MHW-RTG
The Multihundred-Watt radioisotope thermoelectric generators is a type of US radioisotope thermoelectric generator developed for the Voyager spacecrafts, Voyager 1 and Voyager 2.
Each RTG had a total weight of 37.7 kg including about 4.5 kg of Pu-238. It uses 24 pressed plutonium-238 oxide spheres and provides enough heat to generate approximately 157 watts of electrical power initially - halving every 87.7 years.
Each RTG generated about 2400 Watts of thermal power.
Conversion of the decay heat of the plutonium to electrical power used 312 silicon-germanium
thermoelectric couples. The initial thermoelectric couple hot junction temperature was 1273 K with a cold junction temperature of 573 K.
Each Voyager spacecraft has 3 RTGs. Collectively, the RTGs supplied each Voyager spacecraft with 470 watts at launch.
MHW-RTGs were used on the Lincoln Experimental Satellites 8 and 9.
Subsequent US spacecraft used the GPHS-RTG which used similar SiGe thermoelectic devices but a different packaging of the fuel.
The MMRTG is a newer RTG type, used on the Curiosity rover.
