Misplaced Pages

The list of proposed missions to the outer planets is a listing of concept studies for an uncrewed or crewed mission to gas giants. Proposed missions to gas giants are typically based on engineering and scientific assessments of technological capabilities at the time of study. These proposals are usually associated with high-budget space agencies like NASA. Mission profiles may include strategies such as flybys, landers, or other types of system encounters aimed at exploring a gas giant and its moons.

History

Since the discovery of the gas giants, numerous proposed missions have been developed. In February 1969, NASA approved two spacecraft missions under the Pioneer program, managed by Ames Research Center (ARC), to explore Jupiter. In 1970, NASA granted a contract to the TRW Company of Redondo Beach, California, to construct the spacecraft. NASA initially directed the TRW Company to develop the Pioneer spacecraft to ensure that future missions could withstand the intense radiation belts of Jupiter. Each 571 lb (259 kg) spacecraft was equipped with 11 instruments to conduct close-up studies of Jupiter and interplanetary space during transit. Following several technological advancements, Pioneer 10 was launched in 1972 from Cape Canaveral Launch Complex 36A, with the goal of exploring Jupiter, its moons, magnetic field, and radiation belts. During its closest approach on 3 December, it passed within 82,178 mi (132,253 km) of Jupiter, collecting data on the planet and its moons, ultimately transmitting over 500 images by 2 January 1974.

In 1973, Pioneer 11 launched from Cape Canaveral Launch Complex 36B as a backup to the Pioneer 10 spacecraft. By May 1974, the mission trajectory was adjusted to include a gravity assist from Jupiter, redirecting it toward Saturn. On 2 December 1974, Pioneer 11 made a close flyby of Jupiter, passing under the planet's southern pole before being propelled toward Saturn through its northern pole. On 1 September 1979, Pioneer 11 passed within 13,000 mi (21,000 km) of the planet's cloud tops at a speed of 71,000 mph (114,000 km/h).

In August 1977, Voyager 2 launched from Cape Canaveral Space Force Station to explore Jupiter, Saturn, Uranus, and Neptune during a rare 175-year planetary alignment. The following month, Voyager 1 was launched from the same location. In March 1979, Voyager 1 approached Jupiter and followed 4 months later with Voyager 2's flyby. In November 1980, Voyager 1 approached Saturn, taking a gravity assist to visit Titan and leave the solar system headed north out of the ecliptic plane. Voyager 2 subsequently approached Saturn 9 months later with a gravity assist to further it towards Uranus. In January 1986, Voyager 2 became the first spacecraft to visit Uranus. During its flyby, it discovered 10 new moons, 2 new rings, and a magnetic field tilted at 55 degrees off-axis and off-center. In August 1989, Voyager performed its last flyby, going by Neptune and visiting its moon Triton. The gravity assist carried Voyager 2 below the ecliptic plane.

In March 1979, Voyager 1 made its close approach to Jupiter, capturing detailed images of the planet and its moons, with Voyager 2 conducting its flyby four months later. In November 1980, Voyager 1 flew by Saturn, using a gravity assist to explore Titan before leaving the Solar System, traveling north out of the ecliptic plane.

Voyager 2 followed with its own Saturn flyby nine months later, in August 1981, using a gravity assist to set a course for Uranus. In January 1986, Voyager 2 became the first spacecraft to visit Uranus, discovering 10 new moons, 2 new rings, and revealing a magnetic field that was both tilted 55 degrees off its axis and off-center from the planet's core. In August 1989, Voyager 2 conducted its final planetary flyby, passing close to Neptune and its moon Triton, revealing Triton's active geology, including geysers of nitrogen gas. The gravity assist from Neptune sent Voyager 2 on a trajectory below the ecliptic plane.

In October 1989, the Galileo spacecraft was launched on from Kennedy Space Center's Complex 39B. Designed to study Jupiter, its moons, and its surrounding environment, Galileo was the first spacecraft to orbit an outer planet. The mission also included encounters with the asteroids 951 Gaspra and 243 Ida. On 7 December 1995, the Galileo spacecraft reached Jupiter after gravitational assist flybys of Venus and Earth, becoming the first spacecraft to successfully orbit an outer planet. After eight years in Jupiter's orbit, Galileo was intentionally destroyed in Jupiter's atmosphere on 21 September 2003, to avoid contaminating potentially habitable moons. The next orbiter to visit Jupiter was NASA's Juno, which arrived on July 5, 2016.

In October 1990, the Ulysses spacecraft was launched from Kennedy Space Center's Complex 39B on a mission to study the Sun at all latitudes. To accomplish this, Ulysses needed to achieve an orbital inclination of about 80°, which required a significant change in heliocentric velocity. Since the energy required for this inclination change was beyond the capabilities of any available launch vehicle, mission planners employed a gravity assist maneuver around Jupiter. In February 1992, Ulysses passed close to Jupiter, utilizing its gravity to alter its trajectory and propel it into a high-inclination orbit around the Sun. This enabled the spacecraft to study the Sun's polar regions. Given its distance from the Sun during the mission, Ulysses could not rely on solar panels for power. Instead, it was equipped with a General Purpose Heat Source Radioisotope Thermoelectric Generator (RTG).

In October 1997, the Cassini–Huygens spacecraft was launched from Cape Canaveral Space Launch Complex 40. The mission was designed to study Saturn and its system, including its rings and moons. The Flagship-class robotic spacecraft consisted of NASA's Cassini orbiter and ESA's Huygens lander, which landed on Saturn's largest moon, Titan. Cassini became the fourth space probe to visit Saturn and the first to enter its orbit, where it operated from 2004 to 2017. The spacecraft's journey to Saturn included flybys of Venus in April 1998 and June 1999, Earth in August 1999, the asteroid 2685 Masursky, and Jupiter in December 2000. Cassini entered Saturn's orbit on 1 July 2004. The mission concluded on 15 September 2017, when Cassini was deliberately sent into Saturn's upper atmosphere to burn up, ensuring that Saturn's moons, which may harbor habitable environments, would not be contaminated.

In January 2006, the New Horizons spacecraft was launched from Cape Canaveral Space Launch Complex 41 on a mission to visit Pluto. To accelerate toward its target, the spacecraft used an Earth-and-solar escape trajectory, achieving a speed of approximately 16.26 km/s (10.10 mi/s; 58,500 km/h; 36,400 mph), and later performed a gravity assist flyby of Jupiter. Before reaching Jupiter, New Horizons had a brief encounter with the asteroid 132524 APL. New Horizons made its closest approach to Jupiter on 28 February 2007, at a distance of 2.3 million kilometers (1.4 million miles). The gravity assist from Jupiter increased the spacecraft's speed and allowed it to continue on its trajectory toward Pluto. The flyby also served as a comprehensive test of New Horizons' scientific instruments, returning valuable data on Jupiter's atmosphere, moons, and magnetosphere. On 14 July 2015, at 11:49 UTC, New Horizons flew 12,500 km (7,800 mi) above Pluto's surface, which at the time was 34 AU from the Sun.

In August 2011, the Juno spacecraft was launched from Cape Canaveral Space Force Station Space Launch Complex 41 on a mission to study Jupiter. Juno spent five years traveling to Jupiter, accomplishing a gravity assist from Earth in October 2013 to increase its velocity. Upon arrival at Jupiter, the spacecraft performed an orbit insertion burn, reducing its speed to be captured by the planet's gravity. The mission was originally scheduled to conclude in February 2018 after completing 37 orbits of Jupiter. However, the mission was extended through 2025 to conduct 42 additional orbits, including close flybys of Jupiter's moons Ganymede, Europa, and Io. At the end of its mission, Juno is planned to be deorbited and burned up in Jupiter's outer atmosphere to suppress the risk of biological contamination of its moons.

In October 2021, the Lucy spacecraft was launched from Cape Canaveral Space Force Station Space Launch Complex 41 on a mission to study eight different asteroids, including two main-belt asteroids and six Jupiter trojans. The spacecraft conducted its first Earth gravity assist on 16 October 2022. After a planned flyby of the asteroid 152830 Dinkinesh in 2023, Lucy will perform a second gravity assist from Earth in 2024. In 2025, it will fly by the inner main-belt asteroid 52246 Donaldjohanson. In 2027, Lucy will reach the L₄ Trojan cloud and conduct flybys of four Trojans: 3548 Eurybates and its satellite, 15094 Polymele, 11351 Leucus, and 21900 Orus. After these encounters, the spacecraft will return to Earth in 2031 for another gravity assist, which will send it toward the L₅ Trojan cloud. In 2033, Lucy is scheduled to fly by the binary Trojan 617 Patroclus and its satellite Menoetius. The mission is expected to conclude with the Patroclus–Menoetius flyby, but at that point, Lucy will remain in a stable, six-year orbit between the L4 and L5 Trojan clouds, leaving the possibility open for a mission extension.

As of December 2024, two spacecraft are en route to Jupiter: the Jupiter Icy Moons Explorer (JUICE) and the Europa Clipper. Both missions aim to study Jupiter and its moons, with JUICE focusing on Ganymede, Callisto, and Europa, and the Europa Clipper specifically targeting Europa's potential habitability.

Jupiter

Eight spacecraft have been launched to explore Jupiter, along with two others completing gravity-assist flybys.

Mission		Spacecraft	Launch date	Carrier rocket	Operator	Mission Type	Outcome
1	Argo	Argo	c. 2020s	N/A	NASA	Flyby	Cancelled
		Cancelled due to shortage of plutonium-238 required for the radioisotope thermoelectric generators (RTG). Proposed to have used a Jupiter gravity assist to propel it toward Saturn.
2	BRUIE	Buoyant Rover for Under-Ice Exploration	N/A	N/A	NASA	Europa lander	In progress
		Currently in progress, with potential plans to explore Europa and Enceladus.
3	Europa Lander	Europa Lander	2025–2030	Space Launch System or a commercial rocket	NASA	Lander	In progress
		Would depend on the Europa Clipper to select a landing site and assess radiation levels. Once landed, it would search for biosignatures and authenticate and determine the proximity of liquid water.
4	Europa Orbiter	Europa Orbiter	2003	Space Shuttle	NASA	Orbiter	Cancelled
		Canceled in 2002 due to concerns over extreme radiation levels near Jupiter. Would have determined the presence of a subsurface ocean and identified potential sites for future lander missions.
5	Flyby of Io with Repeat Encounters	Flyby of Io with Repeat Encounters	2024	Atlas V	NASA	Orbiter	In progress
		The FIRE spacecraft would use three gravity assists to reach Jupiter in six years, orbit the planet, and conduct 10 close flybys of Io, some at altitudes as low as 100 km (62 mi).
6	Innovative Interstellar Explorer	Innovative Interstellar Explorer	c. 2014	Delta IV Heavy with a stack of Star 48 and Star 37 or the Atlas V 551 with a Star 48.	NASA	Flyby	Cancelled
		Cancelled due to missed launch windows and unavailable materials. Planned to use a Jupiter gravity assist to reach interstellar space and study magnetic fields, cosmic rays, and their effects on a spacecraft exiting the Solar System.
7	Interstellar Probe	Interstellar Probe	Between 2036 and 2041	Space Launch System Block 2	NASA	Flyby	In progress
		Designed to explore and study the heliosphere and interstellar space, using a Jupiter gravity assist to increase its speed, after which the probe would travel at approximately 6–7 AU (560,000,000–650,000,000 mi; 900,000,000–1.05×10 km) per year, exiting the heliosphere within 16 years.
8	Io Volcano Observer	Io Volcano Observer	January 2029	N/A	NASA	Flyby	In progress
		Designed to study tidal heating as a key planetary process, investigating where and how it is generated within Io, how it reaches the surface, and how Io evolves over time.
9	Jupiter Europa Orbiter	Jupiter Europa Orbiter	2020	Delta IV Heavy or Atlas V	NASA	Orbiter	Cancelled
		Canceled after NASA approved the Europa Clipper mission. It was intended to study Europa, Io, and Jupiter's magnetosphere.
10	Jupiter Ganymede Orbiter	Jupiter Ganymede Orbiter	2020	Ariane 5	ESA	Orbiter	Cancelled
		Canceled after being superseded by the Jupiter Icy Moons Explorer mission in a vote. It was intended to study Ganymede, Callisto, and Jupiter's magnetosphere.
11	Jupiter Icy Moons Orbiter	Jupiter Icy Moons Orbiter	May 2015 – January 2016	Delta IV Heavy Baseline	NASA	Orbiter	Cancelled
		Canceled due to a shift in NASA's priorities, which favored crewed space missions instead. The probe would have confirmed the potential existence of a subsurface ocean beneath Europa's surface, with Ganymede and Callisto also being targeted for exploration.
12	Jupiter Magnetospheric Orbiter	Jupiter Magnetospheric Orbiter	2020	N/A	JAXA	Orbiter	Cancelled
		Canceled due to JAXA's inability to launch the mission in time for cooperative observation with JUICE. It would have studied Jupiter's magnetosphere as a model for an astrophysical magnetized disk.
13	Laplace-P	Laplace-P	2026	Angara-A5 with the KVTK upper stage	Roscosmos	Lander	Cancelled
		Canceled in 2017 due to funding issues. It was designed to study the Jovian moon system and include a lander for Ganymede exploration.
14	New Horizons 2	New Horizons 2	N/A	N/A	NASA	Flyby	Cancelled
		Cancelled due to shortage of plutonium-238 required for the radioisotope thermoelectric generators (RTG). The mission would have used a Jupiter gravity assist and a Uranus flyby to reach and explore Kuiper belt objects.
15	OKEANOS	Oversize Kite-craft for Exploration and Astronautics in the Outer Solar system	2026	H-IIA or H3	JAXA	Flyby	Cancelled
		Cancelled after being superseded by LiteBIRD in a vote. Would have studied Jupiter's Trojan asteroids using a hybrid solar sail for propulsion.
16	Pioneer H	Pioneer H	1974	N/A	NASA	Flyby	Cancelled
		Cancelled as the mission proposal was never accepted by NASA, it would have flown by Jupiter as a third Pioneer probe alongside Pioneer 10 and 11. The spacecraft now resides in the National Air and Space Museum in Washington, D.C.
17	Shensuo	Shensuo	May 2024	N/A	CNSA	Flyby	Planned
		The IHP-1 and IHP-2 missions will use Jupiter gravity assists to accelerate into interstellar space. Once there, they will study anomalous cosmic rays, interplanetary dust, and the interstellar medium.
18	SMARA	SMARA	N/A	N/A	ESA	Entry probe	In progress
		Microprobes proposed to launch with the Jupiter Icy Moons Explorer, designed to study Jupiter's atmosphere and capture photographs during descent.
19	Tianwen-4	Tianwen-4	September 2029	Long March 5	CNSA	Orbiter	Planned
		Will investigate magnetic field interactions with plasma in the Jovian system, analyze atmospheric composition, study the internal structures and surfaces of Ganymede or Callisto, and examine the space environment around these Galilean moons.
20	Trident	Trident	25 October 2025 with a backup in October 2026	N/A	NASA	Flyby	In progress
		Proposed mission to study Triton's surface and cryovolcanism, using a Jupiter gravity assist and a flyby of Io in 2032 to accelerate toward Neptune.
21	Tsiolkovsky mission	Tsiolkovsky mission	c. 1990s	N/A	Soviet space program	Flyby	Cancelled
		Proposed mission to use a Jupiter gravity assist to approach within five to seven solar radii to study the Sun, with a derivative spacecraft potentially targeting Saturn and beyond.

Saturn

Four spacecraft have explored Saturn: Pioneer 11, Voyager 1, and Voyager 2 conducted flybys, while Cassini–Huygens entered orbit and deployed Huygens into Titan's atmosphere.

Mission		Spacecraft	Launch date	Carrier rocket	Operator	Mission Type	Outcome
1	AVIATR	Aerial Vehicle for In situ and Airborne Titan Reconnaissance	2020	Atlas V 521	NASA	Lander	Cancelled
		Cancelled as the National Research Council's “Decadal Survey” did not prioritize Titan exploration, and development of the advanced Stirling radioisotope generator was halted. The mission proposed an airplane concept for exploring Saturn's moon Titan.
2	Breakthrough Enceladus mission	Breakthrough Enceladus mission	N/A	N/A	Breakthrough Initiatives	Orbiter	In progress
		Proposed to search for life on Saturn's moon Enceladus by detecting microbes in its water plumes and using ice-penetrating radar to study the moon's subsurface ocean.
3	Dragonfly	Dragonfly	5–25 July 2028	Falcon Heavy	NASA	Lander	Planned
		Part of the New Frontiers program, the mission will deploy a robotic rotorcraft to Saturn's moon Titan to evaluate its potential for microbial habitability and investigate its prebiotic chemistry across multiple sites.
4	Enceladus Explorer	Enceladus Explorer	N/A	N/A	German Aerospace Center and seven German universities	Orbiter and lander	In progress
		Funded by the German Aerospace Center, the mission is a research collaboration among seven German universities. It includes a lander equipped with the IceMole probe and an orbiter designed primarily to serve as a communications relay between the lander and Earth.
5	Enceladus Icy Jet Analyzer	Enceladus Icy Jet Analyzer	N/A	N/A	NASA	Orbiter	In progress
		Proposed time-of-flight mass spectrometer mission designed to detect prebiotic molecules, such as amino acids, and biosignatures in the plumes of Saturn's moon Enceladus.
6	Enceladus Life Finder	Enceladus Life Finder	N/A	N/A	NASA	Orbiter	In progress
		Designed to evaluate the habitability of Enceladus's subsurface ocean, Saturn's sixth-largest moon.
7	Enceladus Life Signatures and Habitability	Enceladus Life Signatures and Habitability	N/A	N/A	NASA	Orbiter	In progress
		Proposed to search for biosignatures and assess Enceladus's habitability.
8	Enceladus Orbilander	Enceladus Orbilander	October 2038	Space Launch System Block 2	NASA	Orbiter and lander	In progress
		Planned to orbit Enceladus for 18 months to sample its water plumes, followed by a two-year surface mission to analyze materials for signs of life.
9	Explorer of Enceladus and Titan	Explorer of Enceladus and Titan	N/A	N/A	ESA/NASA	Orbiter	In progress
		Proposed to study the origin and evolution of volatile-rich icy worlds by examining Enceladus and Titan, assess their habitability and potential for life, and explore Titan as an Earth-like world with a dynamic climate and landscape.
10	Journey to Enceladus and Titan	Journey to Enceladus and Titan	N/A	N/A	NASA	Orbiter	Cancelled
		Cancelled after being superseded by Lucy in a vote. The mission aimed to conduct high-resolution mass spectroscopy mapping to analyze the processes shaping Saturn's moons, while assessing the habitability potential of Enceladus and Titan.
11	Kronos	Kronos	N/A	N/A	ESA/NASA	Orbiter	In progress
		Proposed to analyze Saturn's atmospheric composition, gravity, and magnetic fields, with two atmospheric probes aiding in close-up imaging of its rings.
12	Life Investigation For Enceladus	Life Investigation For Enceladus	Late 2021	N/A	NASA	Orbiter	In progress
		Proposes sending a robotic spacecraft to collect particles from Saturn's moon Enceladus and return them to Earth for detailed analysis, searching for biomolecules and potential signs of life.
13	Oceanus	Oceanus	February 2024	N/A	NASA	Orbiter	Cancelled
		Cancelled as it was not selected for development under the New Frontiers program. Proposed to travel to Saturn's moon Titan to evaluate its habitability.
14	Saturn Atmospheric Entry Probe	Saturn Atmospheric Entry Probe	30 August 2027	N/A	NASA	Entry probe	In progress
		Proposes robotic spacecraft designed to deploy a single probe into Saturn's atmosphere for in-depth study.
15	SPRITE	Saturn PRobe Interior and aTmospheric Explorer	November 2024	Atlas V 401	NASA	Entry probe	Cancelled
		Canceled after not being selected for development under the New Frontiers program. The probe would have been an atmospheric entry probe designed to travel independently to Saturn, enter its atmosphere, and collect in situ measurements during descent.
16	Titan Lake In-situ Sampling Propelled Explorer	Titan Lake In-situ Sampling Propelled Explorer	N/A	N/A	CAB/SENER/ESA	Lander	In progress
		The mission proposed landing on Ligeia Mare to navigate the lake for 6–12 months. If approved by ESA, it would study the liquid hydrocarbon sea, perform scientific measurements, and explore the surrounding terrain and northern coast of Titan.
17	Titan Mare Explorer	Titan Mare Explorer	2016	Atlas V 411	NASA	Lander	In progress
		The mission aimed to measure Titan's organic constituents, conduct the first nautical exploration of an extraterrestrial sea, analyze its composition, and potentially study its shoreline.
18	Titan Saturn System Mission	Titan Saturn System Mission	Between 2020 and 2029	Delta IV Heavy, Space Launch System Block IB, or Atlas V	NASA	Orbiter and lander	Cancelled
		Canceled due to funding constraints and prioritization of other planetary exploration goals. The mission aimed to study Saturn's moons Titan and Enceladus, focusing on their atmospheres, surfaces, and potential signs of life.
19	Titan Submarine	Titan Submarine	2030s-2040s	N/A	NASA	Lander	In progress
		Proposed to detect the elemental and chemical properties of Titan's water, undersea rocks, and minerals, as well as identify undersea seismic activity. The submarine would also measure the depth and temperature of specific locations within Titan's lakes.
20	Titan Winged Aerobot	Titan Winged Aerobot	N/A	N/A	NASA	Orbiter	In progress
		Proposed aerobot designed to fly through Titan's atmosphere, analyzing its composition and measuring temperature variations.

Uranus

Voyager 2 is the only spacecraft to visit Uranus, conducting a single flyby during its grand tour of the outer planets.

Mission		Spacecraft	Launch date	Carrier rocket	Operator	Mission Type	Outcome
1	MUSE	MUSE	September 2026, November 2029 if delayed	Ariane 6	ESA	Orbiter	In progress
		Proposed to investigate Uranus's atmosphere, interior, moons, rings, and magnetosphere, including deploying an atmospheric probe to study why Uranus emits minimal heat.
2	OCEANUS	Origins and Composition of the Exoplanet Analog Uranus System	2030	Atlas V 511 or SLS	NASA	Orbiter	In progress
		Proposed to investigate the structure of Uranus's magnetosphere and interior, enabling detailed studies not achievable with a flyby mission.
3	ODINUS	Origins, Dynamics, and Interiors of the Neptunian and Uranian Systems	2034	N/A	ESA	Orbiter	In progress
		Proposed to enhance the Uranus Orbiter and Probe mission by including twin orbiters, Freyr, named after the Norse mythological figure, being the proposed spacecraft mission to explore Uranus, each dedicated to studying Neptune and Uranus.
4	Tianwen-4	Tianwen-4	September 2029	Long March 5	CNSA	Orbiter	Planned
		Proposed to orbit Jupiter and Callisto, then fly by Uranus in March 2045 to study solar wind evolution in interplanetary space and its interactions with planetary magnetospheres.
5	Uranus Orbiter and Probe	Uranus Orbiter and Probe	Not earlier than 2031	Falcon Heavy	NASA	Orbiter	In progress
		Proposed to study Uranus and its moons, along with deploying an atmospheric probe to analyze Uranus's atmosphere.
6	Uranus Pathfinder	Uranus Pathfinder	2022, in baseline concept January 2025	N/A, in baseline concept an Atlas V 551	ESA	Orbiter	Cancelled
		Proposed under ESA's Cosmic Vision 2015–2025, it would have used gravity assists from Earth, Venus, and Saturn. At Uranus, it planned a 45-day polar orbit with close periapsis distances to study the planet's gravitational and magnetic fields.

Neptune

Voyager 2 is the only spacecraft to visit Neptune, conducting a single flyby during its grand tour of the outer planets.

Mission		Spacecraft	Launch date	Carrier rocket	Operator	Mission Type	Outcome
1	Argo	Argo	c. 2020s	N/A	NASA	Flyby	Cancelled
		Cancelled due to shortage of plutonium-238 required for the radioisotope thermoelectric generators (RTG). Would've focused on Neptune and its largest moon, Triton, addressing questions raised by Voyager 2's 1989 flyby and would've provided insights into the formation and evolution of ice giants.
2	Neptune Odyssey	Neptune Odyssey	2033	Space Launch System proposed, Falcon Heavy as the alternative	NASA	Orbiter	In progress
		Proposed to enter a retrograde orbit around Neptune for simultaneous study of Triton, the mission would also deploy an atmospheric probe to analyze Neptune's atmosphere.
3	New Horizons 2	New Horizons 2	N/A	N/A	NASA	Flyby	Cancelled
		Cancelled due to a shortage of plutonium-238 for the radioisotope thermoelectric generator, the probe was proposed to fly by Neptune and Triton, with 66652 Borasisi considered as a potential follow-up target.
4	ODINUS	Origins, Dynamics, and Interiors of the Neptunian and Uranian Systems	2034	N/A	ESA	Orbiter	In progress
		Proposed to enhance the Uranus Orbiter and Probe mission by including twin orbiters, Freyja, named after the Norse mythological figure, being the proposed spacecraft mission to explore Neptune, each dedicated to studying Neptune and Uranus.
5	Shensuo	IHP-2	May 2024	N/A	CNSA	Flyby	Planned
		Proposed to use gravity assists from Earth, Jupiter, and Neptune, the mission aims to fly by Neptune in January 2038, passing just 1,000 kilometers above its cloud tops. The probe may also release an atmospheric impactor before the flyby.
6	Triton Hopper	Triton Hopper	N/A	N/A	NASA	Lander	In progress
		Proposed to harvest the nitrogen ice on the surface of Triton and use it as propellant for multiple short flights to explore a variety of locations on the moon.
7	Trident	Trident	25 October 2025 with a backup in October 2026	N/A	NASA	Flyby	In progress
		Proposed mission to study Triton's surface and cryovolcanism, using a Jupiter gravity assist and a flyby of Io in 2032 to accelerate toward Neptune.

Pluto and trans-Neptunian objects

One spacecraft has visited a dwarf planet and trans-Neptunian object: New Horizons, which performed flybys of Pluto and the Kuiper belt object 486958 Arrokoth.

Mission		Spacecraft	Launch date	Carrier rocket	Operator	Mission Type	Outcome
1	Fusion-Enabled Pluto Orbiter and Lander	Fusion-Enabled Pluto Orbiter and Lander	N/A	N/A	NASA	Orbiter and lander	In progress
		A probe equipped with a Direct Fusion Drive (DFD) propulsion system, planned to orbit and land on Pluto.
2	Shensuo	IHP-1	May 2024	N/A	CNSA	Flyby	Planned
		A proposed probe in the Shensuo program (Chinese: 神梭), planned to launch alongside IHP-2 and the proposed IHP-3. IHP-1 will use gravity assists from Earth in October 2025 and December 2027, followed by a Jupiter flyby in March 2029, on its way to the heliosphere. During its journey to interstellar space, it is expected to encounter 50000 Quaoar and its moon Weywot in 2040.
3	Persephone	Persephone	N/A	N/A	NASA	Orbiter	In progress
		Proposed to orbit Pluto for three years, investigating the possibility of a subsurface ocean.
4	New Horizons 2	New Horizons 2	N/A	N/A	NASA	Flyby	Cancelled
		A proposed probe that would've flew by trans-Neptunian objects using a gravity assist from Uranus.
5	Pluto Hop, Skip, and Jump	Pluto Hop, Skip, and Jump	N/A	N/A	NASA	Lander	In progress
		A proposed probe designed to land on Pluto, similar to the concept of the Triton Hopper mission.
6	Pluto Kuiper Express	Pluto Kuiper Express	December 2004	Delta II or Space Shuttle	NASA	Orbiter	Cancelled
		A proposed probe to fly by Pluto, with a planned 2004 launch, a Jupiter assist in 2006, and a Pluto arrival by 2012. Canceled in 2000, it inspired the New Horizons mission, which launched in 2006 and reached Pluto in 2015.

Notes

1. Mission is still in progress despite being cancelled.

References

1. Uri, John (3 September 2019). "40 Years Ago: Pioneer 11 First to Explore Saturn". nasa.gov. Retrieved 22 December 2024.
2. Uri, John (2 March 2022). "50 Years Ago: Pioneer 10 Launches to Explore Jupiter". nasa.gov. Retrieved 22 December 2024.
3. "PIA02855: Voyager 1 "Blue Movie"". photojournal.jpl.nasa.gov. Jet Propulsion Laboratory. 19 December 2000. Retrieved 28 December 2024.
4. Flandro, Gary (1966). "Fast Reconnaissance Missions to the Outer Solar System Using Energy Derived from the Gravitational Field of Jupiter" (PDF). Astronautica Acta. 12: 329–337. Archived (PDF) from the original on 30 March 2019. Retrieved 1 June 2024.
5. "Voyager 1 - NASA Science". science.nasa.gov. Retrieved 23 December 2024.
6. "Voyager 2 - NASA Science". science.nasa.gov. Retrieved 23 December 2024.
7. "Galileo – Overview". NASA Solar System Exploration. Retrieved December 7, 2021.
8. "Welcome to the HIA Ulysses Project". Herzberg Institute of Astrophysics. Archived from the original on 17 August 2011. The Herzberg Institute of Astrophysics (HIA) of the National Research Council of Canada provided instrumentation and test equipment for the COsmic ray and Solar Particle INvestigation (COSPIN) on the Ulysses spacecraft. The COSPIN instrument consists of five sensors which measure energetic nucleons and electrons over a wide range of energies. This was the first participation by Canada in a deep-space interplanetary mission.
9. "Ulysses". Radioisotope Power Systems. NASA. Archived from the original on 3 March 2024.
10. "Cassini Captures Images and Sounds of Saturn Storm". jpl.nasa.gov. 6 July 2011. Archived from the original on 2 February 2019. Retrieved 28 December 2024.
11. "Outer Planets and Ocean Worlds Program". science.nasa.gov. NASA. Retrieved 12 July 2017.
12. P. Dyches; D. C. Brown; L. Cantillo (29 August 2017). "Saturn Plunge Nears for Cassini Spacecraft". science.nasa.gov. NASA. Retrieved 30 August 2017.
13. Dennis Overbye (8 September 2017). "Cassini Flies Toward a Fiery Death on Saturn". The New York Times. Retrieved 10 September 2017.
14. "New Horizons, The First Mission to Pluto and the Kuiper Belt: Exploring Frontier Worlds" (PDF) (Press Kit). Applied Physics Laboratory. January 16, 2007.
15. Dvorsky, George (June 9, 2015). "Here's Why The New Horizons Spacecraft Won't Be Stopping At Pluto". io9. Retrieved July 12, 2017.
16. Scharf, Caleb A. (February 25, 2013). "The Fastest Spacecraft Ever?". Scientific American. Retrieved July 12, 2017.
17. Whitwam, Ryan (December 13, 2017). "New Horizons Space Probe Target May Have its Own Tiny Moonlet – ExtremeTech". Ziff Davis. Retrieved January 24, 2019.
18. Chang, Kenneth (July 14, 2015). "NASA's New Horizons Spacecraft Completes Flyby of Pluto". The New York Times. Archived from the original on January 18, 2018. Retrieved July 14, 2015.
19. Dunn, Marcia (July 14, 2015). "Pluto close-up: Spacecraft makes flyby of icy, mystery world". Excite. Associated Press (AP). Archived from the original on July 16, 2015. Retrieved July 14, 2015.
20. "New Horizons". NASA. Retrieved March 10, 2023.
21. Chang, Kenneth (June 28, 2016). "NASA's Juno Spacecraft Will Soon Be in Jupiter's Grip". The New York Times. Archived from the original on August 14, 2018. Retrieved June 30, 2016.
22. "NASA's Shuttle and Rocket Launch Schedule". NASA. Archived from the original on September 13, 2008. Retrieved February 17, 2011. This article incorporates text from this source, which is in the public domain.
23. Brown, Dwayne; Cantillo, Laurie; Agle, D. C. (February 17, 2017). "NASA's Juno Mission to Remain in Current Orbit at Jupiter" (Press release). NASA. Archived from the original on February 20, 2017. Retrieved March 13, 2017. This article incorporates text from this source, which is in the public domain.
24. Carter, Jamie. "Self-Destruction Of $1.4 Billion Spacecraft At Jupiter Scrubbed By NASA As It Returns More Stunning Images". Forbes. Retrieved November 11, 2022.
25. Chang, Kenneth (July 5, 2016). "NASA's Juno Spacecraft Enters Jupiter's Orbit". The New York Times. Archived from the original on May 2, 2019. Retrieved July 5, 2016.
26. Greicius, Tony (September 21, 2015). "Juno – Mission Overview". NASA. Archived from the original on September 7, 2018. Retrieved October 2, 2015. This article incorporates text from this source, which is in the public domain.
27. Juno Mission Profile & Timeline Archived November 25, 2011, at the Wayback Machine
28. Hille, Karl (2019-10-21). "NASA's Lucy Mission Clears Critical Milestone". NASA. Archived from the original on 22 October 2019. Retrieved 2020-12-05. This article incorporates text from this source, which is in the public domain.
29. "Lucy: The First Mission to the Trojan Asteroids". NASA. 21 April 2017. Archived from the original on 6 December 2020. Retrieved 2021-10-16. This article incorporates text from this source, which is in the public domain.
30. Lee Kanayama (16 October 2022). "Lucy completes its first Earth gravity assist after a year in space". www.nasaspaceflight.com. NASA Spaceflight.com. Archived from the original on 15 October 2022. Retrieved 24 October 2022.
31. Merzdorf, Jessica (25 January 2023). "NASA's Lucy Team Announces New Asteroid Target". NASA. Archived from the original on 25 January 2023. Retrieved 26 January 2023.
32. "NASA Awards Launch Services Contract for Lucy Mission". nasa.gov. NASA. 31 January 2019. Archived from the original on 1 February 2019. Retrieved 29 March 2021. This article incorporates text from this source, which is in the public domain.
33. Dreier, Casey; Lakdawalla, Emily (30 September 2015). "NASA announces five Discovery proposals selected for further study". The Planetary Society. Archived from the original on 26 July 2020. Retrieved 2 October 2015.
34. Chang, Kenneth (6 January 2017). "A Metal Ball the Size of Massachusetts That NASA Wants to Explore". The New York Times. Archived from the original on 7 January 2017. Retrieved 2 March 2017.
35. "Juice factsheet". esa.int. Retrieved 28 December 2024.
36. "Overview - Mission — NASA's Europa Clipper". europa.nasa.gov. Retrieved 28 December 2024.
37. ^ Betz, Eric (24 August 2015). "NASA's next big spacecraft mission could visit an ice giant". Astronomy Magazine. Retrieved 2016-11-07.
38. Gough, Evan (22 November 2019). "Aquatic Rover Drives on the Underside of the Ice in Antarctica". Universe Today.
39. "NASA Kills Europa Orbiter". Space.com. Archived from the original on 10 February 2002. Retrieved 26 February 2009.
40. "Europa Orbiter".
41. ^ Flyby of Io with Repeat Encounters: A conceptual design for a New Frontiers mission to Io. Terry-Ann Suer, Sebastiano Padovan, Jennifer L. Whitten, Ross W.K. Potter, Svetlana Shkolyar, Morgan Cable, Catherine Walker, Jamey Szalay, Charles Parker, John Cumbers, Diana Gentry, Tanya Harrison, Shantanu Naidu, Harold J. Trammell, Jason Reimuller, Charles J. Budney, Leslie L. Lowes. Advances in Space Research, Volume 60, Issue 5, 1 September 2017, Pages 1080–1100
42. Flyby of Io with Repeat Encounters (FIRE): A New Frontiers Mission Designed to STudy the Innermost Volcanic Body in the Solar System. (PDF) R. W. K. Potter, M. L. Cable, J. Cumbers, D. M. Gentry, T. N. Harrison, S. Naidu, S. Padovan6, C. W. Parker, J. Reimuller, S. Shkolyar, T-A. Suer, J. R. Szalay, H. J. Trammell, C. C. Walker, J. L. Whitten and C. J. Budney. 44th Lunar and Planetary Science Conference (2013).
43. Innovative interstellar explorer 7 pages
44. Innovative Interstellar Explorer Feb 2006 slides
45. "Update on Innovative Interstellar Explorer". Centauri Dreams. 2011-12-20. Retrieved 2017-02-21.
46. David, Leonard (July 6, 2005). "Voyage to the Stars: NASA Study Mulls Options". Space.com.
47. McNutt, Ralph; Paul, Michael; Brandt, Pontus; Kinnison, Jim. "Interstellar Probe: Humanity's Journey to Interstellar Space" (PDF). Interstellar Probe. Johns Hopkins Applied Physics Laboratory. Retrieved 23 December 2021.
48. Stone, Richard (28 July 2022). "'Voyager on steroids.' Mission would probe mysterious region beyond our Solar System". Science. doi:10.1126/science.ade1070. Retrieved 15 August 2022.
49. ^ McEwen, A. S. (2021). The Io Volcano Observer (IVO) (PDF). Lunar and Planetary Science Conference. Abstract #1352. Retrieved 9 February 2021.
50. Elizabeth Howell (20 June 2015). "NASA's Europa Mission Approved for Next Development Stage". Space.com. Retrieved 21 June 2015.
51. Stephen Battersby (5 November 2009). "A drop in the bucket is plenty". The National. Retrieved 8 November 2009.
52. "Selection of the L1 mission" (PDF). ESA. 17 April 2012. ESA/SPC(2012)12.
53. Berger, Brian (February 7, 2005). "NASA 2006 Budget Presented: Hubble, Nuclear Initiative Suffer". Space.com. Retrieved June 6, 2007.
54. Exploration of Jovian System by ESA-JUICE Mission: Participation of Japanese Teams. International Astrobiology Workshop 2013. November 28–30, 2013. Sagamihara, Kanagawa, Japan.
55. "РФ планирует доставить свои исследовательские аппараты к Юпитеру к 2032 году" (in Russian). TASS. 5 July 2016. Retrieved 2017-01-08.
56. Advanced Russian Mission Laplace-P to Study the Planetary System of Jupiter: Scientific Goals, Objectives, Special Features and Mission Profile. M. B. Martynov, P. V. Merkulov, I. V. Lomakin, P. A. Vyatlev, A. V. Simonov, E. V. Leun, A. A. Barabanov, A. F. Nasyrov. Solar System Research December 2017, Volume 51, Issue 7, pp 555–562. doi:10.1134/S0038094617070127
57. Струговец, Дмитрий (15 July 2017). "Вице-президент РАН: сроки реализации лунной программы сдвинулись ради проекта "ЭкзоМарс"". TASS. Archived from the original on 5 July 2018.
58. Anderson, Kenneth; Bearden, David; et al. (May 31, 2005). Final report of the New Horizons II review panel (PDF) (Report). Lunar and Planetary Institute.
59. Bruno, Claudio; Czysz, Paul A. (2009). Future spacecraft propulsion systems: enabling technologies for space exploration. Springer Praxis books in astronautical engineering (2. ed.). Berlin: Springer. p. 378. ISBN 978-3-540-88814-7.
60. Moore, Jeff (June 5, 2004). "Revolution Afoot– Cheaper, More Frequent Outer Planets Missions – New Horizons II Workshop". Spacenews. Retrieved March 2, 2023.
61. SCIENCE AND EXPLORATION IN THE SOLAR POWER SAIL OKEANOS MISSION TO A JUPITER TROJAN ASTEROID T. Okada, T. Iwata, J. Matsumoto, T. Chujo, Y. Kebukawa, J. Aoki, Y. Kawai, S. Yokota, Y. Saito, K. Terada, M. Toyoda, M. Ito, H. Yabuta, H. Yurimoto, C. Okamoto, S. Matsuura, K. Tsumura, D. Yonetoku, T. Mihara, A. Matsuoka, R. Nomura, H. Yano, T. Hirai, R. Nakamura, S. Ulamec, R. Jaumann, J.-P. Bibring, N. Grand, C. Szopa, E. Palomba, J. Helbert, A. Herique, M. Grott, H. U. Auster, G. Klingelhoefer, T. Saiki, H. Kato, O. Mori, J. Kawaguchi; 49th Lunar and Planetary Science Conference 2018 (LPI Contrib. No. 2083)
62. INVESTIGATION OF THE SOLAR SYSTEM DISK STRUCTURE DURING THE CRUISING PHASE OF THE SOLAR POWER SAIL MISSION T. Iwata, T. Okada, S. Matsuura, K. Tsumura, H. Yano, T. Hirai, A. Matsuoka, R. Nomura, D. Yonetoku, T. Mihara, Y. Kebukawa, M. ito, M. Yoshikawa, J. Matsu-moto, T. Chujo, and O. Mori; 49th Lunar and Planetary Science Conference 2018 (LPI Contrib. No. 2083)
63. Trajectory Design for Jovian Trojan Asteroid Exploration via Solar Power Sail Archived 31 December 2017 at the Wayback Machine Takanao Saiki, Osam Mori The Institute of Space and Astronautical Science (ISAS), JAXA 2017
64. JAXA Sail to Jupiter's Trojan Asteroids Paul Gilster, Centauri Dreams 15 March 2017
65. Sampling Scenario for the Trojan Asteroid Exploration Mission Archived 2017-12-31 at the Wayback Machine Jun Matsumoto, Jun Aoki, Yuske Oki, Hajime Yano; 2015
66. "Assembling for NASM the Pioneer 10 replica". NASM Space Archives. Archived from the original on June 9, 2007. Retrieved 2 May 2012.
67. ^ Wu, Weiren; Yu, Dengyun; Huang, Jiangchuan; Zong, Qiugang; Wang, Chi; Yu, Guobin; He, Rongwei; Wang, Qian; Kang, Yan; Meng, Linzhi; Wu, Ke; He, Jiansen; Li, Hui (2019-01-09). "Exploring the solar system boundary". Scientia Sinica Informationis. 49 (1): 1. doi:10.1360/N112018-00273. ISSN 2095-9486. S2CID 86476811.
68. ^ Jones, Andrew (November 19, 2019). "China Considers Voyager-like Mission to Interstellar Space". Planetary.org. The Planetary Society. Retrieved 29 April 2021.
69. ^ Wang, Chi; Li, Hui; Guo, Xiaocheng; Xu, Xinfeng (2021-01-27). "太阳系边际探测项目的科学问题". 深空探测学报(中英文） (in Chinese). 7 (6): 517–524. doi:10.15982/j.issn.2096-9287.2020.20200058. ISSN 2096-9287. Retrieved 1 July 2021.
70. Brabaw, Kasandra (February 18, 2015). "Tiny Microprobes Could Explore Jupiter's Atmosphere By 2030". Space.com. Retrieved 2016-03-07.
71. ^ CNSA Watcher (23 December 2023). "Tianwen-4, launching Sept 2029, will journey to Jupiter using Venus & Earth gravity assists. Targeting Jupiter capture by Dec 2035 & a Uranus flyby in March 2045, the mission includes 2 probes, one exploring Jupiter's system and another flying by Uranus" (Tweet) – via Twitter.
72. ^ Xu, Lin; Zou, Yongliao; Jia, Yingzhuo (2018). "China's planning for deep space exploration and lunar exploration before 2030" (PDF). Chinese Journal of Space Science. 38 (5): 591–592. Bibcode:2018ChJSS..38..591X. doi:10.11728/cjss2018.05.591. S2CID 256881663.
73. ^ "Proposed NASA Mission Would Visit Neptune's Curious Moon Triton". NASA. 16 June 2020. Retrieved 2 July 2020. This article incorporates text from this source, which is in the public domain.
74. ^ "Implementation of Trident: A Discovery-Class Mission To Triton" (PDF). Universities Space Research Assotiation. 23 March 2019. Retrieved 26 March 2019.
75. Zak, Anatoly (February 5, 2013). "Planetary spacecraft". Russian Space Web. Retrieved May 13, 2016.
76. ^ Ortiz, Lillian (2 January 2012). "AVIATR: An Airplane Mission for Titan". Universe Today. Retrieved 2 August 2013.
77. ^ Barnes; et al. (March 2012). "AVIATR – Aerial Vehicle for In-situ and Airborne Titan Reconnaissance". Experimental Astronomy. 33 (1): 55–127. Bibcode:2012ExA....33...55B. doi:10.1007/s10686-011-9275-9.
78. "The ASRG Cancellation in Context". Future Planetary Exploration. December 8, 2013.
79. "Private mission may get us back to Enceladus sooner than NASA". New Scientist. 22 November 2017. Retrieved 2019-02-17.
80. Anderson, Paul Scott (November 27, 2018). "A billionaire's plan to search for life on Enceladus". EarthSky. Retrieved 2019-02-17.
81. Wall, Mike (November 9, 2018). "Billionaire Yuri Milner's Breakthrough Initiatives Eyes Private Mission to Seek Alien Life". Space.com. Retrieved 2019-02-17. Breakthrough Initiatives was investigating the feasibility of launching a probe that would look for signs of life in the plume of water vapor and other material wafting from Enceladus' south polar region.
82. Čadek, Ondřej; Tobie, Gabriel; Van Hoolst, Tim; et al. (2016). "Enceladus's internal ocean and ice shell constrained from Cassini gravity, shape, and libration data". Geophysical Research Letters. 43 (11): 5653–5660. Bibcode:2016GeoRL..43.5653C. doi:10.1002/2016GL068634. ISSN 1944-8007.
83. ^ A. A. Donaldson (25 November 2024). "NASA Awards Launch Services Contract for Dragonfly Mission". NASA. Retrieved 26 November 2024.
84. R. D. Lorenz; E. P. Turtle; J. W. Barnes; M. G. Trainer; D. Adams; et al. (October 2018). "Dragonfly: A Rotorcraft Lander Concept for Scientific Exploration at Titan" (PDF). Johns Hopkins APL Technical Digest. 34 (3). APL: 374–387. Retrieved 3 March 2021.
85. "NASA Selects Johns Hopkins APL-Led Mission to Titan for Further Development". APL. 21 December 2017. Archived from the original on 26 April 2018.
86. ^ Konstantinidis, Konstantinos; Flores Martinez, Claudio L.; Dachwald, Bernd; Ohndorf, Andreas; Dykta, Paul (February 2015). "A lander mission to probe subglacial water on Saturn׳s moon Enceladus for life". Acta Astronautica. 106: 63–89. Bibcode:2015AcAau.106...63K. doi:10.1016/j.actaastro.2014.09.012. Retrieved 11 April 2015.
87. ^ Konstantinidis, Konstantinos (2013). Enceladus Explorer (EnEx): A Lander Mission to Probe Subglacial Water Pockets on Saturn's Moon Enceladus For Life. 64th International Astronautical Congress.
88. Enceladus Icy Jet Analyzer (ENIJA) : Search for life with a high resolution TOF-MS for in situ characterization of high dust density regions. (PDF) R. Srama, F. Postberg, H. Henke), T. Klopfer, Y. Li, J. Simolka, S. Bugiel, S. Kempf, J. Hillier, N. Khawaja, M. Trieloff, B. Abel, G. Moragas-Klostermeyer, H. Strack, J. Schmidt, R. Soja, Z. Sternovsky, T. Spohn. EPSC Abstracts, Vol. 10, EPSC2015-769, European Planetary Science Congress 2015.
89. Lunine, Jonathan I.; Waite, Jack Hunter Jr.; Postberg, Frank; Spilker, Linda J. (2015). Enceladus Life Finder: The search for life in a habitable moon (PDF). 46th Lunar and Planetary Science Conference (2015). Houston (TX): Lunar and Planetary Institute.
90. Clark, Stephen (April 6, 2015). "Diverse destinations considered for new interplanetary probe". Space Flight Now. Retrieved April 7, 2015.
91. "Proposed New Frontiers Missions". Future Planetary Exploration. 4 August 2017. Archived from the original on 20 September 2017. Retrieved 2017-09-20.
92. McIntyre, Ocean (17 September 2017). "Cassini: The legend and legacy of one of NASA's most prolific missions". Spaceflight Insider. Archived from the original on 20 September 2017. Retrieved 2017-09-20.
93. ^ MacKenzie, Shannon M.; Kirby, Karen W.; Greenauer, Peter J.; Neveu, Marc; Gold, Rob; Davila, Alfonso; Lunine, Jonathan I.; Cable, Morgan; Craft, Kate; Eigenbrode, Jennifer; Glein, Christopher; Hofgartner, Jason; Mckay, Christopher; Phillips-Lander, Charity; Waite, Hunter; Burton, Dana; Seifert, Helmut; Boye, Jeff; Brock, Spencer; Chen, Michelle; Coker, Rob; Colonel, Grace; Criss, Tom; Crowley, Doug (14 October 2020). "Enceladus Orbilander: A Flagship Mission Concept for Astrobiology". NASA Technical Reports Server. Retrieved 26 April 2024.
94. Mitri, Giuseppe; Tobie, Gabriel; Postberg, Frank; Soderblom, Jason M.; Wurz, Peter; Barnes, Jason W.; Berga, Marco; Coustenis, Athena; D'Ottavio, Andrea; Hayes, Alexander G.; Hayne, Paul O.; Lebreton, Jean-Pierre; Lorenz, Ralph D.; Martelli, Andrea; Petropoulos, Anastassios E.; Yen, Chen-wan L.; Reh, Kim R.; Sotin, Christophe; Srama, Ralf; Tortora, Paolo (June 2017). Poster 14: Explorer of Enceladus and Titan (E2T). Titan Aeronomy and Climate. France: NASA. Bibcode:2016tac..confE..26M. Archived from the original on 2021-08-29. Retrieved 2017-09-16.
95. "Updated: NASA taps missions to tiny metal world and Jupiter Trojans". Science | AAAS. 2017-01-04. Retrieved 2017-01-04.
96. "NASA Selects Two Missions to Explore the Early Solar System". January 4, 2017. Retrieved January 4, 2017.
97. Kane, Van (3 April 2014). "Discovery Missions for an Icy Moon with Active Plumes". The Planetary Society. Retrieved 2015-04-09.
98. Sotin, C.; Altwegg, K.; Brown, R.H.; et al. (2011). JET: Journey to Enceladus and Titan (PDF). 42nd Lunar and Planetary Science Conference. Lunar and Planetary Institute.
99. Marty, B.; Guillot, T.; Coustenis, A.; et al. (2009). "Kronos: exploring the depths of Saturn with probes and remote sensing through an international mission". Experimental Astronomy. 23 (3): 947–976. Bibcode:2009ExA....23..977M. doi:10.1007/s10686-008-9094-9.
100. Kane, Van (December 2, 2014). "Selecting the Next Creative Idea for Exploring the Solar System". Planetary Society. Retrieved 2015-02-10.
101. Wall, Mike (December 6, 2012). "Saturn Moon Enceladus Eyed for Sample-Return Mission". Space.com. Retrieved 2015-04-10.
102. Tsou, Peter; Brownlee, D.E.; McKay, Christopher; Anbar, A.D.; Yano, H. (August 2012). "LIFE: Life Investigation For Enceladus A Sample Return Mission Concept in Search for Evidence of Life". Astrobiology. 12 (8): 730–742. Bibcode:2012AsBio..12..730T. doi:10.1089/ast.2011.0813. PMID 22970863. S2CID 34375065.
103. Tsou, Peter; Anbar, Ariel; Atwegg, Kathrin; Porco, Carolyn; Baross, John; McKay, Christopher (2014). "LIFE - Enceladus Plume Sample Return via Discovery" (PDF). 45th Lunar and Planetary Science Conference. Retrieved 2015-04-10.
104. Tsou, Peter (2013). "LIFE: Life Investigation For Enceladus - A Sample Return Mission Concept in Search for Evidence of Life". Jet Propulsion Laboratory. 12 (8): 730–42. Bibcode:2012AsBio..12..730T. doi:10.1089/ast.2011.0813. PMID 22970863. Archived from the original (.doc) on 2015-09-01. Retrieved 2015-04-10.
105. Sotin, C., Hayes, A., Malaska, M., Nimmo, F., Trainer, M. D., Tortora, P.. (2017). "OCEANUS: A New Frontiers orbiter to study Titan’s potential habitability." 19th EGU General Assembly, EGU2017, proceedings from the conference held 23–28 April 2017 in Vienna, Austria., p.10958
106. Beebe, Reta (September 2010). "Saturn Atmospheric Entry Probe Trade Study". Retrieved 2 August 2013. (Archived from the original).
107. Squyres, Steve. "Vision and Voyages For Planetary Science in the Decade 2013-2022" (PDF). National Research Council. Archived from the original (PDF) on 2011-11-14.
108. Saturn Atmospheric Entry Probe mission study (PDF). Planetary Science Decadal Survey (2010). NASA and Planetary Science Decadal Survey. April 2010.
109. Jeff Foust, NASA selects Titan drone for next New Frontiers mission SpaceNews June 27, 2019. Retrieved July 15, 2019
110. "Proposed Space Boat Could Explore Lakes On Saturn's Moon Titan". Space.com. 1 October 2012. Retrieved 10 August 2015.
111. Urdampilleta, I; Prieto-Ballesteros, O; Rebolo, R; Sancho, J (2012). TALISE: Titan Lake In-situ Sampling Propelled Explorer (PDF). European Planetary Science Congress 2012. EPSC Abstracts.
112. "Navigating the seas of Titan, Saturn's largest moon". Sciencedaily.com. 2012-09-27. Retrieved 2013-02-25.
113. "Paddleboat Mission to Titan Proposed". Universetoday.com. 2012-09-27. Retrieved 2013-02-25.
114. Taylor, Kate (May 9, 2011). "NASA picks project shortlist for next Discovery mission". TG Daily. Archived from the original on October 6, 2018. Retrieved May 20, 2011.
115. Creech, Stephen (April 2014). "NASA's Space Launch System: A Capability for Deep Space Exploration" (PDF). Strategy & Partnerships Space Launch System (SLS) Program.
116. "ESA internal study report on ESA contributions to Tandem/TSSM available". ESA. 12 February 2009.
117. Rincon, Paul (2009-02-20). "Jupiter in space agencies' sights". BBC News. Retrieved 2009-02-20.
118. Hall, Loura (14 June 2014). "Titan Submarine: Exploring the Depths of Kraken". Nasa.gov. Retrieved 14 April 2024.
119. "Titan Winged Aerobot". Global Aerospace Corporation. July 6, 2016. Retrieved 17 July 2016.
120. ^ Costa, M.; Bocanegra, T.; Bracken, C.; et al. (June 2012). Mission to the Uranus System: MUSE. Unveiling the evolution and formation of icy giants (PDF). 2012 Post Alpbach Summer School. Madrid, Spain.
121. Bocanegra-Bahamón, Tatiana (2015). "MUSE Mission to the Uranian System: Unveiling the evolution and formation of ice giants" (PDF). Advances in Space Research. 55 (9): 2190–2216. Bibcode:2015AdSpR..55.2190B. doi:10.1016/j.asr.2015.01.037.
122. Elder, C. M; Bramson, A. M; Blum, L. W; Chilton, H. T; Chopra, A; Chu, C; Das, A; Davis, A; Delgado, A; Fulton, J; Jozwiak, L; Khayat, A; Landis, M. E; Molaro, J. L; Slipski, M; Valencia, S; Watkins, J; Young, C. L; Budney, C. J; Mitchell, K. L (2017). "New Frontiers-Class Missions to the Ice Giants". Planetary Science Vision 2050 Workshop. 1989: 8147. Bibcode:2017LPICo1989.8147E.
123. ^ The ODINUS Mission Concept. White paper submitted to the European Space Agency call for L2 and L3 science themes (2013). Diego Turrini, Romolo Politi, Roberto Peron, Davide Grassi, Christina Plainaki, Mauro Barbieri, David M. Lucchesi, Gianfranco Magni, Francesca Altieri, Valeria Cottini, Nicolas Gorius, Patrick Gaulme, François-Xavier Schmider, Alberto Adriani, Giuseppe Piccioni.
124. ^ Turrini, Diego; Politi, Romolo; Peron, Roberto; Grassi, Davide; Plainaki, Christina; Barbieri, Mauro; Lucchesi, David M.; Magni, Gianfranco; Altieri, Francesca; Cottini, Valeria; Gorius, Nicolas; Gaulme, Patrick; Schmider, François-Xavier; Adriani, Alberto; Piccioni, Giuseppe (2014). "The ODINUS Mission Concept – The Scientific Case for a Mission to the Ice Giant Planets with Twin Spacecraft to Unveil the History of our Solar System". arXiv:1402.2472 .
125. ^ Noreika, Alius (13 February 2014). "Uranus and Neptune exploration could be the next ESA milestone". Technology.org. Retrieved 1 April 2016.
126. ^ Simon, Amy; Nimmo, Francis; Anderson, Richard C. (7 June 2021). "Journey to an Ice Giant System: Uranus Orbiter and Probe". Planetary Mission Concept for the 2023–2032 Planetary Science Decadal Survey. NASA. Retrieved 1 May 2022.
127. ^ (Line 562–4)
128. Hansen, C. J.; et al. (27 August 2009). "Neptune Science with Argo – A Voyage through the Outer Solar System". Jet Propulsion Laboratory. CiteSeerX 10.1.1.439.5280. A launch opportunity to the outer Solar System via Neptune opens in 2015 and lasts through the end of 2019, with backup options in 2020. It allows trajectories with reasonably short trip times to Neptune (8-11 years) and the Kuiper Belt (an additional 3-5 years), as well as low Triton approach speeds <17 km/sec.
129. "Argo: Exploring the Neptune System and Beyond" (PDF). EPSC Abstracts. European Planetary Science Congress. 2009. Retrieved 2016-11-07.
130. ^ Abigail Rymer; Brenda Clyde; Kirby Runyon (August 2020). "Neptune Odyssey: Mission to the Neptune-Triton System" (PDF). Retrieved 18 April 2021.
131. Origins, Worlds, and Life: A Decadal Strategy for Planetary Science and Astrobiology 2023-2032 (Prepublication ed.). National Academies Press. 19 January 2023. p. 800. doi:10.17226/26522. ISBN 978-0-309-47578-5. S2CID 248283239. Retrieved 30 April 2022.
132. Foust, Jeff (19 April 2022). "Planetary science decadal endorses Mars sample return, outer planets missions". SpaceNews. Retrieved 19 April 2022.
133. ^ Anderson, Kenneth; Bearden, David; et al. (May 31, 2005). Final report of the New Horizons II review panel (PDF) (Report). Lunar and Planetary Institute.
134. Jones, Andrew (16 April 2021). "China to launch a pair of spacecraft towards the edge of the solar system". SpaceNews. SpaceNews. Retrieved 29 April 2021.
135. Machado-Rodriguez, Jonathan; Landis, Geoffrey A. (2017). "Analysis of a Radioisotope Thermal Rocket Engine". 55th AIAA Aerospace Sciences Meeting. doi:10.2514/6.2017-1445. hdl:2060/20170006624. ISBN 978-1-62410-447-3.
136. Ferreira, Becky (August 28, 2015). "Why We Should Use This Jumping Robot to Explore Neptune". Vice Motherboard. Retrieved 11 February 2017.
137. The next Pluto mission—an orbiter and lander?. Nancy Atkinson, PhysOrg. 27 April 2017.
138. "New videos simulate Pluto and Charon flyby; return mission to Pluto proposed". August 2021. Archived from the original on 4 September 2021. Retrieved 4 September 2021.
139. "Global Aerospace Corporation to present Pluto lander concept to NASA". EurekAlert!. Retrieved 2018-07-08.
140. Savage, Donald (2000-12-20). "NASA seeks proposals for Pluto mission; plans to restructure outer planet program" (Press release). Washington, DC: NASA. Retrieved 2015-07-18.
141. "NASA Halts Work on Mission to Pluto". The New York Times. 2000-09-23. Retrieved 2015-07-18.

v t e Spacecraft missions to Jupiter
Flybys	Pioneer program Pioneer 10 11 Voyager program Voyager 1 2 Ulysses Cassini–Huygens New Horizons
Orbiters	Galileo Juno (active)
Atmospheric probes	Galileo Probe
En route	Jupiter Icy Moons Explorer (JUICE) (2023, insertion 2031) Europa Clipper (2024, insertion 2030)
Planned missions	Tianwen-4 (2029, insertion 2035)
Proposed missions	Shensuo (2020s) Europa Lander (2025) Interstellar Probe (2036)
Cancelled or not developed	Argo Europa Jupiter System Mission-Laplace Jupiter Europa Orbiter Jupiter Ganymede Orbiter Jupiter Magnetospheric Orbiter Europa Orbiter FIRE Innovative Interstellar Explorer Io Volcano Observer Jovian Europa Orbiter Jupiter Icy Moons Orbiter Laplace-P New Horizons 2 OKEANOS Pioneer H SMARA Trident Tsiolkovsky mission
Related topics	Exploration of Jupiter Atmosphere of Jupiter Magnetosphere of Jupiter Moons of Jupiter Io Exploration Europa Ganymede Callisto Rings of Jupiter Deep Space Network Missions to outer planets Colonization of the outer Solar System
Missions are ordered by launch date. Sign indicates failure en route or before intended mission data returned. indicates use of the planet as a gravity assist en route to another destination.

v t e Spacecraft missions to Saturn
Past	Flybys Pioneer 11 Voyager 1 Voyager 2 Orbiters Cassini–Huygens timeline retirement Landers Huygens (on Titan)
Planned	Dragonfly (to Titan, 2028)
Proposed	Saturn, rings Kronos Saturn Atmospheric Entry Probe SPRITE Titan Saturn System Mission Enceladus Enceladus Orbilander Breakthrough Enceladus mission Enceladus Life Finder Enceladus Life Signatures and Habitability Enceladus Explorer Life Investigation For Enceladus Titan AVIATR Oceanus TALISE Titan Mare Explorer Several moons Explorer of Enceladus and Titan Journey to Enceladus and Titan
There are no ongoing missions to Saturn

v t e Jupiter
Outline of Jupiter
Geography	Atmosphere Great Red Spot Magnetosphere Rings Jupiter's North Pole Jupiter's South Pole
Moons	Inner Metis Adrastea Amalthea Thebe Galilean Io Europa Ganymede Callisto Irregular Himalia group Themisto Carpo group Valetudo Ananke group Carme group Pasiphae group
Astronomy	General Jupiter-crossing minor planets Solar eclipses Trojans Greek camp Trojan camp Impacts Comet Shoemaker–Levy 9 2009 Jupiter impact event 2010 Jupiter impact event 2016 Jupiter impact event
Exploration, orbital missions	Current Juno Past Cassini–Huygens Galileo project Galileo New Horizons Pioneer program Pioneer 10 Pioneer 11 Ulysses Voyager program Voyager 1 Voyager 2 Future Jupiter Icy Moons Explorer (2023, en route) Europa Clipper (2024, en route) Tianwen-4 (2029) Proposed Laplace-P (2023) Shensuo (2024) Io Volcano Observer (2026) SMARA (2030) Enceladus Orbilander (2038)
Related	Fiction Mythology
Category Solar System portal

v t e Neptune
Outline of Neptune
Geography	Great Dark Spot Small Dark Spot Rings
Moons	Naiad Thalassa Despina Galatea Larissa Hippocamp Proteus Triton Nereid Halimede Sao S/2002 N 5 Laomedeia Psamathe Neso S/2021 N 1
Astronomy	Discovery Urbain Le Verrier Johann Gottfried Galle John Couch Adams Heinrich Louis d'Arrest William Lassell General Kuiper belt Neptune-crossing minor planets Trojans 385571 Otrera 385695 Clete 2001 QR322 2004 KV18 2005 TN53 2006 RJ103 2007 VL305 2008 LC18 2011 HM102
Exploration	Past Voyager 2 (1989 flyby) Proposals Shensuo Neptune Odyssey ODINUS Triton Hopper Trident Not selected Argo Mariner Mark II New Horizons 2
Related	Fiction Mythology
Category Portal

v t e Pluto
Atmosphere Climate Geology
Geography (features)	Regions "Brass Knuckles" Safronov Sharaf Harrington Vucub-Came Hun-Came Meng-pʻo Belton Cadejo Hayabusa Lowell Morgoth Pioneer Tombaugh "The Heart" Venera Viking Voyager Hills and mountains Baret Montes Challenger Colles Coleta de Dados Colles Hillary Montes Piccard Mons Tenzing Montes Wright Mons Plains Sputnik Planitia Valleys and depressions Adlivun Cavus Lineae Luna Linea Craters Burney
Moons	Charon Hydra Kerberos Nix Styx
Exploration	New Horizons
Astronomy	Official definitions Definition of planet IAU definition of planet Scientist opinions Alan Stern Michael E. Brown Neil deGrasse Tyson Discovery Planet X Lowell Observatory Percival Lowell Clyde Tombaugh Roger Putnam General Double planet Dwarf planet Planet Plutino Trans-Neptunian object Kuiper belt
Related	Fiction Mythology Venetia Burney

• Outer planets
• Missions to the planets
• Lists of space missions