Cassini’s Radioisotope Thermoelectric Generator (RTG)

Color image of a spacecraft power system.
A radioisotope thermoelectric generator extends from the Cassini spacecraft.
NASA/JPL-Caltech
October 6, 1997
CreditNASA
Language
  • english

ORIGINAL CAPTION: At Launch Complex 40 on Cape Canaveral Air Station, one of three radioisotope thermoelectric generators (RTGs) is being installed on the Cassini spacecraft.

RTGs are lightweight, compact spacecraft electrical power systems that have flown successfully on U.S. missions for several decades. These generators produce power by converting heat into electrical energy; the heat is provided by the natural radioactive decay of plutonium-238 oxide, a non-weapons-grade material.

RTGs enable spacecraft to operate at significant distances from the Sun where solar power systems would not be feasible. Cassini will travel two billion miles to reach Saturn and another 1.1 billion miles while in orbit around Saturn. Cassini is undergoing final preparations for liftoff on a Titan IVB/Centaur launch vehicle, with the launch window opening at 4:55 a.m. EDT, Oct. 13.