A New Approach to the Design of Navigation Constellations around MARS: The MARCO POLO Evolutionary System
- Paper number
IAC-06-C1.8.05
- Author
Mr. Fabrizio Pirondini, DEIMOS Space S.L., Spain
- Coauthor
Mr. Antonio Fernández, DEIMOS Space S.L., Spain
- Coauthor
Dr. Guy Janin, European Space Agency/ESOC, Germany
- Year
2006
- Abstract
The Aurora Programme represents the European long-term strategy for the robotic and human exploration of the Solar System. A recent study on a European Martian GNSS aimed at providing incremental navigation services to the Aurora Programme’s Mars missions is described in the paper “Martian GNSS: Preliminary Design and Performance Analysis of a European Evolutionary System” presented at the IAC 2005, where the MARCO POLO Programme is introduced. This paper focuses on the design of the Martian navigation constellations envisaged in the MARCO POLO Programme, where an evolutionary approach satisfies increasing high-level requirements, allowing the incremental development and deployment of the system in line with the needs of the Aurora Programme. Three constellation typologies have been studied, each one designed as a stand-alone system, in order to design an evolutionary and modular Martian GNSS spanning over 25 years of operations. The three constellations have been designed using navigation performances as the main figure of merit, optimising the number of satellites and their orbital elements. The first phase of Aurora concentrates on technology demonstrators and has coarse navigation requirements, with no need for real-time navigation. Hence, the first constellation of Martian navigation satellites in the frame of the MARCO POLO Programme, dubbed MP-I, has been designed for 2-D navigation without real-time capabilities. The figure of merit for the design of this constellation is the Mean of Position Accuracy Response Time (MPART). The resulting constellation with four satellites on four different orbital planes resembles the vintage Transit system. With the precursors to manned Aurora missions the positioning and navigation requirements become more stringent, and real-time 3-D navigation would greatly improve the chances of mission success. Nevertheless, a full-scale global navigation system is still considered too ambitious. The MP-II constellation is therefore designed to provide 3-D real-time navigation only on a small area of the planet, centred on the foreseen landing site. In order to do so, a 4-fold satellite visibility shall be available locally. The constellation is also designed to be re-configurable in order to change the location of its optimum service point, so as to be able to shift between different Aurora users after a few months, should the necessity arise. The MP-II constellation is composed of two elements: a constellation of three Mars-Stationary satellites, providing two-fold coverage in a limited area, and a five-satellite Walker constellation, providing the remaining two folds of required coverage. In the last phase of the Aurora Programme, incorporating manned missions, positioning and navigation requirements are very stringent and real-time, 3-D navigation is key to mission success. At this stage the programme is considered mature enough to envision a true global navigation system. Hence, the design process aims at guaranteeing a global 4-fold satellite visibility, with very high availability. The constellation design is based on the optimisation of a Walker scheme, in which all the satellites are placed into circular orbits at the same altitude and inclination. The resulting 55:21/3/2 constellation was found to provide the required performances at a minimum cost, assuming also a spare satellite per plane. The strategy and problematics of constellation deployment, maintenance and end-of-life disposal have also been addressed for each constellation.
- Abstract document
- Manuscript document
IAC-06-C1.8.05.pdf (🔒 authorized access only).
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