This is a list of active space probes which have escaped

Earth orbit Earth orbits the Sun at an average distance of 149.60 million km (92.96 million mi) in a counterclockwise direction as viewed from above the Northern Hemisphere. One complete orbit takes days (1 sidereal year), during which time Earth ...

. It includes lunar space probes, but does not include

space probe A space probe is an artificial satellite that travels through space to collect scientific data. A space probe may orbit Earth; approach the Moon; travel through interplanetary space; flyby, orbit, or land or fly on other planetary bodies; or ent ...

s orbiting at the Sun–Earth

Lagrangian point In celestial mechanics, the Lagrange points (; also Lagrangian points or libration points) are points of equilibrium for small-mass objects under the influence of two massive orbiting bodies. Mathematically, this involves the solution of th ...

s (for these, see

List of objects at Lagrangian points This is a list of known objects which occupy, have occupied, or are planned to occupy any of the five Lagrange points of two-body systems in space. Sun–Earth Lagrange points Sun–Earth L1 is the Lagrange point located approximately 1.5 mi ...

). A craft is deemed "active" if it is still able to transmit usable data to Earth (whether or not it can receive commands). The craft are further grouped by mission status – "en route", "mission in progress" or "mission complete" – based on their primary mission. For example, though ''

Voyager 1 ''Voyager 1'' is a space probe launched by NASA on September 5, 1977, as part of the Voyager program to study the outer Solar System and interstellar space beyond the Sun's heliosphere. Launched 16 days after its twin ''Voyager 2'', ''Voya ...

'' is still contactable is enroute to the Oort Cloud and has exited our solar system, it is listed as "mission complete" because its primary task of studying

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but ...

and

Saturn Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine and a half times that of Earth. It has only one-eighth the average density of Earth; h ...

has been accomplished. Once a probe has reached its first primary target, it is no longer listed as "en route" whether or not further travel is involved.

Missions in progress

Moon

* ARTEMIS P1/P2 ** Mission: studying the effect of the solar wind on the Moon. Originally launched as Earth satellites, they were later repurposed and moved to lunar orbit. **Launched: February 17, 2007 **Destination:

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

(in

lunar orbit In astronomy, lunar orbit (also known as a selenocentric orbit) is the orbit of an object around the Moon. As used in the space program, this refers not to the orbit of the Moon about the Earth, but to orbits by spacecraft around the Moon. The ...

) **Arrival: July 2011 **Institution:

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

Lunar Reconnaissance Orbiter The Lunar Reconnaissance Orbiter (LRO) is a NASA robotic spacecraft currently orbiting the Moon in an eccentric polar mapping orbit. Data collected by LRO have been described as essential for planning NASA's future human and robotic missions t ...

**Mission: Orbiter engaged in lunar mapping intended to identify safe landing sites, locate potential resources on the Moon, characterize the radiation environment, and demonstrate new technology. **Launched: 18 June 2009 **Destination:

(in

) **Arrival: 23 June 2009 **Institution:

Queqiao ''Queqiao'' relay satellite (), also known as the Chang'e 4 Relay, is a communications relay and radio astronomy satellite for the Chang'e 4 lunar farside mission. As part of the Chinese Lunar Exploration Program, the China National Space Admi ...

**Mission:

Halo orbit A halo orbit is a periodic, three-dimensional orbit near one of the L1, L2 or L3 Lagrange points in the three-body problem of orbital mechanics. Although a Lagrange point is just a point in empty space, its peculiar characteristic is that it ca ...

er serving as communications satellite for Chang'e 4 lunar far-side mission; conducting joint China-Netherlands low frequency astronomy experiment. **Launched: 21:28 UT on 20 May 2018 **Destination: in

halo orbit A halo orbit is a periodic, three-dimensional orbit near one of the L1, L2 or L3 Lagrange points in the three-body problem of orbital mechanics. Although a Lagrange point is just a point in empty space, its peculiar characteristic is that it ca ...

about Earth-Moon L₂ **Arrival: 14 June 2018 **Institution: CNSA *Lander, Rover: Chang'e 4 **Mission: Lander engaging in low-frequency radio spectrometry experiment, neutron and dosimetry experiment, and biological experiment. Rover seeking to characterize lunar far-side environment (including possible lunar mantle material) using visible/near-infrared spectrometer, ground penetrating radar, cameras, and neutral particle analyzer. **Launched: 18:23 UT on 8 December 2018 **Destination:

Lunar Lunar most commonly means "of or relating to the Moon". Lunar may also refer to: Arts and entertainment * ''Lunar'' (series), a series of video games * "Lunar" (song), by David Guetta * "Lunar", a song by Priestess from the 2009 album ''Prior t ...

far side **Arrival: 02:26 UT on 3 January 2019 **Institution: CNSA * Chandrayaan-2 **Mission: engaged in lunar topography and mineralogy, elemental abundance, the lunar exosphere, and signatures of hydroxyl and water. **Launched: 22 July 2019 **Destination:

(in

) **Arrival: 7 September 2019 **Institution:

ISRO The Indian Space Research Organisation (ISRO; ) is the national space agency of India, headquartered in Bengaluru. It operates under the Department of Space (DOS) which is directly overseen by the Prime Minister of India, while the Chairman ...

CAPSTONE CAPSTONE (Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment) is a lunar orbiter that will test and verify the calculated orbital stability planned for the Lunar Gateway space station. The spacecraft is a 12- ...

**Mission: Lunar orbiting CubeSat that will test and verify the calculated orbital stability planned for the Gateway space station. **Launched: 28 June 2022 **Destination:

(in a Near-rectilinear halo orbit (NRHO)) **Arrival: 14 November 2022 **Institution:

*Danuri ( Korea Pathfinder Lunar Orbiter) **Mission: Lunar Orbiter by the

Korea Aerospace Research Institute The Korea Aerospace Research Institute (KARI), established in 1989, is the aeronautics and space agency of South Korea. Its main laboratories are located in Daejeon, in the Daedeok Science Town. KARI's vision is to continue building upon indig ...

(KARI) of

South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is formed ...

. The orbiter, its science payload and ground control infrastructure are technology demonstrators. The orbiter will also be tasked with surveying lunar resources such as

water ice Water ice could refer to: *Ice formed by water (as opposed to other substances) *The alternate term for various similar frozen fruit-flavoured desserts: **Italian ice primarily in Philadelphia and the Delaware Valley **Sorbet Sorbet (), also c ...

uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...

helium-3 Helium-3 (3He see also helion) is a light, stable isotope of helium with two protons and one neutron (the most common isotope, helium-4, having two protons and two neutrons in contrast). Other than protium (ordinary hydrogen), helium-3 is the ...

silicon Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic tab ...

, and

aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...

, and produce a topographic map to help select future lunar landing sites. **Launched: 4 August 2022 **Destination:

(in

) **Arrival: 16 December 2022 (enroute) **Institution: collaboration between KARI and

Lunar Polar Hydrogen Mapper Lunar Polar Hydrogen Mapper, or LunaH-Map, is one of 10 CubeSats launched with Artemis 1 on 16 November 2022. Along with Lunar IceCube and LunIR, LunaH-Map will help investigate the possible presence of water-ice on the Moon. Arizona State Un ...

**Mission: Lunar Orbiter to search for evidence of lunar water ice inside permanently shadowed craters using its neutron detector. **Launched: 16 November 2022 **Destination:

(in

) **Arrival: November 2022 (enroute) **Institution:

Lunar IceCube Lunar IceCube is a NASA nanosatellite orbiter mission to prospect, locate, and estimate amount and composition of water ice deposits on the Moon for future exploitation by robots or humans. It was launched as a secondary payload mission on Ar ...

**Mission: Lunar Orbiter that will uses its infrared spectrometer to detect water and organic compounds in the lunar surface and

exosphere The exosphere ( grc, ἔξω "outside, external, beyond", grc, σφαῖρα "sphere") is a thin, atmosphere-like volume surrounding a planet or natural satellite where molecules are gravitationally bound to that body, but where the densit ...

. **Launched: 16 November 2022 **Destination:

(in

) **Arrival: November 2022 (enroute) **Institution:

* EQUULEUS **Mission:

er to image the Earth's

plasmasphere The plasmasphere, or inner magnetosphere, is a region of the Earth's magnetosphere consisting of low-energy (cool) plasma. It is located above the ionosphere. The outer boundary of the plasmasphere is known as the plasmapause, which is defined by ...

, impact craters on the Moon's far side and L2 experiments. **Launched: 16 November 2022 **Destination: in

about Earth-Moon L₂ **Arrival: November 2022 (enroute) **Institution:

JAXA The is the Japanese national air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satellites into orb ...

Lunar Flashlight Lunar Flashlight is a low-cost CubeSat lunar orbiter mission to explore, locate, and estimate size and composition of water ice deposits on the Moon for future exploitation by robots or humans. The spacecraft, of the 6U CubeSat format, w ...

**Mission: Lunar orbiting CubeSat that will explore, locate, and estimate size and composition of water ice deposits on the Moon for future exploitation by robots or humans. **Launched: 11 December 2022 **Destination:

**Arrival: April 2023 (enroute) **Institution:

Mercury

* BepiColombo ** Mission: Spacecraft consists of the Mercury Transfer Module (MTM), Mercury Planetary Orbiter (MPO), and the Mercury Magnetospheric Orbiter (MMO or ''Mio''). MTM and MPO are built by

ESA , owners = , headquarters = Paris, Île-de-France, France , coordinates = , spaceport = Guiana Space Centre , seal = File:ESA emblem seal.png , seal_size = 130px , image = Views in the Main Control Room (1205 ...

while the MMO is mostly built by

. Once the MTM delivers the MPO and MMO to Mercury orbit, the two orbiters will have the following objectives: to study Mercury's form, interior structure, geology, composition, and craters; to study the origin, structure, and dynamics of its magnetic field; to characterize the composition and dynamics of Mercury's vestigial atmosphere; to test Einstein's theory of general relativity; to search for asteroids sunward of Earth; and to generally study the origin and evolution of a planet close to a parent star. **Launched: 01:45:28 UT on 19 October 2018 **Destination:

Mercury Mercury commonly refers to: * Mercury (planet), the nearest planet to the Sun * Mercury (element), a metallic chemical element with the symbol Hg * Mercury (mythology), a Roman god Mercury or The Mercury may also refer to: Companies * Merc ...

**Arrival: En route (anticipated to enter Mercury polar orbit on 5 December 2025) **Institution:

Venus

Akatsuki may refer to: * Akatsuki (spacecraft), an uncrewed Venus orbiter * , any of three classes of destroyers of the Imperial Japanese Navy * , any of three destroyers of the Imperial Japanese Navy * ''Akatsuki'' (train), operated between Kyoto and Na ...

** Mission: The first

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

ese

Venus Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never fa ...

ian probe. Also known as ''Planet-C'' and ''Venus Climate Orbiter'', ''Akatsuki'' failed to enter Venusian orbit in December 2010. It continued to function and entered Venus orbit in 2015. **Launched: 20 May 2010 **Destination:

**Arrival: 7 December 2015 **Institution:

**Subprobes:

IKAROS IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun) is a Japan Aerospace Exploration Agency (JAXA) experimental spacecraft. The spacecraft was launched on 20 May 2010, aboard an H-IIA rocket, together with the ''Akatsuki'' (V ...

and Shin'en

Mars

Odyssey over Martian Sunrise DVIDS684264

*''

2001 Mars Odyssey ''2001 Mars Odyssey'' is a robotic spacecraft orbiting the planet Mars. The project was developed by NASA, and contracted out to Lockheed Martin, with an expected cost for the entire mission of US$297 million. Its mission is to use spectr ...

'' **Mission: Mars Odyssey was designed to map the surface of Mars and also acts as a relay for the ''

Curiosity Curiosity (from Latin '' cūriōsitās'', from ''cūriōsus'' "careful, diligent, curious", akin to ''cura'' "care") is a quality related to inquisitive thinking such as exploration, investigation, and learning, evident by observation in humans ...

'' rover. Its name is a tribute to the novel and film '' 2001: A Space Odyssey''. **Launched: 7 April 2001 **Destination:

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...

**Arrival: 24 October 2001 **Institution:

*'' Mars Express'' **Mission: Mars orbiter designed to study the planet's atmosphere and geology, search for sub-surface water, and deploy the

Beagle 2 The ''Beagle 2'' is an inoperative British Mars lander that was transported by the European Space Agency's 2003 ''Mars Express'' mission. It was intended to conduct an astrobiology mission that would have looked for evidence of past life on Mar ...

lander. In 2017 the mission was extended until at least the end of 2020. **Launched: 2 June 2003 **Destination:

**Arrival: 25 December 2003 **Institution:

**Lander:

(mission failed; contact lost at separation but found in 2015 on surface) * *'' Mars Reconnaissance Orbiter'' **Mission: the second NASA satellite orbiting Mars. It is specifically designed to analyze the landforms, stratigraphy, minerals, and ice of the red planet. **Launched: 12 August 2005 **Destination:

**Arrival: 10 March 2006 **Institution:

*Lander: ''Curiosity'' rover **Mission: searching for evidence of organic material on Mars, monitoring methane levels in the atmosphere, and engaging in exploration of the landing site at Gale Crater. **Launched: 26 November 2011 **Destination:

**Arrival: 6 August 2012 **Institution:

* MAVEN — ''Mars Atmosphere and Volatile Evolution''. **Mission: study the Martian upper atmosphere and its gradual loss to space **Launched: 18 November 2013 **Destination:

**Arrival: September 2014 **Institution:

* Trace Gas Orbiter ( ExoMars 2016) **Mission: study methane and other trace gases in the Martian atmosphere **Launched: 14 March 2016 **Destination:

**Arrived: 19 October 2016 (Mars orbit insertion), 21 April 2018 (final orbit) **Institution:

**Lander: Schiaparelli (crashed upon landing attempt) *

Emirates Mars Mission , ''Al-Amal'') , manufacturer = , dry_mass = 550 kg , launch_mass = 1350 kg, including800 kg hydrazine fuel1,350 kg , payload_mass = , dimensions = 2.37 m × 2.90 m , power = 1800 watts from t ...

**Mission: study weather and atmosphere. **Launched: 19 July 2020 **Destination:

**Arrival: 9 February 2021 **Institution: UAESA * Tianwen-1 orbiter **Mission: find evidence for current and past life and produce Martian surface maps. Orbital studies of Martian surface morphology, soil, and atmosphere. **Launched: 23 July 2020 **Destination:

**Arrival: 10 February 2021 **Institution: CNSA *'' Zhurong'' rover **Mission: find evidence for current and past life and in-situ studies of Martian surface morphology, soil, and atmosphere. **Launched: 23 July 2020 **Destination:

**Arrival: 10 February 2021 **Landing: 14 May 2021 **Deployment date: 22 May 2021 **Institution: CNSA *Lander: ''Perseverance'' rover **Mission: searching for evidence of organic material on Mars, and engaging in exploration of the landing site at Jezero crater. **Launched: 30 July 2020 **Destination: Jezero crater,

**Arrival: 18 February 2021 **Institution:

*Rotorcraft: ''Ingenuity '' helicopter **Mission: experimental scout for Perseverance rover. Completed 1st flight on Mars **Launched: 30 July 2020 **Destination: Jezero crater,

**Arrival: 18 February 2021 **Deployment date: 4 April 2021 **Institution:

Asteroids and comets

*''

Hayabusa2 is an asteroid sample-return mission operated by the Japanese state space agency JAXA. It is a successor to the ''Hayabusa'' mission, which returned asteroid samples for the first time in June 2010. ''Hayabusa2'' was launched on 3 December 2 ...

'' **Mission: asteroid study and sample-return **Launched: 3 December 2014 **First Destination:

162173 Ryugu 162173 Ryugu, provisional designation , is a near-Earth object and a potentially hazardous asteroid of the Apollo group. It measures approximately in diameter and is a dark object of the rare spectral type Cb, with qualities of both a C-type ...

**Arrival: 27 June 2018 **Left Ryugu: 12 November 2019 **Second Destination: **Institution:

**Lander probe:

MASCOT A mascot is any human, animal, or object thought to bring luck, or anything used to represent a group with a common public identity, such as a school, professional sports team, society, military unit, or brand name. Mascots are also used as fi ...

and MINERVA-II * OSIRIS-REx **Mission: asteroid study and sample-return **Launched: 8 September 2016 **Destination:

101955 Bennu 101955 Bennu (provisional designation ) is a carbonaceous asteroid in the Apollo group discovered by the LINEAR Project on 11 September 1999. It is a potentially hazardous object that is listed on the Sentry Risk Table and has the highest cumula ...

**Arrival: 3 December 2018 **Left Bennu: 10 May 2021 **Destination: 99942 Apophis **Arrival: April 2029 **Institution:

* Lucy **Mission: to flyby 8 Jupiter trojan and one main belt asteroid **Launched: 15 October 2021 **Destination:

52246 Donaldjohanson 52246 Donaldjohanson, provisional designation , is a carbonaceous Erigonian asteroid from the inner regions of the asteroid belt, approximately in diameter. It was discovered on 2 March 1981, by American astronomer Schelte Bus at the Siding Spr ...

**Arrival: 20 April 2025 **Institution:

LICIACube Light Italian CubeSat for Imaging of Asteroids (LICIACube, ) is a six-unit CubeSat of the Italian Space Agency (ASI). LICIACube is a part of the Double Asteroid Redirection Test (DART) mission and carries out observational analysis of the Didy ...

**Mission: to flyby a binary

65803 Didymos 65803 Didymos (provisional designation ) is a sub-kilometer asteroid and binary system that is classified as a potentially hazardous asteroid and near-Earth object of the Apollo group. The asteroid was discovered in 1996 by the Spacewatch surv ...

asteroid system,

and

Dimorphos (65803) Didymos I Dimorphos (provisional designation S/2003 (65803) 1) is a minor-planet moon of the near-Earth asteroid 65803 Didymos, with which it forms a binary system. It has a diameter of and has been characterised as a low-density rubb ...

**Launched: 24 November 2021 **Destination:

and

(flyby) **Arrival: 26 September 2022 **Institution: ASI

Heliocentric orbit

* Parker Solar Probe **Mission: observation of solar wind, magnetic fields, and coronal energy flow. **Launched: 12 August 2018 **Destination: low solar orbit, perihelion 6.9 million km **Arrival: 19 January 2019 **Institution:

Solar Orbiter The Solar Orbiter (SolO) is a Sun-observing satellite developed by the European Space Agency (ESA). SolO, designed to obtain detailed measurements of the inner heliosphere and the nascent solar wind, will also perform close observations of the ...

** Mission: detailed measurements of the inner heliosphere and nascent solar wind, and close observations of the polar regions of the Sun. ** Launched: 10 February 2020 **Destination: High inclination solar orbit ** Arrival: Operational orbit in 2023 **Institution:

CubeSat for Solar Particles CubeSat for Solar Particles (CuSP) was a low-cost 6U CubeSat to orbit the Sun to study the dynamic particles and magnetic fields. The principal investigator for CuSP is Mihir Desai, at the Southwest Research Institute (SwRI) in San Antonio, T ...

** Mission: study particles and magnetic fields. **Destination: Solar Orbit ** Launched and Arrived: 16 November 2022 **Institution:

Outer Solar System

*''

Juno Juno commonly refers to: *Juno (mythology), the Roman goddess of marriage and queen of the gods *Juno (film), ''Juno'' (film), 2007 Juno may also refer to: Arts, entertainment and media Fictional characters *Juno, in the film ''Jenny, Juno'' *Ju ...

'' **Mission: studying

from polar orbit. Intended to de-orbit into the Jovian atmosphere after 2021. **Launched: 5 August 2011 **Destination:

**Arrival: 4 July 2016 **Institution:

*''

New Horizons ''New Horizons'' is an Interplanetary spaceflight, interplanetary space probe that was launched as a part of NASA's New Frontiers program. Engineered by the Johns Hopkins University Applied Physics Laboratory (APL) and the Southwest Research ...

'' **Mission: the first spacecraft to study Pluto up close, and ultimately the

Kuiper Belt The Kuiper belt () is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune at 30 astronomical units (AU) to approximately 50 AU from the Sun. It is similar to the asteroid belt, but is far larger—20 times ...

. It was the fastest spacecraft when leaving Earth and will be the fifth probe to leave the Solar System. **Launched: 19 January 2006 **Destination:

Pluto Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of trans-Neptunian object, bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the S ...

and

Charon In Greek mythology, Charon or Kharon (; grc, Χάρων) is a psychopomp, the ferryman of Hades, the Greek underworld. He carries the souls of those who have been given funeral rites across the rivers Acheron and Styx, which separate the wo ...

**Arrival: 14 July 2015 **Left Charon: 14 July 2015 **Destination:

486958 Arrokoth Arrokoth (minor-planet designation 486958 Arrokoth; provisional designation ), formerly nicknamed Ultima Thule, is a trans-Neptunian object located in the Kuiper belt. Arrokoth became the farthest and most primitive object in the Solar System ...

**Arrival: 1 January 2019 **Institution:

*''

'' **Mission: investigating Jupiter and Saturn, and the moons of these planets. Its continuing data feed offered the first direct measurements of the

heliosheath The heliosphere is the magnetosphere, astrosphere and outermost atmospheric layer of the Sun. It takes the shape of a vast, bubble-like region of space. In plasma physics terms, it is the cavity formed by the Sun in the surrounding interst ...

and the heliopause. It is currently the farthest man-made object from Earth, as well as the first object to leave the heliosphere and cross into interstellar space. As of November 2017 it has a distance from the Sun of about 140 astronomical units (AU) (21 billion kilometers, or 0.002 light years), and it will not be overtaken by any other current craft. In August 2012, ''Voyager 1'' became the first human-built spacecraft to enter interstellar space. Though declining, the onboard power source should keep some of the probe's instruments running until 2025. **Launched: 5 September 1977 **Destination:

and

**Arrival: January 1979 **Institution:

**Primary mission completion: November 1980 **Current trajectory: entered interstellar space August 2012 *''

Voyager 2 ''Voyager 2'' is a space probe launched by NASA on August 20, 1977, to study the outer planets and interstellar space beyond the Sun's heliosphere. As a part of the Voyager program, it was launched 16 days before its twin, ''Voyager 1'', on a ...

'' **Mission: studying all four

gas giants A gas giant is a giant planet composed mainly of hydrogen and helium. Gas giants are also called failed stars because they contain the same basic elements as a star. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant ...

. This mission was one of NASA's most successful, yielding a wealth of new information. As of November 2017 it is some 116 AU from the Sun (17.34 billion kilometers), and it is hoped the probe will continue to operate until at least 2020. It has left the heliosphere and crossed into interstellar space in December 2018. As with ''Voyager 1'', scientists are now using ''Voyager 2'' to learn what the Solar System is like beyond the heliosphere. **Launched: 20 August 1977 **Destination:

Uranus Uranus is the seventh planet from the Sun. Its name is a reference to the Greek god of the sky, Uranus (mythology), Uranus (Caelus), who, according to Greek mythology, was the great-grandfather of Ares (Mars (mythology), Mars), grandfather ...

Neptune Neptune is the eighth planet from the Sun and the farthest known planet in the Solar System. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times ...

**Arrival: 9 July 1979 **Institution:

**Primary mission completion: August 1989 **Current trajectory: entered interstellar space December 2018

Retired Notable missions

*''

Pioneer 6 ''Pioneer 6'', ''7'', ''8'', and ''9'' were space probes in the Pioneer program, launched between 1965 and 1969. They were a series of solar-orbiting, spin-stabilized, solar cell- and battery-powered satellites designed to obtain measurements ...

'' **Mission: measurements of the solar wind, solar magnetic field and cosmic rays. Oldest functioning probe (if still operating). Contact was last attempted 8 December 2000 to celebrate its 35th anniversary, and the attempt was successful. **Launched: 16 December 1965 **Destination:

heliocentric orbit A heliocentric orbit (also called circumsolar orbit) is an orbit around the barycenter of the Solar System, which is usually located within or very near the surface of the Sun. All planets, comets, and asteroids in the Solar System, and the Sun i ...

**Institution:

**Mission completion: ? **Current trajectory:

*'' Pioneer 7'' **Mission: measurements of the solar wind, solar magnetic field and cosmic rays. Last contacted 31 March 1995; no attempt has been made since, and this probe may or may not be operational. **Launched: 17 August 1966 **Destination:

**Institution:

**Mission completion: ? **Current trajectory:

*'' Pioneer 8'' **Mission: measurements of the solar wind, solar magnetic field and cosmic rays. Last contacted on 22 August 1996; no attempt has been made since, and this probe may or may not be operational. **Launched: 8 November 1967 **Destination:

**Institution:

**Mission completion: ? **Current trajectory:

ICE Ice is water frozen into a solid state, typically forming at or below temperatures of 0 degrees Celsius or Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaq ...

**Mission: studying the interaction between the solar wind and (1) the Earth's magnetosphere, (2) the tail of comet Giacobini-Zinner, (3) the tail of Halley's Comet. Contact with the probe was lost on 16 September 2014. It is unknown whether contact can be reestablished because the probe's exact orbit is uncertain. **Launched: 12 August 1978 **Destination: halo orbit around Earth-Sun

**Institution:

**Mission completion: 1997 **Current trajectory:

Giotto Giotto di Bondone (; – January 8, 1337), known mononymously as Giotto ( , ) and Latinised as Giottus, was an Italian painter and architect from Florence during the Late Middle Ages. He worked during the Gothic/Proto-Renaissance period. Giot ...

**Mission: flyby and observation of Halley's Comet and Comet Grigg-Skjellerup to capture scientific data and images of the nucleus. The multicolor camera was destroyed in the encounter with Halley, but the probe remained otherwise functional for the second encounter. **Launched: 2 July 1985 **Destination:

Comet Halley Halley's Comet or Comet Halley, officially designated 1P/Halley, is a List of periodic comets, short-period comet visible from Earth every 75–79 years. Halley is the only known short-period comet that is regularly visible to the naked eye fr ...

**Arrival: 14 March 1986 **Institution:

**Mission completion: 14 March 1986 (Halley), 10 July 1992 (Grigg-Skjellerup) **Current trajectory:

*''

Genesis Genesis may refer to: Bible * Book of Genesis, the first book of the biblical scriptures of both Judaism and Christianity, describing the creation of the Earth and of mankind * Genesis creation narrative, the first several chapters of the Book of ...

'' **Mission: solar wind sample return **Launched: 8 August 2001 **Destination: halo orbit around Sun-Earth

**Arrival: 16 November 2001 **Institution:

**Mission completion: sample capsule returned to Earth 8 September 2004; parachutes failed to open, some samples contaminated **Current trajectory (spacecraft bus):

near Sun-Earth point Cassini Saturn Orbit Insertion

*''

Cassini–Huygens ''Cassini–Huygens'' ( ), commonly called ''Cassini'', was a space research, space-research mission by NASA, the European Space Agency (ESA), and the Italian Space Agency (ASI) to send a space probe to study the planet Saturn and its system, i ...

'' **Mission: ''Cassini'' orbiter studying Saturn and its moons after passing Venus and Jupiter; ''Huygens'' landing probe investigating

Titan Titan most often refers to: * Titan (moon), the largest moon of Saturn * Titans, a race of deities in Greek mythology Titan or Titans may also refer to: Arts and entertainment Fictional entities Fictional locations * Titan in fiction, fictiona ...

. ''Cassini'' primarily investigated Saturn's rings, its

magnetosphere In astronomy and planetary science, a magnetosphere is a region of space surrounding an astronomical object in which charged particles are affected by that object's magnetic field. It is created by a celestial body with an active interior dynam ...

, and the geologic composition of its satellites. **Launched: 15 October 1997 **Destination:

**Arrival: 1 July 2004 (Saturn), 14 January 2005 (Titan) **Crashed: 15 September 2017 **Institution: collaboration between

and ASI *Lander: InSight **Mission: to study the deep interior of Mars, with a seismometer and a heat-flow probe. **Launched: 5 May 2018 **Destination:

Elysium Planitia Elysium Planitia, located in the Elysium and Aeolis quadrangles, is a broad plain that straddles the equator of Mars, centered at . It lies to the south of the volcanic province of Elysium, the second largest volcanic region on the planet, a ...

**Arrival: 29 November 2018 **Mission completion: 15 December 2022 **Institution:

References

{{Space exploration lists and timelines Lists of spacecraft Solar System, Active Probes, Active Spaceflight timelines Solar System-related lists

Missions in progress

Moon

Mercury

Venus

Mars

Asteroids and comets

Heliocentric orbit

Outer Solar System

Retired Notable missions

See also

References