As Russell Eberst reported, the orbit of DMSP B5D2-7 (94057A / 23233) recently underwent a sudden change, coincident with a spin-up, which is indicative of an explosive release of some sort: http://satobs.org/seesat/Oct-2009/0150.html Here are before and after elements: DMSP B5D2-7 832 X 849 km 1 23233U 94057A 09289.13842517 .00000056 00000-0 28875-4 0 05 2 23233 98.7446 248.3560 0011640 320.3072 39.7248 14.14729268 07 Arc 20090909.17-1016.16 WRMS resid 0.030 totl 0.016 xtrk DMSP B5D2-7 825 X 855 km 1 23233U 94057A 09299.18090629 .00000040 00000-0 20750-4 0 07 2 23233 98.7618 258.1808 0021164 1.4917 358.6315 14.14824969 01 Arc 20091023.16-1026.2 WRMS resid 0.029 totl 0.019 xtrk The elements of the present orbit are based on six points, over a three day arc, so could change a bit with further observation. The above elements place the explosive event on 2009 Oct 20, near 15:45 UTC or 17:27 UTC. As Russell noted, this event could be similar to the one on DMSP B5D2-6 (91082A / 21798), which NASA's latest satellite fragmentation history says occurred on 2004 Apr 15, and resulted in 79 pieces: http://orbitaldebris.jsc.nasa.gov/library/SatelliteFragHistory/TM-2008-214779.pdf The assessed cause was propulsion; these were the comments: "The spacecraft was non-operational at the time of the event. The electrical power generation system had been passivated by discharging the batteries and disconnecting them from the charging circuit. Virtually no nitrogen remained on board due to a leak detected early in the mission. The only energy source assessed to be on the spacecraft at the time of the event was approximately 6 kg of hydrazine." If the 94057A resulted in debris, then it is likely to enter the public catalogue over the next month or so. Two-lime elements probably would be published. Ted Molczan ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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