Batteries Not Included

Exploring space is a lot like camping -- you need to bring everything with you. And that includes power. So how do scientists 'pack' for deep space missions? And how do you power these probes? NASA's Jim Green explains.

Exploring space is a lot like camping — you need to bring everything with you. And that includes power. I did some reporting on a shortage of a vital resource to provide power in space when solar panels just won’t work. We’ll talk to one NASA scientist who says that shortage is over and the possibilities of exploration are now limitless.

Deep space rovers use this thing called a radioisotope thermoelectric generator – or RTG for short. This is how it works: So when something radioactive decays, it gives of heat. In this case, it’s a marshmallow sized chunk of Plutonium-238. On these rovers is one of these RTGs which turns the heat of the material decaying into electric power.

Now the great thing about RTGS is Plutonium decays for a really long time, like decades, so it’s constantly providing heat and thus providing power.

But at the end of the Cold War, the US scaled back its nuclear weapons production. Well, Plutonium 238 was a product of weapons manufacturing, so there was a diminished supply.

Not until recently did the U.S. Department of Energy get the funding and the go-ahead to produce more Plutonium for NASA to use. And it figured out a way to make it without a big nuclear reactor like they were using before. So they’re ramping up production for folks like Jim Green

Jim Green is the Director of NASA’s Planetary Sciences division. His job is to oversee all these deep space probes and rovers. He gave me a call to talk about how important RTGs are to deep-space exploration.