Plenary Lecture

The Study of an Optimal Earth Observing System Employing Dive and Ascent Satellites

Professor Fumiaki Imado
Department of Mechanical Systems Engineering
Shinshu University
4-17-1 Wakasato Nagano
Nagano 380-8553 JAPAN
E-mail: imado@imado1.shinshu-u.ac.jp
 

Abstract: DAS (Dive and Ascent Satellite) has the ability to change its altitude in the orbital plane. The authors have noticed the characteristics of DAS, and have been studying the optimal (minimum fuel) control of DAS for the purpose of earth observation. In this paper, we propose some constellations of DAS which can observe a wide area of the earth in association with the optimal orbital control of DAS. In the study, the normal orbit of DAS is assumed to be a 400km altitude circular one. As the observable window of one DAS is very limited, we first studied the orbital inclination change of DAS, which was proved to require too much fuel. Next, we studied the extension of the time to reach the observation point. The result also showed that too much fuel is required for changing the reaching time. One of the most important advantages of DAS is that it can observe more precisely by lowering its altitude, however, quick observation is most important, it can enlarge the observable window by increasing the altitude. Following to the concept, some constellations of DAS are studied and proposed. The future work is to construct an optimal constellation with DASes which can observe anywhere on the earth in a short time with minimum fuel consumption.