Recovery opportunities for the BepiColombo mission to Mercury
- Paper number
IAC-07-C1.7.05
- Author
Mr. Daniel Garcia Yarnoz, GMV S.A. at ESA/ESOC, Germany
- Coauthor
Mr. Paolo de Pascale, European Space Agency/ESOC, Germany
- Coauthor
Dr. Rüdiger Jehn, European Space Agency/ESOC, Germany
- Year
2007
- Abstract
ESA’s BepiColombo mission to Mercury is the first mission ever to use solar electric propulsion to reach a planet of the inner solar system. The current baseline trajectory comprises six gravity assists at the Moon, Earth and the inner planets, more than 15000 hours of low-thrust propulsion, and complex strategies for the departure and arrival. The possibility of flame-outs, entering a safe-mode in critical phases, underperformances of the SEP engine (a 10% underperformance is already considered in the mission design) and additional constraints in the thrust direction (stringent solar aspect angle constraints) increase the chances of a less efficient gravity assist or a manoeuvre failure. On the other hand, the flexibility of the low-thrust allows for cheap recoveries and alternatives after such an event.
Due to all these factors, it becomes necessary to study recovery opportunities already during the design phase in order to obtain a robust trajectory. Several critical phases have been identified and alternative solutions in case of failure analysed. At departure, a phasing loop strategy and lunar flyby is employed to escape the Earth’s sphere of influence. Under the assumption of a missed lunar swing-by, recovery by targeting the Moon 28 days later was studied, and solutions were found with slight extra SEP fuel costs for the interplanetary trajectory. Both the Earth to Earth phase and the final phase after the second Mercury flyby have small margins for underperformances or temporary failure of the low-thrust engine. In the first case a recovery option consists of delaying the Earth swing-by for more than one year and jumping into the 2015 back up opportunity, which might however lead to a fuel budget that exceeds the current allocation. In the second case, a delay in the arrival to Mercury by one or more Mercury years provides feasible alternatives with no additional SEP cost. At arrival and insertion, a gravitational capture approach is employed. The design of this strategy already takes into account the possibility of a failure in the main insertion burn. The arrival date was chosen such that the spacecraft is temporarily captured by Mercury even if the engine does not start. Up to three recovery opportunities become available during the subsequent highly eccentric orbits.
This paper presents these four failure scenarios and the solutions adopted in each case. A fuel budget comparison for each alternative is presented.
- Abstract document
- Manuscript document
IAC-07-C1.7.05.pdf (🔒 authorized access only).
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