Future Missions

  1. 01

    Dragonfly (~2028)

    Power for this proposed quadcopter mission to Saturn's Moon Titan would be supplied by a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) mounted in a cylinder on the back of the drone. The proposed launch date is no earlier than July 2028.

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Current Missions

  1. 01

    Mars Perseverance Rover (2020-Present)

    The Perseverance rover is powered and warmed by a multi-mission radioisotope thermoelectric generator (MMRTG). The rover has been exploring the surface of Mars since landing in 2021.

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  2. 02

    Mars Curiosity Rover (2011-Present)

    The Curiosity rover is powered and warmed by a multi-mission radioisotope thermoelectric generator (MMRTG). The rover has been exploring the surface of Mars since landing in 2012.

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  3. 03

    New Horizons (2006-Present)

    New Horizons is powered by a single radioisotope thermoelectric generator (RTG), which transforms the heat from the natural radioactive decay of plutonium oxide into electricity. The compact, rugged General Purpose Heat Source (GPHS)-RTG aboard New Horizons, developed and provided to NASA by the U.S. Department of Energy, carries approximately 11 kilograms (24 pounds) of plutonium oxide fuel.

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  4. 04

    Voyager 1 (1977-Present)

    Voyager 1 is powered by a multi-hundred watt radioisotope thermoelectric generator (MHW-RTG) and warmed by nine radioisotope heater units (RHUs). The MHW-RTGs produced about 158 Watts each at launch in 1977. They are still providing power to the spacecraft more than four decades later.

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  5. 05

    Voyager 2 (1977-Present)

    Voyager 2 is powered by a multi-hundred watt radioisotope thermoelectric generator (MHW-RTG) and warmed by nine radioisotope heater units (RHUs). The MHW-RTGs produced about 158 Watts each at launch in 1977. They are still providing power to the spacecraft more than four decades later.

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The Voyagers owe their ability to operate at such great distances from the Sun to their nuclear electric power sources, which provide the electrical power they need to function.

Dr. Edward Stone

Dr. Edward Stone

Voyager Project Scientist

Past Missions

  1. 01

    Mars Opportunity Rover (2003-2018)

    Opportunity was a solar-powered roradioisotope heater units (RHUs) to heat its instruments during cold Martian nights. The rover explored Mars for almost 15 years, far beyond its planned 90 day mission.

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  2. 02

    Mars Spirit Rover (2003-2011)

    Spirit was a solar-powered rover that used eight radioisotope heater units (RHUs) to heat its instruments during cold Martian nights. The rover explored Mars for more than six years, far beyond its planned 90 day mission.

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  3. 03

    Cassini-Huygens (1997-2017)

    The Cassini-Huygens mission was powered and heated by three general purpose heat source radioisotope thermoelectric generators (GPHS-RTG) and 117 radioisotope heater units (RHUs). The Cassini orbiter carried the RTGs and 82 RHUs. The Huygens Titan probe carried 35 RHUs. Cassini explored for more than 20 years in space.

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  4. 04

    Mars Pathfinder Sojourner Rover (1997)

    Sojourner was a solar-powered rover that used three radioisotope heater units (RHUs) to heat its instruments during cold Martian nights. The rover explored Mars for 83 days.

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  5. 05

    Ulysses (1990-2009)

    The international Ulysses mission used a general purpose heat source radioisotope thermoelectric generator (GPHS-RTGs) to power its long orbits from Jupiter to the poles of the Sun. The spacecraft explored the Sun and our solar system for more than 18 years.

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  6. 06

    Galileo (1989-2003)

    Galileo was powered and warmed by two general purpose heat source radioisotope thermoelectric generators (GPHS-RTGs) and 120 radioisotope heater units (RHUs). The orbiter included 103 RHUs while its atmospheric probe carried 17. Galileo's mission ended in 2003 after 14 years in space.

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  7. 07

    Viking 1 (1976-1982)

    The Viking 1 lander was powered by two SNAP-19 radioisotope thermoelectric generators (RTGs). SNAP stands for Systems for Nuclear Auxilliary Power. Viking 1 operated on the surface of Mars from 1976 to 1982.

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  8. 08

    Viking 2 (1976-1980)

    The Viking 2 lander was powered by two SNAP-19 radioisotope thermoelectric generators (RTGs). SNAP stands for Systems for Nuclear Auxilliary Power. Viking 2 operated on the surface of Mars from 1976 to 1980.

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  9. 09

    Pioneer 11 (1973-1995)

    Pioneer 11 was powered and heated by four SNAP-19 radioisotope thermoelectric generators (RTGs), with heat from twelve radioisotope heater units (RHUs). First to fly past Saturn, the spacecraft transmitted data back to Earth for 22 years.

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  10. 010

    Apollo 17 ALSEP (1972)

    The crew of Apollo 17 set up the last Apollo Lunar Surface Experiments Package (ALSEP) on the Moon. It was powered by one SNAP-27 radioisotope thermoelectric generator (RTG). The experiment concluded in 1977.

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  11. 11

    Apollo 16 ALSEP (1971)

    The crew of Apollo 16 set up an Apollo Lunar Surface Experiments Package (ALSEP) on the Moon. It was powered by one SNAP-27 radioisotope thermoelectric generator (RTG). The experiment concluded in 1977.

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  12. 12

    Pioneer 10 (1973-2003)

    Pioneer 10 was powered and heated by four SNAP-19 RTGs, with heat from twelve Radioisotope Heater Units (RHUs). First to fly past Jupiter, the spacecraft transmitted back to Earth for more than 30 years.

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  13. 13

    Apollo 15 ALSEP (1971)

    The crew of Apollo 15 set up an Apollo Lunar Surface Experiments Package (ALSEP) on the Moon. It was powered by one SNAP-27 radioisotope thermoelectric generator (RTG). The experiment concluded in 1977.

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  14. 14

    Apollo 14 ALSEP (1971)

    The crew of Apollo 14 set up an Apollo Lunar Surface Experiments Package (ALSEP) on the Moon. It was powered by one SNAP-27 radioisotope thermoelectric generator (RTG). The experiment concluded in 1977.

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  15. 15

    Apollo 13 ALSEP (1970)

    Apollo 13 returned to Earth with its SNAP-27 radioisotope thermoelectric generator (RTG) in the Lunar Excursion Module (LEM). Following the astronauts' safe return, the lunar module carrying the RTG fell into deep water in Pacific Ocean.

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  16. 16

    Apollo 12 ALSEP (1969)

    The crew of Apollo 12 set up the first Apollo Lunar Surface Experiments Package (ALSEP) on the Moon. It was powered by one SNAP-27 radioisotope thermoelectric generator (RTG). The experiment concluded in 1977.

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  17. 17

    Apollo 11 EASEP (1969)

    The crew of Apollo 11 set up the prototype Early Apollo Surface Experiment Package (EASEP) package on the Moon. It was heated by two radioisotope heater units (RHUs).

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  18. 18

    Nimbus III (1969-1972)

    Nimbus III was powered by 10,500 solar cells and two SNAP-19B3 radioisotope thermoelectric generators (RTGs). The weather satellite operated until 1970.

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  19. 19

    Nimbus B-1 (1968)

    The failure of the Nimbus B-1 launch vehicle forced its destruction by a range safety officer. The spacecraft and and upper stage sank in Santa Barbara Channel. Its SNAP-19B radioisotope thermoelectric generators (RTG)s were recovered and its fuel was reused for Nimbus III

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RPS Missions by Destination

The logos of NASA and the U.S. Department of Energy at at the center of a hub listing each mission powered by a Radioisotope Power System or heated by a Radioisotope Heating Unit and the destination they explores. Destinations span Venus to the Kuiper Belt and beyond.
RPS-powered spacecraft have explored every planet in our solar system from Venus outward— including the weather systems of Earth—and the polar regions of the Sun, as well as Pluto and the Kuiper Belt.
NASA

RPS-enabled missions have contributed to scientific knowledge across the solar system — and beyond.

Sun
Ulysses (1990-2009 orbit)
Venus
Cassini (2000 flyby)
Galileo (1990 flyby)
Earth
Cassini (1998 flyby )
Galileo (1990 and 1992 flybys )
Nimbus III (1969-1972)
Earth's Moon
Apollo 11-17 (Apollo Lunar Surface Experiment Package (1969-1977)
Mars
Perseverance Rover (2020 - Present)
Curiosity Rover (2012 - Present)
+Opportunity Rover (2004-2018)
+Spirit Rover (2004-2011)
+Sojourner Rover (1997)
Viking 2 Lander (1976-1982)
Viking 1 Lander (1976-1980)
Asteroids
Galileo (1991 and 1993 flybys)
Jupiter and its Moons
New Horizons (2007 Flyby)
Galileo (1995-2003 orbit) | +Galileo atmospheric probe (1995 descent)
Ulysses (1991 flyby, 2004 flyby)
Cassini (2000 Flyby)
Voyager 1 (1979 flyby)
Voyager 2 (1979 flyby)
Saturn and its Moons
Cassini-Huygens (2004-2017) | +Huygens Titan probe (2005)
Voyager 1 (1980)
Voyager 2 (1980)
Pioneer 11 (1973)
Uranus and its Moons
Voyager 2 (1986 flyby)
Neptune and its Moons
Voyager 2 (1989 flyby)
Pluto and its Moons
New Horizons (2015 flyby)
Kuiper Belt
New Horizons (2019 flyby)
Comets
Galileo (1994 observation)
Interstellar Space
Voyager 1 (2012-Present)
Voyager 2 (2018-Present)
Note: Pioneers 10 and 11 and New Horizons also are on interstellar trajectories.
+Solar- or battery-powered missions enabled by Radioisotope Heater Units (RHUs)

NASA RPS Missions by Type

A radial hub with the Sun at the center shows the science destinations of Radioisotope Power System missions. There have been five flyby missions, four orbiters, three rovers and three landers.
Radioisotope Power Systems (RPS) have provided the power to explore, discover, and understand our solar system and beyond. This graphic shows the type and destinations of RPS missions where science was performed.
NASA/JPL-Caltech

NASA RPS Missions List

Mission
Power
Source
RHUs
Type
Launch Date
Outcome
SNAP-19 B2
Meteorology (Earth)
5/18/1968
Unsuccessful
SNAP-19 B3
Meteorology (Earth)
4/14/1969
Successful
Solar
2
Lunar Experiment
7/16/1969
Successful
SNAP-27
Lunar Experiment
11/14/1969
Successful
SNAP-27
Lunar Experiment
4/11/1970
Unsuccessful
SNAP-27
Lunar Experiment
1/31/1971
Successful
SNAP-27
Lunar Experiment
7/26/1971
Successful
SNAP-19
12
Jupiter Flyby
3/2/1972
Successful
SNAP-27
Lunar Experiment
4/16/1972
Successful
SNAP-27
Lunar Experiment
12/7/1972
Successful
SNAP-19
12
Jupiter Flyby
Saturn Flyby
4/5/1973
Successful
SNAP-19
Mars Landing
8/20/1975
Successful
SNAP-19
Mars Landing
9/9/1975
Successful
MHW-RTG
9
Jupiter Flyby
Saturn Flyby
Uranus Flyby
Neptune Flyby
Interstellar Space
8/20/1977
In Flight
MHW-RTG
9
Jupiter Flyby
Saturn Flyby
Interstellar Space
9/5/1977
In Flight
GPHS-RTG
120
Jupiter Orbiter
10/18/1989
Successful
GPHS-RTG
Jupiter Flybys
Solar Orbiter
10/6/1990
Successful
Solar
3
Mars Rover
12/4/1996
Successful
GPHS-RTG
117
Saturn Orbiter
10/15/1997
Successful
Solar
8
Mars Rover
6/10/2003
Successful
Solar
8
Mars Rover
7/7/2003
Successful
GPHS-RTG
Pluto Flyby
KBO Flyby
1/19/2006
In Flight
MMRTG
Mars Rover
11/26/2011
Exploring Martian Surface
MMRTG
Mars Rover
7/30/2020
Exploring Martian Surface
MMRTG
Titan Moon Rover (Saturn)
~2028
Future Mission
Missions in bold are currently operating.