I have failed a number of times to find USA 116 over periods up to -5/+10 minutes from the last known amateur elset: 05249.USA 116 1 23728U 95066A 05249.06868391 0.00001700 00000-0 86728-4 0 05 2 23728 97.8648 18.4474 0285000 66.4251 293.5748 14.87800711 08 On March 01 2006 it could be about: 06060.USA 116 search 1 23728U 95066A 06060.00000000 .00001340 00000-0 68362-4 0 11 2 23728 97.8648 193.2006 0283660 207.3796 265.9304 14.88274589 26166 In this 176 day interval the AOP decreased from 66.4251 to about 207 by about 3.36 deg/day, ie it passed 0 twice and 180 once. Near these times (perigee at equator) drag usually increases. So I interpolated the MeanMotion from my available elsets at the times AOP had these values, and computed the average drag factor ndot2 from these over the years when eccentricity is about .030. I also computed ndot2 for USA 161 for the same dates - not the same AOP. So these average values should reflect the atmospheric conditions over the intervals, but could deviate in size. (Using consecutive elsets instead gives extremely irregular results for these relatively low-drag satellites) In fact the values do show the expected strong correlation, and I arrived at ndot2=.00001340 for this period, and Vec2TLE.exe gave me the search elset above. Unfortunately I have not had the weather to test this elset, and forecasts for the next five days do not look better. -- Björn Gimle -- -- COSPAR 5919, MALMA, 59.2615 N, 18.6206 E, 33 m -- -- COSPAR 5918, HAMMARBY, 59.2985 N, 18.1045 E, 44 m -- -- COSPAR 5920, FRUVIK, 59.3260 N, 18.4820 E, 11 m -- ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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