Speaker
Mrs
Itziar Barat
(Deimos Space @ ESA/ESTEC)
Description
The orbit control for LEO missions is becoming more and more demanding in terms of manoeuvring. This paper proposes a simplified algorithm in order to calculated on board the drag make-up manoeuvres.
It is not pretended to give a full solution of the problem, but a starting point for future implementations. There are two main rationale of calculating this manoeuvres on-board, the first one is to mitigate the operational load to prepare and execute them, the second one is to remove the uncertainty on the orbit evolution between the manoeuvre calculation to its execution time, mainly due to the atmospheric drag. The resulting operational concept allows to keep very tight orbit control with high accuracy and low operational load.
The proposed algorithm compares the actual time of ascending node crossing with respect to the reference one. The delta-time provides the shift with respect to the reference ground-track while its increment allows to determine the altitude of the satellite. When a threshold in the ground-track shift is reached a manoeuvre is triggered based on the current altitude.
Alternative more complex calculations can be implemented allowing applications for formation flying. For example improving the on-board knowledge of the position of the other satellites in the constellation.
The algorithm is based on the one used to control the ground-track of GOCE, therefore it is not only applicable to chemical propulsion or cold gas, but on the contrary it is highly appropriate to low thrust missions. It introduces also the concept of micro-manoeuvres, that allows to emulate a low thrust control with medium thrust propulsion.
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Primary authors
Mr
Berthyl Duesmann
(ESA/ESTEC)
Mrs
Itziar Barat
(Deimos Space @ ESA/ESTEC)
