Trajectory Optimization in Hevelius - Lunar Microsatellite Mission
- Paper number
IAC-05-C1.5.05
- Author
Ms. Camilla Colombo, University of Glasgow, United Kingdom
- Coauthor
Mr. Matteo Ceriotti, University of Glasgow, United Kingdom
- Coauthor
Mr. Ettore Scarì, Politecnico di Milano, Italy
- Coauthor
Mr. Massimiliano Vasile, Politecnico di Milano, Italy
- Year
2005
- Abstract
The silvery Moon is still a subject of interest in space research, because of both technological and scientific implications. Therefore, after the Apollo era and the more recent Clementine (1994) and Lunar Prospector (1998) missions, a new exploration phase of our natural satellite is envisaged in the near future. On the other hand, the tight constraints on space mission cost and available transportation systems bring about the need for a reduction in the total mass and consequently a minimization of the total required delta-v. In order to answer to the need for cheap scientific missions to the Moon a multilander mission to her dark side has been recently studied at Politecnico di Milano, by a group of student supervised by a teacher. The mission, called Hevelius, consists of three landers, with miniaturized payloads, that have to be transported by a carrier from a LEO to the surface of the Moon. In addition, a data relay microsatellite has to support the net-lander on the dark side, orbiting on a Halo orbit around L2. To minimize delta-v, a number of options have been devised, exploiting multi-body dynamics. The concept of using stable manifolds of the restricted three-body problem to design low-cost missions has been studied by Howell et al. (1994) to determine appropriate solutions for geocentric transfers and by Belbruno et al. (1987) who proposed new trajectories, exploiting weak stability boundaries (WSB) of the Earth-Sun-Moon system. The long travel time due to these approaches is compensated by the reduction in propellant mass. These innovative concepts required the development of specific tools for trajectory design. In particular, the chaotic dynamics governing those trajectories imply the need for methods that assure global convergence at least to a local optimal solution. A possible way to tackle this problem is generate first guess solutions by using hybrid methods, that combine a global research by Evolutionary Programs and a local optimization by SQP. In the design of Hevelius, different methods for trajectory optimization and multi-body dynamics, have been investigated in order to design low cost trajectories, to reduce the propellant mass and to fulfil the launcher requirements. As operative orbit for the data-relay satellite, several Halo orbits around the point L2 of the Earth-Moon system have been investigated by the linearization of the equation of motion around L2, followed by a shooting procedure, or by using a third-order-approximated dynamic model, refined with an SQP procedure. Trade off of the different orbits was based on maintenance cost, amplitude and slew angles. Earth-Moon transfer exploits stable manifolds leaving Halo orbit, calculated by a backward integration in the RTBP. The total delta-v imposed to reach the manifold is minimized by genetic algorithms, that supply a first guess solution, and by a SQP optimization. In order to phase the departure orbit, the drift effect of J2 and the perturbation effect of the Moon and the Sun have been exploited. The operative orbit selected for the carrier is a Frozen orbit instead. The aim of the carrier transfer orbit is to connect a LEO with the Frozen orbit, with the minimum fuel consumption. This transfer exploits the WSB, where it is possible to obtain a change of inclination and the increase in apogee height with a small impulsive manoeuvre. For this problem a first guess solution has been found, then the result has been optimized with DITAN. Eclipse study and perturbation analysis have been also performed. This paper will present the results of Hevelius mission analysis, focusing on manoeuvre determination and optimization strategies, according to mission goals and constraints. A survey of existent methods for trajectory optimization will be presented, subsequently it will be described how this studies has been exploited and originally combined in Hevelius mission analysis design.
- Abstract document
- Manuscript document
IAC-05-C1.5.05.pdf (🔒 authorized access only).
To get the manuscript, please contact IAF Secretariat.