Mars is about as far away as you can get from Pennsylvania. But energy is energy, and it’s worth highlighting the fact that NASA’s Curiosity rover runs on nuclear power. The radioactive device’s title is a mouthful: it’s a “multi-mission radioisotope thermoelectric generator.”
NASA’s Curiosity rover has landed on Mars and sent back a picture of its nuclear power pack.
The rover’s first grainy photo, from a hazcam at the rear of the rover that will be used to limit risks, shows the left rear wheel, a little bit of soil and a cooling fin from the rover’s radioisotope thermoelectric generator. The generator is the only power source for the one-ton rover, which is supposed to cruise the surface for 23 months.
The previous two rovers, Spirit and Opportunity, used solar panels. But those were sometimes covered with dust, and the rovers ran short of power, especially on short days in the Martian winter. NASA decided that solar power was not suitable for the larger Curiosity, so the vehicle makes electricity from heat that is generated by the radioactive decay of plutonium 238. (That isotope, which is man-made, is not good fuel for a reactor or a bomb because it does not readily split. It does, however, decay rapidly and generate heat.)
This NASA video explains how the generator works: