Exquisite full-scale contractor model of the deep-space Voyager spacecraft nuclear battery made for JPL, set upon a wood-framed base, measuring an overall 20″ x 25.5″ x 20″, and weighing 48 lbs; the RTG cylinder is 15.5” in diameter. The placard on the base reads: "Multihundred-Watt Radioisotope Thermoelectric Generator, General Electric, Full : Scale." The appealing 'cutaway' design of the model reveals the plutonium pellet core. In fine condition. The model will be crated and shipped from California; the buyer is responsible for all associated costs.
Space exploration missions require safe, reliable, long-lived power systems to provide electricity and heat to spacecraft and their scientific instruments. A uniquely capable source of power is the radioisotope thermoelectric generator (RTG)—essentially a nuclear battery that reliably converts heat into electricity. The Multihundred-Watt Radioisotope Thermoelectric Generator (MHW RTG) was developed for the Voyager spacecrafts, Voyager 1 and Voyager 2. These RTGs on Voyager 1 and Voyager 2 have been operating since 1977. Voyager 1 is operating over 13 billion miles from Earth and Voyager 2 recently came fully back on-line, over 11 billion miles from Earth, voyaging farther than any other man-made objects. This is too far from the sun for solar cells to power its electronics, and so JPL designed it to use an RTG to provide power for many decades. Each RTG had a total weight of 37.7 kg including about 4.5 kg of Pu-238; these 24 pressed plutonium-238 oxide spheres provide 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 (SiGe) thermoelectric couples. The initial thermoelectric couple hot junction temperature was 1000°C with a cold junction temperature of 300°C. Each Voyager spacecraft has three RTGs, which collectively supplied each spacecraft with 470 watts at launch. Radioisotope power has been used on eight Earth orbiting missions, eight missions traveling to each of the outer planets, and lunar surface experiment packages for Apollo missions 12 through 17. Some of the outer Solar System missions are the Pioneer, Voyager, Ulysses, Galileo, Cassini, and New Horizons missions.
