and New Horizons (1).

The GPHS-RTG has an overall diameter of 0.422 m and a length of 1.14 m.Each GPHS-RTG has a mass of about 57 kg and generates about 300 watts of electrical power at the start of mission (5.2 We/kg), using about 8.1 kg of Pu-238 which produces about 4,400 watts of thermal power. The plutonium oxide fuel is in 18 GPHSs. Note that the GPHS