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Contingency Operations during Failure of Inertial Attitude Acquisition Due to Star Tracker Blinding for Three-Axes-Stabilized Interplanetary SpacecraftThe three interplanetary ESA missions Mars-Express, Rosetta and Venus-Express (launched 2003, 2004 and 2005 resp.) are three-axes stabilized spacecraft (s/c) that estimate their inertial attitude (i.e. the attitude of the s/c w.r.t. the inertial frame) using measurements from a redundant set of star trackers (STR). Each s/c is equipped with four reaction wheels, a reaction control system based on thrusters and a redundant set of ring laser gyroscopes (gyros). The STR h/w layout of the three s/c is identical whereas there is a difference in the star pattern recognition algorithm of Rosetta which uses five neighbouring stars around a central star instead of star triads. The Rosetta algorithm has been implemented to cope with the presence of false stars which are expected to be seen during operations around the comet. The attitude acquisition capability from lost in space is different also in terms of AOCMS: The survival mode of Rosetta which is entered upon STR failure is presented. The AOCMS of Mars- and Venus-Express manages temporary STR outages during sky occultation by the planet not even by using redundancy. Though, a blinding of both STR during cruise lasting for the order of days confronts the ground operators with the limits of the AOCMS design. The operations and analyses that have been planned and partially been performed to compensate for the outage of the STR are demonstrated for Mars-Express. The caution measures taken before Venus orbit insertion of Venus-Express are detailed.
Document ID
20080012644
Document Type
Conference Paper
Authors
Keil, Joachim (European Space Agency. European Space Operations Center Darmstadt, Germany)
Herfort, Ulrich (European Space Agency. European Space Operations Center Darmstadt, Germany)
Date Acquired
August 24, 2013
Publication Date
September 24, 2007
Publication Information
Publication: Proceedings of the 20th International Symposium on Space Flight Dynamics
Subject Category
Spacecraft Design, Testing and Performance
Distribution Limits
Public
Copyright
Public Use Permitted.

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IDRelationTitle20080012629Analytic PrimaryProceedings of the 20th International Symposium on Space Flight Dynamics