Advanced Stirling Radioisotope Generator Research Articles

FIRE - Flyby of Io with Repeat Encounters: A conceptual design for a New Frontiers mission to Io

A conceptual design is presented for a low complexity, heritage-based flyby mission to Io, Jupiter’s innermost Galilean satellite and the most volcanically active body in the Solar System. The design addresses the 2011 Decadal Survey’s recommendation for a New Frontiers class mission to Io and is based upon the result of the June 2012 NASA-JPL Planetary Science Summer School. A science payload is proposed to investigate the link between the structure of Io’s interior, its volcanic activity, its surface composition, and its tectonics. A study of Io’s atmospheric processes and Io’s role in the Jovian magnetosphere is also planned. The instrument suite includes a visible/near-IR imager, a magnetic field and plasma suite, a dust analyzer, and a gimbaled high gain antenna to perform radio science. Payload activity and spacecraft operations would be powered by three Advanced Stirling Radioisotope Generators (ASRG). The primary mission includes 10 flybys with close-encounter altitudes as low as 100km. The mission risks are mitigated by ensuring that relevant components are radiation tolerant and by using redundancy and flight-proven parts in the design. The spacecraft would be launched on an Atlas V rocket with a delta-v of 1.3km/s. Three gravity assists (Venus, Earth, Earth) would be used to reach the Jupiter system in a 6-year cruise. The resulting concept demonstrates the rich scientific return of a flyby mission to Io.

US planetary sciences to focus on smaller missions, research, and technology development

Heeding community advice, NASA’s planetary science division seeks to scale back its flagship missions while retaining strong international partnerships.

Radioisotope electric propulsion (REP): A near-term approach to nuclear propulsion

Studies over the last decade have shown radioisotope-based nuclear electric propulsion to be enhancing and, in some cases, enabling for many potential robotic science missions. Also known as radioisotope electric propulsion (REP), the technology offers the performance advantages of traditional reactor-powered electric propulsion (i.e., high specific impulse propulsion at large distances from the Sun), but with much smaller, affordable spacecraft. Future use of REP requires development of radioisotope power sources with system specific powers well above that of current systems. The US Department of Energy and NASA have developed an advanced Stirling radioisotope generator (ASRG) engineering unit, which was subjected to rigorous flight qualification-level tests in 2008, and began extended lifetime testing later that year. This advancement, along with recent work on small ion thrusters and life extension technology for Hall thrusters, could enable missions using REP sometime during the next decade.