Penny-sized "microthrusters" could propel tiny satellites

Space engineers are excited by the prospect of designing and sending tiny ‘cubesats' into orbit — small-scale satellites that are cheap to build, easy to put into space, and can perform highly specialized tasks like clearing out space junk. The problem, however, has been in figuring out a way to reposition these… » 8/20/12 7:50am 8/20/12 7:50am