The Planetary Society issued a TLE of LightSail yesterday afternoon: http://sail.planetary.org/tles/live.txt 355 X 702 km 1 91919U 15999A 15140.67013889 .00040047 00000-0 10233-2 0 04 2 91919 54.9991 339.9648 0250932 182.3369 74.3135 15.12540571 18 It is similar to one of the published pre-launch variants; the main difference is that the inclination is 2 deg less. The manoeuvre to this orbit occurred near its first perigee, which also was near the first descending node of OTV 4, 2015 May 20 15:44:44 UTC, over 45.840 E. Propagating the above orbit to that time and changing inclination, eccentricity and mean motion, yields the following OTV 4 search TLE: OTV 4 search 359 X 361 km 1 74995U 74995A 15140.65606480 .00040047 00000-0 10233-2 0 03 2 74995 39.0000 340.0258 0001000 182.3031 357.6777 15.70500000 09 The inclination is derived from the NOTAM, assuming no yaw-steering. I cannot rule out yaw-steering; therefore, the true inclination may well be different, perhaps up to several degrees higher. This result is similar to the 74996 TLE I posted pre-launch (the main difference is ~2 deg in RAAN). I offer the 74995 TLE in support of the search for OTV 4. It should be used with reasonable allowance for uncertainty in the mean motion and inclination. Historically, the X-37B has tended to maintain a constant altitude for long periods, achieved by means of frequent small manoeuvres to counter the effects of drag. Large orbit manoeuvres have been infrequent; however, X-37B is highly manoeuvrable, which has the potential to complicate the search. Ted Molczan _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-lReceived on Thu May 21 2015 - 08:41:39 UTC
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