View source for Cassini–Huygens

{{italic title}}
{{Infobox spaceflight |auto=all 
| name                  =''Cassini–Huygens''
| names_list            =
| image                 = Cassini Saturn Orbit Insertion.jpg
| image_caption         = Artist's concept of ''Cassini''{{'s}} [[orbit insertion]] around Saturn
| image_size            = 276px
| mission_type          = ''Cassini'': [[Saturn]] orbiter<br />''Huygens'': [[Titan (moon)|Titan]] lander
| operator              = ''Cassini'': [[NASA]]{{\}}[[Jet Propulsion Laboratory|JPL]] <br /> ''Huygens'': [[European Space Agency|ESA]]{{\}}[[Italian Space Agency|ASI]]
| COSPAR_ID             = 1997-061A
| SATCAT                = 25008
| website               =
* {{url|https://saturn.jpl.nasa.gov/|NASA}}
* {{url|http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens|ESA}}
* {{url|http://www.asi.it/en/activity/solar-system-exploration/cassini-huygens|ASI}}
| mission_duration      = {{plainlist|
* '''Overall''':
** {{pad|1em}}<small>{{time interval|15 October 1997 08:43|15 September 2017 12:08|show= yd|sep=,}} </small>
** {{pad|1em}}<small>{{time interval|1 July 2004 02:48|15 September 2017 12:08|show= yd|sep=,}} at Saturn</small>
* '''En route''':
** {{pad|1em}}{{time interval|15 October 1997|1 July 2004 02:48|show= yd|sep=,|duration= on}}
* '''Prime mission''':
** {{pad|1em}}{{time interval|1 July 2004 02:48|30 June 2008|show= y|sep=,|duration= on}}
* '''Extended missions''':
** {{pad|1em}}<small>Equinox: {{time interval|31 July 2008|30 September 2010|show= yd|sep=,|duration= on}}</small>
** {{pad|1em}}<small>Solstice: {{time interval|30 September 2010|22 April 2017|show= yd|sep=,|duration= on}}</small>
** {{pad|1em}}<small>Finale: {{time interval|23 April 2017 03:46|15 September 2017 12:08|show= md|sep=,|duration= on}}</small>
 }}
| manufacturer          = ''Cassini'': [[Jet Propulsion Laboratory]] <br /> ''Huygens'': [[Thales Alenia Space]]
| launch_mass           = {{convert|5712|kg|lb|abbr= on}}<ref name=quickfacts /><ref>{{cite web |url= http://space.skyrocket.de/doc_sdat/cassini.htm |title= Cassini / Huygens |work=Gunter's Space Page |first= Gunter Dirk |last= Krebs |accessdate= June 15, 2016}}</ref>
| dry_mass              = {{convert|2523|kg|lb|abbr= on}}<ref name=quickfacts>{{cite web |url= https://saturn.jpl.nasa.gov/mission/about-the-mission/quick-facts/ |title= Cassini–Huygens: Quick Facts |publisher= NASA |accessdate= August 20, 2011}}</ref>
| payload_mass          =
| dimensions            =
| power                 = ~885&nbsp;watts (BOL)<ref name=quickfacts/><br /> ~670&nbsp;watts (2010)<ref name="barber">{{cite web |url= http://saturn.jpl.nasa.gov/news/cassiniinsider/insider20100823/ |title= Insider's Cassini: Power, Propulsion, and Andrew Ging |publisher= NASA |first= Todd J. |last= Barber |date= August 23, 2010 |accessdate= August 20, 2011 |url-status= dead |archiveurl= https://web.archive.org/web/20120402002307/http://saturn.jpl.nasa.gov/news/cassiniinsider/insider20100823/ |archivedate= April 2, 2012 }}</ref> <br /> ~663&nbsp;watts (EOM/2017)<ref name="quickfacts"/>

| launch_date           = {{start-date| October 15, 1997, 08:43:00}}&nbsp;UTC
| launch_rocket         = [[Titan IV| Titan IV(401)B]] B-33
| launch_site           = [[Cape Canaveral Air Force Station|Cape Canaveral]] [[Cape Canaveral Air Force Station Space Launch Complex 40|SLC-40]]
| launch_contractor     =

| disposal_type         = [[Cassini retirement|Controlled entry into Saturn]]
| last_contact          = September 15, 2017
* 11:55:39 UTC X-band telemetry
* 11:55:46 UTC S-band radio science<ref>{{cite interview |title= Cassini Post-End of Mission News Conference |date= September 15, 2017 |publisher= NASA Television |location= Pasadena, CA}}</ref>

| orbit_reference       = Kronocentric
| apsis                 = krone

|interplanetary         =
 {{Infobox spaceflight/IP
  |type                 = flyby
  |note                 = Gravity assist
  |object               = [[Venus]]
  |arrival_date         = April 26, 1998
  |distance             = {{convert|283|km|mi|abbr=on}}
 }}
 {{Infobox spaceflight/IP
  |type                 = flyby
  |note                 = Gravity assist
  |object               = [[Venus]]
  |arrival_date         = June 24, 1999
  |distance             = {{convert|623|km|mi|abbr= on}}
 }}
 {{Infobox spaceflight/IP
  |type                 = flyby
  |note                 = Gravity assist
  |object               = [[Earth]]-[[Moon]] system
  |arrival_date         = August 18, 1999, 03:28&nbsp;UTC
  |distance             = {{convert|1171|km|mi|abbr= on}}
 }}
 {{Infobox spaceflight/IP
  |type                 = flyby
  |note                 = Incidental
  |object               = [[2685 Masursky]]
  |arrival_date         = January 23, 2000
  |distance             = {{convert|1600000|km|mi|abbr= on}}
 }}
 {{Infobox spaceflight/IP
  |type                 = flyby
  |note                 = Gravity assist
  |object               = [[Jupiter]]
  |arrival_date         = December 30, 2000
  |distance             = {{convert|9852924|km|mi|abbr= on}}
 }}
 {{Infobox spaceflight/IP
  |type                 = orbiter
  |object               = [[Saturn]]
  |arrival_date         = July 1, 2004, 02:48&nbsp;UTC
 }}
 {{Infobox spaceflight/IP
  |type                 = lander
  |object               = [[Titan (moon)|Titan]]
  |component            = ''[[Huygens (spacecraft)|Huygens]]''
  |arrival_date         = January 14, 2005
 }}

| programme             = [[Large Strategic Science Missions]]
| previous_mission      = ''[[Galileo (spacecraft)|Galileo]]''
| next_mission          = [[Mars Science Laboratory]]
}}
'''''Cassini–Huygens''''', ({{IPAc-en|k|ə|ˈ|s|iː|n|i|_|ˈ|h|ɔɪ|ɡ|ən|z}} {{respell|kə|SEE|nee|_|HOY|gənz}}) often referred to as '''''Cassini''''', was a joint space-research mission by [[NASA]], the [[European Space Agency]] (ESA), and the [[Italian Space Agency]] (ASI). Its goal was to study [[Saturn]] and its system, including its [[Rings of Saturn|rings]] and [[Moons of Saturn|moons]], using a [[Space probe|robotic spacecraft]]. The mission included NASA's Cassini space probe and ESA's [[Huygens (spacecraft)|Huygens lander]], which landed on Saturn's largest moon, Titan in 2005.<ref>{{cite web |url=https://science.nasa.gov/about-us/smd-programs/outer-planets-flagship/ |title=Outer Planets Flagship - Science Mission Directorate |publisher=NASA |access-date=July 12, 2017 |archive-date=May 13, 2017 |archive-url=https://web.archive.org/web/20170513161116/https://science.nasa.gov/about-us/smd-programs/outer-planets-flagship |url-status=dead }}</ref> Cassini was the fourth spacecraft to visit Saturn and the first to [[orbit]] around it, a mission that lasted from 2004 to 2017. The mission was named after astronomers [[Giovanni Cassini]] and [[Christiaan Huygens]].

Launched on October 15, 1997, Cassini spent nearly 20 years in space. It orbited Saturn for 13 years, starting from July 1, 2004, and studied the planet and its surroundings during that time.<ref name="NYT-20151218-jc">{{cite news |last= Corum |first= Jonathan |title= Mapping Saturn's Moons |url= https://www.nytimes.com/interactive/2015/12/18/science/space/nasa-cassini-maps-saturns-moons.html |date= December 18, 2015 |work= [[The New York Times]] |access-date= December 18, 2015}}</ref> 

The journey to Saturn included passing close by [[Venus]] (April 1998 and July 1999), [[Earth]] (August 1999), the [[asteroid]] [[2685 Masursky]], and [[Jupiter]] (December 2000). Cassini's mission ended on September 15, 2017, when it entered [[Atmosphere of Saturn|Saturn's upper atmosphere]] and burned up to avoid any risk of [[:wikt:contamination|contaminating]] [[Moons of Saturn|Saturn's potentially habitable moons]] with [[microbe]]s from Earth. The mission exceeded expectations – NASA's Jim Green called Cassini-Huygens a "mission of firsts"<ref>{{Cite web | url= https://www.jpl.nasa.gov/video/details.php?id=1468 | title= Cassini's First Dive Between Saturn and its Rings| website= [[Jet Propulsion Laboratory]]}}</ref> that greatly advanced our knowledge of Saturn, its moons, and rings, and expanded our understanding of where life might exist in our solar system.<ref name="overview"/>

Cassini's mission was originally planned for four years, from June 2004 to May 2008. It was then extended for two more years until September 2010, called the Cassini Equinox Mission. Later, it received a final extension known as the Cassini Solstice Mission, which lasted another seven years until September 15, 2017. On that date, Cassini was directed to enter Saturn's upper atmosphere and burn up.<ref>{{Cite web |title=ESA Science & Technology - Cassini Equinox Mission |url=https://sci.esa.int/web/cassini-huygens/-/43181-cassini-tour-equinox-mission |access-date=2022-08-22 |website=sci.esa.int}}</ref>

The ''[[Huygens (spacecraft)|Huygens]]'' module traveled with Cassini until it separated from the probe on December 25, 2004. It landed on Titan on January 14, 2005, using a [[parachute]]. The separation was helped by the SED (Spin/Eject device), which made it move away at a speed of 0.35 meters per second (1.1 feet per second) and spin at a rate of 7.5 rpm. For about 90 minutes, it sent data back to Earth using Cassini as a relay. This was the first time a spacecraft landed in the outer Solar System and the first time a landing happened on a moon other than [[Moon|Earth's Moon]].

At the end of its mission, Cassini carried out its "Grand Finale": a series of risky passes through gaps between Saturn and its inner rings. This phase aimed to gather as much scientific data as possible before Cassini was destroyed to prevent any risk of contaminating Saturn's moons. This was necessary because if Cassini were to crash into these moons due to power loss or communication issues at the end of its mission, it could potentially contaminate them with Earth microbes. Cassini's mission concluded when it entered Saturn's atmosphere, but scientists will continue analyzing the data it sent back for many years.

== Overview ==
=== Construction ===
Scientists and teams from 27 countries worked together to design, build, launch, and operate the Cassini orbiter and Huygens probe. [[NASA]]'s [[Jet Propulsion Laboratory]] in the [[United States]] managed the mission and built the orbiter. The [[European Space Agency|European Space Research and Technology Centre]] developed the Huygens probe. [[Aérospatiale]] of [[France]], later apart of [[Thales Alenia Space]], put together the probe with help from [[:wikt:various|various]] European countries. The [[Italian Space Agency]] (ASI) provided important parts for the Cassini orbiter, such as [[antenna]]s and scientific instruments. NASA added more scientific instruments and electronic parts, with support from [[CNES]] of France. In April 2008, NASA extended [[:wikt:funding|funding]] for ground operations, renaming the mission as the ''Cassini Equinox Mission''. More funding extensions were announced in February 2010 for the ''Cassini Solstice Mission''. <ref name="overview"/><ref name="ASI-Cassini">{{cite web |url= http://www.asi.it/en/activity/solar-system-exploration/cassini-huygens |title= Cassini-Huygens |publisher= Agenzia Spaziale Italiana |date= December 2008 |access-date= April 16, 2017 |archive-date= September 21, 2017 |archive-url= https://web.archive.org/web/20170921010951/http://www.asi.it/en/activity/solar-system-exploration/cassini-huygens |url-status= dead }}</ref><ref name="MillerEA1996">{{cite book |chapter-url= http://solarsystem.iaps.inaf.it/downloads/VIMS-paper.pdf |first1= Edward A. |last1= Miller |first2= Gail |last2= Klein |first3= David W. |last3= Juergens |first4= Kenneth |last4= Mehaffey |first5= Jeffrey M. |last5= Oseas |title= Cassini/Huygens: A Mission to the Saturnian Systems |chapter= The Visual and Infrared Mapping Spectrometer for Cassini |editor-first1= Linda |editor-last1= Horn |display-authors= etal |volume= 2803 |pages= 206–220 |date= October 1996 |doi= 10.1117/12.253421 |bibcode= 1996SPIE.2803..206M |s2cid= 34965357 |access-date= August 14, 2017 |archive-date= August 9, 2017 |archive-url= https://web.archive.org/web/20170809014235/http://solarsystem.iaps.inaf.it/downloads/VIMS-paper.pdf |url-status= dead }}</ref><ref name="ReiningerFM1994">{{cite book |first1= Francis M. |last1= Reininger |first2= Michele |last2= Dami |first3= Riccardo |last3= Paolinetti |first4= Silvano |last4= Pieri |first5= Silvio |last5= Falugiani |title= Instrumentation in Astronomy VIII |chapter= Visible Infrared Mapping Spectrometer--visible channel (VIMS-V) |editor-first1= David L. |editor-first2= Eric R. |editor-last1= Crawford |editor-last2= Craine |display-authors= etal |volume= 2198 |pages= 239–250 |date= June 1994 |doi= 10.1117/12.176753 |bibcode= 1994SPIE.2198..239R |s2cid= 128716661 }}</ref><ref name="ExtensionTo2010">{{cite news
 |url= https://www.jpl.nasa.gov/news/news.php?feature=1659
 |title= NASA Extends Cassini's Grand Tour of Saturn
 |publisher= NASA{{\}}Jet Propulsion Laboratory
 |first1= Dwayne |last1= Brown
 |first2= Carolina |last2= Martinez |date= April 15, 2008
 |access-date= August 14, 2017}}</ref>

=== Mission ===
==== Launch ====
Cassini-Huygens launched on October 15, 1997, from Cape Canaveral Air Force Station's Space Launch Complex 40. It used a Titan IVB/Centaur rocket, which included a two-stage Titan IV booster rocket, two solid rocket engines, the Centaur upper stage, and a payload enclosure (fairing).<ref>{{cite web |url=http://sci.esa.int/cassini-huygens/33415-summary/ |title=Mission Summary |website=sci.esa.int |language=en-GB |access-date=February 3, 2017}}</ref>

==== Venus and Earth flyby's and cruise to Jupiter ====
The Cassini space probe used gravity to help it travel. It flew by [[Venus]] twice, on April 26, 1998, and June 24, 1999, to gain speed. This let Cassini go out to the [[asteroid belt]] before the Sun's gravity pulled it back.

On August 18, 1999, at 03:28 UTC, Cassini flew by [[Earth]]. One hour and 20 minutes earlier, it passed the Moon at 377,000 kilometers and took some [[calibration]] photos.

On January 23, 2000, at around 10:00 UTC, Cassini flew by the [[asteroid]] [[2685 Masursky]]. It took photos five to seven hours before the flyby. The asteroid was estimated to be 15 to 20 kilometers wide.<ref>{{cite press release |url=http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20000211/ |title=New Cassini Images of Asteroid Available |date=February 11, 2000 |publisher=JPL |access-date=October 15, 2010 |archive-url=https://web.archive.org/web/20100612124753/http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20000211/ |archive-date=June 12, 2010 |url-status=dead  }}</ref>

==== Jupiter flyby ====
[[File:PIA02879 - A New Year for Jupiter and Io.jpg|thumb|left|Cassini image of [[Io (moon)|Io]] in front of [[Jupiter]], taken on January 1, 2001]]
Cassini got close to [[Jupiter]] on December 30, 2000, at 9.7 million kilometers. It took around 26,000 pictures of Jupiter, its [[Rings of Jupiter|ring]]s, and [[Moons of Jupiter|its moons]] during a six-month flyby. These images made the most detailed global color portrait of Jupiter, showing features as small as 60 kilometers across.

One key finding was about Jupiter's [[atmospheric circulation]]. Scientists found that dark "belts" on Jupiter have upwelling air and bright clouds, while the lighter "zones" have sinking air. This was surprising because, on Earth, rising air usually forms clouds.

Cassini also saw a large, dark oval of high atmospheric haze near Jupiter's north pole. [[Infrared]] images showed that the winds near the poles move in opposite directions in different bands.

Cassini's observations of Jupiter's rings showed that the particles in the rings are [[:wikt:irregularly|irregularly]] shaped, not [[:wikt:spherical|spherical]]. These particles likely come from impacts on Jupiter's moons, [[Metis (moon)|Metis]] and [[Adrastea (moon)|Adrastea]], by micrometeorites.

==== Testing Albert Einstein's Theory of Relativity ====
On October 10, 2003, the Cassini mission team announced results of tests on [[Albert Einstein]]'s [[general theory of relativity]]. They used [[radio wave]]s sent from Cassini. These waves passed close to the Sun, and the scientists measured how the frequency changed. According to Einstein's theory, the Sun's gravity curves space-time, causing the radio waves to change frequency.

The experiment found no [[:wikt:deviation|deviations]] from Einstein's theory. Previous tests with the [[Viking program|Viking]] and [[Voyager program|Voyager]] probes matched Einstein's predictions within one part in a thousand.<ref>{{cite web |first=Isabelle |last=Dumé |url=https://physicsworld.com/a/general-relativity-passes-cassini-test/ |date=24 September 2003 |website=Physics World |title=General relativity passes Cassini test}}</ref>

==== New moons of Saturn ====
[[File:PIA18078-PossibleBeginning-NewMoonOfPlanetSaturn-20130415.jpg|thumb|right|The possible formation of a new [[Natural satellite|moon]] was captured on April 15, 2013.]]
In total, the Cassini mission found seven new moons orbiting Saturn.<ref>Meltzer 2015, pp. 346–351</ref> Using images taken by Cassini, researchers identified [[Methone (moon)|Methone]], [[Pallene (moon)|Pallene]], and [[Polydeuces (moon)|Polydeuces]] in 2004,<ref>{{Cite web |title=Newest Saturn moons given names |work=BBC News |date=February 28, 2005 |url=http://news.bbc.co.uk/2/hi/science/nature/4298053.stm |access-date=September 1, 2016}}</ref> although later study revealed that [[Voyager 2]] had already photographed Pallene during its flyby of Saturn in 1981.<ref>{{cite journal| doi = 10.1086/505206| last1 = Spitale| first1 = J. N.| last2 = Jacobson| first2 = R. A.| last3 = Porco| first3 = C. C.| last4 = Owen| first4 = W. M. Jr.| year = 2006| title = The orbits of Saturn's small satellites derived from combined historic and ''Cassini'' imaging observations| url = https://archive.org/details/sim_astronomical-journal_2006-08_132_2/page/692| journal = The Astronomical Journal| volume = 132| issue = 2| pages = 692–710| bibcode = 2006AJ....132..692S| ref = {{sfnRef|Spitale Jacobson et al.|2006}}| doi-access = free}}</ref>

[[File:Moon Daphnis S2005 S1.jpg|thumb|left|Photograph of moon [[Daphnis (moon)|Daphnis]] ]]
On May 1, 2005, Cassini found a new moon in the Keeler gap of [[Rings of Saturn|Saturn's rings]]. Initially named S/2005 S 1, it was later named [[Daphnis (moon)|Daphnis]]. Another moon, originally named S/2007 S 4, was discovered by Cassini on May 30, 2007, and is now known as [[Anthe (moon)|Anthe]]. On February 3, 2009, Cassini discovered a sixth moon roughly 500 meters (0.3 miles) in diameter within Saturn's G-ring, now named [[Aegaeon (moon)|Aegaeon]] (formerly S/2008 S 1).<ref>{{cite web |title=Surprise! Saturn has small moon hidden in ring |work=NBC News |date=March 3, 2009 |url=http://www.msnbc.msn.com/id/29495319/ |archive-url=https://web.archive.org/web/20131217221601/http://www.nbcnews.com/id/29495319/#.VeEvMSVVhBc |archive-date=December 17, 2013 |url-status=dead |access-date=August 29, 2015}}</ref> On November 2, 2009, Cassini found the seventh moon, labeled [[S/2009 S 1]], roughly 300 meters (980 feet) in diameter in Saturn's B-ring system.<ref>{{cite web |first=Daniel W. E. |last=Green |url=http://ciclops.org/view_popup.php?id=5926&js=1 |title=IAU Circular No. 9091 |publisher=CICLOPS |date=November 2, 2009 |access-date=August 20, 2011 |archive-date=June 11, 2011 |archive-url=https://web.archive.org/web/20110611211632/http://ciclops.org/view_popup.php?id=5926&js=1 |url-status=dead }}</ref>

On April 14, 2014, NASA scientists announced the potential start of a new moon forming in Saturn's A Ring.<ref>{{cite web |last1=Platt |first1=Jane |last2=Brown |first2=Dwayne |title=NASA Cassini Images May Reveal Birth of a Saturn Moon |url=http://www.jpl.nasa.gov/news/news.php?release=2014-112 |date=April 14, 2014 |work=[[NASA]] |access-date=April 14, 2014}}</ref>

==== Phoebe flyby ====
[[File:Phoebe arrival and departure mosaics.jpg|thumb|Cassini Phoebe images]]
On June 11, 2004, Cassini flew by Saturn's moon [[Phoebe (moon)|Phoebe]] for the first close-up study of this moon. [[Voyager 2]] had done a distant flyby in 1981 but did not return detailed images. This was Cassini's only chance to closely study Phoebe due to its orbit around Saturn.

The first close-up images were received on June 12, 2004. Scientists saw that Phoebe's surface looked different from other asteroids visited by spacecraft. Some areas of Phoebe's surface appeared very bright, suggesting there might be a lot of water ice just below the surface.<ref>{{cite journal |title=Cassini Imaging Science: Initial results on Phoebe and Iapetus |last1=Porco |first1=C. C. |last2=Baker |first2=E. |last3=Barbara |first3=J. |last4=Beurle |first4=K. |last5=Brahic |first5=A. |last6=Burns |first6=J. A. |last7=Charnoz |first7=S. |last8=Cooper |first8=N. |last9=Dawson D. |first9=D. |last10=Del Genio |first10=A. D. |last11=Denk |first11=T. |last12=Dones |first12=L. |last13=Dyudina |first13=U. |last14=Evans |first14=M. W. |last15=Giese |first15=B. |last16=Grazier |first16=K. |last17=Heifenstein |first17=P. |last18=Ingersoll |first18=A. P. |last19=Jacobson |first19=R. A. |last20=Johnson |first20=T. V. |last21=McEwen |first21=A. |last22=Murray |first22=C. D. |last23=Neukum |first23=G. |last24=Owen |first24=W. M. |last25=Perry |first25=J. |last26=Roatsch |first26=T. |last27=Spitale |first27=J. |last28=Squyres |first28=S. |last29=Thomas |first29=P. C. |last30=Tiscareno |first30=M. |last31=Turtle |first31=E. |last32=Vasavada |first32=A. R. |last33=Veverka |first33=J. |last34=Wagner |first34=R. |last35=West |first35=R. |journal=Science |volume=307 |pages=1237–1242 |year=2005 |doi=10.1126/science.1107981 |pmid=15731440 |issue=5713 |bibcode=2005Sci...307.1237P|s2cid=20749556 |url=https://authors.library.caltech.edu/36635/7/Porco_Iapetus_SOM.pdf }}</ref>

==== Cassini's orbital insertion ====
On July 1, 2004, Cassini flew through the gap between Saturn's [[Rings of Saturn|F and G rings]] and entered orbit around Saturn, becoming the first spacecraft to do so. This followed a seven-year journey.

The ''Saturn Orbital Insertion'' (SOI) maneuver was complex. Cassini had to turn its [[antenna]] away from Earth to protect its instruments from ring particles. After crossing the ring plane, it rotated again to point its engine along its flight path and fired the engine to slow down by 622 m/s. This allowed Saturn's gravity to capture Cassini around 8:54 pm [[Pacific Daylight Time]] on June 30, 2004. During this maneuver, Cassini passed within 20,000 km (12,000 mi) of Saturn's cloud tops.

==== Titan flybys ====
Cassini's first flyby of Saturn's largest moon, [[Titan (moon)|Titan]], occurred on July 2, 2004, just a day after entering orbit. It came within 339,000 km (211,000 mi) of Titan, capturing images through special filters that could penetrate the moon's thick haze. These images revealed south polar clouds likely made of [[methane]], along with surface features of different in brightness.

On October 27, 2004, Cassini performed the first of 45 planned close flybys of Titan, passing 1,200 km (750 mi) above its surface. It transmitted nearly four [[Gigabyte|gigabit]]s of data back to Earth, including the first radar images showing Titan's hazy-covered terrain. These images showed Titan's surface to be flat, with [[:wikt:elevations|elevations]] not exceeding about 50 m (160 ft). The flyby significantly increased the resolution of Titan's imaging, providing pictures up to 100 times clearer than previous ones. Cassini's observations also revealed [[Lakes of Titan|methane lakes]] on Titan's surface, resembling Earth's [[lake|water lake]]s.

==== Huygens lands on Titan ====
{{main|Huygens (spacecraft)}}
[[File:Huygens surface color.jpg|thumb|left|First image of the surface of Titan's surface]]
On December 25, 2004, the [[Huygens probe]] left Cassini and traveled to [[Titan (moon)|Titan]]. On January 14, 2005, Huygens landed on Titan, bouncing and sliding to a stop. It discovered pebbles made of [[ice|water ice]] on an orange surface covered in [[methane]] haze. Huygens' images revealed [[river]]s of liquid methane, drainage channels, and dry lakebeds, indicating recent water activity. Although no permanent lakes were found at the landing site, later Cassini data confirmed lakes in Titan's polar regions.

Huygens sent data back to Earth, and scientists figured out the surface was damp sand made of ice grains, with rounded rocks and pebbles suggesting water movement. The temperature was extremely cold at −179.3 °C; −290.8 °F, and methane took up 5% of the atmosphere. Light levels on Titan were much dimmer than on Earth, casting an orange hue due to Titan's atmospheric haze. After 90 minutes, Huygens stopped sending data, even though it was designed to last longer.<ref>{{cite web |title=HUYGENS: THE TOP 10 DISCOVERIES AT TITAN |url=https://sci.esa.int/web/cassini-huygens/-/55221-huygens-titan-science-highlights |website=[[European Space Agency]] |accessdate=9 July 2024}}</ref><ref>{{cite journal|title=Rain, winds and haze during the Huygens probe's descent to Titan's surface|volume=438|issue=7069|pages=765–778|journal= Nature|date=2005|doi=10.1038/nature04126|pmid=16319829|last1=Tomasko|first1=M. G.|last2=Archinal|first2=B.|last3=Becker|first3=T.|last4=Bézard|first4=B.|last5=Bushroe|first5=M.|last6=Combes|first6=M.|last7=Cook|first7=D.|last8=Coustenis|first8=A.|last9=De Bergh|first9=C.|last10=Dafoe|first10=L. E.|last11=Doose|first11=L.|last12=Douté|first12=S.|last13=Eibl|first13=A.|last14=Engel|first14=S.|last15=Gliem|first15=F.|last16=Grieger|first16=B.|last17=Holso|first17=K.|last18=Howington-Kraus|first18=E.|last19=Karkoschka|first19=E.|last20=Keller|first20=H. U.|last21=Kirk|first21=R.|last22=Kramm|first22=R.|last23=Küppers|first23=M.|last24=Lanagan|first24=P.|last25=Lellouch|first25=E.|last26=Lemmon|first26=M. |last27=Lunine |first27=Jonathan I. |last28=McFarlane|first28=E.|last29=Moores|first29=J.|last30=Prout|first30=G. M.|display-authors=29|bibcode=2005Natur.438..765T|s2cid=4414457}}</ref>

==== Enceladus flybys ====
In 2005, during its first two close flybys of the moon [[Enceladus (moon)|Enceladus]], Cassini found changes in the local [[magnetic field]] that suggest there's a thin but important atmosphere around Enceladus. Other tests at that time show that the main part of this atmosphere is likely [[:wikt:ionized|ionized]] [[water vapor]]. Cassini also saw [[geyser]]s of [[ice|water ice]] shooting out from Enceladus's south pole. This makes scientists think Enceladus could be putting bits of itself into Saturn's [[Rings of Saturn|E ring]]. Scientists began to guess there could be pools of liquid water near the moon's surface that make these eruptions.<ref>{{cite web |first1=Jia-Rui |last1=Cook |first2=Dyawne C. |last2=Brown |url=http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=639 |title=Cassini Spacecraft Captures Images and Sounds of Big Saturn Storm |publisher=JPL |date=July 6, 2011 |access-date=August 20, 2011 |url-status=dead |archive-url=https://web.archive.org/web/20080303154427/http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=639 |archive-date=March 3, 2008 }}</ref>

On March 12, 2008, Cassini flew close to Enceladus, getting within 50 km of its surface. It went through the plumes coming from the southern geysers and found water, [[carbon dioxide]], and different [[hydrocarbon]]s using its [[Mass spectrometry|mass spectrometer]]. Cassini also used an [[Infrared spectroscopy|infrared spectrometer]] to map surface features that are hotter than their surroundings. A problem with its software stopped Cassini from gathering data with its [[cosmic dust]] analyzer.<ref>[http://www.nasa.gov/mission_pages/cassini/media/cassini-20080310.html "''Cassini'' Spacecraft to Dive Into Water Plume of Saturn Moon"]. {{Webarchive|url=https://web.archive.org/web/20201109074429/http://www.nasa.gov/mission_pages/cassini/media/cassini-20080310.html |date=November 9, 2020 }}</ref><ref>[http://www.nasa.gov/mission_pages/cassini/media/cassini-20080326.html "''Cassini'' Tastes Organic Material at Saturn's Geyser Moon"]. {{Webarchive|url=https://web.archive.org/web/20210720225341/https://www.nasa.gov/mission_pages/cassini/media/cassini-20080326.html |date=July 20, 2021 }}. NASA, March 26, 2008</ref>

On November 21, 2009, Cassini did its eighth flyby of Enceladus, this time with a different path that took it within 1,600 km of the surface. The ''Composite Infrared Spectrograph'' (CIRS) tool made a map of heat coming from the "tiger stripe" area known as Baghdad Sulcus. This data made a detailed and high-quality picture of the southern side of the moon [[tidally locked|facing]] Saturn.<ref>{{cite web |url=http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20091121 |title=Cassini Sends Back Images of Enceladus as Winter Nears |access-date=December 13, 2018 |archive-url=https://web.archive.org/web/20160311101952/http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20091121/ |archive-date=March 11, 2016 |url-status=dead  }}</ref>

[[File:Enceladus PIA06191.jpg|thumb|Image of Enceladus's surface]]
By April 3, 2014, almost ten years after Cassini started orbiting Saturn, NASA shared proof of a large [[salt]]y [[Salt water|ocean of liquid water]] under Enceladus's icy shell. This salty ocean touches the moon's rocky center and makes Enceladus a top spot in the Solar System that could have [[alien life]]. On June 30, 2014, NASA marked ten years of Cassini's trip to Saturn and its moons. They highlighted finding water activity on Enceladus and other big discoveries.<ref>{{cite news |last=Amos |first=Jonathan |url=https://www.bbc.com/news/science-environment-26872184 |title=Saturn's Enceladus moon hides 'great lake' of water |work=BBC News |date=April 3, 2014 |access-date=April 7, 2014}}</ref><ref name="SCI-20140404">{{cite journal |last1=Iess |first1=L. |last2=Stevenson |first2=D. J. |last3=Parisi |first3=M. |last4=Hemingway |first4=D. |last5=Jacobson |first5=R. A. |last6=Lunine |first6=Jonathan I. |last7=Nimmo |first7=F. |last8=Armstrong |first8=J. W. |last9=Asmar |first9=S. W. |last10=Ducci |first10=M. |last11=Tortora |first11=P. |title=The Gravity Field and Interior Structure of Enceladus |date=April 4, 2014 |journal=[[Science (journal)|Science]] |volume=344 |number=6179 |pages=78–80 |doi=10.1126/science.1250551 |bibcode=2014Sci...344...78I |pmid=24700854|s2cid=28990283 |url=https://authors.library.caltech.edu/45462/7/Iess-SM.pdf }}</ref><ref name="Guardian-20140403">{{cite news |last=Sample |first=Ian |title=Ocean discovered on Enceladus may be best place to look for alien life |url=https://www.theguardian.com/science/2014/apr/03/ocean-enceladus-alien-life-water-saturn-moon |newspaper=The Guardian |access-date=April 3, 2014|date=April 3, 2014 }}</ref><ref name="NASA-20140625">{{cite web |last1=Dyches |first1=Preston |last2=Clavin |first2=Whitney |title=Cassini Celebrates 10 Years Exploring Saturn |url=http://www.jpl.nasa.gov/news/news.php?release=2014-203 |date=June 25, 2014 |work=[[NASA]] |access-date=June 25, 2014}}</ref>

In September 2015, NASA said data from Cassini show the way Enceladus moves doesn't fit with its core. This led to the idea that the underground ocean under its ice might cover the whole moon.<ref>{{cite web |url=http://www.jpl.nasa.gov/news/news.php?release=2015-298 |title=Cassini Finds Global Ocean in Saturn's Moon Enceladus |website=[[Jet Propulsion Laboratory]] |access-date=September 14, 2015}}</ref>

On October 28, 2015, Cassini flew near Enceladus, getting within 49 km of its surface and going through the ice cloud above the south pole.<ref>{{cite web |url=http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20151028/ |title=Deepest-Ever Dive Through Enceladus Plume Completed |publisher=Jet Propulsion Laboratory |access-date=October 29, 2015 |date=October 28, 2015}}</ref>

On December 14, 2023, scientists said they found [[hydrogen cyanide]] and other [[organic matter]] in the plumes of Enceladus for the first time. This matter could be very important for life, helping alien microbial life to survive or start on the moon.<ref>{{cite news |last=Chang |first=Kenneth |title=Poison Gas Hints at Potential for Life on an Ocean Moon of Saturn |quote=A researcher who has studied the icy world said 'the prospects for the development of life are getting better and better on Enceladus'. |url=https://www.nytimes.com/2023/12/14/science/enceladus-moon-cyanide-life-saturn.html |date=14 December 2023 |work=[[The New York Times]] |url-status=live |archiveurl=https://archive.today/20231214210144/https://www.nytimes.com/2023/12/14/science/enceladus-moon-cyanide-life-saturn.html |archivedate=14 December 2023 |accessdate=15 December 2023 }}</ref><ref name="NA-20231214">{{cite journal |last=Peter |first=Jonah S. |display-authors=et al. |title=Detection of HCN and diverse redox chemistry in the plume of Enceladus |url=https://www.nature.com/articles/s41550-023-02160-0 |date=14 December 2023 |journal=[[Nature Astronomy]] |volume=8 |issue=2 |pages=164–173 |doi=10.1038/s41550-023-02160-0 |url-status=live |archiveurl=https://archive.today/20231215144349/https://www.nature.com/articles/s41550-023-02160-0 |archivedate=15 December 2023 |accessdate=15 December 2023 |arxiv=2301.05259 |s2cid=255825649 }}</ref>

==== Radio occultations of Saturn's rings ====
In May 2005, Cassini started a series of radio [[occultation]] experiments aimed at measuring the size and [[:wikt:distribution|distribution]] of particles in Saturn's rings and studying [[Atmosphere of Saturn|Saturn's atmosphere]]. For more than four months, the spacecraft orbited Saturn in orbits designed for these experiments. During the experiments, Cassini passed behind Saturn's ring plane as observed from Earth and sent [[radio wave]]s through the ring particles. Scientists on Earth analyzed the radio signals received, saw changes in frequency, phase, and power of the signal to understand the structure and composition of Saturn's rings.

==== Spokes in rings verified ====
On September 5, 2005, Cassini captured images showing spokes in Saturn's rings, which were first noticed by visual observer [[Stephen James O'Meara]] in 1977. The [[Voyager program|Voyager]] space probes later confirmed this discovery in the early 1980s.<ref>{{cite web |url=http://photojournal.jpl.nasa.gov/catalog/PIA05380 |title=Catalog Page for PIA05380: Approach to Saturn |publisher=NASA Jet Propulsion Laboratory|date= February 26, 2004|access-date=August 20, 2011}}</ref><ref>{{cite web |url=http://csep10.phys.utk.edu/astr161/lect/saturn/rings.html|archive-url=https://web.archive.org/web/20131212134646/http://csep10.phys.utk.edu/astr161/lect/saturn/rings.html|archive-date=December 12, 2013 |title=The Rings of Saturn |publisher=Department of Physics and Astronomy, University of Tennessee in Knoxville |access-date=December 5, 2013}}</ref>

==== Discovery of lakes on Titan ====
[[File:PIA09184 -Titan Sea and Lake Superior.jpg|right|thumb|[[Ligeia Mare]], on the left, as compared at scale to [[Lake Superior]].]]
[[File:PIA18430-SaturnMoon-Titan-EvolvingFeature-20140821.jpg|thumb|left|upright=1.364|Time scale of mysterious disappearing island in [[Ligeia Mare]]]]
Radar pictures taken on July 21, 2006, seem to reveal [[lake]]s of liquid [[hydrocarbon]]s like [[methane]] and [[ethane]] in the northern parts of Titan. This marks the first time lakes of this kind have been found anywhere else in the [[universe]] besides [[Earth]]. These lakes vary in size, ranging from one to one hundred kilometers across.<ref>{{cite web |url=http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=679 |title=Cassini Spacecraft Captures Images and Sounds of Big Saturn Storm |publisher=JPL |date=July 6, 2011 |access-date=August 20, 2011 |url-status=dead |archive-url=https://web.archive.org/web/20080430085256/http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=679 |archive-date=April 30, 2008 }}</ref>

On March 13, 2007, the [[Jet Propulsion Laboratory]] announced evidence of seas made of methane and ethane in Titan's northern hemisphere. At least one of these seas is bigger than any of the [[Great Lakes]] in [[North America]].<ref>{{cite web |url=http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=731 |title=Cassini-Huygens: News |publisher=JPL |access-date=August 20, 2011 |url-status=dead |archive-url=https://web.archive.org/web/20080508224740/http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=731 |archive-date=May 8, 2008 }}</ref>

==== Saturn hurricane ====
In November 2006, scientists found a storm at Saturn's south pole with a clear [[eyewall]]. This is like hurricanes on Earth but is the first time it's been seen on another planet. Unlike hurricanes on Earth, this storm stays in one place at the pole. It's 8,000 kilometers (5,000 miles) wide and 70 kilometers (43 miles) tall. The wind inside blows at 560 kilometers per hour (350 miles per hour).<ref>{{cite news |url=http://news.bbc.co.uk/2/hi/science/nature/6135450.stm |title=Huge 'hurricane' rages on Saturn |work=BBC News |date=November 10, 2006 |access-date=November 10, 2006}}</ref>

==== Iapetus flyby ====
[[File:Iapetus equatorial ridge.jpg|thumb|Taken on September 10, 2007, at a distance of 62,331 km (38,731 mi) a mountain on Iapetus is seen]]
On September 10, 2007, Cassini finished its close pass by the peculiar, two-toned, [[walnut]]-shaped moon, [[Iapetus (moon)|Iapetus]]. Photos were taken from 1,600 kilometers (1,000 miles) above its surface. During [[:wikt:transmission|transmission]] of these images to Earth, Cassini was struck by a [[cosmic ray]], causing it to briefly enter [[safe mode]]. However, all data from the flyby were retrieved.<ref>{{cite news |url=http://www.foxnews.com/story/0,2933,296726,00.html |work=Fox News |title=Cassini Probe Flies by Iapetus, Goes into Safe Mode |date=September 14, 2007 |access-date=September 17, 2007 |archive-url=https://web.archive.org/web/20121021112328/http://www.foxnews.com/story/0,2933,296726,00.html |archive-date=October 21, 2012 |url-status=dead  }}</ref>

==== Mission extension ====
On April 15, 2008, Cassini got funding for a 27-month extension. It meant doing 60 more orbits around Saturn, with 21 close passes by [[Titan (moon)|Titan]], seven by [[Enceladus (moon)|Enceladus]], six by [[Mimas (moon)|Mimas]], eight by [[Tethys (moon)|Tethys]], and one each by [[Dione (moon)|Dione]], [[Rhea (moon)|Rhea]], and [[Helene (moon)|Helene]].<ref>{{cite web |title=Cassini's Tour of the Saturn System |url=http://www.planetary.org/explore/topics/cassini_huygens/tour.html#xm |publisher=[[Planetary Society]] |access-date=February 26, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090425172653/http://planetary.org/explore/topics/cassini_huygens/tour.html#xm |archive-date=April 25, 2009 }}</ref> The extra mission started on July 1, 2008, and was named the '''Cassini Equinox Mission''' to match Saturn's [[equinox]].<ref>{{cite web |url=https://www.sciencedaily.com/releases/2008/06/080628223103.htm |title=Cassini To Earth: 'Mission Accomplished, But New Questions Await!' |website=[[Science Daily]] |date=June 29, 2008 |access-date=January 5, 2009}}</ref>

==== Second mission extension ====
A proposal was sent to NASA for a second mission extension from September 2010 to May 2017, initially named the extended-extended mission or XXM.<ref>{{cite web |author=John Spencer |url=http://www.planetary.org/blog/article/00001856/ |title=Cassini's proposed extended-extended mission tour |publisher=Planetary Society |date=February 24, 2009 |access-date=August 20, 2011 |archive-date=June 15, 2010 |archive-url=https://web.archive.org/web/20100615205854/http://planetary.org/blog/article/00001856/ |url-status=dead }}</ref> Approved in February 2010 with a budget of $60 million [[:wikt:annually|annually]], it was renamed the '''Cassini Solstice Mission'''.<ref>[http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20100203/ "NASA Extends Cassini's Tour of Saturn, Continuing International Cooperation for World Class Science"]. {{Webarchive|url=https://web.archive.org/web/20160413185332/http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20100203/ |date=April 13, 2016 }}</ref> This phase involved Cassini orbiting Saturn 155 more times and making 54 additional flybys of [[Titan (moon)|Titan]], along with 11 more of [[Enceladus (moon)|Enceladus]].

==== Great Storm of 2010 and aftermath ====
[[File:Saturn Storm.jpg|thumb|left|Northern hemisphere storm in 2011]]
On October 25, 2012, Cassini saw the aftermath of a huge storm known as the [[Great White Spot]] that appears about every 30 years on Saturn.<ref>{{cite web|last1=Brown|first1=Dwayne|last2=Zubritsky|first2=Elizabeth|last3=Neal-Jones|first3=Nancy|last4=Cook|first4=Jia-Rui|date=25 October 2012|title=NASA Spacecraft Sees Huge Burp At Saturn After Large Storm|publisher=NASA|url=http://www.nasa.gov/home/hqnews/2012/oct/HQ_12-375_Cassini_Burp_Energy.html|url-status=live|access-date=14 April 2021|website=[[NASA]]|archive-url=https://web.archive.org/web/20121027023138/http://www.nasa.gov:80/home/hqnews/2012/oct/HQ_12-375_Cassini_Burp_Energy.html |archive-date=October 27, 2012 }}</ref> Data from Cassini's composite [[Infrared spectroscopy|infrared spectrometer]] (CIRS) showed a powerful burst from the storm, heating Saturn's [[stratosphere]] by 83 K (83 °C; 149 °F) above normal. At the same time, NASA researchers at the [[Goddard Space Flight Center]] in [[Maryland]] detected a sharp increase in [[ethylene]] gas. Ethylene is a colorless gas rare on Saturn, mostly found on Earth from natural and man-made sources.

The storm was first spotted by Cassini on December 5, 2010, in Saturn's north. It's the first storm of its kind observed by a spacecraft orbiting Saturn and the first seen in [[Thermal physics|thermal]] [[infrared]] light, which lets scientists study Saturn's atmosphere temperature and hidden processes. The ethylene spike during the storm was 100 times higher than expected on Saturn. Scientists also found it was the largest and hottest [[vortex]] ever spotted in the Solar System's stratosphere, initially bigger than [[Jupiter]]'s [[Great Red Spot]].

==== Venus transit ====
On December 21, 2012, Cassini watched Venus pass in front of the Sun, a rare event known as a transit. Using its VIMS instrument, Cassini studied [[sunlight]] as it [[Spectroscopy|passed through]] [[Atmosphere of Venus|Venus's atmosphere]]. Earlier, VIMS had studied a similar event involving the [[exoplanet]] [[HD 189733 b]].<ref>{{cite web|last=Cook|first=Jia-Rui|date=20 December 2012|title=Cassini Instrument Learns New Tricks|url=http://www.jpl.nasa.gov/news/news.php?release=2012-406|url-status=live|access-date=14 April 2021|publisher=[[Jet Propulsion Laboratory]], [[NASA]]|archive-url=https://web.archive.org/web/20121222202058/http://www.jpl.nasa.gov/news/news.php?release=2012-406 |archive-date=December 22, 2012 }}</ref>

==== The Day the Earth Smiled ====
On July 19, 2013, the probe turned towards [[Earth]] to take a picture of our planet and [[the Moon]]. This was part of a special portrait capturing the entire Saturn system in natural light, using multiple images. It was unique because NASA announced in advance that a long-distance photo was being taken.<ref>{{cite web |url=https://www.bbc.co.uk/news/science-environment-23419543 |work=BBC News |title=Cassini probe takes image of Earth from Saturn orbit |date=July 23, 2013 |access-date=July 24, 2013}}</ref><ref>{{cite news |last=Overbye |first=Dennis |title=The View From Saturn |url=https://www.nytimes.com/2013/11/12/science/space/the-view-from-saturn.html |date=November 12, 2013 |work=[[The New York Times]] |access-date=November 12, 2013}}</ref> The imaging team encouraged people to smile and wave towards the skies. Carolyn Porco, a Cassini scientist, described the moment as an opportunity to "celebrate life on the Pale Blue Dot".<ref>{{cite web |url=https://www.bbc.co.uk/news/science-environment-23373821 |work=BBC News |title=Smile! Cassini sets up photo of Earth |date=July 19, 2013 |access-date=July 24, 2013}}</ref>

==== Rhea flyby ====
On February 10, 2015, the Cassini spacecraft made a close visit to [[Rhea (moon)|Rhea]], approaching within 47,000 kilometers (29,000 miles).<ref>{{cite web |url=http://saturn.jpl.nasa.gov/mission/saturntourdates/saturntourdates2015/ |title=Saturn Tour Dates: 2015 |publisher=NASA{{\}}Jet Propulsion Laboratory |date=2015 |access-date=May 2, 2017 |url-status=dead |archive-url=https://web.archive.org/web/20150518093211/http://saturn.jpl.nasa.gov/mission/saturntourdates/saturntourdates2015/ |archive-date=May 18, 2015 }}</ref> During this encounter, the spacecraft used its cameras to capture some of the most detailed color images of Rhea to date.<ref>{{cite web |url=http://www.ciclops.org/view/8030/Return-to-Rhea |title=Return to Rhea (NASA Cassini Saturn Mission Images) |publisher=Cassini Imaging Central Laboratory for Operations |date=March 30, 2015 |id=PIA19057 |access-date=May 11, 2015 |archive-date=June 21, 2017 |archive-url=https://web.archive.org/web/20170621114714/http://www.ciclops.org/view/8030/Return-to-Rhea |url-status=dead }}</ref>

==== Hyperion flyby ====
Cassini's most recent flyby of Saturn's moon [[Hyperion (moon)|Hyperion]] occurred on May 31, 2015, from a distance of about 34,000 kilometers (21,000 miles).<ref>{{cite news |url=http://www.jpl.nasa.gov/news/news.php?feature=4606 |title=Cassini Prepares for Last Up-close Look at Hyperion |work=NASA{{\}}Jet Propulsion Laboratory |date=May 28, 2015 |access-date=May 29, 2015}}</ref>
{{Clear}}
{{Multiple image|direction=horizontal|align=center|caption_align=center|width=190
|image1=PIA17193-SaturnMoon-Hyperion-20150531.jpg
|caption1=Hyperion – context view from {{convert|37,000|km|mi|abbr=on}} (May 31, 2015)
|image2=PIA17194-SaturnMoon-Hyperion-20150531.jpg
|caption2=Hyperion – close-up view from {{convert|38,000|km|mi|abbr=on}} (May 31, 2015)
}}

==== Dione flyby ====
Cassini's final flyby of Saturn's moon [[Dione (moon)|Dione]] took place on August 17, 2015, at a distance of about 475 kilometers (295 miles). An earlier flyby occurred on June 16.<ref>{{cite news |url=https://www.nasa.gov/jpl/cassini-to-make-last-close-flyby-of-saturn-moon-dione |title=Cassini to Make Last Close Flyby of Saturn Moon Dione |work=NASA{{\}}Jet Propulsion Laboratory |date=August 13, 2015 |access-date=August 20, 2015 |archive-date=August 15, 2015 |archive-url=https://web.archive.org/web/20150815203246/http://www.nasa.gov/jpl/cassini-to-make-last-close-flyby-of-saturn-moon-dione/ |url-status=dead }}</ref>

==== Saturn's hexagonal storm changes color ====
Between 2012 and 2016, the hexagonal cloud pattern at Saturn's north pole changed color from mostly [[blue]] to more golden. One idea is that this change is due to [[season]]s: as the pole turned towards the Sun, longer exposure to sunlight might have created [[haze]].<ref>{{cite web |url=http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA21049 |title=Changing Colors in Saturn's North |website=[[Jet Propulsion Laboratory]] }}</ref> Before this, from 2004 to 2008, there was less blue color seen across Saturn.<ref>{{cite web |url=http://www.planetary.org/blogs/guest-blogs/1856.html |title=Cassini's Proposed Extended-Extended Mission Tour |publisher=The Planetary Society |first=John |last=Spencer |date=February 24, 2009}}</ref>

<gallery mode=packed heights=180>
File:PIA21049 Changing Colors in Saturn's North.jpg|2012 and 2016: hexagon color changes
File:PIA21611 - Saturn's Hexagon as Summer Solstice Approaches.gif|2013 and 2017: hexagon color changes
</gallery>

=== Grand Finale ===
Cassini's mission ended by flying close to Saturn and going through [[Rings of Saturn|its rings]]. On September 15, 2017, it [[:wikt:intentional|intentionally]] entered [[Atmosphere of Saturn|Saturn's atmosphere]] and was destroyed. This was done to make sure [[Moons of Saturn|Saturn's moons]], which [[Extraterrestrial life|might have life]], would not get any Earth life on them.<ref>{{cite interview |title= Cassini Post-End of Mission News Conference |date= September 15, 2017 |publisher= NASA Television |location= Pasadena, CA}}</ref><ref>{{cite news |last= Overbye |first= Dennis |author-link= Dennis Overbye |title= Cassini Flies Toward a Fiery Death on Saturn |url= https://www.nytimes.com/2017/09/08/science/cassini-saturn-nasa.html |date= September 8, 2017 |work= [[The New York Times]] |access-date= September 10, 2017}}</ref><ref>{{cite web |url=http://www.lpi.usra.edu/opag/march_08_meeting/presentations/spilker.pdf |last=Spilker |first=Linda |title=Cassini Extended Missions |access-date=August 20, 2011}}</ref><ref>{{cite news |last1=Blabber |first1=Phillipa |last2=Verrecchia |first2=Angélique |url=http://www.spacesafetymagazine.com/space-exploration/extraterrestrial-life/cassini-huygens-preventing-biological-contamination/ |title=Cassini-Huygens: Preventing Biological Contamination |work=Space Safety Magazine |date=April 3, 2014 |access-date=August 1, 2015}}</ref>

In 2008, several ways to end the mission were considered. A quick crash into Saturn was rated the best choice because it met all the goals and was cheap and easy to do. Another option was to crash into an icy moon, which was also good because it was cheap and could be done at any time.{{cn|date=July 2024}}

In 2013–14, there were issues with [[NASA]] getting [[U.S. government]] funds for the Grand Finale. It turned out that the Grand Finale had two phases, which were like having two different [[Discovery Program]] missions. This was different from the main Cassini mission. In late 2014, the U.S. government approved the Grand Finale, costing $200 million. This was much less expensive than making two new probes for separate Discovery missions.<ref>{{Cite web|last=Lakdawalla|first=Emily|date=3 September 2014|title=Cassini's awesomeness fully funded through mission's dramatic end in 2017|url=https://www.planetary.org/articles/cassinis-awesomeness-fully|url-status=live|access-date=14 April 2021|website=[[The Planetary Society]]|archive-url=https://web.archive.org/web/20200810164319/https://www.planetary.org/articles/cassinis-awesomeness-fully |archive-date=August 10, 2020 }}</ref>

On November 29, 2016, the spacecraft flew by [[Titan (moon)|Titan]], marking the beginning of the Grand Finale phase that ended with its impact on Saturn.<ref>{{cite web |url=https://saturn.jpl.nasa.gov/news/2861/2016-saturn-tour-highlights/ |title=2016 Saturn Tour Highlights }}</ref><ref>{{Cite news |url=https://www.scientificamerican.com/article/cassini-mission-kicks-off-finale-at-saturn/ |title=Cassini Mission Kicks Off Finale at Saturn |last=Lewin |first=Sarah |work=Scientific American |access-date=November 30, 2016}}</ref> Another flyby of Titan on April 22, 2017, changed Cassini's orbit to pass through the gap between Saturn and its inner ring on April 26. During this pass, Cassini came within about 3,100 km (1,900 mi) of Saturn's cloud layer and 320 km (200 mi) from the visible edge of the inner ring, capturing images of Saturn's atmosphere and sending data starting the next day.<ref>{{cite web |url=https://saturn.jpl.nasa.gov/news/3032/nasa-spacecraft-dives-between-saturn-and-its-rings/ |title=NASA Spacecraft Dives Between Saturn and Its Rings |publisher=NASA{{\}}Jet Propulsion Laboratory |first1=Preston |last1=Dyches |first2=Dwayne |last2=Brown |first3=Laurie |last3=Cantillo |date=April 27, 2017 |access-date=May 2, 2017}}</ref> After completing 22 orbits through the gap, the mission ended with Cassini diving into Saturn's atmosphere on September 15. The signal was lost at 11:55:46 UTC on September 15, 2017, approximately 30 seconds later than thought. It is estimated that the spacecraft burned up about 45 seconds after the last transmission.

In September 2018, NASA received an [[Emmy Award]] for ''Outstanding Original Interactive Program'' for its [[:wikt:portrayal|portrayal]] of the Cassini mission's Grand Finale at Saturn.<ref>{{cite news |last1=McGregor |first1=Veronica |last2=Brown |first2=Dwight |last3=Wendel |first3=JoAnna |title=And the Emmy goes to: Cassini's Grand Finale |url=https://www.jpl.nasa.gov/news/news.php?feature=7232 |date=September 10, 2018 |work=[[NASA]] |access-date=September 10, 2018 }}</ref>

In December 2018, [[Netflix]] broadcasted "NASA's Cassini Mission" as part of their series 7 Days Out, showing the final days of the Cassini mission before the spacecraft crashed into Saturn to complete its Grand Finale.

In January 2019, new research from Cassini's Grand Finale phase was published:
* Scientists measured Saturn's day length: 10 hours, 33 minutes, and 38 seconds.
* Saturn's rings are relatively young, between 10 to 100 million years old.<ref name="overview">{{Cite web|url=https://solarsystem.nasa.gov/missions/cassini/overview|title=Overview {{!}} Cassini|website=Solar System Exploration: NASA Science|access-date=January 25, 2019}}</ref>
{{multiple image |align=center |footer_align=center |total_width=700
 |image1=PIA22766-CassiniOrbitingSaturn-ArtistConcept-20181002.jpg
 |image2=PIA22767-CassiniOrbitingSaturn-Grandfinale-ArtistConcept-20181002.jpg
 |image3=PIA22768-CassiniOrbitsSaturn-FinalDive-ArtistConcept-20181003.jpg
 |footer=''Cassini'' orbiting Saturn before Grand Finale (artist concepts)
}}
{{multiple image |align=center |caption_align=center |total_width=700
 |image1=PIA21896-Saturn-Cassini-ImpactSite-20170915.jpg |caption1=''Cassini'' impact site on [[Saturn]] ([[Spectroscopy|visual]]/[[Infrared spectroscopy|IR]] mapping spectrometer; September 15, 2017)
}}
{{multiple image |align=center |total_width=700
 |image1=Cassini grand finale 2017-04-26 saturn.jpg |caption1=A close-up image of Saturn's atmosphere from about {{convert|1900|mi|km|order=flip|abbr=on}} above the cloud layer, taken by ''Cassini'' on its first dive on April 26, 2017, at the start of the Grand Finale
 |image2=Cassini Final Image.png |caption2=Last image (color) taken by ''Cassini'' as it descended toward Saturn. The image was taken {{convert|634000|km|mi|abbr=on}} above Saturn on September 14, 2017, at 19:59&nbsp;UTC.<ref>{{Cite news |url=https://www.nasa.gov/image-feature/jpl/pia21895/cassinis-final-image |title=Impact Site: Cassini's Final Image |last=Loff |first=Sarah |date=September 15, 2017 |work=NASA |access-date=September 17, 2017 |language=en}}</ref>
 |image3=Cassini's Final Image.png |caption3=Last image (b&w) taken by the imaging cameras on the ''Cassini'' spacecraft (September 14, 2017, at 19:59&nbsp;UTC)
}}
{{multiple image |align=center |caption_align=center |total_width=700
 |image1=Cassini's Grand Finale.ogv |caption1=[[:File:Cassini's Grand Finale.ogv|Video (03:40) detailing ''Cassini''{{'s}} Grand Finale mission and a look back at what the mission has accomplished]]. |alt1=Cassini Grand Finale – This animated video tells the story of ''Cassini''{{'}}s final, daring assignment and looks back at what the mission has accomplished.
}}

==== Missions ====
The spacecraft's operations were organized into several missions. Each mission had main funding and goals.
* Prime Mission: July 2004 to June 2008.
* Cassini Equinox Mission: July 2008 to September 2010, lasting two years longer.
* Cassini Solstice Mission: October 2010 to April 2017, also known as the XXM mission.
* Grand Finale: April 2017 to September 15, 2017, when the spacecraft was directed into Saturn.

Over 260 scientists from 17 [[countries]] helped to the Cassini–Huygens mission, with thousands more involved in designing, manufacturing, and launching the mission.

<gallery mode="packed" heights="180px">
8423 20181 1saturn2016.jpg|Saturn by ''Cassini'', 2016
Cassini Numbers Final.jpg|''Cassini-Huygens'' by the numbers<br/>(September 2017)
PIA17218 – A Farewell to Saturn, Annotated Version.jpg|Farewell to Saturn and moons ([[Enceladus]], [[Epimetheus (moon)|Epimetheus]], [[Janus (moon)|Janus]], [[Mimas]], [[Pandora (moon)|Pandora]] and [[Prometheus (moon)|Prometheus]]) <br/> (September 13, 2017)
</gallery>

== References ==
{{reflist}}

== Other websites ==
* [http://www.suekientz.com/cassini/ Spacecraft Cassini is Visiting Saturn!] — children's stories explaining the Cassini mission
* [http://www.nasa.gov/mission_pages/cassini/main/ Cassini-Huygens Main Page] {{Webarchive|url=https://web.archive.org/web/20121227121247/http://www.nasa.gov/mission_pages/cassini/main/ |date=2012-12-27 }} at [[NASA]]
* [http://saturn.jpl.nasa.gov/ Cassini Mission Homepage] {{Webarchive|url=https://web.archive.org/web/20060428051758/http://saturn.jpl.nasa.gov/ |date=2006-04-28 }} by the Jet Propulsion Laboratory
* [http://solarsystem.nasa.gov/missions/profile.cfm?MCode=Cassini Cassini-Huygens Mission Profile] {{Webarchive|url=https://web.archive.org/web/20131216182800/http://solarsystem.nasa.gov/missions/profile.cfm?MCode=Cassini |date=2013-12-16 }} by NASA's Solar System Exploration
* [http://ciclops.org/ Cassini Imaging Homepage]
* [http://nssdc.gsfc.nasa.gov/planetary/cassini.html Cassini information] by the National Space Science Data Center (NSSDC).
* [http://www.futura-sciences.com/communiquer/g/showgallery.php/cat/525/page/ Photo Gallery - full coverage]
* [http://www.spacedaily.com/news/cassini-01a.html Cassini's Tour de Saturn part A], [http://www.spacedaily.com/news/cassini-01b.html B], [http://www.spacedaily.com/news/cassini-01c.html C], [http://www.spacedaily.com/news/cassini-01d1.html D], [http://www.spacedaily.com/news/cassini-01e.html E], [http://www.spacedaily.com/news/cassini-01f1.html F] – descriptions of the 4-year tour of Saturn by Bruce Moomaw
* [http://www.spaceflightnow.com/cassini/ SpaceflightNow news coverage of the mission] {{Webarchive|url=https://web.archive.org/web/20130203025123/http://spaceflightnow.com/cassini/ |date=2013-02-03 }}
* [http://baltimorechronicle.com/cassini_probe_2.html Countdown to Cancel the Cassini Space Probe] by the Baltimore Peace Network in 1997 due to concerns over the use of plutonium

{{Jupiter spacecraft}}
{{Moons of Saturn}}

[[Category:NASA spacecraft]]
[[Category:European Space Agency spacecraft]]
[[Category:Saturn]]
[[Category:Spacecraft launched in the 1990s]]