Abstract: An unsupported, flexible, quasi-linear phased-array antenna within a space-based radar system which is tethered to a host satellite in free space. The antenna is formed by a plurality of antenna elements which are connected serially along a common axis. The antenna points in an Earth-pointing direction via gravity-gradient forces acting thereon. The phased-array antenna is capable of radiating a narrow electromagnetic beam in the end-fire direction along the array either in a spot or conical beam for detecting, identifying and tracking moving targets on or near the Earth's surface. According to one aspect of the invention, the phased-array antenna forms an elongated conductor which moves through a magnetic field in space for generating electrical power.