Some fifty years into the Space Age, technical societies are deeply committed to the utilization of space. For the military, space is the ultimate high ground from which a variety of surveillance, communications, and navigation systems operate. For industry, the communications and positional/navigational opportunities using space-based systems are virtually unlimited. However, when the plasma between the satellite and the receiver is turbulent, satellite signals scintillate in a manner analogous to the twinkling of starlight as it traverses the turbulent atmosphere, and both communication and navigation systems can be seriously affected.