DMSP F18 is scheduled for launch on 2009 Oct 18, between 16:12 UTC and 16:22 UTC, from Vandenberg AFB, aboard an Atlas 5-401 rocket. The launch vehicle's performance far exceeds mission requirements; so much so, that its Centaur stage will be disposed of in an unusual manner: a heliocentric orbit. That burn will be visible from parts of Europe about 3 h after launch, followed within minutes by the dump of any remaining propellant. Assuming launch at the start of the window, DMSP F18 will enter approximately the following orbit: DMSP F18 838 X 853 km 1 72900U 09291.72202813 .00000000 00000-0 00000-0 0 07 2 72900 98.8000 325.8000 0010000 270.0000 90.0000 14.13250000 08 On the first pass of Europe, beginning near 17:30 UTC, the Centaur is likely to lead the DMSP by several seconds in time. One rev later, at 19:10:07 UTC, while northbound over ~30 N, 6 E, the Centaur will begin a 220 s burn. At 170 s into the burn, it will reach escape velocity. By the end of the burn, it will have considerably exceeded escape velocity, by 1 or 2 km/s, I estimate. My implementations of the SGP models begin to misbehave well short of escape velocity, so for the search elements, I settled for a ~500,000 km apogee: DMSP F18 r 925 X 508891 km 1 72901U 09291.79869216 .00000000 00000-0 00000-0 0 01 2 72901 98.8000 325.9000 9720500 29.8676 359.9900 0.06500000 02 This elset seems to yield the most reasonable altitudes when used with SGP4 or the old SGP. SDP4 yields less accurate results. The blow down will begin at 19:17:14 UTC, and will last for more than 13 min. Spaceflight Now will cover the launch: http://www.spaceflightnow.com/atlas/av017/status.html The press kit is here: http://www.ulalaunch.com/index_launch_info.html Ted Molczan ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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