Editing Europa (moon) (section)

== Exploration ==
{{multiple image
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 |caption1 = In 1973 ''[[Pioneer 10]]'' made the first closeup images of Europa. The probe was too far away to obtain more detailed images.
 |caption2 = Europa seen in detail in 1979 by ''[[Voyager 2]]''
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Gravitational calculations suggested by the start of 20th century that Europa's compsition was water rich, and Earth ground based observations by [[Gerard Kuiper]] revealed 1957 the water ice composition.<ref name="q533">{{cite web | last=Yazgin | first=Evrim | title=Astronomers believe that Jupiter's moon Callisto is a water world | website=Cosmos | date=February 22, 2025 | url=https://cosmosmagazine.com/space/astronomy/callisto-jupiter-moon-water/ | access-date=May 7, 2025}}</ref>

Exploration of Europa began with the Jupiter flybys of ''[[Pioneer 10]]'' and ''[[Pioneer 11|11]]'' in 1973 and 1974, respectively. The first closeup photos were of low resolution compared to later missions. The two Voyager probes traveled through the [[Jovian system]] in 1979, providing more-detailed images of Europa's icy surface. The images caused many scientists to speculate about the possibility of a liquid ocean underneath. 
Starting in 1995, the [[Galileo (spacecraft)|''Galileo'' space probe]] orbited Jupiter for eight years, until 2003, and provided the most detailed examination of the Galilean moons to date. It included the "Galileo Europa Mission" and "Galileo Millennium Mission", with numerous close flybys of Europa.<ref>[https://web.archive.org/web/20041104092641/http://solarsystem.nasa.gov/galileo/mission/journey-extended.cfm The Journey to Jupiter: Extended Tours – GEM and the Millennium Mission]. Solarsystem.nasa.gov. Retrieved on 23 July 2013.</ref> In 2007, ''[[New Horizons]]'' imaged Europa, as it flew by the Jovian system while on its way to [[Pluto]].<ref>{{cite web|url=http://photojournal.jpl.nasa.gov/catalog/PIA09246|title=PIA09246: Europa|date=2 April 2007|work=NASA photojournal|access-date=9 March 2016|archive-date=6 March 2016|archive-url=https://web.archive.org/web/20160306211111/http://photojournal.jpl.nasa.gov/catalog/PIA09246|url-status=live}}</ref> In 2022, the ''[[Juno (spacecraft)|Juno]]'' orbiter flew by Europa at a distance of 352&nbsp;km (219&nbsp;mi).<ref name="NYT-20220930"/><ref name="nasa-20220929">{{cite web |url=https://www.nasa.gov/feature/jpl/nasa-s-juno-shares-first-image-from-flyby-of-jupiter-s-moon-europa |title=NASA's Juno Shares First Image From Flyby of Jupiter's Moon Europa |work=[[NASA]] |date=29 September 2022 |access-date=30 September 2022 |archive-date=1 October 2022 |archive-url=https://web.archive.org/web/20221001003306/https://www.nasa.gov/feature/jpl/nasa-s-juno-shares-first-image-from-flyby-of-jupiter-s-moon-europa/ |url-status=live }}</ref>

In 2012, ''[[Jupiter Icy Moons Explorer]]'' (JUICE) was selected by the European Space Agency ([[European Space Agency|ESA]]) as a planned mission.<ref name="selection" /><ref name="l1">[http://planetary.s3.amazonaws.com/assets/resources/ESA/ESA-SPC_20120417_selection-L1-mission.pdf Selection of the L1 mission] {{Webarchive|url=https://web.archive.org/web/20151016065456/http://planetary.s3.amazonaws.com/assets/resources/ESA/ESA-SPC_20120417_selection-L1-mission.pdf |date=16 October 2015 }}. ESA, 17 April 2012. (PDF). Retrieved on 23 July 2013.</ref> That mission includes two flybys of Europa, but is more focused on [[Ganymede (moon)|Ganymede]].<ref name='juice-objectives'>{{cite web | url = http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=50068 | title = JUICE – Science objectives | access-date = 20 April 2012 | date = 16 March 2012 | work = [[European Space Agency]] | archive-date = 8 June 2013 | archive-url = https://web.archive.org/web/20130608082915/http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=50068 | url-status = live }}</ref> It was launched in 2023, and is expected to reach Jupiter in July 2031 after four gravity assists and eight years of travel.<ref name="juice-journey">{{cite web |url=https://www.esa.int/ESA_Multimedia/Videos/2022/03/Juice_s_journey_and_Jupiter_system_tour |title=Juice's journey and Jupiter system tour |work=[[ESA]] |date=29 March 2022 |access-date=3 April 2022 |archive-date=24 September 2022 |archive-url=https://web.archive.org/web/20220924065708/https://www.esa.int/ESA_Multimedia/Videos/2022/03/Juice_s_journey_and_Jupiter_system_tour |url-status=live }}</ref>

In 2011, a Europa mission was recommended by the U.S. [[Planetary Science Decadal Survey]].<ref name="zab">{{cite news | title=Lean U.S. missions to Mars, Jupiter moon recommended | url=https://www.reuters.com/article/us-space-usa-future-idUSTRE7266XJ20110308 | work=Reuters | date=7 March 2011 | last=Zabarenko | first=Deborah | access-date=5 July 2021 | archive-date=7 September 2020 | archive-url=https://web.archive.org/web/20200907012354/https://www.reuters.com/article/us-space-usa-future-idUSTRE7266XJ20110308 | url-status=live }}</ref> In response, NASA commissioned concept studies of a Europa lander in 2011, along with concepts for a Europa flyby (''Europa Clipper''), and a Europa orbiter.<ref>{{cite web | url=http://solarsystem.nasa.gov/missions/profile.cfm?MCode=EAL | title=Europa Lander | access-date=15 January 2014 | work=NASA | url-status=dead | archive-url=https://web.archive.org/web/20140116103022/http://solarsystem.nasa.gov/missions/profile.cfm?MCode=EAL | archive-date=16 January 2014 | df=dmy-all }}</ref><ref>[http://www.lpi.usra.edu/opag/mar2012/presentations/ March 2012 OPAG Meeting] {{Webarchive|url=https://web.archive.org/web/20160303174000/http://www.lpi.usra.edu/opag/mar2012/presentations/ |date=3 March 2016 }}. Lunar and Planetary Institute, NASA. Retrieved on 23 July 2013.</ref> The orbiter element option concentrates on the "ocean" science, while the multiple-flyby element (''Clipper'') concentrates on the chemistry and energy science. On 13 January 2014, the House Appropriations Committee announced a new bipartisan bill that includes $80&nbsp;million in funding to continue the Europa mission concept studies.<ref>{{cite news | first=Amina | last=Khan | title=NASA gets some funding for Mars 2020 rover in federal spending bill | date=15 January 2014 | url=http://www.latimes.com/science/sciencenow/la-sci-sn-federal-spending-omnibus-bill-nasa-congress-65-million-mars-2020-mission-20140115,0,7107985.story | work=Los Angeles Times | access-date=16 January 2014 | archive-date=21 April 2014 | archive-url=https://web.archive.org/web/20140421095615/http://www.latimes.com/science/sciencenow/la-sci-sn-federal-spending-omnibus-bill-nasa-congress-65-million-mars-2020-mission-20140115,0,7107985.story | url-status=live }}</ref><ref>{{cite news | first=Frank C. | last=Girardot | title=JPL's Mars 2020 rover benefits from spending bill | date=14 January 2014 | url=http://www.pasadenastarnews.com/science/20140114/jpls-mars-2020-rover-benefits-from-spending-bill | work=Pasadena Star-News | access-date=15 January 2014 | archive-date=31 July 2017 | archive-url=https://web.archive.org/web/20170731025001/http://www.pasadenastarnews.com/science/20140114/jpls-mars-2020-rover-benefits-from-spending-bill | url-status=live }}</ref>

In July 2013 an updated concept for a flyby Europa mission called ''[[Europa Clipper]]'' was presented by the [[Jet Propulsion Laboratory]] (JPL) and the [[Applied Physics Laboratory]] (APL).<ref>{{cite web |url=http://www.lpi.usra.edu/opag/jul2013/presentations/Clipper_Summary.pdf |title=The Europa Clipper – OPAG Update |date=2013 |first1=Robert |last1=Pappalardo |first2=Brian |last2=Cooke |first3=Barry |last3=Goldstein |first4=Louise |last4=Prockter |first5=Dave |last5=Senske |first6=Tom |last6=Magner |publisher=[[Jet Propulsion Laboratory|JPL]]/[[Applied Physics Laboratory|APL]] |access-date=13 December 2013 |archive-date=25 January 2021 |archive-url=https://web.archive.org/web/20210125054349/https://www.lpi.usra.edu/opag/jul2013/presentations/Clipper_Summary.pdf |url-status=live }}</ref> In May 2015, NASA announced that it had accepted development of the ''Europa Clipper'' mission, and revealed the instruments it would use.<ref name="EuropaClipperAnnounce">{{cite web| url=http://www.nasa.gov/press-release/nasa-s-europa-mission-begins-with-selection-of-science-instruments| title=NASA's Europa Mission Begins with Selection of Science Instruments| work=NASA| date=26 May 2015| access-date=3 July 2015| archive-date=5 July 2015| archive-url=https://web.archive.org/web/20150705103500/http://www.nasa.gov/press-release/nasa-s-europa-mission-begins-with-selection-of-science-instruments/| url-status=live}}</ref> The aim of ''Europa Clipper'' is to explore Europa in order to investigate its [[Planetary habitability|habitability]], and to aid in selecting sites for a future lander. The ''Europa Clipper'' would not orbit Europa, but instead orbit Jupiter and conduct 45 low-altitude [[Planetary flyby|flybys]] of Europa during its envisioned mission. The probe would carry an ice-penetrating radar, short-wave infrared spectrometer, topographical imager, and an ion- and neutral-mass spectrometer. The mission was launched on 14 October 2024 aboard a [[Falcon Heavy]].<ref name="nasa-202107232">{{Cite press release |title=NASA Awards Launch Services Contract for the Europa Clipper Mission |date=23 July 2021 |publisher=NASA |url=https://www.nasa.gov/press-release/nasa-awards-launch-services-contract-for-europa-clipper-mission |last1=Potter |first1=Sean |access-date=23 July 2021 |url-status=live |archive-url=https://web.archive.org/web/20210724020501/https://www.nasa.gov/press-release/nasa-awards-launch-services-contract-for-europa-clipper-mission/ |archive-date=24 July 2021}} {{PD-notice}}</ref>

=== Future missions ===

Conjectures regarding [[extraterrestrial life]] have ensured a high profile for Europa and have led to steady lobbying for future missions.<ref name="Europabudget">{{cite web |last=David |first=Leonard |url=http://www.space.com/news/060207_europa_budget.html |title=Europa Mission: Lost In NASA Budget |date=7 February 2006 |publisher=Space.com |access-date=25 February 2007 |archive-date=24 December 2010 |archive-url=https://web.archive.org/web/20101224030016/http://www.space.com/news/060207_europa_budget.html |url-status=live }}</ref><ref name="PlanetarySocEuropa">{{cite web|title=Projects: Europa Mission Campaign; Campaign Update: 2007 Budget Proposal |last=Friedman |first=Louis |date=14 December 2005 |url=http://www.planetary.org/programs/projects/explore_europa/update_12142005.html |archive-date=11 August 2011 |url-status=dead |publisher=The Planetary Society |archive-url=https://web.archive.org/web/20110811002508/http://www.planetary.org/programs/projects/explore_europa/update_12142005.html }}</ref> The aims of these missions have ranged from examining Europa's chemical composition to searching for extraterrestrial life in its hypothesized subsurface oceans.<ref name="EuropaLife">{{cite web |title=Thin ice opens lead for life on Europa |first=David L. |last=Chandler |date=20 October 2002 |url=https://www.newscientist.com/article.ns?id=dn2929 |work=New Scientist |access-date=27 August 2017 |archive-date=14 May 2008 |archive-url=https://web.archive.org/web/20080514182430/http://www.newscientist.com/article.ns?id=dn2929 |url-status=live }}</ref><ref name="Muir2002">Muir, Hazel (22 May 2002) [https://www.newscientist.com/article.ns?id=dn2313 ''Europa has raw materials for life''] {{Webarchive|url=https://web.archive.org/web/20080416015647/http://www.newscientist.com/article.ns?id=dn2313 |date=16 April 2008 }}, ''New Scientist''.</ref> Robotic missions to Europa need to endure the high-radiation environment around Jupiter.<ref name="PlanetarySocEuropa" /> Because it is deeply embedded within [[Jupiter's magnetosphere]], Europa receives about 5.40&nbsp;[[Sievert|Sv]] of radiation per day.<ref name="Ringwald2000">Ringwald, Frederick A. (29 February 2000) [http://zimmer.csufresno.edu/~fringwal/w08a.jup.txt ''SPS 1020 (Introduction to Space Sciences) Course Notes''] {{webarchive|url=https://web.archive.org/web/20080725050708/http://zimmer.csufresno.edu/~fringwal/w08a.jup.txt |date=25 July 2008 }}, California State University, csufresno.edu.</ref>

* [[Europa Lander (NASA)|Europa Lander]] is a recent NASA concept mission under study. 2018 research suggests Europa may be covered in tall, jagged ice spikes, presenting a problem for any potential landing on its surface.<ref>{{Cite web|url=https://www.theverge.com/2018/10/8/17948510/jupiter-moon-europa-nasa-clipper-lander-penitentes|title=Future spacecraft landing on Jupiter's moon Europa may have to navigate jagged blades of ice|last=Grush|first=Loren|date=8 October 2018|website=The Verge|access-date=16 April 2019|archive-date=28 March 2019|archive-url=https://web.archive.org/web/20190328070428/https://www.theverge.com/2018/10/8/17948510/jupiter-moon-europa-nasa-clipper-lander-penitentes|url-status=live}}</ref><ref>{{Cite news|url=https://www.washingtonpost.com/science/2018/10/08/jagged-ice-spikes-cover-jupiters-moon-europa-study-suggests/|title=Jagged ice spikes cover Jupiter's moon Europa, study suggests|last=Guarino|first=Ben|date=8 October 2018|newspaper=The Washington Post|access-date=15 April 2019|archive-date=16 April 2019|archive-url=https://web.archive.org/web/20190416012612/https://www.washingtonpost.com/science/2018/10/08/jagged-ice-spikes-cover-jupiters-moon-europa-study-suggests/|url-status=live}}</ref>

=== Old proposals ===
[[File:Cryobot.jpg|thumb|Artist's concept of the [[cryobot]] and its deployed "hydrobot" submersible]]
In the early 2000s, ''[[Jupiter Europa Orbiter]]'' led by NASA and the ''[[Jupiter Ganymede Orbiter]]'' led by the ESA were proposed together as an [[Outer Planet Flagship Mission]] to Jupiter's icy moons called [[Europa Jupiter System Mission]], with a planned launch in 2020.<ref name="NASA2009">{{cite web |url=http://www.nasa.gov/topics/solarsystem/features/20090218.html |title=NASA and ESA Prioritize Outer Planet Missions |access-date=26 July 2009 |publisher=NASA |date=2009 |archive-date=25 August 2011 |archive-url=https://web.archive.org/web/20110825211633/http://www.nasa.gov/topics/solarsystem/features/20090218.html |url-status=live }}</ref> In 2009 it was given priority over ''[[Titan Saturn System Mission]]''.<ref name="Rincon2009">{{cite news |url=http://news.bbc.co.uk/1/hi/sci/tech/7897585.stm |title=Jupiter in space agencies' sights |first=Paul |last=Rincon |work=BBC News |access-date=20 February 2009 |date=20 February 2009 |archive-date=21 February 2009 |archive-url=https://web.archive.org/web/20090221185643/http://news.bbc.co.uk/1/hi/sci/tech/7897585.stm |url-status=live }}</ref> At that time, there was competition from other proposals.<ref name="ESA2007">{{cite web |url=http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=41177 |title=Cosmic Vision 2015–2025 Proposals |date=21 July 2007 |publisher=ESA |access-date=20 February 2009 |archive-date=2 September 2011 |archive-url=https://web.archive.org/web/20110902033453/http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=41177 |url-status=live }}</ref> [[JAXA|Japan]] proposed ''[[Jupiter Magnetospheric Orbiter]]''.

''[[Jovian Europa Orbiter]]'' was an ESA Cosmic Vision concept study from 2007. Another concept was ''Ice Clipper'',<ref name="McKay2002">{{cite journal | title = Planetary protection for a Europa surface sample return: The Ice Clipper mission | journal = Advances in Space Research | date = 2002 | first1 = C. P. | volume = 30 | issue = 6 | pages = 1601–1605 | doi = 10.1016/S0273-1177(02)00480-5 | bibcode = 2002AdSpR..30.1601M | last1 = McKay | url = https://zenodo.org/record/1259969 | access-date = 29 June 2019 | archive-date = 31 July 2020 | archive-url = https://web.archive.org/web/20200731020206/https://zenodo.org/record/1259969 | url-status = live }}</ref> which would have used an impactor similar to the ''[[Deep Impact (spacecraft)|Deep Impact]]'' mission—it would make a controlled crash into the surface of Europa, generating a plume of debris that would then be collected by a small spacecraft flying through the plume.<ref name="McKay2002"/><ref name="Goodman1998">Goodman, Jason C. (9 September 1998) [http://www.madsci.org/posts/archives/oct98/905357947.As.r.html ''Re: Galileo at Europa''] {{Webarchive|url=https://web.archive.org/web/20120301191547/http://www.madsci.org/posts/archives/oct98/905357947.As.r.html |date=1 March 2012 }}, MadSci Network forums.</ref>

''[[Jupiter Icy Moons Orbiter]]'' (JIMO) was a partially developed fission-powered spacecraft with ion thrusters that was cancelled in 2006.<ref name="PlanetarySocEuropa" /><ref name="Budget" /> It was part of [[Project Prometheus]].<ref name="Budget">Berger, Brian; [http://www.space.com/news/nasa_budget_050207.html ''NASA 2006 Budget Presented: Hubble, Nuclear Initiative Suffer''] {{Webarchive|url=https://web.archive.org/web/20090602123151/http://www.space.com/news/nasa_budget_050207.html |date=2 June 2009 }} [[Space.com]] (7 February 2005)</ref> The ''Europa Lander Mission'' proposed a small nuclear-powered Europa lander for JIMO.<ref name="elm">[https://web.archive.org/web/20061006071438/http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/37545/1/05-0403.pdf Abelson & Shirley – Small RPS-Enabled Europa Lander Mission (2005)]. . (PDF). Retrieved on 23 July 2013.</ref> It would travel with the orbiter, which would also function as a communication relay to Earth.<ref name="elm" />

''[[Europa Orbiter]]'' – Its objective would be to characterize the extent of the ocean and its relation to the deeper interior. Instrument payload could include a radio subsystem, [[Lidar|laser altimeter]], [[magnetometer]], [[Langmuir probe]], and a mapping camera.<ref>[http://www.lpi.usra.edu/opag/mar2012/presentations/Europa_Reports/1_Europa_Mission_Studies.pdf 2012 Europa Mission Studies] {{Webarchive|url=https://web.archive.org/web/20130603140459/http://www.lpi.usra.edu/opag/mar2012/presentations/Europa_Reports/1_Europa_Mission_Studies.pdf |date=3 June 2013 }}. OPAG 29 March 2012 (PDF). Lunar and Planetary Institute, NASA. Retrieved on 23 July 2013.</ref><ref>{{citation | contribution=Europa Study 2012 Report | title=Europa Orbiter Mission| author=Europa Study Team | publisher=JPL – NASA | date=1 May 2012 | contribution-url=http://solarsystem.nasa.gov/europa/docs/ES%202012%20Report%20B%20Orbiter%20-%20Final%20-%2020120501.pdf | url=http://solarsystem.nasa.gov/europa/docs/ES%202012%20Report%20B%20Orbiter%20-%20Final%20-%2020120501.pdf | access-date=17 January 2014 | archive-url=https://web.archive.org/web/20140202105451/http://solarsystem.nasa.gov/europa/docs/ES%202012%20Report%20B%20Orbiter%20-%20Final%20-%2020120501.pdf | archive-date=2 February 2014 | url-status=dead | df=dmy-all }}</ref> The ''Europa Orbiter'' received the go-ahead in 1999 but was canceled in 2002. This orbiter featured a special ice-penetrating radar that would allow it to scan below the surface.<ref name="waterworld" />

More ambitious ideas have been put forward including an impactor in combination with a thermal drill to search for [[biosignature]]s that might be frozen in the shallow subsurface.<ref name="Weiss2010">{{Cite journal | last1 = Weiss | first1 = P. | last2 = Yung | first2 = K. L. | last3 = Kömle | first3 = N. | last4 = Ko | first4 = S. M. | last5 = Kaufmann | first5 = E. | last6 = Kargl | first6 = G. | doi = 10.1016/j.asr.2010.01.015 | title = Thermal drill sampling system onboard high-velocity impactors for exploring the subsurface of Europa | journal = Advances in Space Research | volume = 48 | issue = 4 | page = 743 | year = 2011 |bibcode = 2011AdSpR..48..743W | hdl = 10397/12621 | hdl-access = free }}</ref><ref name="Thermal">{{cite web
 |title=Dual Drill Designed for Europa's Ice 
 |last=Hsu 
 |first=J. 
 |url=http://www.astrobio.net/exclusive/3463/dual-drill-designed-for-europa’s-ice 
 |publisher=Astrobiology Magazine 
 |date=15 April 2010 |archive-url=https://web.archive.org/web/20100418204646/http://www.astrobio.net/exclusive/3463/dual-drill-designed-for-europa%E2%80%99s-ice 
 |archive-date=18 April 2010 |url-status=usurped 
}}</ref>

Another proposal put forward in 2001 calls for a large [[nuclear power|nuclear-powered]] "melt probe" ([[cryobot]]) that would melt through the ice until it reached an ocean below.<ref name="PlanetarySocEuropa" /><ref name="Knight2002">{{cite web | last=Knight | first=Will | date=14 January 2002 | url=https://www.newscientist.com/article.ns?id=dn1786 | title=Ice-melting robot passes Arctic test | work=New Scientist | access-date=27 August 2017 | archive-date=17 March 2008 | archive-url=https://web.archive.org/web/20080317083303/http://www.newscientist.com/article.ns?id=dn1786 | url-status=live }}</ref> Once it reached the water, it would deploy an autonomous underwater vehicle ([[AUV|hydrobot]]) that would gather information and send it back to Earth.<ref name="Bridges2000">{{cite web | last=Bridges | first=Andrew | date=10 January 2000 | archive-url=https://web.archive.org/web/20090208150400/http://www.space.com/searchforlife/europa_ocean_update_000110.html | archive-date=8 February 2009 | url-status=live | url=http://www.space.com/searchforlife/europa_ocean_update_000110.html | title=Latest Galileo Data Further Suggest Europa Has Liquid Ocean | publisher=Space.com }}</ref> Both the cryobot and the hydrobot would have to undergo some form of extreme sterilization to prevent detection of Earth organisms instead of native life and to prevent [[Forward-contamination|contamination]] of the subsurface ocean.<ref name="NASSSB">{{Cite book |url=http://www7.nationalacademies.org/ssb/europamenu.html |title=Preventing the Forward Contamination of Europa |date=2000 |publisher=National Academy Press |isbn=978-0-309-57554-6 |location=Washington (DC) |archive-url=https://web.archive.org/web/20080213194509/http://www7.nationalacademies.org/ssb/europamenu.html |archive-date=13 February 2008 |url-status=live}}</ref> This suggested approach has not yet reached a formal conceptual planning stage.<ref name="Powell2005">{{cite journal |title=NEMO: A mission to search for and return to Earth possible life forms on Europa |last1=Powell |first1=Jesse |last2=Powell |first2=James |last3=Maise |first3=George |last4=Paniagua |first4=John |journal=Acta Astronautica |volume=57 |issue=2–8 |pages=579–593 |date=2005|doi=10.1016/j.actaastro.2005.04.003 |bibcode=2005AcAau..57..579P }}</ref>