Exploration of Jupiter#Human exploration

File:Portrait of Jupiter from Cassini.jpg]]

Flights from Earth to other planets in the Solar System have a high energy cost. It requires almost the same amount of energy for a spacecraft to reach Jupiter from Earth's orbit as it does to lift it into orbit in the first place. In astrodynamics, this energy expenditure is defined by the net change in the spacecraft's velocity, or delta-v. The energy needed to reach Jupiter from an Earth orbit requires a delta-v of about 9 km/s,{{cite web | last = Wong | first = Al |date= May 28, 1998 | url = http://www2.jpl.nasa.gov/galileo/faqnav.html | archive-url = https://web.archive.org/web/19970105184300/http://www.jpl.nasa.gov/galileo/faqnav.html | url-status = dead | archive-date = January 5, 1997 | title = Galileo FAQ – Navigation | publisher = NASA |access-date=November 28, 2006}} compared to the 9.0–9.5 km/s to reach a low Earth orbit from the ground.{{cite journal |last1=Burton |first1=Rodney L. |author2=Brown, Kevin; Jacobi, Anthony |title=Low Cost Launch of Payloads to Low Earth Orbit |journal=Journal of Spacecraft and Rockets |year=2006 |volume=43 |pages=696–698 |issue=3 |doi=10.2514/1.16244 |url=http://www.ae.uiuc.edu/ISJ/Reports/BurtonJSRPaper.pdf |bibcode=2006JSpRo..43..696B |url-status=dead |archive-url=https://web.archive.org/web/20091229175301/http://www.ae.uiuc.edu/ISJ/Reports/BurtonJSRPaper.pdf |archive-date=December 29, 2009}} Gravity assists through planetary flybys (such as by Earth or Venus) can be used to reduce the energetic requirement (i.e. the fuel) at launch, at the cost of a significantly longer flight duration to reach a target such as Jupiter when compared to the direct trajectory.Fischer, 1999, p. 44 Ion thrusters capable of a delta-v of more than 10 km/s were used on the Dawn spacecraft. This is more than enough delta-v to do a Jupiter fly-by mission from a solar orbit of the same radius as that of Earth without gravity assist.CRC Handbook of Chemistry and Physics, 64th EDITION, (C) 1983, page F-141

Jupiter has no solid surface on which to land, as there is a smooth transition between the planet's atmosphere and its fluid interior. Any probes descending into the atmosphere are eventually crushed by the immense pressures within Jupiter.{{cite journal|last=Guillot|first=Tristan|title=A comparison of the interiors of Jupiter and Saturn|journal=Planetary and Space Science|volume=47|issue=10–11|pages=1183–1200|year=1999|doi=10.1016/S0032-0633(99)00043-4|bibcode=1999P&SS...47.1183G|arxiv=astro-ph/9907402|s2cid=19024073|url=https://cds.cern.ch/record/394768|access-date=September 27, 2018|archive-date=October 20, 2019|archive-url=https://web.archive.org/web/20191020081612/https://cds.cern.ch/record/394768/|url-status=live}}

A major issue with sending probes to Jupiter is the amount of radiation to which a space probe is subjected, due to the harsh charged-particle environment around Jupiter (for a detailed explanation see Magnetosphere of Jupiter). For example, when Pioneer 11 made its closest approach to the planet, the level of radiation was ten times more powerful than Pioneer{{'}}s designers had predicted, leading to fears that the probes would not survive. With a few minor glitches, the probe managed to pass through the radiation belts, but it lost most of the images of the moon Io, as the radiation had caused Pioneer's imaging photo polarimeter to receive false commands.{{cite book|title=The Depths of Space|author=Wolverton, Mark|publisher=Joseph Henry Press|year=2004|pages=[https://archive.org/details/depthsofspacesto0000wolv/page/130 130]|isbn=978-0-309-09050-6|url=https://archive.org/details/depthsofspacesto0000wolv/page/130}} The subsequent and far more technologically advanced Voyager spacecraft had to be redesigned to cope with the radiation levels. Over the eight years the Galileo spacecraft orbited the planet, the probe's radiation dose far exceeded its design specifications, and its systems failed on several occasions. The spacecraft's gyroscopes often exhibited increased errors, and electrical arcs sometimes occurred between its rotating and non-rotating parts, causing it to enter safe mode, which led to total loss of the data from the 16th, 18th and 33rd orbits. The radiation also caused phase shifts in Galileo's ultra-stable quartz oscillator.{{cite journal|doi=10.1109/TNS.2002.805386|title=The radiation effects on Galileo spacecraft systems at Jupiter|year=2002|author=Fieseler, P.D.|journal=IEEE Transactions on Nuclear Science|volume=49|issue=6|page=2739|last2=Ardalan|first2=S.M.|last3=Frederickson|first3=A.R.|bibcode = 2002ITNS...49.2739F }}

{{multiple image|align=center|total_width=400|caption_align=center|image1=Map of Jupiter (square).jpg|caption1=South pole (Cassini; 2000)|image2=PIA21641-Jupiter-SouthernStorms-JunoCam-cropped.jpg|caption2=South pole (Juno; 2017){{cite news |last=Chang |first=Kenneth |title=NASA's Jupiter Mission Reveals the 'Brand-New and Unexpected' |url=https://www.nytimes.com/2017/05/25/science/nasa-juno-spacecraft-jupiter-storms.html |date=May 25, 2017 |work=The New York Times |access-date=May 27, 2017 |archive-date=November 16, 2018 |archive-url=https://web.archive.org/web/20181116140104/https://www.nytimes.com/2017/05/25/science/nasa-juno-spacecraft-jupiter-storms.html |url-status=live }}|width2=160}}

{{See also|Pioneer 10|Pioneer 11}}

File:Animation of Pioneer 11 trajectory around Jupiter.gif{{'s}} trajectory around Jupiter from 30 November 1974 to 5 December 1974
{{legend2|magenta| Pioneer 11}}{{·}}{{legend2|Lime |Jupiter}}{{·}}{{legend2|Royalblue|Io}}{{·}}{{legend2| Cyan |Europa}} {{·}}{{legend2| Gold |Ganymede}} {{·}}{{legend2| OrangeRed |Callisto}}]]

File:Pioneer 10 jup.jpg

The first spacecraft to explore Jupiter was Pioneer 10, which flew past the planet in December 1973, followed by Pioneer 11 twelve months later. Pioneer 10 obtained the first close-up images of Jupiter and its Galilean moons; the spacecraft studied the planet's atmosphere, detected its magnetic field, observed its radiation belts and determined that Jupiter is mainly fluid.{{cite journal|title= Solar heating and internal heat flow on Jupiter|author1=Andrew P. Ingersoll |author2=Carolyn C. Porco | journal=Icarus|volume=35|issue=1|date=July 1978|pages=27–43|doi=10.1016/0019-1035(78)90058-1|bibcode=1978Icar...35...27I}}{{cite web|title=Pioneer spacecraft sends last signal|author=Michael Mewhinney|publisher=NASA|year=2003|url=http://www.nasa.gov/centers/ames/news/releases/2003/03_25HQ.html|access-date=June 28, 2009|archive-date=June 28, 2012|archive-url=https://web.archive.org/web/20120628154600/http://www.nasa.gov/centers/ames/news/releases/2003/03_25HQ.html|url-status=live}} Pioneer 11 made its closest approach, within some 43,000 km of Jupiter's cloud tops, on December 3, 1974. It obtained dramatic images of the Great Red Spot, made the first observation of Jupiter's immense polar regions, and determined the mass of Jupiter's moon Callisto. The information gathered by these two spacecraft helped astronomers and engineers improve the design of future probes to cope more effectively with the environment around the giant planet.{{cite web|title=The Pioneer missions|year=2007|publisher=NASA|url=http://www.nasa.gov/centers/ames/missions/archive/pioneer.html|access-date=June 28, 2009|archive-date=January 30, 2006|archive-url=https://web.archive.org/web/20060130100401/http://spaceprojects.arc.nasa.gov/Space_Projects/pioneer/PN10%2611.html|url-status=live}}{{cite web|title=Pioneer 11|publisher=NASA|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1973-019A|access-date=June 28, 2009|archive-date=June 13, 2017|archive-url=https://web.archive.org/web/20170613104823/https://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1973-019A|url-status=live}}

File:790106-0203 Voyager 58M to 31M reduced.gif

{{See also|Voyager program|Voyager 1|Voyager 2}}

Voyager 1 began photographing Jupiter in January 1979 and made its closest approach on March 5, 1979, at a distance of 349,000 km from Jupiter's center.{{cite journal|jstor=1748134 | doi = 10.1126/science.204.4396.945|date=June 1979|vauthors=Stone EC, Lane AL|title=Voyager 1 Encounter with the Jovian System |volume= 204 | issue = 4396| pages=945–948 |pmid=17800428|journal=Science |bibcode = 1979Sci...204..945S| s2cid = 44517302}} This close approach allowed for greater image resolution, though the flyby's short duration meant that most observations of Jupiter's moons, rings, magnetic field, and radiation environment were made in the 48-hour period bracketing the approach, even though Voyager 1 continued photographing the planet until April. It was soon followed by Voyager 2, which made its closest approach on July 9, 1979, 576,000 km away from the planet's cloud tops.{{cite web |url=http://ciclops.org/view/3606/First_Close-up_Image_of_Jupiter_from_Voyager_1?js=1 |title=First Close-up Image of Jupiter from Voyager 1 (NASA Voyager Jupiter Encounter Images) |publisher=Ciclops.org |access-date=May 20, 2009 |archive-date=February 15, 2012 |archive-url=https://web.archive.org/web/20120215152950/http://ciclops.org/view/3606/First_Close-up_Image_of_Jupiter_from_Voyager_1?js=1 |url-status=live }}{{cite journal|title=Voyager 2 Encounter with the Jovian System|author1=E. C. Stone |author2=A. L. Lane |date= October 5, 1979|journal=Science|volume=206|issue= 4421|pages= 925–927|doi= 10.1126/science.206.4421.925|pmid=17733909|bibcode = 1979Sci...206..925S |s2cid=46470902 }} The probe discovered Jupiter's ring, observed intricate vortices in its atmosphere, observed active volcanoes on Io, a process analogous to plate tectonics on Ganymede, and numerous craters on Callisto.{{cite journal|doi=10.1126/science.204.4396.951|date=June 1979|vauthors=Smith BA, Soderblom LA, Johnson TV, Ingersoll AP, Collins SA, Shoemaker EM, Hunt GE, Masursky H, Carr MH, Davies ME, Cook AF II, Boyce J, Danielson GE, Owen T, Sagan C, Beebe RF, Veverka J, Strom RG, Mccauley JF, Morrison D, Briggs GA, Suomi, VE|title=The Jupiter System Through the Eyes of Voyager 1|volume=204|issue=4396|pages=951–972 |pmid=17800430|journal=Science|bibcode=1979Sci...204..951S|s2cid=33147728}}

The Voyager missions vastly improved our understanding of the Galilean moons, and also discovered Jupiter's rings. They also took the first close-up images of the planet's atmosphere, revealing the Great Red Spot as a complex storm moving in a counter-clockwise direction. Other smaller storms and eddies were found throughout the banded clouds (see animation on the right).{{cite web | date = January 14, 2003 | url = http://voyager.jpl.nasa.gov/science/jupiter.html | title = Jupiter | publisher = NASA Jet Propulsion Laboratory | access-date = November 28, 2006 | archive-date = June 28, 2012 | archive-url = https://web.archive.org/web/20120628073053/http://voyager.jpl.nasa.gov/science/jupiter.html | url-status = live }} Two new, small satellites, Adrastea and Metis, were discovered orbiting just outside the ring, making them the first of Jupiter's moons to be identified by a spacecraft.{{cite journal|url=http://www.cfa.harvard.edu/iauc/03500/03507.html|journal=IAU Circular|issue=3507|title=Satellites of Jupiter|date=August 26, 1980|author=Brian G. Marsden|access-date=June 5, 2009|archive-date=March 6, 2020|archive-url=https://web.archive.org/web/20200306212733/http://www.cfa.harvard.edu/iauc/03500/03507.html|url-status=live}}(discovery){{cite journal|last= Synnott |first= S.P. |title=1979J3: Discovery of a Previously Unknown Satellite of Jupiter |journal=Science |year=1981|volume=212|issue=4501|pages= 1392 |jstor=1686790 |doi=10.1126/science.212.4501.1392 |pmid=17746259 |bibcode=1981Sci...212.1392S |issn=0036-8075}} A third new satellite, Thebe, was discovered between the orbits of Amalthea and Io.{{cite encyclopedia |last1=Burns |first1=J. A. |last2=Simonelli |last3=Showalter |last4=Hamilton |last5=Porco |first5=Carolyn C. |last6=Throop |last7=Esposito |chapter=Jupiter's Ring-Moon System |title=Jupiter: The Planet, Satellites and Magnetosphere |year=2004 |editor=Bagenal, Fran |editor2=Dowling, Timothy E. |editor3=McKinnon, William B. |chapter-url=http://www.astro.umd.edu/~hamilton/research/preprints/BurSimSho03.pdf |bibcode=2004jpsm.book..241B |page=241 |access-date=May 20, 2009 |archive-date=May 12, 2006 |archive-url=https://web.archive.org/web/20060512204155/http://www.astro.umd.edu/~hamilton/research/preprints/BurSimSho03.pdf |url-status=live }}

The discovery of volcanic activity on the moon Io was the greatest unexpected finding of the mission, as it was the first time an active volcano was observed on a celestial body other than Earth. Together, the Voyagers recorded the eruption of nine volcanoes on Io, as well as evidence for other eruptions occurring between the Voyager encounters.{{cite journal |title=Volcanic eruption plumes on Io |journal=Nature |last1=Strom |first1=R. G. |display-authors=etal |pages=733–736 |volume=280 |issue= 5725|year=1979 |doi=10.1038/280733a0|bibcode = 1979Natur.280..733S |s2cid=8798702 |doi-access=free }}

Europa displayed a large number of intersecting linear features in the low-resolution photos from Voyager 1. At first, scientists believed the features might be deep cracks, caused by crustal rifting or tectonic processes. The high-resolution photos from Voyager 2, taken closer to Jupiter, left scientists puzzled as the features in these photos were almost entirely lacking in topographic relief. This led many to suggest that these cracks might be similar to ice floes on Earth, and that Europa might have a liquid water interior.{{cite journal|title=Fault offsets and lateral crustal movement on Europa: Evidence for a mobile ice shell|author1=Paul M. Schenk |author2=William B. McKinnon |journal= Icarus|volume=79|issue=1|date=May 1989|pages=75–100|doi=10.1016/0019-1035(89)90109-7|bibcode=1989Icar...79...75S}} Europa may be internally active due to tidal heating at a level about one-tenth that of Io, and as a result, the moon is thought to have a thin crust less than {{convert|30|km|mi|sp=us}} thick of water ice, possibly floating on a {{convert|50|km|mi|adj=mid|-deep|sp=us}} ocean.{{cite journal|doi=10.1016/0019-1035(83)90053-2 |title=Voyager photometry of Europa |author=Buratti, B|journal=Icarus|volume=55|issue=1|pages=93 |bibcode=1983Icar...55...93B|last2=Veverka|first2=Joseph|date=1983 }}

{{See also|Ulysses (spacecraft)}}

On February 8, 1992, the Ulysses solar probe flew past Jupiter's north pole at a distance of 451,000 km.{{cite journal|doi= 10.1126/science.257.5076.1503|jstor= 2879932|date=September 1992|vauthors= Smith EJ, Wenzel KP, Page DE|title= Ulysses at Jupiter: An Overview of the Encounter|volume= 257|issue= 5076|pages= 1503–1507|pmid= 17776156|journal= Science|bibcode= 1992Sci...257.1503S|s2cid= 19307704|url= http://pdfs.semanticscholar.org/cc3e/4f9e8fd467b19c1ff02d88a521d8c64adf77.pdf|archive-url= https://web.archive.org/web/20190303155949/http://pdfs.semanticscholar.org/cc3e/4f9e8fd467b19c1ff02d88a521d8c64adf77.pdf|url-status= dead|archive-date= 2019-03-03}} This swing-by maneuver was required for Ulysses to attain a very high-inclination orbit around the Sun, increasing its inclination to the ecliptic to 80.2 degrees.{{cite web | author1 = K. Chan | author2 = E. S. Paredes | author3 = M. S. Ryne | year = 2004 | url = http://www.aiaa.org/Spaceops2004Archive/downloads/papers/SPACE2004sp-template00447F.pdf | title = Ulysses Attitude and Orbit Operations: 13+ Years of International Cooperation | publisher = American Institute of Aeronautics and Astronautics | access-date = November 28, 2006 | url-status = dead | archive-url = https://web.archive.org/web/20051214075825/http://www.aiaa.org/Spaceops2004Archive/downloads/papers/SPACE2004sp-template00447F.pdf | archive-date = December 14, 2005}} The giant planet's gravity bent the spacecraft's flightpath downward and away from the ecliptic plane, placing it into a final orbit around the Sun's north and south poles. The size and shape of the probe's orbit were adjusted to a much smaller degree, so that its aphelion remained at approximately 5 AU (Jupiter's distance from the Sun), while its perihelion lay somewhat beyond 1 AU (Earth's distance from the Sun). During its Jupiter encounter, the probe made measurements of the planet's magnetosphere. Since the probe had no cameras, no images were taken. In February 2004, the probe arrived again at the vicinity of Jupiter. This time the distance from the planet was much greater—about 120 million km (0.8 AU)—but it made further observations of Jupiter.{{cite journal | doi = 10.1016/j.pss.2006.01.007 | pages = 21–31 | title = Localized "Jets" of Jovian electrons observed during Ulysses' distant Jupiter flyby in 2003–2004 | year = 2007 | issue = 1–2 | journal = Planetary and Space Science | volume = 55 | last1 = Mckibben | first1 = R | last2 = Zhang | first2 = M | last3 = Heber | first3 = B | last4 = Kunow | first4 = H | last5 = Sanderson | first5 = T | bibcode=2007P&SS...55...21M}}{{cite web |url=http://ulysses.jpl.nasa.gov/science/jupiter_two.html |title=Ulysses – Science – Jupiter Distant Encounter Selected References |publisher=NNASA |access-date=October 21, 2008 |url-status=dead |archive-url=https://web.archive.org/web/20080923065057/http://ulysses.jpl.nasa.gov/science/jupiter_two.html |archive-date=September 23, 2008}}

{{See also|Cassini–Huygens}}

In 2000, the Cassini probe, en route to Saturn, flew by Jupiter and provided some of the highest-resolution images ever taken of the planet. It made its closest approach on December 30, 2000, and made many scientific measurements. About 26,000 images of Jupiter were taken during the months-long flyby. It produced the most detailed global color portrait of Jupiter yet, in which the smallest visible features are approximately {{convert|60|km|mi|abbr=on}} across.{{cite journal|title= The Cassini–Huygens flyby of Jupiter|vauthors=Hansen CJ, Bolton SJ, Matson DL, Spilker LJ, Lebreton JP|journal=Icarus |volume=172|issue= 1|pages= 1–8|year=2004 | doi = 10.1016/j.icarus.2004.06.018|bibcode=2004Icar..172....1H}}

A major finding of the flyby, announced on March 5, 2003, was of Jupiter's atmospheric circulation. Dark belts alternate with light zones in the atmosphere, and the zones, with their pale clouds, had previously been considered by scientists to be areas of upwelling air, partly because on Earth clouds tend to be formed by rising air. Analysis of Cassini imagery showed that the dark belts contain individual storm cells of upwelling bright-white clouds, too small to see from Earth. Anthony Del Genio of NASA's Goddard Institute for Space Studies said that "the belts must be the areas of net-rising atmospheric motion on Jupiter, [so] the net motion in the zones has to be sinking".{{cite web|url=http://saturn.jpl.nasa.gov/news/press-releases-03/20030306-pr-a.cfm|archive-url=https://web.archive.org/web/20071121185126/http://saturn.jpl.nasa.gov/news/press-releases-03/20030306-pr-a.cfm|archive-date=November 21, 2007 |title=Cassini-Huygens: News-Press Releases-2003 |publisher=NASA |url-status=dead|access-date=October 21, 2008}}

Other atmospheric observations included a swirling dark oval of high atmospheric-haze, about the size of the Great Red Spot, near Jupiter's north pole. Infrared imagery revealed aspects of circulation near the poles, with bands of globe-encircling winds, and adjacent bands moving in opposite directions. The same announcement also discussed the nature of Jupiter's rings. Light scattering by particles in the rings showed the particles were irregularly shaped (rather than spherical) and likely originated as ejecta from micrometeorite impacts on Jupiter's moons, probably on Metis and Adrastea. On December 19, 2000, the Cassini spacecraft captured a very-low-resolution image of the moon Himalia, but it was too distant to show any surface details.

File:Tvashtarvideo.gif, as recorded by New Horizons in 2008]]

{{See also|New Horizons}}

The New Horizons probe, en route to Pluto, flew by Jupiter for a gravity assist and was the first probe launched directly towards Jupiter since the Ulysses in 1990. Its Long Range Reconnaissance Imager (LORRI) took its first photographs of Jupiter on September 4, 2006.{{cite web|last=Alexander|first=Amir|date=September 27, 2006|url=http://www.planetary.org/news/2006/0927_New_Horizons_Snaps_First_Picture_of.html|title=New Horizons Snaps First Picture of Jupiter|publisher=The Planetary Society|access-date=December 19, 2006|url-status=dead|archive-url=https://web.archive.org/web/20070221220556/http://www.planetary.org/news/2006/0927_New_Horizons_Snaps_First_Picture_of.html|archive-date=February 21, 2007}} The spacecraft began further study of the Jovian system in December 2006, and made its closest approach on February 28, 2007.{{cite web|url=http://pluto.jhuapl.edu/news_center/news/092606.html |title=Jupiter, Ahoy!|website=New Horizons Web Site |publisher=Johns Hopkins University |access-date=November 2, 2008 |url-status=dead |archive-url=https://web.archive.org/web/20080907192302/http://pluto.jhuapl.edu/news_center/news/092606.html |archive-date=September 7, 2008}}{{cite journal|arxiv=0709.4417|doi=10.1007/s11214-007-9295-y|title=The New Horizons Pluto Kuiper Belt Mission: An Overview with Historical Context|year=2008|author=Stern, S. Alan|journal=Space Science Reviews|volume=140|issue=1–4|pages=3–21|bibcode = 2008SSRv..140....3S |s2cid=119197398}}{{cite news|title=NASA Spacecraft Gets Boost From Jupiter for Pluto Encounter.|publisher=The America's Intelligence Wire |date=February 28, 2007|url= http://www.accessmylibrary.com/coms2/summary_0286-29823040_ITM |url-status=dead |archive-url=https://web.archive.org/web/20090705090005/http://www.accessmylibrary.com/coms2/summary_0286-29823040_ITM |archive-date=July 5, 2009 |access-date=March 23, 2014}}

Although close to Jupiter, New Horizons{{'}} instruments made refined measurements of the orbits of Jupiter's inner moons, particularly Amalthea. The probe's cameras measured volcanoes on Io, studied all four Galilean moons in detail, and made long-distance studies of the outer moons Himalia and Elara.{{cite journal|arxiv=0709.4278|doi=10.1007/s11214-007-9271-6|title=Long-Range Reconnaissance Imager on New Horizons|year=2008|journal=Space Science Reviews|volume=140|issue=1–4|pages=189–215|last1=Cheng|first1=A. F.|last2=Weaver|first2=H. A.|last3=Conard|first3=S. J.|last4=Morgan|first4=M. F.|last5=Barnouin-Jha|first5=O.|last6=Boldt|first6=J. D.|last7=Cooper|first7=K. A.|last8=Darlington|first8=E. H.|last9=Grey|first9=M. P.|last10=Hayes|first10=J. R.|last11=Kosakowski|first11=K. E.|last12=Magee|first12=T.|last13=Rossano|first13=E.|last14=Sampath|first14=D.|last15=Schlemm|first15=C.|last16=Taylor|first16=H. W.|bibcode = 2008SSRv..140..189C |s2cid=118330150|display-authors=8}} The craft also studied Jupiter's Little Red Spot and the planet's magnetosphere and tenuous ring system.{{cite web|title=Fantastic Flyby|date=May 1, 2007|publisher=NASA|url=https://science.nasa.gov/headlines/y2007/01may_fantasticflyby.htm|access-date=July 2, 2009|url-status=dead|archive-url=https://web.archive.org/web/20090725133611/http://science.nasa.gov/headlines/y2007/01may_fantasticflyby.htm|archive-date=July 25, 2009}}

On March 19, 2007, the Command and Data Handling computer experienced an uncorrectable memory error and rebooted itself, causing the spacecraft to go into safe mode. The craft fully recovered within two days, with some data loss on Jupiter's magnetotail. No other data loss events were associated with the encounter. Due to the immense size of the Jupiter system and the relative closeness of the Jovian system to Earth in comparison to the closeness of Pluto to Earth, New Horizons sent back more data to Earth from the Jupiter encounter than the Pluto encounter.

{{Main|Galileo project|Galileo (spacecraft)}}

File:Animation of Galileo trajectory around Jupiter.gif{{'s}} trajectory around Jupiter from 1 August 1995 to 30 September 2003
{{legend2|magenta| Galileo}}{{·}}{{legend2| Lime |Jupiter}}{{·}}{{legend2|OrangeRed|Io}}{{·}}{{legend2|RoyalBlue|Europa}}{{·}}{{legend2| Gold |Ganymede}}{{·}}{{legend2|Cyan|Callisto}}]]

The first spacecraft to orbit Jupiter was the Galileo orbiter, which went into orbit around Jupiter on December 7, 1995. It orbited the planet for over seven years, making 35 orbits before it was destroyed during a controlled impact with Jupiter on September 21, 2003.{{cite web|url=http://www.jpl.nasa.gov/news/fact_sheets/galileo0309.pdf|title=Galileo Mission to Jupiter|publisher=NASA/Jet Propulsion Laboratory|access-date=July 9, 2009|archive-date=July 10, 2012|archive-url=https://web.archive.org/web/20120710091653/http://www.jpl.nasa.gov/news/fact_sheets/galileo0309.pdf|url-status=live}} During this period, it gathered a large amount of information about the Jovian system; the amount of information was not as great as intended because the deployment of its high-gain radio transmitting antenna failed.{{cite web |last=McConnell |first=Shannon |date=April 14, 2003 |url=http://www2.jpl.nasa.gov/galileo/ |archive-url=https://web.archive.org/web/19970105070343/http://www.jpl.nasa.gov/galileo/ |url-status=dead |archive-date=January 5, 1997 | title = Galileo: Journey to Jupiter |publisher=NASA/Jet Propulsion Laboratory |access-date=November 28, 2006 }} The major events during the eight-year study included multiple flybys of all of the Galilean moons, as well as Amalthea (the first probe to do so).{{cite journal|last1=Thomas|first1=P.C.|last2=Burns|first2=J.A.|last3=Rossier|first3=L.|display-authors=etal|title=The Small Inner Satellites of Jupiter|journal=Icarus|year=1998|volume=135|issue=1|pages=360–371|doi=10.1006/icar.1998.5976| bibcode=1998Icar..135..360T|doi-access=free}} It also witnessed the impact of Comet Shoemaker–Levy 9 as it approached Jupiter in 1994 and released an atmospheric probe into the Jovian atmosphere in December 1995.{{cite web |url=http://nssdc.gsfc.nasa.gov/planetary/others.html |last=Williams |first=David R. |title=Ulysses and Voyager 2 |access-date=August 25, 2008 |work=Lunar and Planetary Science |publisher=National Space Science Data Center |archive-date=October 24, 2008 |archive-url=https://web.archive.org/web/20081024123110/http://nssdc.gsfc.nasa.gov/planetary/others.html |url-status=live }}

File:SL9ImpactGalileo.jpg images taken several seconds apart shows the appearance of the fireball appearing on the dark side of Jupiter from one of the fragments of Comet Shoemaker–Levy 9 hitting the planet.]]

Cameras on the Galileo spacecraft observed fragments of Comet Shoemaker–Levy 9 between 16 and 22 July 1994 as they collided with Jupiter's southern hemisphere at a speed of approximately 60 kilometres per second. This was the first direct observation of an extraterrestrial collision of Solar System objects.{{cite web |url=http://nssdc.gsfc.nasa.gov/planetary/comet.html |title=Comet Shoemaker–Levy 9 Collision with Jupiter |access-date=August 26, 2008 |publisher=National Space Science Date Center, NASA |date=February 2005 |archive-url=https://web.archive.org/web/20130219011148/http://nssdc.gsfc.nasa.gov/planetary/comet.html |archive-date=February 19, 2013 |url-status=dead}} While the impacts took place on the side of Jupiter hidden from Earth, Galileo, then at a distance of 1.6 AU from the planet, was able to see the impacts as they occurred. Its instruments detected a fireball that reached a peak temperature of about 24,000 K, compared to the typical Jovian cloudtop temperature of about 130 K (−143 °C), with the plume from the fireball reaching a height of over 3,000 km.{{cite journal |last=Martin |first=Terry Z. |date=September 1996 |title=Shoemaker–Levy 9: Temperature, Diameter and Energy of Fireballs |journal=Bulletin of the American Astronomical Society |volume=28 |pages=1085 |bibcode=1996DPS....28.0814M}}

An atmospheric probe was released from the spacecraft in July 1995, entering the planet's atmosphere on December 7, 1995. After a high-g descent into the Jovian atmosphere, the probe discarded the remains of its heat shield, and it parachuted through 150 km of the atmosphere, collecting data for 57.6 minutes, before being crushed by the pressure and temperature to which it was subjected (about 22 times Earth normal, at a temperature of 153 °C).{{cite web|url=http://www.jpl.nasa.gov/news/fact_sheets/galileo0309.pdf|publisher=NASA|access-date=November 1, 2008|title=Galileo Mission to Jupiter|archive-date=July 10, 2012|archive-url=https://web.archive.org/web/20120710091653/http://www.jpl.nasa.gov/news/fact_sheets/galileo0309.pdf|url-status=live}} It would have melted thereafter, and possibly vaporized. The Galileo orbiter itself experienced a more rapid version of the same fate when it was deliberately steered into the planet on September 21, 2003, at a speed of over 50 km/s, in order to avoid any possibility of it crashing into and contaminating Europa.{{cite web |url=http://212.58.226.17:8080/1/hi/sci/tech/664834.stm |title=BBC News | SCI/TECH | Crash plan for Galileo spaceprobe |publisher=212.58.226.17:8080 |date=March 3, 2000 |access-date=May 20, 2009 |url-status=dead |archive-url=https://archive.today/20090705094139/http://212.58.226.17:8080/1/hi/sci/tech/664834.stm |archive-date=July 5, 2009}}

Major scientific results of the Galileo mission include:{{cite book|isbn=978-3-540-34681-4|author1=Rosaly M. C. Lopes |author2=John R. Spencer. |year=2007|publisher=Springer|location=Berlin|title=Io after Galileo : a new view of Jupiter's volcanic moon}}{{cite book|isbn=978-0-387-40212-3|pages=166–182|author=P. Bond|year=2004|publisher=Springer|location=New York; Berlin|title=Stepping stones to the cosmos : the story of planetary exploration}}{{cite web |url=http://nssdc.gsfc.nasa.gov/planetary/galileo.html |title=Galileo Project Information |publisher=Nssdc.gsfc.nasa.gov |access-date=May 24, 2009 |archive-date=May 27, 2009 |archive-url=https://web.archive.org/web/20090527215605/http://nssdc.gsfc.nasa.gov/planetary/galileo.html |url-status=live }}{{cite web|url=http://solarsystem.nasa.gov/galileo/discovery.cfm |archive-url=https://web.archive.org/web/20041102101202/http://www.solarsystem.nasa.gov/galileo/discovery.cfm |url-status=dead |archive-date=November 2, 2004 |title=Solar System Exploration: Galileo Legacy Site: Discovery Highlights |publisher=Solarsystem.nasa.gov |date=August 9, 2007 |access-date=May 24, 2009}}{{cite book|isbn=978-0-387-98764-4|author=Daniel Fischer|year=1999|publisher=Copernicus|location=New York|title=Mission Jupiter : the spectacular journey of the Galileo spacecraft|url=https://archive.org/details/missionjupitersp0000fisc|url-access=registration}}

• the first observation of ammonia clouds in another planet's atmosphere—the atmosphere creates ammonia ice particles from material coming up from lower depths;
• confirmation of extensive volcanic activity on Io—which is 100 times greater than that found on Earth; the heat and frequency of eruptions are reminiscent of early Earth;
• observation of complex plasma interactions in Io's atmosphere which create immense electrical currents that couple to Jupiter's atmosphere;
• providing evidence for supporting the theory that liquid oceans exist under Europa's icy surface;
• first detection of a substantial magnetic field around a satellite (Ganymede);
• magnetic data evidence suggesting that Europa, Ganymede and Callisto have a liquid-saltwater layer under the visible surface;
• evidence for a thin atmospheric layer on Europa, Ganymede, and Callisto known as a 'surface-bound exosphere';
• understanding of the formation of the rings of Jupiter (by dust kicked up as interplanetary meteoroids which smash into the planet's four small inner moons) and observation of two outer rings and the possibility of a separate ring along Amalthea's orbit;
• identification of the global structure and dynamics of a giant planet's magnetosphere.

On December 11, 2013, NASA reported, based on results from the Galileo mission, the detection of "clay-like minerals" (specifically, phyllosilicates), often associated with organic materials, on the icy crust of Europa, moon of Jupiter.{{cite web |last=Cook |first=Jia-Rui c. |title=Clay-Like Minerals Found on Icy Crust of Europa |url=http://www.jpl.nasa.gov/news/news.php?release=2013-362 |date=December 11, 2013 |work=NASA |access-date=December 11, 2013 |archive-date=January 30, 2020 |archive-url=https://web.archive.org/web/20200130044515/https://www.jpl.nasa.gov/news/news.php?release=2013-362 |url-status=live }} The presence of the minerals may have been the result of a collision with an asteroid or comet according to the scientists.

{{Update|date=July 2016|section}}

{{Main|Juno (spacecraft)}}

File:Animation of Juno trajectory around Jupiter.gif{{'s}} trajectory around Jupiter from 1 June 2016 to 21 October 2025
{{legend2|magenta| Juno}}{{·}}{{legend2| Lime |Jupiter}}]]

NASA launched Juno on August 5, 2011, to study Jupiter in detail. It entered a polar orbit of Jupiter on July 5, 2016. The spacecraft is studying the planet's composition, gravity field, magnetic field, and polar magnetosphere. Juno is also searching for clues about how Jupiter formed, including whether the planet has a rocky core, the amount of water present within the deep atmosphere, and how the mass is distributed within the planet. Juno also studies Jupiter's deep winds,[https://web.archive.org/web/20110713125816/http://www.jupitertoday.com/news/viewpr.rss.html?pid=16990 NASA Selects New Frontiers Concept Study: Juno Mission to Jupiter | Jupiter Today – Your Daily Source of Jupiter News]{{cite web |url=http://juno.wisc.edu/ |title=Juno – NASA's Second New Frontiers Mission to Jupiter |access-date=October 24, 2007 |archive-date=February 3, 2019 |archive-url=https://web.archive.org/web/20190203190204/http://juno.wisc.edu/ |url-status=live }}

which can reach speeds of 600 km/h.{{cite web|title=Storm Winds Blow in Jupiter's Little Red Spot|author=Buckley, M.|url=http://www.jhuapl.edu/newscenter/pressreleases/2008/080520.asp|date=May 20, 2008|publisher=Johns Hopkins Applied Physics Laboratory|access-date=October 16, 2008|archive-url=https://web.archive.org/web/20120304051438/http://www.jhuapl.edu/newscenter/pressreleases/2008/080520.asp|archive-date=March 4, 2012|url-status=dead}}{{cite web|title=Jupiter's Little Red Spot Growing Stronger|author=Steigerwald, Bill|publisher=NASA Goddard Space Center|date=October 10, 2006|url=http://www.nasa.gov/centers/goddard/news/topstory/2006/little_red_spot.html|access-date=October 16, 2008|archive-date=April 5, 2012|archive-url=https://web.archive.org/web/20120405155701/http://www.nasa.gov/centers/goddard/news/topstory/2006/little_red_spot.html|url-status=live}}

Among early results, Juno gathered information about Jovian lightning that revised earlier theories.{{cite journal|title=Prevalent lightning sferics at 600 megahertz near Jupiter's poles|journal=Nature |last1=Connerney |first1=John |last2=Gurnett |first2=Donald|last3=Hospodarsky|first3=George|last4=Kurth|first4=William|last5=Santolík|first5=Ondřej|last6=Imai|first6=Masafumi|last7=Kolmašová|first7=Ivana |last8=Tabataba-Vakili|first8=Fachreddin|last9=Steffes|first9=Paul|display-authors=1|volume=558|issue=7708|pages=87–90|date=June 2018|doi=10.1038/s41586-018-0156-5|pmid=29875484|bibcode=2018Natur.558...87B |s2cid=46952214}} Juno provided the first views of Jupiter's north pole, as well as insights about Jupiter's aurorae, magnetic field, and atmosphere.{{Cite web|title=Overview {{!}} Juno|url=https://solarsystem.nasa.gov/missions/juno/overview/|url-status=live|access-date=May 19, 2021|website=NASA|archive-date=May 19, 2021|archive-url=https://web.archive.org/web/20210519143102/https://solarsystem.nasa.gov/missions/juno/overview/}}

Juno made many discoveries that are challenging existing theories about Jupiter's formation. When it flew over the poles of Jupiter it imaged clusters of stable cyclones that exist at the poles.{{Cite web |title=NASA's Juno Navigators Enable Jupiter Cyclone Discovery |url=https://www.jpl.nasa.gov/news/nasas-juno-navigators-enable-jupiter-cyclone-discovery |access-date=May 14, 2022 |website=NASA Jet Propulsion Laboratory (JPL) |language=en-US}} It found that the magnetosphere of Jupiter is uneven and chaotic. Using its Microwave Radiometer Juno found that the red and white bands that can be seen on Jupiter extend hundreds of kilometers into the Jovian atmosphere, yet the interior of Jupiter isn't evenly mixed. This has resulted in the theory that Jupiter doesn't have a solid core as previously thought, but a "fuzzy" core made of pieces of rock and metallic hydrogen. This peculiar core may be a result of a collision that happened early on in Jupiter's formation.{{Cite web |last=Crockett |first=Christopher |date=June 8, 2020 |title=What has the Juno spacecraft taught us about Jupiter? |url=https://astronomy.com/news/2020/06/jupiter-revealed |access-date=May 14, 2022 |website=Astronomy.com |language=en}}

{{main|Jupiter Icy Moons Explorer}}

ESA's Jupiter Icy Moons Explorer (JUICE) has been selected as part of ESA's Cosmic Vision science program. It was launched on 14 April 2023 and, after a series of flybys in the inner Solar System, arrives in Jupiter in 2031.{{cite conference |last1=Witasse |first1=O. |last2=Altobelli |first2=N. |last3=Andres |first3=R. |last4=Atzei |first4=A. |last5=Boutonnet |first5=A. |last6=Budnik |first6=F. |last7=Dietz |first7=A. |last8=Erd |first8=C. |last9=Evill |first9=R. |last10=Lorente |first10=R. |last11=Munoz |first11=C. |last12=Pinzan |first12=G. |last13=Scharmberg |first13=C. |last14=Suarez |first14=A. |last15=Tanco |first15=I. |last16=Torelli |first16=F. |last17=Torn |first17=B. |last18=Vallat |first18=C. |author19=JUICE Science Working Team |url=https://meetingorganizer.copernicus.org/EPSC2021/EPSC2021-358.html |title=JUICE (Jupiter Icy Moon Explorer): Plans for the cruise phase |conference=Europlanet Science Congress (EPSC) 2021 |date=July 2021 |access-date=August 28, 2021 |doi=10.5194/epsc2021-358 |archive-date=August 28, 2021 |archive-url=https://web.archive.org/web/20210828003850/https://meetingorganizer.copernicus.org/EPSC2021/EPSC2021-358.html |url-status=live |doi-access=free |url-access=subscription }} In 2012, the European Space Agency's selected the JUICE as its first Large mission, replacing its contribution to EJSM, the Jupiter Ganymede Orbiter (JGO).{{cite news | first = Jonathan | last = Amos | url = https://www.bbc.co.uk/news/science-environment-17917102 | title = Esa selects 1bn-euro Juice probe to Jupiter | access-date = December 14, 2013 | date = May 2, 2012 | work = BBC News Online | archive-date = May 11, 2020 | archive-url = https://web.archive.org/web/20200511181342/https://www.bbc.co.uk/news/science-environment-17917102 | url-status = live }} The partnership for the Europa Jupiter System Mission has since ended, but NASA will continue to contribute the European mission with hardware and an instrument.{{Cite web | url = http://www.jpl.nasa.gov/news/news.php?release=2013-069 | title = NASA and JPL Contribute to European Jupiter Mission | access-date = December 14, 2013 | date = February 21, 2013 | work = JPL | archive-date = December 15, 2013 | archive-url = https://web.archive.org/web/20131215064249/http://www.jpl.nasa.gov/news/news.php?release=2013-069 | url-status = live }}

{{main|Europa Clipper}}

The Europa Clipper is a NASA mission that will focus on studying Jupiter's moon Europa.{{cite news | title = Europa Clipper | date = November 2013 | publisher = NASA | url = http://solarsystem.nasa.gov/missions/profile.cfm?MCode=EuropaClipper&Display=ReadMore | work = Jet Propulsion Laboratory | access-date = December 14, 2013 | archive-url = https://web.archive.org/web/20131213193916/http://solarsystem.nasa.gov/missions/profile.cfm?MCode=EuropaClipper&Display=ReadMore | archive-date = December 13, 2013 | url-status = dead}} It was launched on 14 October 2024,{{cite web|last=Foust|first=Jeff|url=https://spacenews.com/nasa-to-use-commercial-launch-vehicle-for-europa-clipper/|title=NASA to use commercial launch vehicle for Europa Clipper|publisher=SpaceNews|date=February 10, 2021|access-date=February 10, 2021}} and will enter Jovian orbit after a 5.5-year cruise and gravity assists by Mars and Earth. The spacecraft would fly by Europa at least an intended 49 times to minimize radiation damage.

China's CNSA is planning to launch its two Shensuo (formerly Interstellar Express) spacecraft in 2026 to flyby Jupiter on the way to explore the heliosphere. Separately, CNSA has announced plans to launch its Tianwen-4 mission to Jupiter around 2030 which will enter orbit around Callisto.{{Cite web |last=Theresa |first=Deena |date=2022-09-23 |title=China's Tianwen 4 to target Jupiter and Uranus with two spacecraft on one rocket |url=https://interestingengineering.com/innovation/tianwen-4-jupiter-and-uranus-two-spacecraft-one-rocket |access-date=2023-04-17 |website=interestingengineering.com |language=en-US}}{{Cite magazine |date=2022-09-23 |title=China Unveils Plans to Send Spacecraft to Jupiter and Uranus |url=https://time.com/6216133/china-aims-for-jupiter-and-uranus/ |access-date=2023-04-17 |magazine=Time |language=en}}{{Cite web |last=Andrew Jones published |date=2022-09-22 |title=China wants to probe Uranus and Jupiter with 2 spacecraft on one rocket |url=https://www.space.com/china-probes-jupiter-uranus-same-launch |access-date=2023-04-17 |website=Space.com |language=en}} In addition, they plan to launch the Solar Polar Orbit Observatory towards Jupiter as a gravity assist, performing a similar mission to Ulysses in order to get into a high-inclination solar orbit.{{Cite web |last=Jones |first=Andrew |date=2025-02-25 |title=China to send a spacecraft out of the ecliptic to study the Sun's poles |url=https://spacenews.com/china-to-send-a-spacecraft-out-of-the-ecliptic-to-study-the-suns-poles/ |access-date=2025-02-25 |website=SpaceNews |language=en-US}}{{Cite twitter |number=1894339064217657637 |user=AJ_FI |title=China to launch the solar polar-orbit observatory mission in 2029 to study the Sun's poles |first=Andrew |last=Jones |date=25 February 2025 |access-date=25 February 2025}}

India's ISRO announced plans to launch an Indian mission to Jupiter in the 2020s.{{Cite web |date=January 4, 2017 |title=After Mars, ISRO targeting missions to Venus and Jupiter |url=https://www.thehindubusinessline.com/news/science/after-mars-isro-targeting-missions-to-venus-and-jupiter/article9459642.ece |url-status=live |archive-url=https://web.archive.org/web/20190822081038/https://www.thehindubusinessline.com/news/science/after-mars-isro-targeting-missions-to-venus-and-jupiter/article9459642.ece |archive-date=August 22, 2019 |access-date=2019-08-22 |website=@businessline |language=en}}

Because of the possibility of subsurface liquid oceans on Jupiter's moons Europa, Ganymede and Callisto, there has been great interest in studying the icy moons in detail. Funding difficulties have delayed progress. The Europa Orbiter{{cite web |url=http://trs-new.jpl.nasa.gov/dspace/handle/2014/20516 |title=The Europa Orbiter Mission Design |access-date=May 20, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20120223210553/http://trs-new.jpl.nasa.gov/dspace/handle/2014/20516 |archive-date=February 23, 2012}} was a planned NASA mission to Europa, which was canceled in 2002.{{cite web |url=http://www.space.com/news/nasa_budget_020204.html |title=NASA Kills Europa Orbiter |publisher=Space.com |date=February 4, 2002 |access-date=May 20, 2009 |archive-date=February 10, 2002 |archive-url=https://web.archive.org/web/20020210015816/http://www.space.com/news/nasa_budget_020204.html |url-status=live }} Its main objectives included determining the presence or absence of a subsurface ocean and identifying candidate sites for future lander missions. NASA's JIMO (Jupiter Icy Moons Orbiter), which was canceled in 2005,{{cite news | first=Brian | last=Berger | title=White House scales back space plans | work=NBC News | date=February 7, 2005 | url=http://www.nbcnews.com/id/6928404 | access-date=January 2, 2007 | archive-date=October 29, 2013 | archive-url=https://web.archive.org/web/20131029210930/http://www.nbcnews.com/id/6928404/ | url-status=dead }} and a European Jovian Europa Orbiter mission were also studied,{{cite web | last=Atzei | first=Alessandro | date=April 27, 2007 | url=http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=35982 | title=Jovian Minisat Explorer | publisher=ESA | access-date=May 8, 2008 | archive-date=February 29, 2012 | archive-url=https://web.archive.org/web/20120229181415/http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=35982 | url-status=live }} but were superseded by the Europa Jupiter System Mission.

The Europa Jupiter System Mission (EJSM) was a joint NASA/ESA proposal for exploration of Jupiter and its moons. In February 2009 it was announced that both space agencies had given this mission priority ahead of the Titan Saturn System Mission.{{cite web | author1=Talevi, Monica | author2=Brown, Dwayne | date=February 18, 2009 | title=NASA and ESA Prioritize Outer Planet Missions | url=http://www.nasa.gov/topics/solarsystem/features/20090218.html | access-date=February 18, 2009 | archive-date=August 25, 2011 | archive-url=https://web.archive.org/web/20110825211633/http://www.nasa.gov/topics/solarsystem/features/20090218.html | url-status=live }}{{cite news | first=Paul | last=Rincon | date=February 18, 2009 | title=Jupiter in space agencies' sights | url=http://news.bbc.co.uk/1/hi/sci/tech/7897585.stm | work=BBC News | access-date=February 28, 2009 | archive-date=February 21, 2009 | archive-url=https://web.archive.org/web/20090221185643/http://news.bbc.co.uk/1/hi/sci/tech/7897585.stm | url-status=live }} The proposal included a launch date of around 2020 and consisted of the NASA-led Jupiter Europa Orbiter, and the ESA-led Jupiter Ganymede Orbiter.{{cite web |author=Tim Brice |url=http://opfm.jpl.nasa.gov/europajupitersystemmissionejsm/jupiterganymedeorbiterjgoconcept/ |title=Outer Planet Flagship Mission: Jupiter Ganymede Orbiter (JGO) Concept |publisher=Opfm.jpl.nasa.gov |access-date=May 24, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20120217002618/http://opfm.jpl.nasa.gov/europajupitersystemmissionejsm/jupiterganymedeorbiterjgoconcept/ |archive-date=February 17, 2012}}{{cite web |url=http://www.lpi.usra.edu/opag/sg_opf_8_08.pdf |title=Outer Planet Flagship Mission: Briefing to the OPAG Steering Committee |access-date=October 14, 2008 |last=OPF Study Team |date=August 28, 2008 |publisher=Outer Planets Assessment Group |archive-date=October 11, 2012 |archive-url=https://web.archive.org/web/20121011105958/http://www.lpi.usra.edu/opag/sg_opf_8_08.pdf |url-status=live }}{{cite web | url=http://sci.esa.int/science-e/www/area/index.cfm?fareaid=107 | title=Laplace: A mission to Europa & Jupiter system | publisher=ESA | access-date=January 23, 2009 | archive-date=July 14, 2012 | archive-url=https://web.archive.org/web/20120714200604/http://sci.esa.int/science-e/www/area/index.cfm?fareaid=107 | url-status=live }} ESA's contribution had encountered funding competition from other ESA projects.{{cite news | first=Sergio | last=Volonte | date=July 10, 2007 | title=Cosmic Vision 2015–2025 Proposals | url=http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=41177 | publisher=ESA | access-date=February 18, 2009 | archive-date=September 2, 2011 | archive-url=https://web.archive.org/web/20110902033453/http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=41177 | url-status=live }} However, the Jupiter Europa Orbiter (JEO), NASA's contribution, was considered by the Planetary Decadal Survey to be too expensive. The survey supported a cheaper alternative to JEO.{{Cite web |url=https://solarsystem.nasa.gov/multimedia/downloads/Decadal_Exec_Summary.pdf |title=Executive Survey (Visions and Voyages for Planetary Science 2013 – 2022) |access-date=December 15, 2013 |archive-url=https://web.archive.org/web/20130904105430/http://solarsystem.nasa.gov/multimedia/downloads/Decadal_Exec_Summary.pdf |archive-date=September 4, 2013 |url-status=dead }} In the end, the whole EJSM mission, with all the proposed spacecraft from NASA and ESA (and JAXA), was cancelled (along with various related Roscosmos proposals). However, the ESA JUICE spacecraft and the NASA Europa Clipper spacecraft, which grew out of the cancelled EJSM, were built later.

{{Further|Space colonization#Moons of outer planets|}}

While scientists require further evidence to determine the extent of a rocky core on Jupiter, its Galilean moons provide the potential opportunity for future human exploration.

In 2003, NASA proposed a program called Human Outer Planets Exploration (HOPE) that involved sending astronauts to explore the Galilean moons.{{cite journal|last1=Troutman|first1=P.A.|last2=Bethke|first2=K.|display-authors=etal|journal=AIP Conference Proceedings|date=January 28, 2003|volume=654|pages=821–828|doi=10.1063/1.1541373|title=Revolutionary Concepts for Human Outer Planet Exploration (HOPE)|hdl=2060/20030063128|hdl-access=free|bibcode=2003AIPC..654..821T|s2cid=109235313 }}
{{cite conference|title=Revolutionary Concepts for Human Outer Planet Exploration (HOPE)|date=February 3, 2003|author1=Pat Troutman|author2=Kristen Bethke|conference=SPACE TECHNOLOGY & APPLICATIONS INTERNATIONAL "Expanding the Frontiers of Space" FORUM (STAIF - 2003) February 2–6, 2003 Albuquerque, New Mexico |url=http://www.nasa-academy.org/soffen/travelgrant/bethke.pdf|access-date=July 2, 2009|url-status=dead|archive-url=https://web.archive.org/web/20120119170143/http://www.nasa-academy.org/soffen/travelgrant/bethke.pdf|archive-date=January 19, 2012}} NASA has projected a possible attempt some time in the 2040s.{{cite web|title=High Power MPD Nuclear Electric Propulsion (NEP) for Artificial Gravity HOPE Missions to Callisto|author1=Melissa L. McGuire|author2=James Gilland|publisher=NASA|year=2003|access-date=June 30, 2009|url=http://trajectory.grc.nasa.gov/aboutus/papers/STAIF-2003-177.pdf|archive-url=https://web.archive.org/web/20120305055810/http://trajectory.grc.nasa.gov/aboutus/papers/STAIF-2003-177.pdf|archive-date=March 5, 2012|url-status=dead}} In the Vision for Space Exploration policy announced in January 2004, NASA discussed missions beyond Mars, mentioning that a "human research presence" may be desirable on Jupiter's moons.{{cite web|title=Vision for Space Exploration|year=2003|publisher=NASA|url=http://www.nasa.gov/pdf/55583main_vision_space_exploration2.pdf|access-date=July 2, 2009|archive-date=June 4, 2016|archive-url=https://web.archive.org/web/20160604011940/http://www.nasa.gov/pdf/55583main_vision_space_exploration2.pdf|url-status=live}} Before the JIMO mission was cancelled, NASA administrator Sean O'Keefe stated that "human explorers will follow."{{cite web|title=NASA plans to send new robot to Jupiter|publisher=SpaceDaily|year=2004|url=http://www.spacedaily.com/reports/NASA_plans_to_send_new_robot_to_Jupiter.html|access-date=June 30, 2009|archive-date=September 5, 2012|archive-url=https://web.archive.org/web/20120905020330/http://www.spacedaily.com/reports/NASA_plans_to_send_new_robot_to_Jupiter.html|url-status=live}}

The Jovian system in general poses particular disadvantages for human missions because of the severe radiation conditions prevailing in Jupiter's magnetosphere and the planet's particularly deep gravitational well.

Jupiter would deliver about 36 Sv (3600 rem) per day to unshielded astronauts at Io and about 5.4 Sv (540 rems) per day to unshielded astronauts at Europa,{{cite web |date=February 28, 2000 |title=SPS 1020 (Introduction to Space Sciences) |publisher=California State University, Fresno |author=Frederick A. Ringwald |url=http://zimmer.csufresno.edu/~fringwal/w08a.jup.txt |access-date=July 4, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20080725050708/http://zimmer.csufresno.edu/~fringwal/w08a.jup.txt |archive-date=July 25, 2008}} which is a decisive aspect due to the fact that already an exposure to about 0.75 Sv over a period of a few days is enough to cause radiation poisoning, and about 5 Sv over a few days is fatal.Robert Zubrin, Entering Space: Creating a Spacefaring Civilization, section: Colonizing the Jovian System, pp. 166–170, Tarcher/Putnam, 1999, {{ISBN|1-58542-036-0}}. In 1997, the Artemis Project designed a plan to fly humans to Europa.{{cite journal|last1=Kokh|first1=Peter|author2=Kaehny, Mark; Armstrong, Doug; Burnside, Ken|url=http://asi.org/adb/06/09/03/02/110/europa2-wkshp.html|title=Europa II Workshop Report|journal=Moon Miner's Manifesto|issue=110|date=November 1997|access-date=June 26, 2009|archive-date=June 7, 2019|archive-url=https://web.archive.org/web/20190607102248/http://asi.org/adb/06/09/03/02/110/europa2-wkshp.html|url-status=live}} According to this plan, explorers would drill down into the Europan ice crust, entering the postulated subsurface ocean, where they would inhabit artificial air pockets.{{cite news|url=http://www.space.com/missionlaunches/missions/europa_colonies_010606-1.html|title=Humans on Europa: A Plan for Colonies on the Icy Moon|work=Space.com|date=June 6, 2001|access-date=May 10, 2006|archive-date=July 20, 2010|archive-url=https://web.archive.org/web/20100720053951/http://www.space.com/missionlaunches/missions/europa_colonies_010606-1.html|url-status=live}}

Ganymede is the Solar System's largest moon and the Solar System's only known moon with a magnetosphere, but this does not shield it from cosmic radiation to a noteworthy degree, because it is overshadowed by Jupiter's magnetic field. Ganymede receives about 0.08 Sv (8 rem) of radiation per day. Callisto is farther from Jupiter's strong radiation belt and subject to only 0.0001 Sv (0.01 rem) a day. For comparison, the average amount of radiation taken on Earth by a living organism is about 0.0024 Sv per year; the highest natural radiation levels on Earth are recorded around Ramsar hot springs at about 0.26 Sv per year.

One of the main targets chosen by the HOPE study was Callisto. The possibility of building a surface base on Callisto was proposed, because of the low radiation levels at its distance from Jupiter and its geological stability. Callisto is the only Galilean satellite on which a crewed base is feasible. The levels of ionizing radiation on Io, Europa and long-term on Ganymede, are hostile to human life, and adequate protective measures have yet to be devised.{{cite web|url=https://technologyonscience.blogspot.com/2019/01/missions-jupiter-blogspot.html|title=Earlier Missions Exploring Jupiter|author=Avanish Sharma|date=January 13, 2019|website=Technology on Science|access-date=2019-11-30|archive-date=November 4, 2019|archive-url=https://web.archive.org/web/20191104084659/https://technologyonscience.blogspot.com/2019/01/missions-jupiter-blogspot.html|url-status=live}}

NASA has speculated on the feasibility of mining the atmospheres of the outer planets, particularly for helium-3, an isotope of helium that is rare on Earth and could have a very high value per unit mass as thermonuclear fuel.Robert Zubrin, Entering Space: Creating a Spacefaring Civilization, section: Settling the Outer Solar System: The Sources of Power, pp. 158–160, Tarcher/Putnam, 1999, {{ISBN|1-58542-036-0}}{{cite report|author=Jeffrey Van Cleve|author2=Carl Grillmair|author3=Mark Hanna|url=http://www.mines.edu/research/srr/2001abstracts/vancleve.PDF|title=Helium-3 Mining Aerostats in the Atmosphere of Uranus|url-status=dead|archive-url=https://web.archive.org/web/20060630164712/http://www.mines.edu/research/srr/2001abstracts/vancleve.PDF|archive-date=June 30, 2006|work=Abstract for Space Resources Roundtable|access-date=May 10, 2006}} Factories stationed in orbit could mine the gas and deliver it to visiting craft.{{cite web|title=Atmospheric Mining in the Outer Solar System|date=October 2006|author=Bryan Palaszewski|publisher=Glenn Research Center|url=http://gltrs.grc.nasa.gov/reports/2006/TM-2006-214122.pdf|access-date=July 2, 2009|url-status=dead|archive-url=https://web.archive.org/web/20090327051914/http://gltrs.grc.nasa.gov/reports/2006/TM-2006-214122.pdf|archive-date=March 27, 2009}}

It could be possible to build a surface base that would produce fuel for further exploration of the Solar System.

• Exploration of Mercury
• Exploration of Venus
• Exploration of Mars
• Exploration of Saturn
• Exploration of Uranus
• Exploration of Neptune

{{Reflist|30em}}

{{Library resources box}}

• [http://nssdc.gsfc.nasa.gov/planetary/chronology.html Chronology of Lunar and Planetary Exploration]
• [http://nssdc.gsfc.nasa.gov/planetary/planets/jupiterpage.html NASA missions to Jupiter]

{{Jupiter}}

{{Planetary exploration}}

{{Jupiter spacecraft}}

{{Voyager program}}

{{Solar System}}

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Category:Jupiter

Category:Spaceflight

Category:Discovery and exploration of the Solar System

Category:Solar System