NASA Relaxing Some Rules as to Where an RTG Can be Used on Future Space Probe Missions

Ideas for new NASA mission can now include spacecraft powered by plutonium

Researchers proposing spacecraft ideas for NASA's Discovery program - an initiative to develop deep-space missions that usually cost less than half a billion dollars - will be allowed to incorporate a special kind of radioactive battery in the designs for their vehicles.

From article, (NASA is giving scientists more choices for how to power their future spacecraft to explore the Solar System. Researchers proposing spacecraft ideas for NASA’s Discovery program — an initiative to develop deep-space missions that usually cost less than half a billion dollars — will be allowed to incorporate a special kind of radioactive battery in the designs for their vehicles. And that could potentially allow these missions to get more science done and go deeper into space.

Discovery proposals can now incorporate a type of power system known as a radioisotope thermoelectric generators, or RTGs. These generators are powered by radioactive material — a type of metal called plutonium-238. The metal naturally decays over time, producing heat that is then converted into electrical energy.

 NASA has been using RTGs to power some of its spacecraft since the 1960s. However, NASA banned the use of these systems in the upcoming proposals for the Discovery program, since the United States has had a very limited supply of plutonium-238. Now it seems the US may have enough of the material to spare for the program. After consulting with the Department of Energy, NASA decided to lift the ban on RTGs for the Discovery program, according to a memo sent out over the weekend by James Green, the director of NASA’s Planetary Science Division.

The Department of Energy said that its recent success in producing more plutonium-238 in the US helped NASA make this decision. DOE’s Oak Ridge National Laboratory in Tennessee has produced 350 grams of the material, some of which will be incorporated in NASA’s next Mars rover. “These recent successes have reduced risks associated with future plutonium supplies and factored into NASA’s announcement last week to include radioisotope power systems in its Discovery 2018 Announcement of Opportunity,” a spokesperson for DOE said in a statement to The Verge. “The Department is committed to supporting NASA’s efforts to make radioisotope power systems available to support its space exploration goals.”

The change may be possible since there is a while before the new Discovery mission has to be ready, allowing time for more Pu-238 to be produced. NASA plans to post a final draft of the Discovery program’s call for submissions in 2019, and then the finalist will be chosen in 2021. The target launch date for the mission is some time before the end of 2026.)

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