Orbit lifetime prediction and safety considerations

Many space missions involving the employment of man-made satellites require orbits relatively close to the earth's surface. The satellites in low earth orbit (LEO) slowly lose energy, and eventually decay in the lower atmosphere. Normally, a complete breakup of the spacecraft, accompanied by ablation and vaporization, precludes ground impact. Up until now, direct satellite impacts have not been found responsible for damage to life or limb with the possible exception of one Cuban cow. However, in connection with the latest developments related to launching capabilities, the odds of a large satellite component surviving reentry may be expected to increase. The present investigation is concerned with the parameters which determine orbital lifetime, their relative importance, and the consequences of their uncertainty. Attention is also given to safety considerations and the establishment of principles of notification and risk assessment/minimization.