European scientists are developing a breed of battery for space missions that is powered by nuclear waste. The European Space Agency (ESA) hopes that the technology will, by the end of the decade…Ministers at ESA’s ministerial council meeting in Paris on 22 and 23 November, 2022 agreed to fund a €29-million (US$30-million) program called European Devices Using Radioisotope Energy (ENDURE). This aims to develop long-lasting heat and electricity units powered by the radioactive element americium-241, in time for a series of ESA Moon missions in the early 2030s.

Americium, a by-product of plutonium decay, has never been used as a fuel. For missions in which solar power would not suffice — either because of shade or because of distance from the Sun — ESA has relied on US or Russian partners, which have used plutonium-238 batteries to power missions since the space race. 

The lack of a power source has long restricted the solo missions that European scientists propose, and limited others. The agency felt its lack of radioisotope power keenly in 2014, when its comet-landing Philae probe was operational for less than three days because it ended up in a shaded spot where its solar panels were useless. “For years, European scientists have been saying that if you want to go far, or to dark and cold places, there is no other way,” says Coustenis.

Americium’s big advantage over plutonium is that it is cheaper and more abundant, repurposing waste that would otherwise be useless…Americium has a longer half-life than plutonium-238, which means it lasts longer but packs less power per gram. But because americium is more readily available, producing one watt of power costs about one-fifth as much as it does using plutonium…

Excerpts from Elizabeth Gibney, How Nuclear Waste Will Help Spacecraft Explore the Moon and Beyond, Nature, Dec. 6, 2022