Pointing of a space based platform (attitude control) is a very important parameter. The body needs to be "aimed" at a particular geographical reference point for a number of reasons. Tight antenna patterns, spot beams, command links, not to mention solar arrays at the sun for power capability. The loss of a power system to me infers a loss of attitude control also. Whatever form that takes, momentum wheels, thrusters, magneto coils, all need power to operate. Perhaps the inertial reference was lost causing invalid inputs to one of the control systems. Bottom line is, if a satellite "depoints", it becomes useless to its users and very difficult for its operators to control. Command and telemetry revert to small omni antennas that suffer from degraded link budgets. There is also a fair amount of luck involved in the recovery process. There is always the possibility that a command you send may make the problem worse. They are lucky that they were able to recover it. It may still end up being a short period geosync "flasher". td >From: "satcom" <john@satcom.freeserve.co.uk> >To: <SeeSat-L@satobs.org> >CC: <fpspace@friends-partners.org> >Subject: Eutelsat W1 recovery...... statement from operator >Date: Thu, 11 Aug 2005 17:20:07 -0000 > >Following my report yesterday that Eutelsat W1 ( geo 10 degs east ) had >suffered some kind of failure , the operators have now put out a statement. > >I'm not quite sure what is meant by depointing.....apart from the fact that >everything went off for about nine hours....but until the full >investigation is completed it looks like this is as much as we will get. ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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