ORBITAL TRAFFIC MANAGEMENT FOR NON-GEO SYSTEMS

摘要

The operation of constellations in non-GEO space creates risks falling into three major categories: (1) physical collisions between operating satellites. (2) physical collisions with debris, and (3) electronic interference events. Electronic interference can be either up-link or down-link. For GEO systems frequency re-use is made possible by longitudinal (spatial) separation of satellites into two- or three-degree slots spaced around the equator, similar to cars parked along a curbing, separated by white spacing lines. For non-GEO satellites constantly in motion, such a simple means of maintaining spatial separation is not immediately apparent. Described in this paper is an ordered system, or constellation, of elliptical-orbit satellites that appears to ground observers as a slowly moving grid that maintains almost constant inter-satellite separation both in-track and cross-track. Now, the analogy is to a multi-lane superhighway, wherein all cars maintain two-way separation by staying in lanes and by maintaining a decent interval from cars in front. A prime advantage of using elliptical orbits is the ease with which they can be de-orbited and burned up on planned re-entry- thus removing or greatly reducing the danger of expired satellites or debris from colliding with active satellites. Yet another advantage is the higher elevation angles prevalent while satellites are in their active arcs- at and on either side of apogee. Long-term solutions for reducing both electronic interference events and future debris damage in space must include, as a prerequisite, improved elliptic-orbit constellation designs recognized as international standards for space orbital traffic management.