GGSE-1


The Gravity Gradient Stabilization Experiment was a technology satellite launched simultaneously with four other satellites on January 11, 1964 by the US military from Vandenberg AFB aboard a Thor Augmented Delta-Agena D rocket. This was the first in the series that developed designs and deployment techniques later applied to the NOSS/Whitecloud reconnaissance satellites.

Spacecraft and Mission

GGSE-1 was an ovoid satellite based on a similar bus to SOLRAD 7A, with which it was launched into orbit. GGSE-1 was equipped with a passive oscillatory damping mechanism attached to the spacecraft via a 28-foot rod of metal tape. The entire mechanism and rod together weighed less than 4.5 kg.
The damping mechanism, developed by General Electric, comprised a metal sphere, 12.7 cm in diameter, containing another metal sphere with a silicone damping fluid between. A small bar magnet attached to the inner sphere aligned that sphere with the earth's magnetic field. As the satellite oscillated about its local vertical because of gravity gradient forces, the outer sphere of the damper rotated about the inner sphere, dissipating the oscillatory energy in the form of heat from the viscous drag of the fluid.
This system was more effective than the damping spring-and-weight system used on a previously launched Transit satellite in that it provided equal damping about all three axes of the satellite while the older damper provided no damping about the yaw axis and less damping of the roll axis than for pitch. The new damper also was effective immediately whereas the older technique required several weeks for the spring-mass to compress into operational position.
This system successfully oriented the satellite to a local vertical within 5 degrees of accuracy and damped out oscillations within three days of orbit.

Status

As of March 5, 2019, GGSE-1 is still in orbit and its position can be tracked.