NASA’s deep space explorations might be in trouble as Plutonium-238 reserves deplete

There is currently no viable replacement for Plutonium-238 with NASA, says a report in Wired. Solar power is too weak to power the systems on board, nuclear fission systems would be too bulky and chemical batteries will never have a large enough capacity, according to NASA. Plutonium-238 is found naturally in extremely small quantities, but largely produced as a byproduct of making nuclear weapons.

The only natural supplies of plutonium-238 vanished eons before the Earth was formed some 4.6 billion years ago. The US Department of Energy (DOE) was able to produce 50 gms of the precious metal in 2015 – the first time in the preceding 27 years, according to Wired. The amount is not very large, as probes like the Mars 2020 rover require upto 4 Kgs of the fuel, but it is a start.