# List of missions to the outer planets

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A total of nine spacecraft have been launched on missions that involve visits to the outer planets; all nine missions involve encounters with Jupiter, with four spacecraft also visiting Saturn. One spacecraft, Voyager 2, also visited Uranus and Neptune. The nine missions include two, Ulysses and New Horizons, whose primary objectives were not outer planets, but which flew past Jupiter to gain gravity assists en route to a polar orbit around the Sun (Ulysses), and to Pluto (New Horizons). Pluto was considered a planet at the time that New Horizons launched, but was reclassified as a dwarf planet. Cassini–Huygens also flew past Jupiter for a gravity assist on its mission to explore Saturn.
Only three of the missions to the outer planets have been orbiters: Galileo orbited Jupiter for eight years, while Cassini orbited Saturn for thirteen years. Juno has been orbiting Jupiter since 2016.

## Summary

| SystemSpacecraft | Jupiter Jupiter trojans | Saturn | Uranus Uranus trojans | Neptune Neptune trojans | Pluto Trans-Neptunian objects |
| Pioneer 10 | 1973 flyby Jupiter and moons | | | | |
| Pioneer 11 | 1974 flyby Jupiter and moons | 1979 flyby Saturn and moons | | | |
| Voyager 1 | 1979 flyby Jupiter and moons | 1980 flyby Saturn and moons | | | |
| Voyager 2 | 1979 flyby Jupiter and moons | 1981 flyby Saturn and moons | 1986 flyby Uranus and moons | 1989 flyby Neptune and moons | |
| Ulysses | 1992, 2004 gravity assist Jupiter | | | | |
| Galileo | 1995–2003 orbiter Jupiter and moons 1995 atmospheric Jupiter | | | | |
| Cassini–Huygens | 2000 gravity assist Jupiter and moons | 2004–2017 orbiter Saturn and moons 2005 lander Titan | | | |
| New Horizons | 2007 gravity assist Jupiter and moons | | | | 2015 flyby Pluto and moons 2019 flyby 486958 Arrokoth |
| Juno | 2016–2025 orbiter Jupiter | | | | |
| Lucy | 2027– flyby mission (launched 2021) 3548 Eurybates 15094 Polymele 11351 Leucus 21900 Orus 617 Patroclus | | | | |
| Jupiter Icy Moons Explorer | 2031– orbiter mission (launched 2023) Jupiter and Ganymede | | | | |
| Europa Clipper | 2030– orbiter mission (launched 2024) Europa | | | | |

## Jupiter

Nine spacecraft have been launched to explore Jupiter, with two other spacecraft making gravity-assist flybys.
New Horizons, although eventually targeting Pluto, used Jupiter for a gravity assist and had an extensive almost half year observation campaign of Jupiter and its moons (hence it is counted in the eight).
| Mission | Mission | Spacecraft | Launch date | Carrier rocket | Operator | Mission Type | Outcome |
| 1 | Pioneer 10 | Pioneer 10 | 3 March 1972 | Atlas SLV-3C Centaur-D | NASA | Flyby | Successful |
| Humanity's first object to attain Solar system's escape velocity. First probe to traverse the asteroid belt, to reach Jovanian system, to use a gravity assist and to leave the proximity of Solar systems' planets. Held the record for fastest human-made object at the time and the most distant one until Voyager 1 overtook in 1998. Closest approach towards Jupiter was at 02:25 UTC on 4 December 1973. Flew by Callisto, Ganymede, Europa and Io at long distances. Final signal received on 23 January 2003, 12 billion km (80 AU; 7.5 billion mi) from Earth. ||||||
| 2 | Pioneer 11 | Pioneer 11 | 6 April 1973 | Atlas SLV-3D Centaur-D1A | NASA | Flyby | Successful |
| Closest approach towards Jupiter at 05:22 UTC on 3 December 1974. Flew by Callisto, Ganymede, Io and Europa . First probe to reach Saturnian system. Final contact was roughly at a distance of 6.5 billion km (43 AU; 4.0 billion mi) ||||||
| 3 | Voyager 2 | Voyager 2 | 20 August 1977 | Titan IIIE Centaur-D1T | NASA | Flyby | Successful |
| Closest approach at 22:29 on 9 July 1979. Flew past Callisto, Ganymede, Europa, Amalthea and Io at long distances. Later flew past Saturn, Uranus and Neptune. Oldest active space probe at 47 years, 6 months, 6 days. Currently studying interstellar medium. At a distance of 136.1 AU (20.4 billion km; 12.7 billion mi) from Earth as of May 2024 ||||||
| 4 | Voyager 1 | Voyager 1 | 5 September 1977 | Titan IIIE Centaur-D1T | NASA | Flyby | Successful |
| Closest approach at 12:05 UTC on 5 March 1979. Flew past Amalthea, Europa, Ganymede and Callisto at long distances. Later flew past Saturn. First probe to depart heliosphere and enter interstellar medium. Most distant human-made object at a distance of 162.7 AU (24.3 billion km; 15.1 billion mi) from Earth as of May 2024. ||||||
| 5 | Galileo project | Galileo | 18 October 1989 | Space Shuttle Atlantis STS-34 / IUS | NASA | Orbiter | Successful |
| 5 | Galileo project | Atmopsheric entry probe | 18 October 1989 | Space Shuttle Atlantis STS-34 / IUS | NASA | Atmospheric probe | Successful |
| First probe to enter Jupiter's atmosphere. Entered at 22:04 UTC on 7 December 1995 and operated for 57 minutes; main spacecraft entered orbit at 00:27 UTC on 8 December. Spacecraft was deorbited on 21 September 2003, impacting Jupiter's atmosphere at 18:57:18 UTC. ||||||
| – | Ulysses | Ulysses | 6 October 1990 | Space Shuttle Discovery STS-41 / IUS | NASA/ESA | Flyby | Successful |
| Flyby on 8 February 1992 to reach a high-inclination heliocentric orbit. Also made a distant incidental flyby on 4 February 2004 ||||||
| – | Cassini–Huygens | Cassini | 15 October 1997 | Titan IV(401)B Centaur-T | NASA/ESA | Flyby | Successful |
| – | Cassini–Huygens | Huygens lander | 15 October 1997 | Titan IV(401)B Centaur-T | NASA/ESA | Flyby | Successful |
| Flyby on 30 December 2000 en route to Saturn ||||||
| 6 | New Horizons | New Horizons | 19 January 2006 | Atlas V 551 | NASA | Flyby | Successful |
| Gravity assist. Major observation campaign from Jan-June. Flyby on 28 February 2007 (closest approach at 05:43:40) en route to Pluto. First probe to flyby Plutonian system. ||||||
| 7 | Juno | Juno | 5 August 2011 | Atlas V 551 | NASA | Orbiter | Operational |
| Entered orbit 4 July 2016. First outer planet explorer probe with solar panels. ||||||
| 8 | Juice | JUICE | 14 April 2023 | Ariane 5 ECA | ESA | Orbiter | En route |
| First interplanetary probe to the outer Solar System planets not launched by the United States and the first set to orbit a moon (Ganymede) other than Earth's Moon. ||||||
| 9 | Europa Clipper | Europa Clipper | 14 October 2024 | Falcon Heavy | NASA | Orbiter | En route |
| Jupiter orbiter with Europa flybys ||||||

## Saturn

Four spacecraft have visited Saturn; Pioneer 11, Voyager 1 and Voyager 2 made flybys, while Cassini–Huygens entered orbit, and deployed a probe into the atmosphere of Titan.
| Mission | Mission | Spacecraft | Launch date | Carrier rocket | Operator | Mission Type | Outcome |
| 1 | Pioneer 11 | Pioneer 11 | 6 April 1973 | Atlas SLV-3D Centaur-D1A | NASA | Flyby | Successful |
| First probe to reach Saturnian system. Closest approach on 1 September 1979 at 16:31 UTC. Flew past Iapetus, Dione, Mimas, Tethys, Enceladus, Rhea and Titan at long distances. Discovered Epimetheus and Janus. ||||||
| 2 | Voyager 2 | Voyager 2 | 20 August 1977 | Titan IIIE Centaur-D1T | NASA | Flyby | Successful |
| Closest approach at 01:21 UTC on 26 August 1981. Flew past Iapetus, Titan, Dione, Mimas, Enceladus, Tethys and Rhea at long distances. Later flew past Uranus and Neptune. ||||||
| 3 | Voyager 1 | Voyager 1 | 5 September 1977 | Titan IIIE Centaur-D1T | NASA | Flyby | Successful |
| Closest approach on 12 November 1980 at 23:45 UTC. Flew past Titan, Tethys, Mimas, Enceladus and Rhea. ||||||
| 4 | Cassini–Huygens | Cassini | 15 October 1997 | Titan IV(401)B Centaur-T | NASA | Orbiter | Successful |
| 4 | Cassini–Huygens | Huygens | 15 October 1997 | Titan IV(401)B Centaur-T | ESA | Titan lander | Successful |
| Entered orbit 1 July 2004. First probe to orbit Saturn. Discovered seven new moons. Hyugens probe became the first spacecraft to land on Titan with the farthest landing from Earth a spacecraft ever made. It was deployed from Cassini and landed at 10:13 UTC on 14 January 2005. Mission concluded on 15 September 2017. ||||||

## Uranus

Voyager 2 is the only spacecraft to have visited Uranus, making a single flyby as part of its grand tour of the outer planets.
| Mission | Mission | Spacecraft | Launch date | Carrier rocket | Operator | Mission Type | Outcome |
| 1 | Voyager 2 | Voyager 2 | 20 August 1977 | Titan IIIE Centaur-D1T | NASA | Flyby | Successful |
| Discovered eleven moons. Flew past Miranda, Ariel, Umbriel, Titania and Oberon. Closest approach at 17:59 UTC on 24 January 1986. Later flew past Neptune. ||||||

## Neptune

Voyager 2 is the only spacecraft to have visited Neptune, making a single flyby as part of its grand tour of the outer planets.
| Mission | Mission | Spacecraft | Launch date | Carrier rocket | Operator | Mission Type | Outcome |
| 1 | Voyager 2 | Voyager 2 | 20 August 1977 | Titan IIIE Centaur-D1T | NASA | Flyby | Successful |
| Discovered Neptunian rings and six new moons. Flew past Galatea, Larissa, Proteus and Triton. Closest approach at 03:26 UTC on 25 August 1989 ||||||

## Pluto and trans-Neptunian objects

New Horizons is the only spacecraft that visited dwarf planet Pluto (in 2015) and the trans-Neptunian object 486958 Arrokoth (in 2019).
| Mission | Mission | Spacecraft | Launch date | Carrier rocket | Operator | Mission Type | Outcome |
| 1 | New Horizons | New Horizons | 19 January 2006 | Atlas V (551) AV-010 + Star 48B 3rd stage | NASA | Flyby | Successful |
| Flew by Pluto in July 2015, flew past Arrokoth on 1 January 2019. ||||||

## Statistics
### Major milestones
#### Legend

Milestone achieved  Milestone not achieved  En route † First to achieve
Planets :
| Country/Agency | Jupiter | Jupiter | Jupiter | Saturn | Saturn | Saturn | Uranus | Neptune |
| Country/Agency | Flyby | Orbit | Artmospheric entry | Flyby | Orbit | Artmospheric entry | Flyby | Flyby |
| Country/Agency | United States | Pioneer 10, 1973 † | Galileo, 1995 † | Atmospheric probe, 1995 † | Pioneer 11, 1979 † | Cassini, 2004 † | Cassini, 2017 † | Voyager 2, 1986 † | Voyager 2, 1989 † |
| ESA | Ulysses, 1992 | — | — | — | — | — | — | — |
Galilean moons :
| Country/Agency | Ganymede | Ganymede | Callisto | Io | Europa |
| Country/Agency | Flyby | Orbit | Flyby | Flyby | Flyby |
| United States | Pioneer 10, 1973 † | — | Pioneer 10, 1973 † | Pioneer 10, 1973 † | Pioneer 10, 1973 † |
| ESA | Juice, TBD 2034 | Juice, TBD 2034 | — | — | — |
Major Saturnian moons :
| Country/Agency | Titan | Titan | Titan | Rhea | Iapetus | Dione | Tethys | Enceladus | Mimas |
| Country/Agency | Flyby | Orbit | Lander | Flyby | Flyby | Flyby | Flyby | Flyby | Flyby |
| United States | Pioneer 11, 1979 † | — | — | Pioneer 11, 1979 † | Pioneer 11, 1979 † | Pioneer 11, 1979 † | Pioneer 11, 1979 † | Pioneer 11, 1979 † | Pioneer 11, 1979 † |
| ESA | — | — | Huygens, 2005 † | — | — | — | — | — | — |

## Future missions

| Mission | Spacecraft | Launch date | Carrier rocket | Operator |
| Planned missions |||||
| Dragonfly | Dragonfly | TBD July 2028 | Falcon Heavy | NASA |
| Titan robotic rotorcraft ||||
| Tianwen-4 | Tianwen-4 | TBD September 2029 | Long March 5 | CNSA |
| Tianwen-4 | Uranus flyby probe | TBD September 2029 | Long March 5 | CNSA |
| Jupiter and Callisto orbiter; Flyby past Uranus with mission extension planned for interstellar journey ||||
| Solar Polar Orbit Observatory | Solar Polar Orbit Observatory | NET 2029 | TBD | CNSA |
| Will use a Jupiter gravity assist to reach high-inclination heliocentric orbit ||||
| Proposed missions |||||
| IHP-1 | Shensuo | TBD | TBD | CNSA |
| Interstellar heliospheric probe with Jovian gravity assist; planned flybys of Jupiter and 50000 Quaoar ||||
| IHP-2 | Shensuo | TBD | TBD | CNSA |
| Interstellar heliospheric probe with Jovian gravity assist; planned flybys of Jupiter, Neptune, Triton and a Kuiper belt object ||||
| Uranus Orbiter and Probe | Uranus orbiter | NET 2031 | Falcon Heavy (expendable) | NASA |
| Uranus Orbiter and Probe | Uranus probe | NET 2031 | Falcon Heavy (expendable) | NASA |
| Uranus orbiter after a flyby of Jupiter; Uranus atmospheric probe ||||
| Enceladus Orbilander | Enceladus Orbilander | NET 2038 | | NASA |
| Enceladus orbiter/lander ||||