[X] My Assistant

[Tom Womack]

http://www.spaceref.com/news/viewnews.html?id=1237

reprints an interesting Aviation Week article suggesting a push for proposals for new Discovery-sized missions to use closed-loop Stirling cycle nuclear power systems, aiming for launch around 2013. It's unclear how the shortage of 238Pu is being resolved, though the Stirling-cycle devices use two 250W_thermal units of 238Pu for 143W output, whilst the Cassini/New Horizons RTG uses eighteen units for 285W electrical output.

http://nspires.nasaprs.com/external/viewre...ationDocument=1 is a summary of the specs of the Advanced Stirling Radioisotope Generator; http://esto.nasa.gov/conferences/nstc2007/...ations/D2P1.pdf is quite a nice presentation of the technology development.

The engineering history seems to be by way of Stirling-type cryocoolers, of which ten have been running for more than 10k hours each.