Morning This is not uncommon - many of the high altitude objects- especially those in GTO orbits have a low perigee and a high apogee and decay rapidly. The mechanics of how the orbit decays is quite interesting-I think it was discussed on SeeSat quite some time ago - Im not an expert on this so had best not say too much but the orbit tries to circularize with apogee coming down very rapidly whilst perigee height tries to increase but eventually the satellite looses its battle.. On the 23 Jan 2009 I reported to SeeSat an observation of an Atlas 5 Centaur rocket - 08016B- catalog number #32764. At the time of observation the prediction program used gave an apogee of 4300 kms but a perigee of 87 kms and doing 10 revs/day. Ive just checked on this object and the program reports "Object decayed" . At the end of Jnauary it had decreased its orbital period to around 14 revs/day and had an enormous drag term. Guess this could make an interesting amateur observation program -- try and observe objects like this as they speed through perigee - just how low can one go without being destroyed ? For the bigger/brighter objects it might even produce quite a spectacular display - there are plenty of objects to watch .... Cheers Greg ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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