The principle is to use the Earth's gravitational field and tidal forces to keep the spacecraft aligned in the desired orientation. The gravity of the Earth decreases according the inverse-square law, and by extending the long axis perpendicular to the orbit, the "lower" part of the orbiting structure will be more attracted to the Earth. The effect is that the satellite will tend to align its axis of minimum moment of inertia vertically.
Publication No. WO/2010/034074 Published on April 1, Assigned to Technological Resources for Gravity Gradient Detection Detector (Australian Inventors)
Apr 01, 2010; GENEVA, April 2 -- Frank Joachim Van Kann, Australia, has developed a detector for detecting a gravity gradient. The patent has...