PAGE CONTENTS
Objectives
The objective of the study “Optimisation of NS, EW Station Keeping Manoeuvres for Geo Satellites Using Electric Propulsion” was to develop a design & analysis tool to optimise full electric station-keeping, bringing thus the EP-based station-keeping strategies from TRL 2-3 to TRL 4-5.
The developed STAKE (STAtion-Keeping with Electric propulsion ) tool is based on an optimiser from ASTOS Solutions, GESOP, which is used to compute the optimum manoeuvres according to several constraints and modular spacecraft and thrusters configurations.
The objective of this study was to develop a design & verification environment to support full electric station-keeping optimisation, the so-called STAKE (STAtion-Keeping with Electric propulsion) tool. It handles station-keeping in geostationary orbit with full electric or hybrid propulsion based on an optimiser from ASTOS Solutions, GESOP, which is used to compute the optimum manoeuvres.
STAKE tool has two complementary roles: the optimisation of the Station-Keeping strategies for a given thrusters configuration, and the optimisation of a thrusters configuration for a given station-keeping strategy by tuning the thrusters directions.
Several options for cost and constraints functions are available. It is especially possible to control the satellite angular momentum while fulfilling the station-keeping requirements in terms of station-keeping box. The satellite definition is representative and modular: the thrusters configuration can be defined as well as the reflectors & solar panels configuration.
Using STAKE tool, sensitivity to different on-station longitudes and spacecraft configurations has been analysed. Robustness of the station-keeping strategy has also been assessed with the tool.
Challenges
The first challenge within STAKE tool conception and development phases were the mathematical definition of the Station-Keeping and of the Thrusters Optimization as optimization problems together with the integration of GESOP optimizer.
Then a major challenge in the tool development was to make available all the relevant cost and constraints functions to support system level analyses. This leaded to develop new constraints such as kinetic momentum with TOMs or modulated thrusts and power.
Finally after the development of STAKE tool on Linux platform, the portage of the tool on Mac and Windows platform were important and new issues. In particular on Windows platform on which all the Bourne Shell scripts had to be recoded in Python language.
Plan
The study was based on a four steps standard logic:
- Review of the State-of-the-art EP technology & Station-Keeping strategies,
- STAKE software functional design and architecture,
- STAKE software development and validation,
- Analysis using STAKE software.
Current Status
Completed.