Future Missions

  1. Artist’s concept of Dragonfly soaring over the dunes of Saturn’s moon Titan.
    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.

    Proposed Launch: July 2028

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Current Missions

  1. Perseverance Mars rover took a selfie over a rock with two holes where the rover used its robotic arm to drill rock core samples.
    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.

    Launch: July 30, 2020 | 11:50 UTC
    Mars Landing: Feb. 8, 2021 | 20:55 UTC

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  2. Curiosity Mars rover's selfie
    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.

    Launch: Nov. 26, 2011 | 15:02 UTC
    Mars Landing: Aug. 6, 2012 | 05:32 UTC

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  3. New Horizons
    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.

    Launch: Jan. 19, 2006 | 19:00 UTC
    Pluto Flyby: July 14, 2015 | 11:48:45 UTC
    Arrokoth Flyby: Jan. 1, 2019 | O:533 UTC

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  4. Artist's concept of the Voyager spacecraft
    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.
    Voyager power was in stable operation at 225 We in November 2023.

    Launch: Sept. 5, 1977 | 12:56:01 UTC
    Jupiter Flyby: Mar. 5, 1979
    Saturn Flyby: Nov. 12, 1980
    Entered Interstellar Space: Aug. 25, 2012

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  5. A Voyager spacecraft is shown in deep space among distant stars and gases.
    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.
    Voyager 2's power was in stable operation at 225 We in April 2024.

    Launch: Aug. 20, 1977 | 14:29:44 UTC
    Jupiter Flyby: July 9, 1979
    Saturn Flyby: Aug. 26, 1981
    Uranus Flyby: Jan. 24, 1986
    Neptune Flyby: Aug. 25, 1989
    Entered Interstellar Space: Nov. 5, 2018

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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 (1936-2024)

Dr. Edward Stone (1936-2024)

Former Voyager Project Scientist

Past Missions

  1. An artistic illustration of a golf cart-sized rover on the surface of Mars.
    01

    Mars Opportunity Rover (2003-2019)

    Opportunity 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 almost 15 years, far beyond its planned 90 day mission.

    Launch: July 8, 2003 | 03:18:15 UTC
    Landing: Jan. 25, 2004 | 04:54:22.7 UTC
    End of Mission: Feb. 13, 2019

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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.

    Launch: July 7, 2003 | 17:58:46 UTC
    Landing: Jan. 4, 2004 | 04:35 UTC
    End of Mission: May 25, 2011

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  3. Spacecraft heating up in Saturn's atmosphere.
    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.

    Launch: Oct. 15, 1997 | 08:43:00 UTC
    Saturn Orbit Insertion: July 1, 2004 | 02:48 UTC
    End of Mission: Sept. 15, 2017 | 11:55:46 UTC

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  4. A microwave-sized rover pushes up against a rock in this landscape on Mars. The rover's landing platform and tire tracks in the soil also are visible.
    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.

    Launch: July 7, 2003 | 6:58:00 UT
    Landing: July 4, 1997 | 16:56:55 UTC
    End of Mission: Sept. 27, 1997

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  5. Artist's concept of Ulysses spacecraft.
    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.

    Launch: Oct. 6, 1990 | 11:47:16 UTC
    First Solar Polar Pass (Southern): June-Nov. 1994
    First Solar Polar Pass (Northern): Jun 19-Sept. 1995
    Closest approach to Sun (124 million miles or 200 million km): Mar, 12, 1995
    End of Mission: Jun 30, 2009

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  6. Artist's concept of a spacecraft at Jupiter
    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 after 14 years in space.

    Launch: Oct. 18, 1989 | 16:53:40 UTC
    Jupiter Orbit Insertion: Dec. 8, 1995
    End of Mission: Sept. 21, 2003 | 19:43:14 UTC

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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 for more than six years.

    Launch: Aug. 20, 1975 | 21:22:00 UTC
    Mars Orbit Insertion: June 19, 1976
    Landing: July 20, 1976 | 11:53:06 UTC
    End of Orbiter Mission: Aug. 7, 1980
    End of Lander Mission: Nov. 11, 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 for almost four years.

    Launch: Sept. 9, 1975 | 18:39:00 UTC
    Mars Orbit Insertion: Aug. 7, 1976
    Mars Landing: Sept. 3, 1976 | 22:58:20 UT
    End of Orbiter Mission: July 24, 1978
    End of Lander Mission: April 12, 1980

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  9. A spacecraft travels through the darkness of deep space with the faint glow of the Milky Way in the background.
    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.

    Launch: April 6, 1973 | 02:11:00 UTC
    Jupiter Flyby: Dec. 3, 1974
    Saturn Flyby: Sept. 1, 1979
    End of Mission: Nov. 24, 1995

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  10. An experiment collects data on the surface of the Moon.
    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.

    Launch: Dec. 7, 1972 | 05:33:00 UTC
    Landing: Dec. 11, 1972 | 19:54:58 UTC
    End of Mission: Dec. 19, 1972
    End of ALSEP Experiments: 1977

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  11. An experiment collects data on the surface of the Moon.
    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.

    Launch: April 16, 1972 | 17:54:00 UTC
    Landing: April 21, 1972 | 02:23:35 UTC
    End of Mission: April 27, 1972
    End of ALSEP Experiments: 1977

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  12. Illustrated Pioneer 10 at Jupiter
    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.

    Launch: Mar, 2, 1972 | 01:49:04 UTC
    First Through Main Asteroid Belt: July 1872
    First to Jupiter (Flyby): Dec. 4, 1973
    End of Mission: Jan. 23, 2003

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  13. An astronaut in a spacesuit leans over to install an experiment on the Moon.
    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.

    Launch: July 26, 1971 | 13:34:00.6 UTC
    Landing: July 30, 1971 | 22:16:29 UTC
    End of Mission: Aug. 7, 1971
    End of ALSEP Experiments: 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.

    Launch: Jan. 31, 1971 | 21:03:02 UTC
    Landing: Feb. 5, 1971 | 09:18:11 UTC
    End of Mission: Feb. 9, 1971
    End of ALSEP Experiments: 1977

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  15. A trio of smiling astronauts step off a helicopter onto the deck of an aircraft carrier in the ocean.
    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.

    Launch: April 11, 1970 | 18:07:41 UTC
    Landing: N/A
    End of Mission: April 17, 1970
    End of ALSEP Experiment: N/A

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  16. An astronaut in a spacesuit removes a cylinder from the side of a lunar lander on the Moon.
    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.

    Launch: Nov. 14, 1969 | 16:22:00 UTC
    Landing: Nov. 19, 1969 | 06:54:35 UTC
    End of Mission: Nov. 24, 1969
    End of ALSEP Experiments: 1977

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  17. An astronaut in a spacesuit installs an experiment on the surface of the Moon. The lunar landing module is visible in the background.
    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).

    Launch: July 16, 1969 | 13:32:00 UTC
    Landing: July 20, 1969 | 20:17:40 UTC
    End of Mission: July 24, 1969
    End of EASEP Experiment: Aug. 27, 1969

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  18. 18

    Nimbus III (1969-1972)

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

    Launch: April 14, 1969 | 07:54:03 UTC
    End of Mission: Jan. 22, 1972

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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.

    Launch: May 18, 1968 | 08:23:00 UTC
    End of Mission: May 18, 1968

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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.