Gravity Gradient Stabilization Experiment (GGSE-1)
Mission typeGravity-gradient stabilization
COSPAR ID1964-001B
SATCAT no.00728
Start of mission
Launch date11 January 1964, 5:00:00 (1964-01-11UTC05Z) UTC
RocketThor Augmented Delta-Agena D
Launch siteVandenberg AFB
Orbital parameters
Reference systemGeocentric
RegimeLow Earth
Launch of GGSE-1

The Gravity Gradient Stabilization Experiment (GGSE-1) was a technology satellite launched simultaneously with four other satellites (including Solrad 7A and Poppy 3) on January 11, 1964[1] 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.[2]


As of March 5, 2019, GGSE-1 is still in orbit and its position can be tracked.[3]


  1. ^ "Astronautics and Aeronautics, 1964" (PDF). Retrieved 2018-12-30.
  2. ^ "'Gravity Gradient Device Orients Satellite". Aviation Week and Space Technology. New York: McGraw Hill Publishing Company. February 24, 1964. Retrieved February 21, 2019.
  3. ^ "GGSE 1 (GGRS) - NORAD 728 - 3D Online Satellite Tracking". Retrieved March 5, 2019.