NASA and The Aerospace Corporation of El Segundo, CA are preparing to flight test 'micro spacecraft' as early as 2006. The first versions would be attached to larger space vehicles as 'black box' flight recorders to provide an independent monitor of conditions as standard-sized craft attempt to land on other planets.
Black boxes used in the aviation industry record conditions like speed, altitude and crew conversations; recovery of the black box helps investigators determine the cause of crashes. Lightweight, low-cost micro spacecraft would start by testing miniature sensor systems capable of gathering temperature, pressure and other data. They can also test heat shields that will someday protect human astronauts.
Finally, scientists envision using micro spacecraft to do systematic studies of other planets; in particular, they could conduct on location studies of Venus, whose clouded atmosphere and hot surface conditions preclude human exploration (at least for a while).
Read more about microspacecraft; you might also be interested in the EyeBallOmni-directional suveillance sensor, another facet of this same idea.
(This Science Fiction in the News story used with permission from Technovelgy.com - where science meets fiction.)