Ted Molczan wrote: >Ed Cannon reported an unidentified satellite in this post: > >http://www2.satellite.eu.org/seesat/Aug-2001/0231.html > >I believe that this object probably is USA 159 r (26881 / 01033B), the Titan IV >2nd stage of the DSP satellite launched on 2001 Aug 06 at 07:28 UTC. ... >I suggest the following search orbit, which is the above orbit, propagated to >the time of Ed's observation > >1 77002U 01228.12618056 .00439299 00000-0 52085-3 0 00 >2 77002 28.6455 181.9913 0373000 183.5141 268.1500 15.41279729 05 I also believe that Ed spotted the Centaur, but I have a slightly different search elset. I assumed that the two Spacecom elsets had some basis in reality. The mean motion for these elsets implies that 121 revolutions took place between the two epochs. What if the correct number is 122, not 121? I adjusted the drag and mean motion of the two elsets to arrive at the following: 1 26881U 01033B 01218.36215998 .00350000 00000-0 00000+0 0 18 2 26881 28.6968 249.1085 0243087 78.4785 282.1509 15.32300000 11 1 26881U 01033B 01226.28993968 .00350000 00000-0 00000+0 0 27 2 26881 28.6968 195.6121 0243087 165.2938 177.1552 15.37800000 1228 These two elsets are consistent with each other and consistent with Ed's observation. So I updated the second elset to the time of Ed's observation: USA 159 r 1 26881U 01033B 01228.10964050 0.00350000 00000-0 29718-2 0 00 2 26881 28.6968 183.0519 0243087 185.6723 174.3262 15.38904161 02 Unfortunately, the BStar term for this elset is much too high (based on past experience). Therefore it seems advisable to change the eccentricity up to the nominal value: USA 159 r 1 26881U 01033B 01228.10938691 0.00350000 00000-0 53502-3 0 01 2 26881 28.6968 183.0304 0370000 185.7071 174.2914 15.39074020 03 This is a more reasonable BStar value, so this is my recommended search orbit. The difference for this evening's predictions for Austin, TX between Ted's elset and my elset is about 90 seconds. The pass for Texas is very favorable about 9:20 PM CDT. Mike McCants ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www2.satellite.eu.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Thu Aug 16 2001 - 12:37:24 PDT