Radioisotope Power Systems (RPS) have provided the power to explore some of the deepest, darkest, and most distant destinations in the solar system and beyond. Voyager 1 is NASA’s furthest traveled spacecraft, and its science mission has been enabled by RPS for 45 years.
On Sept. 5, NASA will be celebrating the anniversary of the Voyager 1 launch that was managed by NASA's Glenn Research Center’s (formerly NASA Lewis) Launch Vehicles Program Office, and launched out of Cape Canaveral on a Titan IIIE-Centaur rocket. The Voyager Mission was designed and is managed by NASA’s Jet Propulsion Laboratory. Voyager is NASA’s longest operating mission, thanks to the enabling power and heat from its RPS, and the twin probes are the first spacecraft to explore interstellar space.
Each probe is equipped with 3 RPS called Multi-Hundred Watt (MHW) Radioisotope Thermoelectric Generators (RTGs). Each MHW RTG generated and output of 158 Watts electric at the beginning of mission, offering Voyager about 474 watts of electricity to power its science payload. The RTGs convert heat from the natural decay of plutonium oxide into useable power to power the spacecraft. The excess heat is used to warm the instrumentation enabling them to work in the coldness of space. This production decreases over time, as the radioisotope reaches its half-life of ~87 years. The Voyager team has strategically turned off non-essential systems to extend the life of the mission as much as possible.
Forty-five years later, the RTGs are producing about 230 watts of electricity and the spacecraft is still providing valuable science returns from interstellar space. The spacecraft will continue to use the heat and power from the RTG until the output diminishes too much to support the instruments and critical systems. The Radioisotope Power System (RPS) used by Voyager 1 have enabled the spacecraft to explore some of the most distant destinations in our solar system and it was the first to begin exploring interstellar space. With over sixty years of successful use in the United States, RPS will continue to provide NASA the power to explore our solar system and beyond.
by Kristin Jansen, NASA Glenn Research Center