Session
Technical Session III: New Missions & Applications/Military
Abstract
Most satellites operating in orbit are spatially distributed in one of the following regions: LEO (below 600 nm and below), MEO (Molniya and GPS), and GEO (synchronous circular). Other than Molniya and a few similar systems, little use has been made of either elliptic orbits or the 'middle-ground' orbits lying between 600 nm and synchronous altitude. This paper explores the potential for exploiting these less populated regions and demonstrates that analyzing system optimization parametrically may in fact, also dictate an increasing interest in this new territory. A non-dimensional coverage parameter is presented which indicates that the 'efficiency' of an orbit may indeed be optimized for altitudes between 1000 to 10,000 nm. This factor usually appears to peak at slightly under 2000 nm. Elliptical orbits (requiring less booster energy than circular orbits of like period) can provide better coverage for specific geographical areas of interest by properly locating the apogee and by using repeating ground tracks. Although radiation has been a significant factor, a judicious choice of orbits coupled with advanced technologies to harden electronic circuits and solar cells may alleviate radiation effects. The increasing use of multi-satellite arrays, or constellations, demands that system costs be minimized; an obvious approach is to design for the minimum number of satellites (and boosters) required to satisfy the requirements.
Populating the Abyss-Investigating More Efficient Orbits -or- "Getting More Miles to the Gallon for Your (Space) Vehicle"
Most satellites operating in orbit are spatially distributed in one of the following regions: LEO (below 600 nm and below), MEO (Molniya and GPS), and GEO (synchronous circular). Other than Molniya and a few similar systems, little use has been made of either elliptic orbits or the 'middle-ground' orbits lying between 600 nm and synchronous altitude. This paper explores the potential for exploiting these less populated regions and demonstrates that analyzing system optimization parametrically may in fact, also dictate an increasing interest in this new territory. A non-dimensional coverage parameter is presented which indicates that the 'efficiency' of an orbit may indeed be optimized for altitudes between 1000 to 10,000 nm. This factor usually appears to peak at slightly under 2000 nm. Elliptical orbits (requiring less booster energy than circular orbits of like period) can provide better coverage for specific geographical areas of interest by properly locating the apogee and by using repeating ground tracks. Although radiation has been a significant factor, a judicious choice of orbits coupled with advanced technologies to harden electronic circuits and solar cells may alleviate radiation effects. The increasing use of multi-satellite arrays, or constellations, demands that system costs be minimized; an obvious approach is to design for the minimum number of satellites (and boosters) required to satisfy the requirements.
