Magnetic dipole tractor beam control system

#The present invention relates generally to satellite maneuvering systems, and more particularly, to a magnetic dipole tractor beam control system.

#Spacecraft are directed through various maneuvers to guide them along a variety of celestial paths (e.g., interplanetary voyages and orbits around astronomical bodies such as the Earth) to perform a variety of functions (e.g., weather or planet surface monitoring, commercial communications and scientific observations). These spacecraft maneuvers include ones which initially place a spacecraft in a predetermined celestial path, ones which maintain a desired spacecraft station in the celestial path and ones which maintain a desired spacecraft attitude in the celestial path. In an exemplary case in which the celestial path is a geosynchronous Earth orbit, these spacecraft maneuvers are typically referred to as orbital transferring, stationkeeping and attitude controlling.

#Spacecraft maneuvers are accomplished by the application of forces and torques to the spacecraft. Typically, orbital transferring and stationkeeeping are achieved by directing force vectors through the center of mass of spacecraft so as to obtain changes in spacecraft position without disturbing spacecraft attitude. In contrast, attitude controlling is typically achieved by spacing force vectors from the center of mass to thereby generate torque vectors which realize attitude changes.

#In order that the invention may be well understood, there will now be described some embodiments thereof taken by way of example, reference being made to the accompanying drawings in which:

#FIG. 1 is perspective view of a spacecraft in an orbital plane about a celestial body;

#FIG. 2 is a simplified, perspective view of the spacecraft of FIG. 1 which shows it co-located with another spacecraft in an orbital box;

#In the following Figures, the same reference numerals will be used to identify identical components of the various views. The present invention is illustrated with respect to a magnetic dipole tractor beam control system particularly suited for the aerospace field. However, the present invention is applicable to various and other uses that may require a magnetic dipole tractor beam control system.

#FIG. 1 illustrates a spacecraft 20, which is traveling along a celestial path. In this exemplary illustration, the celestial path is an orbit 22 about the Earth 24 and the spacecraft is a body-stabilized spacecraft whose attitude can be defined relative to an orthogonal coordinate system 26. The coordinate system 26 has an origin at the spacecraft's center of mass and includes a yaw axis 28 which is directed from the origin towards the center of the Earth 24. A pitch axis 30 is orthogonal to the spacecraft's orbital plane 32 and a roll axis 34 is aligned with the satellite's velocity vector.

#Solar cell arrays 36 and 37 typically extend from the spacecraft so that they can rotate about some selected axis (frequently the pitch axis 30) to enhance their exposure to the Sun. Antennas (e.g., the antennas 38 and 39) are usually directed towards the Earth for communication and thrusters 40 and 41 are carried on the spacecraft's body 44 to facilitate stationkeeping and attitude control.