref name="here-now"/><ref>{{cite web|url=http://spacecollege.org/isee3/isee-3-reboot-project-technical-update-1-may-2014.html|title=ISEE-3 Reboot Project Technical Update 1 May 2014|publisher=Space College|first=Dennis|last=Wingo|date=May 1, 2014}}</ref>

=== Replacing lost hardware ===
Earlier in 2014, officials with the [[Organization:Goddard Space Flight Center|Goddard Space Flight Center]] said the [[Astronomy:NASA Deep Space Network|NASA Deep Space Network]] equipment necessary to transmit signals to the spacecraft had been decommissioned in 1999, and was too expensive to replace.<ref>{{cite web|url=http://www.planetary.org/blogs/emily-lakdawalla/2014/02070836-isee-3.html|title=ICE/ISEE-3 to return to an Earth no longer capable of speaking to it|publisher=The Planetary Society|first=Emily|last=Lakdawalla|date=February 7, 2014}}</ref> However, project members were able to find documentation for the original equipment and were able to simulate the complex modulator/demodulator electronics using modern [[Software-defined radio|software-defined radio]] (SDR) techniques and open-source programs from the [[Software:GNU Radio|GNU Radio]] project. They obtained the needed hardware, an off-the-shelf SDR transceiver,<ref>{{cite web|url=https://www.ettus.com/blog/2014/07/contacting-a-36-year-old-space-craft-why-not|title=The ISEE-3 Reboot Project: a dream SDR application|publisher=Ettus Research|first=Balint|last=Seeber|date=July 7, 2014|access-date=February 28, 2018|archive-date=1 March 2018|archive-url=https://web.archive.org/web/20180301044607/https://www.ettus.com/blog/2014/07/contacting-a-36-year-old-space-craft-why-not|url-status=dead}}</ref> and power amplifier,<ref name="Hardware 2014-05-15">{{cite web|url=http://spacecollege.org/isee3/isee-3-reboot-project-status-and-schedule-for-first-contact.html|title=ISEE-3 Reboot Project Status and Schedule for First Contact|publisher=Space College|first=Keith|last=Cowing|date=May 15, 2014|access-date=May 20, 2014}}</ref> and installed it on the {{cvt|305|m}} [[Astronomy:Arecibo Observatory|Arecibo dish antenna]] on 19 May 2014.<ref name="Hardware 2014-05-15"/><ref name="Arecibo antenna">{{cite web|url=http://www.rockethub.com/42228|title=ISEE-3 Reboot Project by Space College, Skycorp, and SpaceRef|publisher=RocketHub|date=May 20, 2014|access-date=May 20, 2014|archive-url=https://web.archive.org/web/20140520082230/http://www.rockethub.com/42228|archive-date=May 20, 2014|url-status=dead}}</ref> Once they gained control of the spacecraft, the capture team planned to shift the primary ground station to the {{cvt|21|m}} dish located at [[Organization:Morehead State University|Morehead State University]] Space Science Center of Kentucky.<ref name="Hardware 2014-05-15"/> The {{cvt|20|m}} dish antenna in [[Astronomy:Bochum Observatory|Bochum Observatory]], {{wipe|Germany}}, would be a support station.<ref name="Hardware 2014-05-15"/>

Although NASA was not funding the project, it made advisors available and gave approval to try to establish contact. On 21 May 2014, NASA announced that it had signed a Non-Reimbursable [[Astronomy:Space Act Agreement|Space Act Agreement]] with the ISEE-3 Reboot Project. "This is the first time NASA has worked such an agreement for use of a spacecraft the agency is no longer using or ever planned to use again", officials said.<ref name="NASAagreement">{{cite press release|url=http://www.nasa.gov/press/2014/may/nasa-signs-agreement-with-citizen-scientists-attempting-to-communicate-with-old/index.html|title=NASA Signs Agreement with Citizen Scientists Attempting to Communicate with Old Spacecraft|publisher=NASA|first1=Steve|last1=Cole|first2=Dennis|last2=Wingo|date=May 21, 2014}} {{PD-notice}}</ref>

=== Contact reestablished ===
On 29 May 2014, the reboot team successfully commanded the probe to switch into Engineering Mode to begin to broadcast telemetry.<ref name="npr29may14">{{cite web|url=https://www.npr.org/blogs/thetwo-way/2014/05/29/317190053/after-decades-of-silent-wandering-nasa-probe-phones-home|title=After Decades Of Silent Wandering, NASA Probe Phones Home|publisher=National Public Radio|first=Scott|last=Neuman |date=May 29, 2014}}</ref><ref>{{cite news|url=http://www.nasa.gov/content/citizen-scientists-successfully-communicate-with-spacecraft-0/index.html|title=Citizen Scientists Successfully Communicate with Spacecraft|publisher=NASA|date=May 30, 2014|access-date=May 31, 2014}} {{PD-notice}}</ref>

On 26 June 2014, project members using the [[Astronomy:Goldstone Deep Space Communications Complex|Goldstone Deep Space Communications Complex]] DSS-24 antenna achieved synchronous communication and obtained the four ranging points needed to refine the spacecraft's orbital parameters.<ref>{{cite web|url=http://spacecollege.org/isee3/isee-3-status-26-june-2014-dsn-ranging-success.html|title=ISEE-3 Status 26 June 2014: DSN Ranging Success|publisher=Space College|first=Keith|last=Cowing|date=June 26, 2014|access-date=June 26, 2014}}</ref> The project team received approval from NASA to continue operations through at least 16 July 2014, and made plans to attempt the orbital maneuver in early July.<ref name="here-now">{{cite news|url=http://hereandnow.wbur.org/2014/06/27/isee3-satellite-npr|title=A Retired Satellite Gets Back To Work|publisher=National Public Radio |series=Here & Now|date=June 27, 2014|access-date=June 27, 2014}}</ref><ref>{{cite web|url=http://spacecollege.org/isee3/isee-3-status-27-june-2014-another-dsn-ranging-success.html|title=ISEE-3 Status 27 June 2014: Another DSN Ranging Success|publisher=Space College|first=Keith|last=Cowing|date=June 27, 2014}}</ref>

On 2 July 2014, the reboot project fired the thrusters for the first time since 1987. They spun up the spacecraft to its nominal roll rate, in preparation for the upcoming trajectory correction maneuver in mid-July.<ref>{{cite news|url=http://www.spacenews.com/article/civil-space/41133isee-3-propulsion-system-awakens-at-11th-hour|archive-url=https://archive.today/20140707063037/http://www.spacenews.com/article/civil-space/41133isee-3-propulsion-system-awakens-at-11th-hour|url-status=dead|archive-date=July 7, 2014|title=ISEE-3 Propulsion System Awakens at 11 Hour|publisher=SpaceNews|date=July 3, 2014|access-date=July 3, 2014}}</ref><ref>{{cite web|url=http://spacecollege.org/isee3/isee-3-engines-fired-for-spin-up.html|title=ISEE-3 Engines Fired For Spin-Up|publisher=Space College|date=July 2, 2014|access-date=July 2, 2014}}</ref>

On 8 July 2014, a longer sequence of thruster firings failed, apparently due to loss of the [[Chemistry:Nitrogen|nitrogen]] gas needed to pressurize the fuel tanks.<ref name="ISEE3-20140710"/><ref name="NYT-20140718"/><ref name="NYT-20140709"/>

On 24 July 2014, the ISEE-3 Reboot Team announced that all attempts to change orbit using the ISEE-3 propulsion system had failed. Instead, the team said, the ''ISEE-3 Interplanetary Citizen Science Mission'' would gather data as the spacecraft flies by the Moon on 10 August 2014 and enters a heliocentric orbit similar to Earth's. The team began shutting down propulsion components to maximize the electrical power available for the science experiments.<ref>{{cite web|url=http://spacecollege.org/isee3/announcing-the-isee-3-interplanetary-citizen-science-mission.html|title=Announcing the ISEE-3 Interplanetary Citizen Science Mission|publisher=Space College|first=Keith|last=Cowing|date=July 24, 2014}}</ref>

On 30 July 2014, the team announced that it still planned to acquire data from as much of ISEE-3's 300-day orbit as possible. With five of the 13 instruments on the spacecraft still working, the science possibilities included listening for [[Astronomy:Gamma-ray burst|gamma-ray burst]]s, where observations from additional locations in the [[Astronomy:Solar System|Solar System]] can be valuable. The team was also recruiting additional receiving sites around the globe to improve diurnal coverage, in order to upload additional commands while the spacecraft is close to Earth and later to receive data.<ref>{{cite news|url=http://www.space.com/26679-vintage-nasa-spacecraft-interplanetary-science-isee3.html|title=Vintage NASA Spacecraft to Tackle Interplanetary Science|publisher=Space.com|first=Elizabeth|last=Howell|date=July 30, 2014}}</ref>

On 10 August 2014 at 18:16 UTC, the spacecraft passed about {{cvt|15600|km}} from the surface of the Moon. It will continue in its heliocentric orbit, and will return to the vicinity of Earth in 2031.<ref name="NYT-20140808">{{cite news|url=https://www.nytimes.com/2014/08/09/science/space/09zombie.html|title=Rudderless Craft to Get Glimpse of Home Before Sinking Into Space's Depths|newspaper=The New York Times |first=Kenneth|last=Chang|date=August 8, 2014|access-date=August 9, 2014}}</ref>

=== Contact lost ===
On 25 September 2014, the Reboot team announced that contact with the probe was lost on 16 September 2014. It is unknown whether contact can be reestablished because the probe's exact orbit is uncertain. The spacecraft's post-lunar flyby orbit takes it further from the Sun, causing electrical power available from its solar arrays to drop, and its battery failed in 1981. Reduced power could have caused the craft to enter a [[Engineering:Safe mode (spacecraft)|safe mode]], from which it may be impossible to awaken without the precise orbital location information needed to point transmissions at the craft.<ref name=lost/>

== Spacecraft design ==
[[Image:ISEE-C (ISEE 3) in dynamic test chamber.jpg|thumb|upright=1.0|right|The ISEE-3 (later ICE), undergoing testing and evaluation.]]

The ICE spacecraft is a barrel-like cylindrical shape covered by solar panels. Four long antennas protrude equidistant around the circumference of the spacecraft, spanning {{cvt|91|m}}.<ref>{{cite web |url=http://spacecollege.org/isee3/what-isee-3-really-looks-like.html|title=What ISEE-3 Really Looks Like|publisher=Space College|first=Keith|last=Cowing|date=June 7, 2014}}</ref> It has a dry mass of {{cvt|390|kg}} and can generate nominal power of 173 watts.

=== Payload ===
ICE carries 13 scientific instruments to measure plasmas, energetic particles, waves, and fields.<ref name="nasa_sse"/><ref name="eoportal-isee3"/> {{As of|2014|07}}, five were known to be functional. It does not carry a camera or imaging system. Its detectors measure high energy particles such as X- and gamma-rays, solar wind, plasma and cosmic particles. A data handling system gathers the scientific and engineering data from all systems in the spacecraft and formats them into a serial stream for transmission. The transmitter output power is five watts.

=== Scientific payload and experiments ===
* Cosmic Ray Electrons and Nuclei
* Ground Based Solar Studies Experiment
* Heavy Isotope Spectrometer Telescope
* High Energy Cosmic Ray Experiment
* Low Energy Cosmic Ray Experiment
* Low Energy Proton Experiment, also known as the Energetic Particle Anisotropy Spectrometer (EPAS)
* Medium Energy Cosmic Ray Experiment
* Plasma Composition Experiment
* Plasma Wave Instrument
* Radio Mapping Experiment
* Solar Wind Plasma Experiment, failed after 26 February 1980
* Vector Helium Magnetometer
* X-Rays and Electrons Instrument

== References ==
{{Reflist}}

== Publications ==
* {{cite book|title=Comet Encounters|publisher=American Geophysical Union|first1=Thomas J.|last1=Birmingham|first2=Alexander J.|last2=Dessler|year=1998|bibcode=1998coen.book.....B|isbn=978-1-118-66875-7}}

* {{cite journal|title=Descriptions of Experimental Investigations and Instruments for the ISEE Spacecraft|journal=IEEE Transactions on Geoscience Electronics|first1=K. W.|last1=Ogilvie|first2=A.|last2=Durney |first3=T.|last3=von Rosenvinge|volume=GE-16|issue=3|pages=151–153|date=July 1978|doi=10.1109/TGE.1978.294535|bibcode=1978ITGE...16..151.|s2cid=10197087|doi-access=free}}

* {{cite journal|title=The International Cometary Explorer Mission to Comet Giacobini-Zinner|journal=Science|first1=Tycho T.|last1=von Rosenvinge|first2=John C.|last2=Brandt|first3=Robert W.|last3=Farquhar |volume=232|issue=4748|pages=353–356|date=April 1986|doi=10.1126/science.232.4748.353|bibcode=1986Sci...232..353V|pmid=17792143|s2cid=45258658|url=https://zenodo.org/record/1230968}}

== External links ==
* [http://heasarc.gsfc.nasa.gov/docs/heasarc/missions/isee3.html ISEE-3/ICE profile] by NASA HEASARC
* [https://web.archive.org/web/20150610112432/http://solarsystem.nasa.gov/missions/profile.cfm?MCode=ISEEICE ISEE-3/ICE profile] by NASA Solar System Exploration
* [http://spacecollege.org/isee3/ ISEE-3 Reboot Project homepage] at SpaceCollege.com
* [https://web.archive.org/web/20190331234658/http://spacecraftforall.com/ A Spacecraft for All], an interactive site created in cooperation with [[Company:Google|Google]] to support the ISEE-3 Reboot Project

{{Fairchild Aircraft}}
{{Explorer program}}
{{Sun spacecraft}}
{{Comet spacecraft}}

[[Category:Derelict space probes]]
[[Category:Missions to comets]]
[[Category:NASA space probes]]
[[Category:Explorers Program]]
[[Category:Spacecraft using halo orbits]]

{{Sourceattribution|International Cometary Explorer}}