Olympus end of life anomaly — a perseid meteoroid impact event?

Abstract

On August 11, 1993 at 23:32 Zulu (UT), the OLYMPUS satellite lost earth pointing and began spinning, leading to a chain of events which culminated with the satellite's demise. The spacecraft automatic control system attempted to despin and reorient the spacecraft but was unsuccessful. These manoeuvers caused significant fuel depletion. During reacquisition under manual control, it was determined that insufficient fuel remained to return to station. The decision was made to take OLYMPUS out of service, removing the spacecraft as far as possible from the geosynchronous orbit.The morning of August 12 was predicted to be the peak of the Perseid's meteoroid shower. There was the possibility that the meteoroid stream might reach storm conditions with relatively fresh material released during the last appearance of Comet Swift-Tuttle returning near the Earth. Assessments of the situation had indicated that it was unlikely to be a problem, but an on-board micro-accelerometer package was operated to record impacts, and operators and support staff were put on special alert in case of operational difficulties.This paper will describe the spacecraft, the sequence of events, tests and analysis, and make operational and design recommendations. While an impact by a meteoroid could not be proven, it is a possible scenario. The impact by a small meteoroid may have generated a plasma triggering a discharge of charged surfaces entering the grounded spacecraft via the umbilical and an external sensor. Such a scenario is particularly interesting for other spacecraft since the Perseid shower is likely to be worse for the next few years.