ULA reported yesterday that NROL-101 is targeted for launch on 2020 Nov 08 at 22:36 UTC, from Cape Canaveral, pending range approval. The launch vehicle is Atlas V-531 with a medium length fairing. https://spaceflightnow.com/2020/11/02/atlas-5-nrol-101-av-090-mission-status-center/ The NOTAMs reveal that the target orbit is high inclination. I estimate at least a 57 degree parking orbit, perhaps a few degrees higher. The launch time has regressed 4.4 min/d on average since Nov 3, which is consistent with a planar launch window of a Molniya orbit. I speculate that the payload is a 4th generation SDS relay satellite, as discussed in an earlier message: http://satobs.org/seesat/Nov-2020/0021.html Marco Langbroek's pre-flight estimated elements are available here: http://launchtower.langbroek.org/ Here are mine, based on the above launch time: Parking 209 X 262 km 1 78301U 78301A 20313.98997685 .00000000 00000-0 00000-0 0 01 2 78301 60.0091 295.2414 0040000 106.8858 180.0000 16.14000000 05 MECO2 258 X 16775 km 1 78302U 78302A 20313.98997685 .00010087 00000-0 10000-2 0 02 2 78302 60.0097 295.2422 5544404 286.8848 0.0033 4.77567019 02 Parking 191 X 795 km 1 78303U 78303A 20313.98761574 .00000000 00000-0 00000-0 0 01 2 78303 62.5000 296.3630 0439500 90.0105 180.0266 15.23880000 01 MECO2 727 X 38378 km 1 78304U 78304A 20313.98761574 .00000000 00000-0 00000-0 0 03 2 78304 62.5000 296.3630 7260000 266.0000 0.5000 2.07900000 08 The epoch of these TLEs is close to the time of MECO2. TLEs 78301 and 78302 are based on the orbits we determined from our optical and radio tracking of the SDS 3-4 launch in December 2007. The launch vehicle was Atlas V-401. TLEs 78303 and 78304 are based on the orbits I estimated for SDS 2-5, launched in January 1998 on an Atlas 2A rocket. It is the only SDS launched from Cape Canaveral, that the upper stage inserted into nearly its final 2.006 rev/d orbit. The LEO parking orbit is derived from the partial elements reported to the U.N. The MECO2 orbit is estimated from the known elements of the Centaur, after numerical propagation to the day of launch. Happy hunting! Ted Molczan _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-lReceived on Fri Nov 06 2020 - 07:55:30 UTC
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