Spacecraft momentum management system

A system for managing the momentum of a spacecraft having a spacecraft body and a solar panel comprising:

• a sun sensor for determining the location of the sun;
• a gyroscope for determining the roll, pitch and yaw rates of the spacecraft;
• a suite of tachometers for determining the amount of any stored momentum in the spacecraft;
• a controller in communication with said sun sensor, said gyroscope and said tachometers to determine if the spacecraft is in the desired state;
• apparatus for determining any overturning momentum accumulated in said spacecraft;
• and
• apparatus for determining any windmill momentum accumulated in said spacecraft;
• and
• apparatus for adjusting said spacecraft to drive said overturning momentum and said windmill momentum towards zero without the use of thrusters whereby the spacecraft can remain in a sunhold attitude indefinitely.

A method for maintaining a spacecraft in a momentum safe state indefinitely, comprising:

• rotating said spacecraft about a sunline;
• monitoring the position of said sun;
• sensing the spin rate of the spacecraft;
• sensing the spin rate of the spacecraft;
• sensing the amount of stored momentum in the spacecraft;
• communicating said sun position, said spin rate, and said amount of stored momentum into a controller;
• monitoring spacecraft momentum in an overturning plane;
• monitoring spacecraft momentum about a windmill axis;
• spinning said spacecraft without the use of thrusters at a slower rate when said overturning momentum is located in half-space of said overturning plane exceeding an estimated spacecraft torque unit vector.