The following elements have been derived from observations by Leo Barhorst, Russell Eberst, David Hopkins, Marco Langbroek, Alberto Rango and Mike Waterman: USA 276 388 X 411 km 1 42689U 17022A 17153.82560436 .00005488 00000-0 75944-4 0 03 2 42689 50.0056 114.2278 0016538 121.0056 239.2540 15.56240034 05 Arc 20170528.83-0602.84 WRMS resid 0.095 totl 0.011 xtrk Below are updated conjunction estimates for the closest approaches on 2017 Jun 03 (today) with range <= ~100 km. ISS sub-satellite point USA 276 sub-sat point ------------------------- ------------------------- TCA Range Lat Lon Alt Lat Lon Alt UTC km deg deg km deg deg km 11:43:10 85.70 43.30 N 170.83 E 410.56 43.69 N 170.02 E 391.47 12:29:10 55.09 43.94 S 22.31 W 418.35 44.14 S 22.89 W 424.12 13:15:33 26.55 43.78 N 146.27 E 410.73 43.86 N 146.09 E 391.52 14:01:47 12.01 43.91 S 45.79 W 418.33 43.87 S 45.68 W 424.01 14:47:55 50.69 44.25 N 121.69 E 410.89 44.03 N 122.15 E 391.58 15:34:25 76.15 43.85 S 69.20 W 418.29 43.56 S 68.41 W 423.90 16:20:13 113.74 44.83 N 96.80 E 411.09 44.31 N 97.91 E 391.67 The above differ slightly from those I posted yesterday. For USA 276, I used the above TLE. For ISS, I used NASA's current estimated TLE for June 3: https://spaceflight.nasa.gov/realdata/sightings/SSapplications/Post/JavaSSOP/orbit/ISS/SVPOST.html 1 25544U 98067A 17154.59563486 .00016717 00000-0 10270-3 0 9023 2 25544 51.6395 106.0758 0004785 233.6024 126.4688 15.53983228 19632 If the intention is to perform an actual rendezvous, instead of, or in addition to a series of fly-bys, then USA 276 could manoeuvre to match the plane of ISS near one of the above times. If it is a no-show tonight in the above orbit, then it would be prudent to look for it in close proximity to ISS, or somewhere along its track. If delta-V is a significant constraint, then the minimum energy manoeuvre would occur on Jun 24, when USA 276 and ISS would have the same RAAN, leaving only a 1.6 deg change of inclination. Ted Molczan _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-lReceived on Sat Jun 03 2017 - 08:08:31 UTC
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