I had a paper accepted for the Conference on Small Satellites this coming August. I'm inviting comment and speculation.
We've seen spacecraft for some uses shrink considerably, to the point where 1-kg CubeSats can do useful science. The military, through the TacSat and ORS programs, is flying relatively small (<400 kg) craft with multispectral imaging and other high-tech capabilities, while Army SMDC has put up its own communications nanosatellite. Computers on chips, carbon nanotubes, etc. have already brought dramatic breakthroughs. What's in the future, 10-30 yearsdown the road? Cooperating swarms, ever-tinier spacecraft, deep-space micro-constellations, or things we haven't even put on drawing boards yet?