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Multi-mission radioisotope thermoelectric generator

January 01, 1970

The multi-mission radioisotope thermoelectric generator (MMRTG) is a type of radioisotope thermoelectric generator (RTG) developed for NASA space missions[1] such as the Mars Science Laboratory (MSL), under the jurisdiction of the United States Department of Energy's Office of Space and Defense Power Systems within the Office of Nuclear Energy. The MMRTG was developed by an industry team of Aerojet Rocketdyne and Teledyne Energy Systems.

Diagram of a MMRTG.

Background edit

Space exploration missions require safe, reliable, long-lived power systems to provide electricity and heat to spacecraft and their science instruments. A uniquely capable source of power is the radioisotope thermoelectric generator (RTG) – essentially a nuclear battery that reliably converts heat into electricity.[2] Radioisotope power has been used on eight Earth orbiting missions, eight missions to the outer planets, and the Apollo missions after Apollo 11 to the Moon. The outer Solar System missions are the Pioneer 10 and 11, Voyager 1 and 2, Ulysses, Galileo, Cassini and New Horizons missions. The RTGs on Voyager 1 and Voyager 2 have been operating since 1977.[3] In total, over the last four decades, 26 missions and 45 RTGs have been launched by the United States.

Function edit

Solid-state thermoelectric couples convert the heat produced by the natural decay of the radioisotope plutonium-238 to electricity.[4] The physical conversion principle is based on the Seebeck effect, obeying one of the Onsager reciprocal relations between flows and gradients in thermodynamic systems. A temperature gradient generates an electron flow in the system. Unlike photovoltaic solar arrays, RTGs are not dependent upon solar energy, so they can be used for deep space missions.

History edit

In June 2003, the Department of Energy (DOE) awarded the MMRTG contract to a team led by Aerojet Rocketdyne. Aerojet Rocketdyne and Teledyne Energy Systems collaborated on an MMRTG design concept based on a previous thermoelectric converter design, SNAP-19, developed by Teledyne for previous space exploration missions.[5] SNAP-19s powered Pioneer 10 and Pioneer 11 missions[4] as well as the Viking 1 and Viking 2 landers.

Design and specifications edit

The MMRTG is powered by eight Pu-238 dioxide general-purpose heat source (GPHS) modules, provided by the US Department of Energy (DOE). Initially, these eight GPHS modules generate about 2 kW thermal power.

The MMRTG design incorporates PbTe/TAGS thermoelectric couples (from Teledyne Energy Systems), where TAGS is an acronym designating a material incorporating tellurium (Te), silver (Ag), germanium (Ge) and antimony (Sb). The MMRTG is designed to produce 125 W electrical power at the start of mission, falling to about 100 W after 14 years.[6] With a mass of 45 kg[7] the MMRTG provides about 2.8 W/kg of electrical power at beginning of life.

The MMRTG design is capable of operating both in the vacuum of space and in planetary atmospheres, such as on the surface of Mars. Design goals for the MMRTG included ensuring a high degree of safety, optimizing power levels over a minimum lifetime of 14 years, and minimizing weight.[2]

Usage in space missions edit

 
The multi-mission radioisotope thermoelectric generator of Mars Science Laboratory.

Curiosity, the MSL rover that was successfully landed in Gale Crater on August 6, 2012, uses one MMRTG to supply heat and electricity for its components and science instruments. Reliable power from the MMRTG will allow it to operate for several years.[2]

On February 20, 2015, a NASA official reported that there is enough plutonium available to NASA to fuel three more MMRTGs like the one used by the Curiosity rover.[8][9] One was used by Mars 2020 and its Perseverance rover.[8] The other two have not been assigned to any specific mission or program,[9] and could be available by late 2021.[8]

A MMRTG was successfully launched into space on July 30, 2020, aboard the Mars 2020 mission, and is now being used to supply the scientific equipment on the Perseverance rover with heat and power. The MMRTG used by this mission is the F-2 built by Teledyne Energy Systems, Inc. and Aerojet Rocketdyne under contract with the US Department of Energy (DOE) with a lifespan of up to 17 years.[10]

The upcoming NASA Dragonfly mission to Saturn's moon Titan will use one of the two MMRTGs for which the Aerojet Rocketdyne/Teledyne Energy Systems team has recently received a contract.[11] The MMRTG will be used to charge a set of lithium ion batteries, and then use this higher-power-density supply to fly a quad helicopter in short hops above the surface of Titan.[12]

Cost edit

The MMRTG cost an estimated US$109,000,000 to produce and deploy, and US$83,000,000 to research and develop.[13] For comparison the production and deployment of the GPHS-RTG was approximately US$118,000,000.

See also edit

References edit

  1. ^ (PDF). Jet Propulsion Laboratory. March 2011. Archived from the original (PDF) on 2019-05-18. Retrieved 2015-03-13.
  2. ^ a b c   This article incorporates public domain material from Space Radioisotope Power Systems Multi-Mission Radioisotope Thermoelectric Generator (PDF). National Aeronautics and Space Administration. Retrieved 2016-07-05. (pdf) October 2013
  3. ^ Bechtel, Ryan. (PDF). US Department of Energy. Archived from the original (PDF) on 2012-02-01.
  4. ^ a b SNAP-19: Pioneer F & G, Final Report 2018-04-01 at the Wayback Machine, Teledyne Isotopes, 1973
  5. ^ (PDF). Archived from the original (PDF) on 2011-12-16. Retrieved 2011-11-21.{{cite web}}: CS1 maint: archived copy as title (link)
  6. ^ (PDF). Archived from the original (PDF) on 2012-08-09. Retrieved 2009-05-12.{{cite web}}: CS1 maint: archived copy as title (link)
  7. ^ (PDF). Archived from the original (PDF) on 2014-02-02. Retrieved 2013-04-22.{{cite web}}: CS1 maint: archived copy as title (link)
  8. ^ a b c Leone, Dan (11 March 2015). "U.S. Plutonium Stockpile Good for Two More Nuclear Batteries after Mars 2020". Space News. Retrieved 2015-03-12.
  9. ^ a b Moore, Trent (12 March 2015). . Blastr. Archived from the original on 2015-03-14. Retrieved 2015-03-13.
  10. ^ Campbell, Colin. "NASA's Mars 2020 rover, Perseverance, set to launch into space Thursday with power source built in Hunt Valley". Baltimore Sun. Retrieved 16 February 2021.
  11. ^ "Aerojet Rocketdyne Receives Contract for up to Two More MMRTGs for Future Deep Space Exploration Missions". Bloomberg.com. 12 February 2021. Retrieved 16 February 2021.
  12. ^ ""Dragonfly: NASA's Newest Nuclear Powered Spacecraft"". Beyond NERVA. July 9, 2019. Retrieved 2020-10-28.
  13. ^ Werner, James Elmer; Johnson, Stephen Guy; Dwight, Carla Chelan; Lively, Kelly Lynn (July 2016). Cost Comparison in 2015 Dollars for Radioisotope Power Systems -- Cassini and Mars Science Laboratory (Report). doi:10.2172/1364515. OSTI 1364515.

External links edit

 
Wikimedia Commons has media related to Multi-Mission Radioisotope Thermoelectric Generator (MMRTG).
  • Idaho National Laboratory MMRTG page with photo-based "virtual tour"
  • DOE to crank out new plutonium-238 in 2019

January 01, 1970
multi, mission, radioisotope, thermoelectric, generator, multi, mission, radioisotope, thermoelectric, generator, mmrtg, type, radioisotope, thermoelectric, generator, developed, nasa, space, missions, such, mars, science, laboratory, under, jurisdiction, unit. The multi mission radioisotope thermoelectric generator MMRTG is a type of radioisotope thermoelectric generator RTG developed for NASA space missions 1 such as the Mars Science Laboratory MSL under the jurisdiction of the United States Department of Energy s Office of Space and Defense Power Systems within the Office of Nuclear Energy The MMRTG was developed by an industry team of Aerojet Rocketdyne and Teledyne Energy Systems Diagram of a MMRTG Contents 1 Background 2 Function 3 History 4 Design and specifications 5 Usage in space missions 6 Cost 7 See also 8 References 9 External linksBackground editSpace exploration missions require safe reliable long lived power systems to provide electricity and heat to spacecraft and their science instruments A uniquely capable source of power is the radioisotope thermoelectric generator RTG essentially a nuclear battery that reliably converts heat into electricity 2 Radioisotope power has been used on eight Earth orbiting missions eight missions to the outer planets and the Apollo missions after Apollo 11 to the Moon The outer Solar System missions are the Pioneer 10 and 11 Voyager 1 and 2 Ulysses Galileo Cassini and New Horizons missions The RTGs on Voyager 1 and Voyager 2 have been operating since 1977 3 In total over the last four decades 26 missions and 45 RTGs have been launched by the United States Function editSolid state thermoelectric couples convert the heat produced by the natural decay of the radioisotope plutonium 238 to electricity 4 The physical conversion principle is based on the Seebeck effect obeying one of the Onsager reciprocal relations between flows and gradients in thermodynamic systems A temperature gradient generates an electron flow in the system Unlike photovoltaic solar arrays RTGs are not dependent upon solar energy so they can be used for deep space missions History editIn June 2003 the Department of Energy DOE awarded the MMRTG contract to a team led by Aerojet Rocketdyne Aerojet Rocketdyne and Teledyne Energy Systems collaborated on an MMRTG design concept based on a previous thermoelectric converter design SNAP 19 developed by Teledyne for previous space exploration missions 5 SNAP 19s powered Pioneer 10 and Pioneer 11 missions 4 as well as the Viking 1 and Viking 2 landers Design and specifications editThe MMRTG is powered by eight Pu 238 dioxide general purpose heat source GPHS modules provided by the US Department of Energy DOE Initially these eight GPHS modules generate about 2 kW thermal power The MMRTG design incorporates PbTe TAGS thermoelectric couples from Teledyne Energy Systems where TAGS is an acronym designating a material incorporating tellurium Te silver Ag germanium Ge and antimony Sb The MMRTG is designed to produce 125 W electrical power at the start of mission falling to about 100 W after 14 years 6 With a mass of 45 kg 7 the MMRTG provides about 2 8 W kg of electrical power at beginning of life The MMRTG design is capable of operating both in the vacuum of space and in planetary atmospheres such as on the surface of Mars Design goals for the MMRTG included ensuring a high degree of safety optimizing power levels over a minimum lifetime of 14 years and minimizing weight 2 Usage in space missions editThis section needs to be updated Please help update this article to reflect recent events or newly available information March 2023 nbsp The multi mission radioisotope thermoelectric generator of Mars Science Laboratory Curiosity the MSL rover that was successfully landed in Gale Crater on August 6 2012 uses one MMRTG to supply heat and electricity for its components and science instruments Reliable power from the MMRTG will allow it to operate for several years 2 On February 20 2015 a NASA official reported that there is enough plutonium available to NASA to fuel three more MMRTGs like the one used by the Curiosity rover 8 9 One was used by Mars 2020 and its Perseverance rover 8 The other two have not been assigned to any specific mission or program 9 and could be available by late 2021 8 A MMRTG was successfully launched into space on July 30 2020 aboard the Mars 2020 mission and is now being used to supply the scientific equipment on the Perseverance rover with heat and power The MMRTG used by this mission is the F 2 built by Teledyne Energy Systems Inc and Aerojet Rocketdyne under contract with the US Department of Energy DOE with a lifespan of up to 17 years 10 The upcoming NASA Dragonfly mission to Saturn s moon Titan will use one of the two MMRTGs for which the Aerojet Rocketdyne Teledyne Energy Systems team has recently received a contract 11 The MMRTG will be used to charge a set of lithium ion batteries and then use this higher power density supply to fly a quad helicopter in short hops above the surface of Titan 12 Cost editThe MMRTG cost an estimated US 109 000 000 to produce and deploy and US 83 000 000 to research and develop 13 For comparison the production and deployment of the GPHS RTG was approximately US 118 000 000 See also edit nbsp Nuclear technology portal Advanced Stirling radioisotope generator Nuclear power in space Radioisotope thermoelectric generator RTG Thermoelectric effect Seebeck effect generating an electrical current from a temperature gradient Peltier effect generating a temperature gradient from an electrical current Thomson effect heating or cooling of a current carrying conductor with a temperature gradientReferences edit Radioisotope Power Systems for Space Exploration PDF Jet Propulsion Laboratory March 2011 Archived from the original PDF on 2019 05 18 Retrieved 2015 03 13 a b c nbsp This article incorporates public domain material from Space Radioisotope Power Systems Multi Mission Radioisotope Thermoelectric Generator PDF National Aeronautics and Space Administration Retrieved 2016 07 05 pdf October 2013 Bechtel Ryan Radioisotope Missions PDF US Department of Energy Archived from the original PDF on 2012 02 01 a b SNAP 19 Pioneer F amp G Final Report Archived 2018 04 01 at the Wayback Machine Teledyne Isotopes 1973 Archived copy PDF Archived from the original PDF on 2011 12 16 Retrieved 2011 11 21 a href Template Cite web html title Template Cite web cite web a CS1 maint archived copy as title link Archived copy PDF Archived from the original PDF on 2012 08 09 Retrieved 2009 05 12 a href Template Cite web html title Template Cite web cite web a CS1 maint archived copy as title link Archived copy PDF Archived from the original PDF on 2014 02 02 Retrieved 2013 04 22 a href Template Cite web html title Template Cite web cite web a CS1 maint archived copy as title link a b c Leone Dan 11 March 2015 U S Plutonium Stockpile Good for Two More Nuclear Batteries after Mars 2020 Space News Retrieved 2015 03 12 a b Moore Trent 12 March 2015 NASA can only make three more batteries like the one that powers the Mars rover Blastr Archived from the original on 2015 03 14 Retrieved 2015 03 13 Campbell Colin NASA s Mars 2020 rover Perseverance set to launch into space Thursday with power source built in Hunt Valley Baltimore Sun Retrieved 16 February 2021 Aerojet Rocketdyne Receives Contract for up to Two More MMRTGs for Future Deep Space Exploration Missions Bloomberg com 12 February 2021 Retrieved 16 February 2021 Dragonfly NASA s Newest Nuclear Powered Spacecraft Beyond NERVA July 9 2019 Retrieved 2020 10 28 Werner James Elmer Johnson Stephen Guy Dwight Carla Chelan Lively Kelly Lynn July 2016 Cost Comparison in 2015 Dollars for Radioisotope Power Systems Cassini and Mars Science Laboratory Report doi 10 2172 1364515 OSTI 1364515 External links edit nbsp Wikimedia Commons has media related to Multi Mission Radioisotope Thermoelectric Generator MMRTG NASA Radioisotope Power Systems website RTG page Idaho National Laboratory MMRTG page with photo based virtual tour DOE to crank out new plutonium 238 in 2019 Retrieved from https en wikipedia org w index php title Multi mission radioisotope thermoelectric generator amp oldid 1223316138, wikipedia, wiki, book, books, library,

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