Refined orbital architecture for targets of naval interest

Abstract

The objective of this research is to address the feasibility of designing prograde orbits for commercial electro-optical satellites. This study explores prograde orbits (inclined less than 90°) populated by small, inexpensive but proven commercial satellites, like SkySat-1 of SkyBox Imaging Inc. The benefits of using prograde orbits are increased coverage duration and decreased revisit, or gap, times for point targets at most latitudes. Disadvantages include a reduction of high-latitude target coverage (sometimes completely), a more elaborate ground architecture, and the increased expense of populating a constellation of these satellites—to mitigate the laws of orbital mechanics—in order to achieve the desired benefits of prograde inclinations. This thesis considers orbital plane inclinations of 30°, 45°, and 60°; designs a few 24-satellite prograde constellations; and compares the performance of these newly formed constellations to the traditional sun synchronous orbit. As anticipated by the orbital mechanics, the results show that annual coverage can increase up to 6.5 times, average access increases up to 6.94 per day, and revisit time can be reduced to as low as 2.0 hours. In addition, the approximate annual life-cycle cost will likely fall beneath $0.5 billion.