Halo Orbit Determination in Mission Analysis of Hevelius - Lunar Microsatellite Mission
- Paper number
IAC-05-C1.1.08
- Author
Mr. Matteo Ceriotti, University of Glasgow, United Kingdom
- Coauthor
Ms. Camilla Colombo, University of Glasgow, United Kingdom
- Coauthor
Mr. Ettore Scarì, Politecnico di Milano, Italy
- Year
2005
- Abstract
After more than 40 years, the Moon has become an object of interest again. It is a scientific and strategic objective, a test-bed for the newest technologies, and it can be a launch pad towards Mars and other celestial bodies. However, the present technology and economical resources are deeply different from the ones available at the time of the first human missions. The recent trend is to design low-cost space missions. This introduces stringent requirements on mass and propellant, and so demands for a minimisation of the delta-Vs. In order to meet these requirements, a multilander mission to the dark side of the Moon, called Hevelius, has been recently studied during an university course at Politecnico di Milano. Three landers, with miniaturized payloads, are supervised by a data relay microsatellite (100 kg class) and are transported by a carrier from a LEO to the surface of the Moon, on which they perform a semi-hard landing. Moreover, the carrier has to map the lunar gravitational field and the landing site. The Hevelius Mission Analysis subsystem focused on the restricted three-body dynamics of the Earth-Moon system. Since the relay satellite must continuously see the dark side of the Moon, a operative Halo orbit around the second Lagrangian point has been chosen. Low-cost transfers to the Halo, for the relay satellite, and to a low-altitude lunar orbit, for the carrier, are needed. Studies on the invariant manifolds of the three-body problem (Howell et al.) brought a method to find first-guess solutions for the design of low-cost transfers. The need to optimize the transfer cost led to the use of several non-linear optimization algorithms, like genetics and Sub-Quadratic Programming (SQP). For the relay satellite, three different ways have been followed to determine the optimal Halo orbit, including a first order linearization (that led to a Lissajous orbit) and a third order Legendre polynomial expansion of gravitational field. This led to have three different families of Halos, which have been optimized, in order to guarantee the minimum maintaining cost. Perturbations have been considered. Then, a trade off between three candidate Halos has been made; the best compromise between manoeuvres required to maintain a periodic motion, requirements derived from the telecommunication subsystem, slew angles and manoeuvres required to point the Earth and the Moon, and eclipses has been investigated. Transfer orbit to the Halo has been made by backward integration, starting from different points and perturbing the state vectors in the direction of the unstable backward eigenvectors of the linearised problem. This procedure leads to the identification of the stable manifolds of the orbit. Only manifolds that transit near L1 have been considered. The trajectory has been optimized minimizing the sum of delta-Vs with a genetic algorithm at first and then with a SQP method. The results of this study are totally consistent with high-level requirements and with the modern trend of investing in small and cost-reduced missions. This paper focuses on Hevelius mission analysis, and in particular on the techniques used for the determination and the optimization of the Halo orbits, starting from a survey of different studies in this field. A deep investigation of the choice of the best target Halo orbit and relative manifolds for the mission - involving the trade off among various choices - is described in detail in the following.
- Abstract document
- Manuscript document
IAC-05-C1.1.08.pdf (🔒 authorized access only).
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