Hi all, We might have another classified payload going into an unusual orbit tomorrow. NROL-47 is slated to launch from Vandenberg SLC-6 tomorrow January 10. The Maritime Broadcast Warning window opens at 20:30 UT and ends January 9 at 1:26 UT. The launch hazard areas and Upper Stage deorbit hazard area from the Broadcast Warnings point to an unusual orbital inclination: 108.6 degrees. Some websites (e.g. Spaceflight 101) have speculated NROL-47 is the fifth TOPAZ (FIA Radar) based on the fact that it is launched westwards into retrograde orbit. If so, it is going into a different kind of orbit than the previous four ones, both regarding inclination (the four FIA satelites have an orbital inclination of 123.0 deg) and orbital altitude. The launch azimuth from the launch hazard areas published differs by 20 degrees from previous FIA launches. And there is no need for a dogleg manoeuvre, as previous FIA launches launched directly into a 123.0 degrees inclination orbit. From what appears to be the Upper Stage de-orbit hazard area near Antarctica and the time it opens (23:23 UT) as well as its shape, an orbital altitude near 1500 km is indicated. Previous FIA are in 1100 km orbits. So the identity of NROL-47 remains a questionmark and I am not convinced it must be a FIA/TOPAZ. It could be some other new radar (the retrograde orbit suggests it is a radar satellite). Here is an orbit estimate for launch on 10 January 20:30 UT: NROL-47 launch 2018-01-10 20:30 UT 1495 x 1505 km 1 70000U 18999A 18010.85416667 .00000000 00000-0 00000-0 0 09 2 70000 108.6398 105.5134 0006347 166.4011 308.2684 12.41559515 01 Here is an alternative orbit for an 1100 km orbital altitude (FIA, but in a different orbital plane): NROL-47 launch 2018-01-10 20:30 UT 1100 x 1110 km 1 70001U 18999A 18010.85416667 .00000000 00000-0 00000-0 0 00 2 70001 108.5831 105.5134 0006682 166.4011 304.1188 13.41149813 06 Allow for several minutes difference in pass time and several degrees cross-track. South Africa might have visibility on the first pass near 21:38 UT and the second pass near 23:30 UT. - Marco ----- Dr Marco Langbroek - SatTrackCam Leiden, the Netherlands. e-mail: sattrackcam_at_langbroek.org Cospar 4353 (Leiden): 52.15412 N, 4.49081 E (WGS84), +0 m ASL Cospar 4355 (Cronesteyn): 52.13878 N, 4.49937 E (WGS84), -2 m ASL Station (b)log: http://sattrackcam.blogspot.com Twitter: _at_Marco_Langbroek ----- _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-lReceived on Tue Jan 09 2018 - 16:57:36 UTC
This archive was generated by hypermail 2.3.0 : Tue Jan 09 2018 - 16:58:26 UTC