Spacecraft spin stabilization system

Claim 2

A gyroscopic spin stabilization system for a satellite comprising, in combination, spin/despin control means for spinning saId satellite at a selected rate and in a selected direction about a predetermined spin axis and tending to spin stabilize said spin axis, and a substantially constant speed angular momentum flywheel mounted aboard said satellite such that the angular momenta of said flywheel and said spinning satellite add together to produce a net non-zero angular momentum, the angular momentum of said flywheel being effective to increase said net angular momentum to a value sufficient to gyroscopically stabilize the spin axis of said satellite in a desired attitude when the spin of said satellite is insufficient by itself to accomplish such spin stabilization.

Claim 3

The spin stabilization system as specified in claim 1 wherein the axis of rotation of said flywheel is parallel to the spin axis of said satellite.

Claim 4

The satellite spin stabilization system specified in claim 1 and further including nutation damper means mounted aboard said satellite for eliminating wobble of said satellite about said satellite spin axis.

Claim 5

The satellite spin stabilization system specified in claim 1 wherein said angular momentum flywheel includes a rotating rim member formed of a material in which no eddy currents are generated during rotation of said rim member.

Claim 6

The satellite spin stabilization system specified in claim 1 wherein said spin/despin control means comprises, in combination, means responsive to the geomagnetic field for producing a pair of output signals proportional to the geomagnetic field components that exists respectively along two perpendicular axes of said satellite in a plane normal to the spin axis of said satellite, a pair of electromagnets, one of which is mounted in alignment with each of said perpendicular satellite axes, and means connecting said signal producing means to said pair of electromagnets for energizing said electromagnets with said output signals to produce torque on said satellite effective to spin said satellite in a selected one of two opposite directions about said spin axis.

Claim 7

The spin stabilization system as specified in claim 1 further including control means for controlling the direction and rate of rotation for said flywheel whereby said net angular momentum is variable between first and second preselected limits, said first preselected limit being selected to have a value at which said flywheel generates an angular momentum effective to increase said net angular momentum to a value sufficient to stabilize the spin axis of said satellite in a desired attitude when the spin of said satellite is insufficient by itself to accomplish such spin stabilization, said second preselected limit being selected to have a value at which said flywheel generates an angular momentum effective to reduce said net angular momentum to a value at which the attitude of the spin axis of said satellite can be varied, and further including spin axis attitude control means for adjusting the attitude of the spin axis of said satellite as desired.

Claim 8

The satellite spin stabilization system specified in claim 6 wherein said spin axis attitude control means comprises, electromagnet means mounted in alignment with the spin axis of said satellite, and means for energizing said electromagnet means to produce a magnetic dipole moment parallel with said spin axis which interact with said geomagnetic field to precess said spin axis to a desired attitude.

Claim 9

The satellite spin stabilization system specified in claim 6 wherein the axis of rotation of said flywheel and the spin axis of said satellite are parallel, whereby the angular momentum of said flywheel is effective to add to the angular momentum of said satellite when said flywheel and said satellite are spinning in the same direction and to subtract from the angular momentum of said satellite when said flywheel and said satellite are spinning in opposite directions.

Claim 10

The satellite spin stabilization system specified in claim 8 wherein said flywheel includes, a rim member capable of rotating and defining a concentration of mass within said flywheel, said rim member being formed of a material in which no eddy currents are generated during rotation of said rim member, and caging means for locking and unlocking said rotatable rim member, as desired.

Claim 11

The satellite spin stabilization system specified in claim 9 further including nutation damper means mounted aboard said satellite for eliminating wobble of said satellite about said satellite spin axis.