system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does the reactor onboard of Curiosity work?
gpt
There's a block of plutonium that naturally stays hot all the time. It's wrapped in a material that creates electricity from heat. It's also used to keep the rover warm during the cold night.

It's expected that the plutonium will stay hot for at least 10-15 years.