One of the greatest challenges of any space mission is creating enough power to operate it. While gasoline powered engines suffice on Earth, there are no refueling stations in space.
A potential solution is to harness the power of the Sun using solar panels, or even solar sails. But this is not always possible for various reasons. So researchers have begun designing highly efficient power plants, called Stirling Engines, which use the heat from radioactive decay and convert that energy into electricity.