Space Programs

Satellites and Spacecraft

What is the typical electrical power source for spacecraft?

For most satellites and spacecraft that operate inside the orbit of Mars, solar panels are the easiest way to generate electrical power. They convert sunlight into electric current, which can then be stored in batteries for use by the craft’s many power-consuming activities. Beyond a few hundred million miles from the Sun, however, solar panels do not work very well because the sunlight is too weak. For those more distant missions—such as the Galileo, the Cassini, and the Voyager spacecraft—a power source called a radioisotope thermoelectric generator (RTG) has historically been used very effectively.


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