> > The possible major re-boost manoeuvre had not occurred as of Greg's > observation on Nov 24, at 20:27 UTC. > > It now seems unlikely that the KeyHoles will manoeuvre at the current > opportunity, but since I don't know the exact tolerances (in terms of > allowable distance of perigee from equator), I am continuing the alert > a bit longer. > > I expect the next re-boost opportunity to occur on or about 2000 Dec 03, when > USA 116's argument of perigee crosses the equator. > I'd be surprised if it was delayed that long. The perigee position is most relevant if the inclination, and with that the precession rate of the orbital plane, needs to be adjusted. Since USA 116 and 129 orbits are quite similar in that respect, the major operating requirement may be the separation of the ground tracks, so one is approximately midway between the tracks of the other, especially on the daylight side? At the time of the April 26 reboost, USA 116 passed 159.7 minutes after USA 129, 8.3 degrees east of USA 116's track. During summer, this reached a minimum of 134 minutes (and 14.8 degrees east). See http://www.algonet.se/~b_gimle/lostfoun.htm On Sep.07 it reached 159.9 minutes again (and 8.4 degrees, so the relative precession was almost nil), and USA 129 got a small reboost. This was so small, that about four weeks later the situation was the same, however this time USA 116's apogee was lowered! (From two elsets before, and two elsets after (diff >55 days) the reboost was not until Oct.14-20). Again, the correction was so small that it wouldn't last long. On Nov.18 the separation reached 159.9 minutes (and 8.5 degrees) again, and on Nov.24 it had increased another 5 minutes. On Dec.03 it would become as high as 173 minutes, and have a very unsymmetric ground track separation - 5.3 degrees only. My guess is that the major reboost was performed on day 329. ----------------------------------------------------------------- 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 : Sun Nov 26 2000 - 05:30:50 PST