Continuous Thrust Formation Maneuvering Around the Libration Points
- Paper number
IAC-07-C1.6.09
- Author
Mr. Hui Yu, Tsinghua University, China
- Coauthor
Dr. Hexi Baoyin, Tsinghua University, China
- Coauthor
Dr. Gong Shengping, Tsinghua University, China
- Coauthor
Dr. Junfeng Li, China
- Year
2007
- Abstract
Spacecraft formation flying and halo orbit missions at libration points have been studied in great detail. The combination of them has also been proposed to implement more ambitious space missions such as DARWIN, MAXIM etc. The libration points of the Sun-Earth three-body system have been recognized as very ideal place to operate some special space missions, in which a spacecraft usually needs to be controlled very accurately. It is found that controlling a spacecraft at a libration point requires very low level of engine thrust, because it is under extremely small amount of perturbations around that point. Therefore, the low thrust engines become one of the most competitive candidates for this kind of missions. Using the Pontryagin maximum principle, this paper formulates the optimal control problem of the satellite formation keeping and reconfiguration around the Sun-Earth libation point with low thrust maneuver. The system equations are linearized around a halo or Lissajous orbit, which may be the nominal orbit or the orbit of the leader spacecraft. Under this framework, the energy optimal formation keeping becomes a LQR like time-varying problem, which can be analytically solved. The energy optimal formation reconfiguration problem is also a time-varying linear system, which can be analytically solved again. The time optimal problem of formation reconfiguration can not be solved analytically and is very intractable because the initial values of the costates are difficult to guess, so the genetic algorithm is employed to deal with this problem.
- Abstract document