Materials Science Seminar-- Thermoelectric Materials for Space Power Generation

Presented by:Dr. Thierry Caillat
Principal Scientist
Power Systems and Sensors Section
Jet Propulsion Laboratory/California Institute of TechnologyAbstract:Of the various static energy conversion technologies considered for Radioisotope Power Systems for space applications, thermoelectric (TE) energy conversion has received the most interest. Radioisotope Thermoelectric Generators (RTGs) generate electrical power by converting the heat released from the nuclear decay of radioactive isotopes (typically plutonium-238) into electricity using a thermoelectric converter. RTGs have been successfully used to power a number of space missions including the Appolo lunar missions, the Viking Mars landers, Pioneer 10 and 11, and the Voyager, Ulysses, Galileo, and Cassini outer planet spacecrafts. These generators have demonstrated their reliability over extended period of time (tens of years) and are compact, rugged, radiation resistant, scalable, and produce no noise, vibration or torque during operation. These properties have made RTGs suitable for autonomous missions in the extreme environment of the outer space and on planetary surface. Converter units use TE materials, which, when operating over a temperature gradient, produce a voltage called the Seebeck voltage. System conversion efficiency for state-of-practice RTGs is about 6%. The most widely used TE materials, in order of increasing temperature, are: Bismuth Telluride (Bi2Te3); lead Telluride (PbTe); tellurides of Antimony, Germanium and Silver (TAGS); lead Tin Telluride (PbSnTe); and silicon Germanium (SiGe). All of these materials except Bi2Te3 have been used in RTGs, which have been flown on space missions. A wide variety of physical, thermal, and thermoelectric properties requirements must be met for the design of reliable thermoelectric RTG converters. An overview of various thermoelectric phenomena and materials is provided in this talk. Space applications and requirements for thermoelectric materials are discussed. Current trends in thermoelectric material research are briefly introduced.First year MASC students are required to attend.

Location: Vivian Hall of Engineering (VHE) - 217

Audiences: Everyone Is Invited

Contact: Petra Pearce