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International Journal of Aerospace Engineering
Volume 2009 (2009), Article ID 561495, 13 pages
Research Article

Repeated Shadow Track Orbits for Space-SunSetter Missions

Department of Mechanical Engineering-Engineering Mechanics, Michigan Tech University, 815 R.L. Smith Bldg, 1400 Townsend Dr., Houghton, MI 49931, USA

Received 14 May 2009; Accepted 10 September 2009

Academic Editor: Tal Shima

Copyright © 2009 Ahmed Gad and Ossama Abdelkhalik. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper introduces a new set of orbits, the “Repeated Shadow Track Orbits.” In these orbits, the shadow of a spacecraft on the Earth visits the same locations periodically every desired number of days. The 𝐽 2 perturbation is utilized to synchronize the spacecraft shadow motion with both the Earth rotational motion and the Earth-Sun vector rotation. Motivation for the design of new shadow track orbits comes from the need to save energy. The general mathematical model to design a Repeated Shadow Track Orbit (RSTO) is presented within this paper. RSTOs' conditions are formulated and numerically solved. Results show the feasibility of RSTOs. An optimization process is also developed to maximize the shadow duration over a given site. A Genetic Algorithm (GA) technique is utilized for optimization.