Plutonium-238, a particularly useful plutonium isotope that has been used to power, among other things, NASA’s Mars rover Curiosity, is being produced in America for the first time since 1988, according to Popular Science. NASA plans to use plutonium-238 to power future space missions, including their planned 2020 rover mission to Mars.
NASA will use plutonium-238 in a radioisotope power system, according to a press release. Radioisotope power systems harness the energy from a volatile isotope’s decay. In this case, as plutonium-238 decays into uranium-234, it radiates an intense amount of heat that can be used as electricity in NASA’s electrical batteries. The heat output also keeps systems and instrument panels warm through the frigid void of interplanetary and interstellar space.
Previously, plutonium-238 had been used by NASA to power the Mars rover, the Mars Viking missions, the New Horizons expedition that recently returned stunning photos of Pluto and the outer solar system, and the Voyager spacecraft, which is carrying a golden disk full of information about the Earth and humanity into interstellar space, hopefully for eventual discovery by an intelligent alien race. Powered by plutonium-238, Voyager is still sending back signals to NASA from 12 billion miles out.
Following the slowdown of the Cold War and development and production of nuclear weapons, the United States and Russia largely ceased production of plutonium-238. This is despite the fact that plutonium-238 is not useful in nuclear weapons.
Right now, there are about 77 pounds of it left in the U.S., only half of which is usable to NASA spacecraft without being further treated or mixed with new plutonium-238. According to Forbes, most of what is left will be used by 2024 in NASA’s Mars 2020 mission and in a planned trip to Jupiter’s moon Europa.
Fifty grams, or 1.8 ounces, is not a huge amount of plutonium-238. The Mars 2020 rover NASA is working on will require close to nine pounds of plutonium-238 to operate, according to Popular Science. But NASA and DOE researchers are optimistic they can scale up the process used to make the initial 50 grams and will be able to produce as much as 3.3 pounds of plutonium-238 a year in the near future.
John Grunsfeld, the associate administrator for NASA’s Science Mission Directorate in Washington, was enthusiastic about the production of plutonium-238 and what it means for the future of NASA’s space exploration and discovery of the cosmos.
“This significant achievement by our teammates at DOE signals a new renaissance in the exploration of our solar system… Radioisotope power systems are a key tool to power the next generation of planetary orbiters, landers and rovers in our quest to unravel the mysteries of the universe.”
According to Popular Mechanics, many NASA space probes are powered by solar energy, but this is only effective up to about as far out as Jupiter. For NASA to travel further, a different power source – like the radioisotope power system driven by plutonium-238 – is necessary. In addition to NASA, radioisotope power systems are also used by the Navy and the Air Force, according to the press release.
Franklin Orr, Under Secretary for Science and Energy at DOE, spoke in the press release of his pride in working with NASA and continuing the DOE’s partnership with NASA.
“As we seek to expand our knowledge of the universe, the Department of Energy will help ensure that our spacecraft have the power supply necessary to go farther than ever before,” said Orr.
[Image via NASA/US Department of Energy]