Editing Jupiter (section)

== Observation ==
[[File:Jupiter-and-its-moons-amateur.jpg|alt=see caption|thumb|Jupiter and four Galilean moons seen through an amateur telescope]]
Jupiter is usually the [[List of brightest natural objects in the sky|fourth-brightest object in the sky]] (after the Sun, the [[Moon]], and [[Venus]]),<ref name="worldbook"/> although at opposition [[Mars#Viewing from Earth|Mars]] can appear brighter than Jupiter. Depending on Jupiter's position with respect to the Earth, it can vary in visual magnitude from as bright as −2.94 at [[Opposition (astronomy)|opposition]] down to −1.66 during [[conjunction (astronomy and astrology)|conjunction]] with the Sun.<ref name="Mallama_and_Hilton"/> The mean [[apparent magnitude]] is −2.20 with a standard deviation of 0.33.<ref name="Mallama_and_Hilton"/> The [[angular diameter]] of Jupiter likewise varies from 50.1 to 30.5 [[arc second]]s.<ref name="fact"/> Favourable oppositions occur when Jupiter is passing through the [[Apsis|perihelion]] of its orbit, bringing it closer to Earth.<ref>{{cite book|chapter=Appendix 3|title=The giant planet Jupiter|last1=Rogers|first1=John H.|date=July 20, 1995|publisher=Cambridge University Press|isbn=978-0-521-41008-3}}</ref> Near opposition, Jupiter will appear to go into [[Apparent retrograde motion|retrograde motion]] for a period of about 121 days, moving backward through an angle of 9.9° before returning to prograde movement.<ref>{{cite book
 | title=The Planet Observer's Handbook
 | first=Fred W.
 | last=Price
 | date=October 26, 2000
| page=140
 | isbn=978-0-521-78981-3
 | publisher=Cambridge University Press
 | url=https://books.google.com/books?id=GnrAVhVZ3wMC&pg=PA140
 | access-date=March 19, 2023
| archive-date=March 26, 2023
| archive-url=https://web.archive.org/web/20230326164802/https://books.google.com/books?id=GnrAVhVZ3wMC&pg=PA140
 | url-status=live
 }}</ref>

Because the orbit of Jupiter is outside that of Earth, the [[Phase angle (astronomy)|phase angle]] of Jupiter as viewed from Earth is always less than 11.5°; thus, Jupiter always appears nearly fully illuminated when viewed through Earth-based telescopes. It was during spacecraft missions to Jupiter that crescent views of the planet were obtained.<ref>{{cite book
 | title=Pioneer Odyssey
 | url=https://history.nasa.gov/SP-349/sp349.htm
 | first1=Richard O.
 | last1=Fimmel
 | first2=William
 | last2=Swindell
 | first3=Eric
 | last3=Burgess
 | year=1974
 | edition=Revised
 | chapter-url=https://history.nasa.gov/SP-349/ch8.htm
 | chapter=8. Encounter with the Giant
 | publisher=NASA History Office
 | access-date=February 17, 2007
| archive-date=December 25, 2017
| archive-url=https://web.archive.org/web/20171225230634/https://history.nasa.gov/SP-349/sp349.htm
 | url-status=live
 }}</ref> A small telescope will usually show Jupiter's four [[Galilean moons]] and the cloud belts across [[Atmosphere of Jupiter|Jupiter's atmosphere]]. A larger telescope with an aperture of {{convert|4|-|6|in|cm|0|abbr=out}} will show Jupiter's Great Red Spot when it faces Earth.<ref>{{cite book | title=Outer Planets | page=47 | first=Glenn F. | last=Chaple | date=2009 | isbn=978-0-313-36571-3 | publisher=ABC-CLIO | series=Greenwood Guides to the Universe | editor1-first=Lauren V. | editor1-last=Jones | editor2-first=Timothy F. | editor2-last=Slater | url=https://books.google.com/books?id=6KXACQAAQBAJ&pg=PA47 | access-date=March 19, 2023 | archive-date=March 26, 2023 | archive-url=https://web.archive.org/web/20230326164803/https://books.google.com/books?id=6KXACQAAQBAJ&pg=PA47 | url-status=live }}</ref><ref>{{cite book
 | title=The Sky at Night: How to Read the Solar System
 | last1=North | first1=Chris | last2=Abel | first2=Paul
 | date=October 31, 2013 | page=183
 | publisher=Ebury Publishing | isbn=978-1-4481-4130-2
}}</ref>

=== History ===

==== Pre-telescopic research ====
[[File:Almagest-planets.svg|thumb|left|Model in the ''[[Almagest]]'' of the longitudinal motion of Jupiter (☉) relative to Earth (🜨)|upright=1.2]]
Observations of Jupiter are attested with the [[Babylonian astronomers]] during the 7th–8th centuries&nbsp;BC.<ref>{{Cite journal |title=Babylonian Observational Astronomy |last=Sachs |first=A. |journal=[[Philosophical Transactions of the Royal Society of London]] |volume=276 |issue=1257 |date=May 2, 1974 |pages=43–50 (see p. 44) |jstor=74273 |doi=10.1098/rsta.1974.0008 |bibcode=1974RSPTA.276...43S|s2cid=121539390 }}</ref> The ancient Chinese knew Jupiter as the '{{tlit|zh|sui}} star' ({{transliteration|zh|Suìxīng}} {{lang|zh|歲星}})<!--not year star--> and established their cycle of twelve [[earthly branches]] based on the approximate number of years it takes Jupiter to revolve around the Sun; the [[Chinese language]] still uses its name ({{lang|zh|歲}}; [[simplified characters|simplified]] as {{lang|zh|岁}}) when referring to years of age. By the 4th century&nbsp;BC, these observations had developed into the [[Chinese zodiac]],<ref name=Homer>{{cite journal |first=Homer H. |last=Dubs |author-link=Homer H. Dubs |title=The Beginnings of Chinese Astronomy |journal=Journal of the American Oriental Society |volume=78 |number=4 |year=1958 |pages=295–300 |doi=10.2307/595793 |jstor=595793 }}</ref> and each year became associated with a [[Tai Sui]] star and [[Chinese gods|god]] controlling the region of the heavens opposite Jupiter's position in the night sky. These beliefs survive in some [[Taoist]] and [[Chinese folk religion|folk religious practices]] and in the East Asian zodiac's twelve animals. The Chinese historian [[Xi Zezong]] has claimed that [[Gan De]], an ancient [[Chinese astronomy|Chinese astronomer]],<ref>{{cite book | title=A Guide to Hubble Space Telescope Objects: Their Selection, Location, and Significance | first1=James L. | last1=Chen | first2=Adam | last2=Chen | date=2015 | page=195 | isbn=978-3-319-18872-0 | publisher=Springer International Publishing | url=https://books.google.com/books?id=qj0wCgAAQBAJ&pg=PA195 | access-date=March 19, 2023 | archive-date=March 26, 2023 | archive-url=https://web.archive.org/web/20230326164802/https://books.google.com/books?id=qj0wCgAAQBAJ&pg=PA195 | url-status=live }}</ref> reported a small star "in alliance" with the planet,<ref>{{cite book | chapter=Facts, Fallacies, Unusual Observations, and Other Miscellaneous Gleanings | title=Weird Astronomy: Tales of Unusual, Bizarre, and Other Hard to Explain Observations | first=David A. J. | last=Seargent | pages=221–282 | isbn=978-1-4419-6424-3 | series=Astronomers' Universe | date=September 24, 2010 }}</ref> which may indicate a sighting of one of [[Moons of Jupiter|Jupiter's moons]] with the unaided eye. If true, this would predate Galileo's discovery by nearly two millennia.<ref>{{cite journal |last=Xi |first=Z. Z. |title=The Discovery of Jupiter's Satellite Made by Gan-De 2000 Years Before Galileo |journal=Acta Astrophysica Sinica |year=1981 |volume=1 |issue=2 |page=87 |bibcode=1981AcApS...1...85X}}</ref><ref>{{cite book |first=Paul |last=Dong |date=2002 |title=China's Major Mysteries: Paranormal Phenomena and the Unexplained in the People's Republic |publisher=China Books |isbn=978-0-8351-2676-2}}</ref>

A 2016 paper reports that [[trapezoidal rule]] was used by [[Babylon]]ians before 50 BC for integrating the velocity of Jupiter along the [[ecliptic]].<ref>{{cite journal |last=Ossendrijver |first=Mathieu |date=January 29, 2016 |title=Ancient Babylonian astronomers calculated Jupiter's position from the area under a time-velocity graph |journal=Science |doi=10.1126/science.aad8085 |pmid=26823423 |volume=351 |issue=6272 |pages=482–484 |bibcode=2016Sci...351..482O |s2cid=206644971 |url=https://www.science.org/doi/full/10.1126/science.aad8085 |access-date=June 30, 2022 |archive-date=August 1, 2022 |archive-url=https://web.archive.org/web/20220801135608/https://www.science.org/doi/full/10.1126/science.aad8085 |url-status=live }}</ref> In his 2nd century work the ''[[Almagest]]'', the Hellenistic astronomer [[Claudius Ptolemaeus]] constructed a [[geocentric]] planetary model based on [[deferent]]s and [[epicycle]]s to explain Jupiter's motion relative to Earth, giving its orbital period around Earth as 4332.38&nbsp;days, or 11.86&nbsp;years.<ref>{{cite book |last=Pedersen |first=Olaf |title=A Survey of the Almagest|date=1974 |publisher=Odense University Press |isbn=9788774920878 |pages=423, 428}}</ref>

==== Ground-based telescope research ====
[[File:Medicean Stars.png|thumb|Galileo's drawings of Jupiter and its "Medicean Stars" from ''[[Sidereus Nuncius]]''|339x339px]]
In 1610, Italian polymath [[Galileo Galilei]] discovered the four largest moons of Jupiter (now known as the [[Galilean moons]]) using a telescope. This is thought to be the first telescopic observation of moons other than Earth's. Just one day after Galileo, [[Simon Marius]] independently discovered moons around Jupiter, though he did not publish his discovery in a book until 1614.<ref>{{cite journal | last=Pasachoff | first=Jay M. |title=Simon Marius's Mundus Iovialis: 400th Anniversary in Galileo's Shadow |journal=Journal for the History of Astronomy |year=2015 |volume=46 |issue=2 |pages=218–234 |bibcode=2015AAS...22521505P |doi=10.1177/0021828615585493|s2cid=120470649 }}</ref> It was Marius's names for the major moons, however, that stuck: Io, Europa, Ganymede, and Callisto. The discovery was a major point in favour of the [[heliocentrism|heliocentric]] theory of the motions of the planets by [[Nicolaus Copernicus]]; Galileo's outspoken support of the Copernican theory led to him being tried and condemned by the [[Inquisition]].<ref>{{cite web | last=Westfall | first=Richard S. | url=http://galileo.rice.edu/Catalog/NewFiles/galilei_gal.html | title=Galilei, Galileo | work=The Galileo Project | publisher=Rice University | access-date=January 10, 2007 | archive-date=January 23, 2022 | archive-url=https://web.archive.org/web/20220123185902/http://galileo.rice.edu/Catalog/NewFiles/galilei_gal.html | url-status=live }}</ref>

In the autumn of 1639, the Neapolitan optician Francesco Fontana tested a 22-palm telescope of his own making and discovered the characteristic bands of the planet's atmosphere.<ref>{{cite journal | first1=Paolo | last1=Del Santo | first2=Leo S. | last2=Olschki | title=On an Unpublished Letter of Francesco Fontana to the Grand-Duke of Tuscany Ferdinand II de' Medici | journal=Galilæana: Journal of Galilean Studies | volume=VI | year=2009 | pages=1000–1017 | url=https://www.torrossa.com/en/resources/an/2242254 | access-date=November 14, 2023 | archive-date=November 15, 2023 | archive-url=https://web.archive.org/web/20231115042550/https://www.torrossa.com/en/resources/an/2242254 | url-status=live }} {{URL| 1=https://bibdig.museogalileo.it/tecanew/opera?bid=917416_6&seq=246} | 2=Alternate URL }}</ref>

During the 1660s, [[Giovanni Domenico Cassini|Giovanni Cassini]] used a new telescope to discover spots in Jupiter's atmosphere, observe that the planet appeared oblate, and estimate its rotation period.<ref name="cassini1">{{cite web | last1=O'Connor | first1=J. J. | last2=Robertson | first2=E. F. | date=April 2003 | url=http://www-history.mcs.st-andrews.ac.uk/Biographies/Cassini.html | title=Giovanni Domenico Cassini | publisher=University of St. Andrews | access-date=February 14, 2007 | archive-date=July 7, 2015 | archive-url=https://web.archive.org/web/20150707025018/http://www-history.mcs.st-andrews.ac.uk/Biographies/Cassini.html | url-status=live }}</ref> In 1692, Cassini noticed that the atmosphere undergoes a differential rotation.<ref>{{cite journal
 | title=The Galileo probe Doppler wind experiment: Measurement of the deep zonal winds on Jupiter
 | last1=Atkinson | first1=David H. | last2=Pollack | first2=James B. | last3=Seiff | first3=Alvin
 | journal=Journal of Geophysical Research
 | volume=103 | issue=E10 | pages=22911–22928 | date=September 1998
 | doi=10.1029/98JE00060 | bibcode=1998JGR...10322911A | doi-access=free }}</ref>

The Great Red Spot may have been observed as early as 1664 by [[Robert Hooke]] and in 1665 by Cassini, although this is disputed. The pharmacist [[Samuel Heinrich Schwabe|Heinrich Schwabe]] produced the earliest known drawing to show details of the Great Red Spot in 1831.<ref>{{cite book |first=Paul |last=Murdin |date=2000 |title=Encyclopedia of Astronomy and Astrophysics |publisher=Institute of Physics Publishing |location=Bristol |isbn=978-0-12-226690-4 |url-access=registration |url=https://archive.org/details/encyclopediaofas0000unse_w5z7 }}</ref> The Red Spot was reportedly lost from sight on several occasions between 1665 and 1708 before becoming quite conspicuous in 1878.<ref>{{cite book
 | title=The giant planet Jupiter
 | first=John H.
 | last=Rogers
 | date=1995
 | pages=188–189
 | isbn=978-0-521-41008-3
 | publisher=Cambridge University Press
 | url=https://books.google.com/books?id=SO48AAAAIAAJ&pg=PA188
 | access-date=March 19, 2023
| archive-date=March 26, 2023
| archive-url=https://web.archive.org/web/20230326164803/https://books.google.com/books?id=SO48AAAAIAAJ&pg=PA188
 | url-status=live
 }}</ref> It was recorded as fading again in 1883 and at the start of the 20th century.<ref>{{cite book | edition=Revised | first1=Richard O. | last1=Fimmel | first2=William | last2=Swindell | first3=Eric | last3=Burgess | date=August 1974 | chapter-url=https://history.nasa.gov/SP-349/ch1.htm | chapter=Jupiter, Giant of the Solar System | title=Pioneer Odyssey | publisher=NASA History Office | access-date=August 10, 2006 | archive-date=August 23, 2006 | archive-url=https://web.archive.org/web/20060823034429/http://history.nasa.gov/SP-349/ch1.htm | url-status=live }}</ref>

Both [[Giovanni Alfonso Borelli|Giovanni Borelli]] and Cassini made careful tables of the motions of Jupiter's moons, which allowed predictions of when the moons would pass before or behind the planet. By the 1670s, Cassini observed that when Jupiter was on the opposite side of the Sun from Earth, these events would occur about 17&nbsp;minutes later than expected. [[Ole Rømer]] deduced that light does not travel instantaneously (a conclusion that Cassini had earlier rejected),<ref name="cassini"/> and this timing discrepancy was used to estimate the [[speed of light]].<ref>{{cite web | first=Kevin | last=Brown | date=2004 | url=http://www.mathpages.com/home/kmath203/kmath203.htm | title=Roemer's Hypothesis | publisher=MathPages | access-date=January 12, 2007 | archive-date=September 6, 2012 | archive-url=https://archive.today/20120906031735/http://www.mathpages.com/home/kmath203/kmath203.htm | url-status=live }}</ref><ref>{{cite journal
 | title=Cassini, Rømer, and the velocity of light
 | last1=Bobis | first1=Laurence | last2=Lequeux | first2=James
 | journal=Journal of Astronomical History and Heritage
 | volume=11 | issue=2 | pages=97–105
 | date=July 2008 | doi=10.3724/SP.J.1440-2807.2008.02.02 | bibcode=2008JAHH...11...97B | s2cid=115455540 }}</ref>

In 1892, [[E. E. Barnard]] observed a fifth satellite of Jupiter with the {{convert|36|in|adj=on}} refractor at [[Lick Observatory]] in California. This moon was later named [[Amalthea (moon)|''Amalthea'']].<ref>{{cite web |first=Joe |last=Tenn |date=March 10, 2006 |url=http://www.phys-astro.sonoma.edu/BruceMedalists/Barnard/ |title=Edward Emerson Barnard |publisher=Sonoma State University |access-date=January 10, 2007 |archive-date=September 17, 2011 |archive-url=https://web.archive.org/web/20110917023559/http://www.phys-astro.sonoma.edu/BruceMedalists/Barnard/ |url-status=dead }}</ref> It was the last planetary moon to be discovered directly by a visual observer through a telescope.<ref>{{cite web |date=October 1, 2001 |url=http://www2.jpl.nasa.gov/galileo/education/teacherres-amalthea.html |archive-url=https://web.archive.org/web/20011124022331/http://www.jpl.nasa.gov/galileo/education/teacherres-amalthea.html |url-status=dead |archive-date=November 24, 2001 |title=Amalthea Fact Sheet |publisher=NASA/JPL |access-date=February 21, 2007}}</ref> An additional eight satellites were discovered before the flyby of the ''[[Voyager 1]]'' probe in 1979.{{refn |group=lower-alpha |See [[Moons of Jupiter]] for details and cites}}

In 1932, [[Rupert Wildt]] identified [[absorption bands]] of ammonia and methane in the spectra of Jupiter.<ref>{{cite journal |last=Dunham |first=Theodore Jr. |year=1933 |title=Note on the Spectra of Jupiter and Saturn |journal=Publications of the Astronomical Society of the Pacific |volume=45 |issue=263 |pages=42–44 |bibcode=1933PASP...45...42D |doi=10.1086/124297 |doi-access=free}}</ref> Three long-lived anticyclonic features called "white ovals" were observed in 1938. For several decades, they remained as separate features in the atmosphere that approach each other but never merge. Finally, two of the ovals merged in 1998, then absorbed the third in 2000, becoming [[Oval BA]].<ref>{{cite journal | last1=Youssef | first1=A. | last2=Marcus | first2=P. S. | title=The dynamics of jovian white ovals from formation to merger | journal=Icarus | year=2003 | volume=162 | issue=1 | pages=74–93 | bibcode=2003Icar..162...74Y | doi=10.1016/S0019-1035(02)00060-X }}</ref>

==== Radiotelescope research ====
In 1955, Bernard Burke and [[Kenneth Franklin]] discovered that Jupiter emits bursts of radio waves at a frequency of 22.2&nbsp;MHz.<ref name="elkins-tanton"/>{{rp|36}} The period of these bursts matched the rotation of the planet, and they used this information to determine a more precise value for Jupiter's rotation rate. Radio bursts from Jupiter were found to come in two forms: long bursts (or L-bursts) lasting up to several seconds, and short bursts (or S-bursts) lasting less than a hundredth of a second.<ref>{{cite web |last=Weintraub |first=Rachel A. |date=September 26, 2005 |url=http://www.nasa.gov/vision/universe/solarsystem/radio_jupiter.html |title=How One Night in a Field Changed Astronomy |publisher=NASA |access-date=February 18, 2007 |archive-date=July 3, 2011 |archive-url=https://web.archive.org/web/20110703080812/http://www.nasa.gov/vision/universe/solarsystem/radio_jupiter.html |url-status=dead }}</ref>

Scientists have discovered three forms of radio signals transmitted from Jupiter:
* Decametric radio bursts (with a wavelength of tens of metres) vary with the rotation of Jupiter, and are influenced by the interaction of Io with Jupiter's magnetic field.<ref>{{cite web |last=Garcia |first=Leonard N |url=http://radiojove.gsfc.nasa.gov/library/sci_briefs/decametric.htm |title=The Jovian Decametric Radio Emission |publisher=NASA |access-date=February 18, 2007 |archive-date=March 2, 2012 |archive-url=https://web.archive.org/web/20120302222737/http://radiojove.gsfc.nasa.gov/library/sci_briefs/decametric.htm |url-status=live }}</ref>
* Decimetric radio emission (with wavelengths measured in centimetres) was first observed by [[Frank Drake]] and Hein Hvatum in 1959.<ref name="elkins-tanton"/>{{rp|36}} The origin of this signal is a torus-shaped belt around Jupiter's equator, which generates [[cyclotron radiation]] from electrons that are accelerated in Jupiter's magnetic field.<ref>{{cite journal | last1=Klein | first1=M. J. | last2=Gulkis | first2=S. | last3=Bolton | first3=S. J. | year=1996 | url=https://ntrs.nasa.gov/search.jsp?R=20060036302 | title=Jupiter's Synchrotron Radiation: Observed Variations Before, During and After the Impacts of Comet SL9 | journal=Conference at University of Graz | page=217 | publisher=NASA | access-date=February 18, 2007 | bibcode=1997pre4.conf..217K | archive-date=November 17, 2015 | archive-url=https://web.archive.org/web/20151117143101/http://ntrs.nasa.gov/search.jsp?R=20060036302 | url-status=live }}</ref>
* [[Thermal radiation]] is produced by heat in the atmosphere of Jupiter.<ref name="elkins-tanton"/>{{rp|43}}

==== Exploration ====
{{Main|Exploration of Jupiter}}

Jupiter has been visited by automated [[spacecraft]] since 1973, when the space probe ''[[Pioneer 10]]'' passed close enough to Jupiter to send back revelations about its properties and phenomena.<ref>{{cite web | url=https://www.nasa.gov/centers/ames/missions/archive/pioneer.html | title=The Pioneer Missions | publisher=NASA | date=March 26, 2007 | access-date=February 26, 2021 | archive-date=December 23, 2018 | archive-url=https://web.archive.org/web/20181223151213/https://www.nasa.gov/centers/ames/missions/archive/pioneer.html | url-status=live }}</ref><ref>{{cite web | title=NASA Glenn Pioneer Launch History | date=March 7, 2003 | url=http://www.nasa.gov/centers/glenn/about/history/pioneer.html | publisher=NASA – Glenn Research Center | access-date=December 22, 2011 | archive-date=July 13, 2017 | archive-url=https://web.archive.org/web/20170713041117/https://www.nasa.gov/centers/glenn/about/history/pioneer.html | url-status=dead }}</ref> Missions to Jupiter are accomplished at a cost in energy, which is described by the net change in velocity of the spacecraft, or [[delta-v]]. Entering a [[Hohmann transfer orbit]] from Earth to Jupiter from [[low Earth orbit]] requires a delta-v of 6.3&nbsp;km/s,<ref>{{cite book | last1=Fortescue | first1=Peter W. | last2=Stark | first2=John | last3=Swinerd | first3=Graham | title=Spacecraft systems engineering | edition=3rd | publisher=John Wiley and Sons | year=2003 | isbn=978-0-470-85102-9 | page=150 }}</ref> which is comparable to the 9.7&nbsp;km/s delta-v needed to reach low Earth orbit.<ref>{{cite web
 | last=Hirata | first=Chris
 | url=http://www.pma.caltech.edu/~chirata/deltav.html
 | title=Delta-V in the Solar System
 | publisher=California Institute of Technology |access-date=November 28, 2006
| archive-url=https://web.archive.org/web/20060715015836/http://www.pma.caltech.edu/~chirata/deltav.html
 | archive-date=July 15, 2006 |url-status=dead
}}</ref> [[Gravitational slingshot|Gravity assists]] through planetary [[Gravitational slingshot|flybys]] can be used to reduce the energy required to reach Jupiter.<ref name="delta-v">{{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}}</ref>

===== Flyby missions =====
{| class="wikitable floatright"
|+
|-
! Spacecraft
! Closest<br/>approach
! Distance (km)
|-
| ''[[Pioneer 10]]''
| December 3, 1973
| style="text-align: right;" | 130,000
|-
| ''[[Pioneer 11]]''
| December 4, 1974
| style="text-align: right;" | 34,000
|-
| ''[[Voyager 1]]''
| March 5, 1979
| style="text-align: right;" | 349,000
|-
| ''[[Voyager 2]]''
| July 9, 1979
| style="text-align: right;" | 570,000
|-
| rowspan="2" | ''[[Ulysses probe|Ulysses]]''
| February 8, 1992<ref name="ulysses"/>
| style="text-align: right;" | 408,894
|-
| February 4, 2004<ref name="ulysses"/>
| style="text-align: right;" | 120,000,000
|-
| ''[[Cassini–Huygens|Cassini]]''
| December 30, 2000
| style="text-align: right;" | 10,000,000
|-
| ''[[New Horizons]]''
| February 28, 2007
| style="text-align: right;" | 2,304,535
|}

Beginning in 1973, several spacecraft performed planetary flyby manoeuvres that brought them within the observation range of Jupiter. The [[Pioneer program|Pioneer]] missions obtained the first close-up images of Jupiter's atmosphere and several of its moons. They discovered that the radiation fields near the planet were much stronger than expected, but both spacecraft managed to survive in that environment. The trajectories of these spacecraft were used to refine the mass estimates of the [[Moons of Jupiter|Jovian system]]. [[Radio occultations]] by the planet resulted in better measurements of Jupiter's diameter and the amount of polar flattening.<ref name="burgess"/>{{rp|47}}<ref name="cosmology 101">{{cite web |last=Lasher |first=Lawrence |date=August 1, 2006 |url=http://spaceprojects.arc.nasa.gov/Space_Projects/pioneer/PNhome.html |title=Pioneer Project Home Page |publisher=NASA Space Projects Division |access-date=November 28, 2006 |url-status=dead |archive-url=https://web.archive.org/web/20060101001205/http://spaceprojects.arc.nasa.gov/Space_Projects/pioneer/PNhome.html |archive-date=January 1, 2006 }}</ref>

Six years later, the [[Voyager program|Voyager]] missions vastly improved the understanding of the [[Galilean moons]] and discovered Jupiter's rings. They also confirmed that the Great Red Spot was anticyclonic. Comparison of images showed that the Spot had changed hues since the Pioneer missions, turning from orange to dark brown. A torus of ionized atoms was discovered along Io's orbital path, which were found to come from erupting volcanoes on the moon's surface. As the spacecraft passed behind the planet, it observed flashes of lightning in the [[Terminator (solar)|night side]] atmosphere.<ref name="burgess"/>{{rp|87}}<ref name="voyager1">{{cite web |date=January 14, 2003 |url=http://voyager.jpl.nasa.gov/science/jupiter.html |title=Jupiter |publisher=NASA/JPL |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 }}</ref>

The next mission to encounter Jupiter was the ''[[Ulysses (spacecraft)|Ulysses]]'' solar probe. In February 1992, it performed a flyby manoeuvre to attain a [[polar orbit]] around the Sun. During this pass, the spacecraft studied Jupiter's magnetosphere, although it had no cameras to photograph the planet. The spacecraft passed by Jupiter six years later, this time at a much greater distance.<ref name="ulysses">{{Cite book | last1=Chan | first1=K. | title=Space OPS 2004 Conference | last2=Paredes | first2=E. S. | last3=Ryne | first3=M. S. | date=2004 | publisher=American Institute of Aeronautics and Astronautics | doi=10.2514/6.2004-650-447 | chapter=Ulysses Attitude and Orbit Operations: 13+ Years of International Cooperation }}</ref>

In 2000, the ''Cassini'' probe flew by Jupiter on its way to Saturn, and provided higher-resolution images.<ref>{{cite journal | last1=Hansen | first1=C. J. | last2=Bolton | first2=S. J. | last3=Matson | first3=D. L. | last4=Spilker | first4=L. J. | last5=Lebreton | first5=J.-P. |title=The Cassini–Huygens flyby of Jupiter |bibcode=2004Icar..172....1H |journal=Icarus |year=2004 |volume=172 |issue=1 |pages=1–8 |doi=10.1016/j.icarus.2004.06.018}}</ref>

The ''[[New Horizons]]'' probe flew by Jupiter in 2007 for a gravity assist en route to [[Pluto]].<ref>{{cite web | url=https://www.nasa.gov/mission_pages/newhorizons/news/nh_jupiter_oct09.html | date=October 9, 2007 | publisher=NASA | title=Pluto-Bound New Horizons Sees Changes in Jupiter System | access-date=February 26, 2021 | archive-date=November 27, 2020 | archive-url=https://web.archive.org/web/20201127014401/http://www.nasa.gov/mission_pages/newhorizons/news/nh_jupiter_oct09.html | url-status=dead }}</ref> The probe's cameras measured plasma output from volcanoes on Io and studied all four Galilean moons in detail.<ref>{{cite web | url=http://www.nasa.gov/mission_pages/newhorizons/news/jupiter_system.html | title=Pluto-Bound New Horizons Provides New Look at Jupiter System | date=May 1, 2007 | publisher=NASA | access-date=July 27, 2007 | archive-date=December 12, 2010 | archive-url=https://web.archive.org/web/20101212052748/http://www.nasa.gov/mission_pages/newhorizons/news/jupiter_system.html | url-status=dead }}</ref>

===== ''Galileo'' mission =====
{{Main|Galileo (spacecraft)}}
[[File:Galileo Preparations - GPN-2000-000672.jpg|left|thumb|''Galileo'' in preparation for mating with the rocket, 1989]]
The first spacecraft to orbit Jupiter was the ''[[Galileo (spacecraft)|Galileo]]'' mission, which reached the planet on December 7, 1995.<ref name="HTUW"/> It remained in orbit for over seven years, conducting multiple flybys of all the Galilean moons and [[Amalthea (moon)|Amalthea]]. The spacecraft also witnessed the impact of [[Comet Shoemaker–Levy 9]] when it collided with Jupiter in 1994. Some of the goals for the mission were thwarted due to a malfunction in ''Galileo''s high-gain antenna.<ref name="galileo">{{cite web |last=McConnell |first=Shannon |date=April 14, 2003 |url=http://solarsystem.nasa.gov/galileo/ |archive-url=https://web.archive.org/web/20041103173530/http://solarsystem.nasa.gov/galileo/ |url-status=dead |archive-date=November 3, 2004 |title=Galileo: Journey to Jupiter |publisher=NASA/JPL |access-date=November 28, 2006}}</ref>

A 340-kilogram titanium [[Galileo (spacecraft)#Galileo entry probe|atmospheric probe]] was released from the spacecraft in July 1995, entering Jupiter's atmosphere on December 7.<ref name="HTUW"/> It parachuted through {{cvt|150|km|0}} of the atmosphere at a speed of about {{cvt|2575|kph}}<ref name="HTUW"/> and collected data for 57.6&nbsp;minutes until the spacecraft was destroyed.<ref>{{cite web |first=Julio |last=Magalhães |date=December 10, 1996 |url=http://spaceprojects.arc.nasa.gov/Space_Projects/galileo_probe/htmls/probe_events.html |title=Galileo Probe Mission Events |publisher=NASA Space Projects Division |access-date=February 2, 2007 |url-status=dead |archive-url=https://web.archive.org/web/20070102143553/http://spaceprojects.arc.nasa.gov/Space_Projects/galileo_probe/htmls/probe_events.html |archive-date=January 2, 2007 }}</ref> 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. [[NASA]] destroyed the spacecraft to avoid any possibility of the spacecraft crashing into and possibly contaminating the moon Europa, [[Life on Europa|which may harbour life]].<ref name="galileo"/>

Data from this mission revealed that hydrogen composes up to 90% of Jupiter's atmosphere.<ref name="HTUW"/> The recorded temperature was more than {{Convert|300|C}}, and the wind speed measured more than 644&nbsp;km/h (>400&nbsp;mph) before the probes vaporized.<ref name="HTUW"/>

===== ''Juno'' mission =====
{{Main|Juno (spacecraft)}}
[[File:Juno prepared for rotation test stand.jpg|alt=see caption|thumb|''Juno'' preparing for testing in a rotation stand, 2011|331x331px]]
NASA's ''[[Juno (spacecraft)|Juno]]'' mission arrived at Jupiter on July 4, 2016, with the goal of studying the planet in detail from a [[polar orbit]]. The spacecraft was originally intended to orbit Jupiter thirty-seven times over a period of twenty months.<ref name="NYT-20160705" /><ref>{{cite web | first=Anthony | last=Goodeill | date=March 31, 2008 | url=http://newfrontiers.nasa.gov/missions_juno.html | title=New Frontiers – Missions – Juno | publisher=NASA | access-date=January 2, 2007 | url-status=dead |archive-url=https://web.archive.org/web/20070203235637/http://newfrontiers.nasa.gov/missions_juno.html | archive-date=February 3, 2007 }}</ref><ref>{{cite web
 | title=Juno, NASA's Jupiter probe
 | publisher=The Planetary Society
 | url=https://www.planetary.org/space-missions/juno
 | access-date=April 27, 2022
| archive-date=May 12, 2022
| archive-url=https://web.archive.org/web/20220512174710/https://www.planetary.org/space-missions/juno
 | url-status=live
 }}</ref> During the mission, the spacecraft will be exposed to high levels of radiation from [[Magnetosphere of Jupiter|Jupiter's magnetosphere]], which may cause the failure of certain instruments.<ref>{{cite web | title=NASA's Juno spacecraft to risk Jupiter's fireworks for science | author=Jet Propulsion Laboratory | date=June 17, 2016 | website=phys.org | url=https://phys.org/news/2016-06-nasa-juno-spacecraft-jupiter-fireworks.html | access-date=April 10, 2022 | archive-date=August 9, 2022 | archive-url=https://web.archive.org/web/20220809222951/https://phys.org/news/2016-06-nasa-juno-spacecraft-jupiter-fireworks.html | url-status=live }}</ref> On August 27, 2016, the spacecraft completed its first flyby of Jupiter and sent back the first-ever images of [[Jupiter's_North_Pole|Jupiter's north pole]].<ref>{{cite web |first=Niall |last=Firth |date=September 5, 2016 |url=https://www.newscientist.com/article/2104558-nasas-juno-probe-snaps-first-images-of-jupiters-north-pole/ |title=NASA's Juno probe snaps first images of Jupiter's north pole |work=New Scientist |access-date=September 5, 2016 |archive-date=September 6, 2016 |archive-url=https://web.archive.org/web/20160906173136/https://www.newscientist.com/article/2104558-nasas-juno-probe-snaps-first-images-of-jupiters-north-pole/ |url-status=live }}</ref>

''Juno'' completed 12 orbits before the end of its budgeted mission plan, ending in July 2018.<ref name="sfnow20170221">{{cite news|url=https://spaceflightnow.com/2017/02/21/nasas-juno-spacecraft-to-remain-in-current-orbit-around-jupiter/|title=NASA's Juno spacecraft to remain in current orbit around Jupiter|publisher=Spaceflight Now|first=Stephen|last=Clark|date=February 21, 2017|access-date=April 26, 2017|archive-date=February 26, 2017|archive-url=https://web.archive.org/web/20170226211013/http://spaceflightnow.com/2017/02/21/nasas-juno-spacecraft-to-remain-in-current-orbit-around-jupiter/|url-status=live}}</ref> In June of that year, NASA extended the mission operations plan to July 2021, and in January of that year the mission was extended to September 2025 with four lunar flybys: one of Ganymede, one of Europa, and two of Io.<ref name="nasa20180606">{{cite web |url=https://www.jpl.nasa.gov/news/news.php?release=2018-130 |title=NASA Re-plans Juno's Jupiter Mission |publisher=NASA/JPL |first1=D. C. |last1=Agle |first2=JoAnna |last2=Wendel |first3=Deb |last3=Schmid |date=June 6, 2018 |access-date=January 5, 2019 |archive-date=July 24, 2020 |archive-url=https://web.archive.org/web/20200724112957/https://www.jpl.nasa.gov/news/news.php?release=2018-130 |url-status=live }}</ref><ref name="nasa20210108">{{Cite web|last=Talbert|first=Tricia|date=January 8, 2021|title=NASA Extends Exploration for Two Planetary Science Missions|url=http://www.nasa.gov/feature/nasa-extends-exploration-for-two-planetary-science-missions|access-date=January 11, 2021|website=NASA|archive-date=January 11, 2021|archive-url=https://web.archive.org/web/20210111161636/https://www.nasa.gov/feature/nasa-extends-exploration-for-two-planetary-science-missions/|url-status=live}}</ref> When ''Juno'' reaches the end of the mission, it will perform a controlled deorbit and disintegrate into Jupiter's atmosphere to avoid the risk of colliding and contaminating Jupiter's moons.<ref name="skytel20170221">{{cite news |url=http://www.skyandtelescope.com/astronomy-news/juno-stay-current-orbit-jupiter/ |title=Juno Will Stay in Current Orbit Around Jupiter |work=Sky & Telescope |first=David |last=Dickinson |date=February 21, 2017 |access-date=January 7, 2018 |archive-date=January 8, 2018 |archive-url=https://web.archive.org/web/20180108063357/http://www.skyandtelescope.com/astronomy-news/juno-stay-current-orbit-jupiter/ |url-status=live }}</ref>

===== Cancelled missions and future plans =====
There is an interest in missions to study Jupiter's larger icy moons, which may have subsurface liquid oceans.<ref>{{Cite web |last=Sori |first=Mike |title=Jupiter's moons hide giant subsurface oceans – two missions are sending spacecraft to see if these moons could support life |url=http://theconversation.com/jupiters-moons-hide-giant-subsurface-oceans-two-missions-are-sending-spacecraft-to-see-if-these-moons-could-support-life-203207 |access-date=May 12, 2023 |website=The Conversation |date=April 10, 2023 |language=en |archive-date=May 12, 2023 |archive-url=https://web.archive.org/web/20230512042246/http://theconversation.com/jupiters-moons-hide-giant-subsurface-oceans-two-missions-are-sending-spacecraft-to-see-if-these-moons-could-support-life-203207 |url-status=live }}</ref> Funding difficulties have delayed progress, causing NASA's ''[[Jupiter Icy Moons Orbiter|JIMO]]'' (''Jupiter Icy Moons Orbiter'') to be cancelled in 2005.<ref>{{cite news |first=Brian |last=Berger |title=White House scales back space plans |publisher=MSNBC |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 }}</ref> A subsequent proposal was developed for a joint NASA/[[European Space Agency|ESA]] mission called [[EJSM/Laplace]], with a provisional launch date around 2020. EJSM/Laplace would have consisted of the NASA-led [[Jupiter Europa Orbiter]] and the ESA-led [[Jupiter Ganymede Orbiter]].<ref>{{cite web |url=http://sci.esa.int/science-e/www/area/index.cfm?fareaid=107 |title=Laplace: A mission to Europa & Jupiter system |publisher=European Space Agency |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 }}</ref> However, the ESA formally ended the partnership in April 2011, citing budget issues at NASA and the consequences on the mission timetable. Instead, ESA planned to go ahead with a European-only mission to compete in its L1 [[Cosmic Vision]] selection.<ref name=esaled>{{cite web|url=http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=48661|title=New approach for L-class mission candidates|publisher=European Space Agency|date=April 19, 2011|last1=Favata|first1=Fabio|access-date=May 2, 2012|archive-date=April 2, 2013|archive-url=https://web.archive.org/web/20130402143829/http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=48661|url-status=live}}</ref> These plans have been realized as the European Space Agency's [[Jupiter Icy Moon Explorer]] (JUICE), launched on April 14, 2023,<ref name="bbc-20230214">{{Cite news|date=April 14, 2023|title=European Space Agency: Blast off for Jupiter icy moons mission|language=en-GB|work=BBC News|url=https://www.bbc.com/news/science-environment-65273857|access-date=April 14, 2023|archive-date=April 14, 2023|archive-url=https://web.archive.org/web/20230414114037/https://www.bbc.com/news/science-environment-65273857|url-status=live}}</ref> followed by NASA's ''[[Europa Clipper]]'' mission, launched on October 14, 2024.<ref>{{cite web|last=Foust|first=Jeff|url=https://spacenews.com/cost-growth-prompts-changes-to-europa-clipper-instruments/|title=Cost growth prompts changes to Europa Clipper instruments|work=Space News|date=July 10, 2020|access-date=July 10, 2020|archive-date=September 29, 2021|archive-url=https://web.archive.org/web/20210929074855/https://spacenews.com/cost-growth-prompts-changes-to-europa-clipper-instruments/|url-status=live}}</ref>

Other proposed missions include the [[Chinese National Space Administration]]'s ''[[Tianwen-4]]'' mission which aims to launch an orbiter to the Jovian system and possibly [[Callisto (moon)|Callisto]] around 2035,<ref>{{cite news
 | title=Jupiter Mission by China Could Include Callisto Landing
 | first=Andrew
 | last=Jones
 | date=January 12, 2021
| publisher=The Planetary Society
 | url=https://www.planetary.org/articles/jupiter-mission-callisto-landing
 | access-date=April 27, 2020
| archive-date=April 27, 2021
| archive-url=https://web.archive.org/web/20210427053454/https://www.planetary.org/articles/jupiter-mission-callisto-landing
 | url-status=live
 }}</ref> and CNSA's ''[[Interstellar Express]]''<ref>{{cite news
 | title=China to launch a pair of spacecraft towards the edge of the solar system
 | first=Andrew
 | last=Jones
 | date=April 16, 2021
| work=Space News
 | url=https://spacenews.com/china-to-launch-a-pair-of-spacecraft-towards-the-edge-of-the-solar-system/
 | access-date=April 27, 2020
| archive-date=May 15, 2021
| archive-url=https://archive.today/20210515103459/https://spacenews.com/china-to-launch-a-pair-of-spacecraft-towards-the-edge-of-the-solar-system/
 | url-status=live
 }}</ref> and NASA's ''[[Interstellar Probe (spacecraft)|Interstellar Probe]]'',<ref>{{cite web
 | first=Lee
 | last=Billings
 | date=November 12, 2019
| website=Scientific American
 | title=Proposed Interstellar Mission Reaches for the Stars, One Generation at a Time
 | url=https://www.scientificamerican.com/article/proposed-interstellar-mission-reaches-for-the-stars-one-generation-at-a-time1/
 | access-date=April 27, 2020
| archive-date=July 25, 2021
| archive-url=https://web.archive.org/web/20210725054502/https://www.scientificamerican.com/article/proposed-interstellar-mission-reaches-for-the-stars-one-generation-at-a-time1/
 | url-status=live
 }}</ref> which would both use Jupiter's gravity to help them reach the edges of the heliosphere.