http://www.sciencedaily.com/releases/2012/03/120329101802.htm Ion engine for small satellites provide mobility unheard-of before. I've been a fan of ion propulsion since the 1960's, when I first understood the advantages of this engine. Besides the microsat propulsion thingy, they should be particularly good for station-keeping duty on larger structures. It remains to be seen, I suppose, as to how well they will scale up for larger jobs. In any case, this application could mean big things for AMSAT, as it affects the very kind of sats that their stuff is most likely to ride on.