Detectability of Satellite Fragmentations in Highly Eccentric Orbits

We consider the fragmentation of a satellite initially in a highly elliptical orbit (HEO) following hypervelocity collision with a debris object in low Earth orbit (LEO). The probability of such a collision is found to be small in the short term, but but the orbital lifetime for objects in HEO is much higher than for objects in circular orbits of similar perigee altitude. Thus the collision hazard they represent to LEO will continue in some cases for many hundreds of years. A 1.5m optical telescope equipped with fast read-out CCD arrays can detect debris of diameter similar to 1 cm in LEO. However, Molniya objects are detected much more efficiently using longer integration times and detecting them at high altitudes with a limiting size similar to 5 cm at 20000km. The choice of observing site and telescope pointing direction can have a significant effect on the detection rate and size dependent selection effects.