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Formation Flight in Low-Earth-Orbit at 150m Distance; AOCS In-Orbit Experience

Schulze, Daniel and Herman, Jacobus and Löw, Sebastian (2012) Formation Flight in Low-Earth-Orbit at 150m Distance; AOCS In-Orbit Experience. 12th International Conference on Space Operations (SpaceOps 2012), 11-15. Juni 2012, Stockhom, Schweden.

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Abstract

AOCS operations for two satellites flying at ~514 km altitude with unprecedented small separation of 150 m upwards pose various new challenges and require creative solutions. Several on-ground safety measures were installed, but due to the short reaction times emphasis always lies with the on-board handling of problems. This is achieved by implementation of a data link (one-way) between the satellites, by the design of a new AOCS safe mode that has no effect on the orbit, by the complete re-work of the TerraSAR-X FDIR concept (Fault Detection, Isolation and Recovery) and by autonomous formation control with a dedicated cold gas system on the second satellite TanDEM-X. This paper describes AOCS operations for the TanDEM-X mission in close formation. Most of the tasks are, thanks to extended safety measures and automated control mechanisms, routine. This will be described in the first section, where a short summary of all AOCS related operations will be given. The second section describes some special activities in connection with the cold gas system and the star trackers on TDX. The investigations and the fine tuning of the GPS receivers on both satellites are also described in this section. Although there was never a threat to the formation, close monitoring is required all the time and some mitigation measures were called for. Finally, the influence of the approaching solar maximum in 2013 will also be described in this section. The last part presents the conclusions and contains some suggestions for future missions.

Document Type:Conference or Workshop Item (Paper)
Title:Formation Flight in Low-Earth-Orbit at 150m Distance; AOCS In-Orbit Experience
Authors:
AuthorsInstitution or Email of Authors
Schulze, DanielD.Schulze@dlr.de
Herman, JacobusJaap.Herman@dlr.de
Löw, SebastianSebastian.Loew@dlr.de
Date:June 2012
Status:Published
Keywords:Formation Flight Low Earth Orbit TanDEM-X Mission
Event Title:12th International Conference on Space Operations (SpaceOps 2012)
Event Location:Stockhom, Schweden
Event Type:international Conference
Event Dates:11-15. Juni 2012
Organizer:DLR / SSC
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Earth Observation
DLR - Research area:Raumfahrt
DLR - Program:R EO - Erdbeobachtung
DLR - Research theme (Project):R - Projekt TanDEM-X
Location: Oberpfaffenhofen
Institutes and Institutions:Space Operations and Astronaut Training
Deposited By: Juliane Geisau
Deposited On:16 Jul 2012 10:48
Last Modified:12 Dec 2013 21:42

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