Estimation of debris cloud temporal characteristics and orbital elements

Abstract The Interplanetary Dust Experiment (IDE), one of the 56 experiments carried by LDEF, was designed to detect impacts of extra-terrestrial particles and orbital debris. The IDE detectors (which covered about one square meter of the surface of LDEF) were sensitive to particles ranging in size from about 0.2 μm to 100 μm. The IDE experiment recorded the location in orbit and approximate origin direction for each impact. The resulting dataset represents perhaps the most extensive record ever gathered of the number and location of impacts due to small particles on a spacecraft in Earth orbit. The IDE dataset shows that impacts often occurred in “bursts” reoccurring each orbit. Such events, which we have designated Multiple Orbit Events, can occur only if the impacting particles are in an Earth orbit that intersects that of LDEF. We have examined several such event sequences in the LDEF IDE dataset and have found orbital debris concentrations distributed in both moderate inclination (ca. 25°–35°) and high inclination (> 60°) orbits. A peak flux of at least 12 impacts/second/sq. meter was detected in one such cloud. This is nearly 4 orders of magnitude above the mean flux observed over the LDEF 5.77 year mission duration.