Where do spacecraft get their power?

Spacecraft cannot carry large supplies of fuel and these aren’t any filling station in space. Instead, many have large panels of solar cells. These capture sunlight and turn it into electricity. The sun always shines in space, so there is always electricity to power the spacecraft. Some space probes travel to the outer planets far from the Sun. There the sunlight is too weak for solar cells, and the probes have small nuclear power plants instead. These plants produce electricity from a small amount of a long-lasting nuclear fuel such as plutonium.