Space Travel 101: Fundamentals of Space Travel

Analysis A radioisotope thermoelectric generator, or RTG, takes the heat that is generated from the natural decay of radioisotope materials and converts it into electricity. RTGs are composed of a heat source, such as plutonium-238, and thermocouples, which convert the heat from the heat source to electricity, which can be used to power the spacecraft. RTGs can supply a spacecraft with continuous power for over twenty years. They have been used over the past three decades in spacecraft that travel far into the solar system, where solar panels can not be used. Because no fusion or fission processes take place in RTGs, scientists do not need to worry about them exploding. However, RTGs produce a lot of heat and radiation, so they are usually mounted on a boom that extends away from the spacecraft's main body, and surrounded by a shield that blocks the heat and radiation. The major problem with RTGs is that the radioactive materials that they require in order to function are very expensive.