ERBS orbit ascent utilizing continuous low thrust maneuvers

The Earth Radiation Budget Satellite (ERBS) is a National Aeronautics and Space Administration (NASA) spacecraft whose purpose is to investigate the components of the earth's radiation budget. The ERBS was deployed in a 57 degree inclined, 352.2 kilometer altitude circular orbit by the NASA Space Transportation System (STS) on October 5, 1984. The spacecraft then ascended to its 603 kilometer, near-circular mission orbit by a series of continuous low-thrust maneuvers. The ERBS was the first free-flyer mission to rely on continuous low thrust to spiral from one circular orbit to another. Careful planning and monitoring of these maneuvers were essential to their successful execution. Errors in the prediction of the propulsion system performance or in burn duration would result in loss of contact with the spacecraft during a maneuver and could result in a premature end to the maneuver and difficulty in computing a definitive orbit.