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Scheduling Strategies for Relay of Mars Rover data via Mars Orbiter and Earth Stations[editovat]

Author: Jördening Jendrik

Diplomové práce 2016

Stáhnout práci v PDF

In this thesis, the relay communication between landed assets on the surface of Mars via a relay orbiter to Earth is studied for its latencies and the times which can be provided for the landed asset to work and for the ground to plan depending on the operational margins, the available ground station network and the available relay orbiters. In this context, an automated solver is developed to evaluate a locally optimal strategy of relay pass assignment respecting the different constraints and is proven to provide a solution close to the globally optimal one. The solver is determining the link opportunities and reasons on them, by minimising a cost function for each relay pass and choosing the cheapest ones in an iterative process. With this solver, it is shown that the best operational approach is to await commands confirmation and to provide the possibility of resending corrupted files. Moreover, it is shown that a 24/7 ground station coverage should be ideally provided, on which priority for booking should be given to relay missions since they depend on the actual timing of the orbiter overflights over the lander. Further- more, it is shown that adding additional relay orbiters increases the solution space drastically, making it desirable to use them. The possibility to restrict cross-agency support is assessed, showing that cross-support is still eligible. Finally, the data volume is shown to be sufficient to fulfil the ExoMars Rover and Surface Platform mission requirements, when using multiple orbiters, even though the solver itself would need extra capabilities to cope with allocating appropriate relay passes.