Pu-238 (IMAGE) DOE/Oak Ridge National Laboratory Caption Pu-238, in pellet form, produces heat that the rover's multi-mission radioisotope thermoelectric generator converts to electricity. Its long half-life makes it ideal for deep-space travel. Credit Jaimee Janiga/ORNL, U.S. Dept. of Energy Usage Restrictions With credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.