METEOROID AND ORBITAL DEBRIS RECORD OF THE LONG DURATION EXPOSURE FACILITY FRAME

The Long Duration Exposure Facility (LDEF) was recovered in January 1990, following 5.7 years of continuous exposure in low Earth orbit. The gravity-stabilized nature of LDEF permits the resolution of the flux and trajectories of impacting meteoroids and space-debris particulates. We have completed the collection of high-resolution stereoscopic video imaging of all impact features on the entire LDFE, and present here the preliminary results for the aluminum frame of the spacecraft. The raw data indicate possible extreme directionalities in impacting particulates for sizes greater than approximately 0.1 mm in diameter, which are not explained by current modeling. Following a Gaussian curve fit to the data, the leading-edge/trailing-edge ratio of large impact feature frequency observed for the LDEF is approximately 20.1, in good agreement with existing models (Zook, H. A., "Flux vs Direction of Impacts on LDEF by Meteoroids and Orbital Debris," Lunar and Planetary Science XXI, Lunar and Planetary Inst., Houston, TX, 1990, pp. 1385-1386). Finally, we present a list of recommendations for further LDEF analyses that will be necessary to ensure the safe design of spacecraft.