controlling the eccentricity of polar lunar orbits
- Paper number
IAC-08.C1.3.6
- Author
Dr. Othon Winter, UNESP, Brazil
- Coauthor
Dr. Decio Cardozo Mourão, Brazil
- Coauthor
Dr. Cristiano Fiorilo de Melo, Instituto Nacional de Pesquisas Espaciais (INPE), Brazil
- Coauthor
Dr. Silvia Maria Giuliati Winter, Universidade Estadual Paulista-UNESP, Brazil
- Coauthor
Prof. Elbert E.N. Macau, Instituto Nacional de Pesquisas Espaciais (INPE), Brazil
- Coauthor
Dr. José Leonardo Ferreira, Universidade de Brasília, Brazil
- Year
2008
- Abstract
Recently, several nations presented plans to reach the Moon. Satellites have been launched and many more are planned for following years. The expectations are that in the near future there will be a lunar base. The lunar poles are particularly of interest since seems to be where water can be found. Therefore, long living satellites in polar lunar orbits will be needed. It is well known that lunar satellites in polar orbits suffer a high increase on the eccentricity due to the gravitational perturbation of the Earth. That effect is a natural consequence of the Kozai resonance. The final fate of such satellites is the collision with the Moon. Therefore, the control of the orbital eccentricity leads to the control of the satellite's lifetime. In the present work we study this problem and introduce an approach in order to keep the orbital eccentricity of the satellite at low values. The whole work was made considering two systems; the 3-body problem, Moon-Earth-satellite and the 4-body problem, Moon-Earth-Sun-satellite. First, we simulated the systems considering a satellite with initial eccentricity equals to 0.0001 and a range of initial altitudes between 100km and 2000km. In such simulations we followed the evolution of the satellite's eccentricity. We also obtained an empirical expression for the length of time needed to occur the collision with the Moon as a function of the initial altitude. The results found for the 3-body model were not significantly different from those found for the 4-body model. Secondly, using low thrust propulsion, we introduced a correction of the eccentricity every time it reached the value 0.001. These simulations were made considering a set of different thrust values, from 0.1N up to 1N that can be obtained by using Hall Plasma Thrusters. In each run we measured the length of time, T, needed to correct the eccentricity value (from e=0.001 to e=0.0001). From these results we obtained empirical expressions of T as a function of the initial altitude and as a function of the thrust value. In all these cases, the results found for the 3-body model were also not significantly different from those found for the 4-body model.
- Abstract document
- Manuscript document
IAC-08.C1.3.6.pdf (🔒 authorized access only).
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