Both payloads were about 2 s early on Peter Wakelin's consecutive passes, revealing that they had manoeuvred a bit lower, and approximately matched their orbital periods. Their along-track separation was about constant, at approx 25.7 s of time. To update the payloads' orbits, I used Peter's post-manoeuvre observations to update the epoch, RAAN, mean anomaly and mean motion: Observation arc 2003 Dec 07.70 - 07.78 UTC: NOSS leader 0.0 0.0 0.0 4.9 v 1 71001U 03054A 03341.76384611 .00000057 00000-0 10000-3 0 07 2 71001 63.4167 290.1495 0132436 179.7256 180.3864 13.39773455 01 WRMS residuals = 0.014 deg Observation arc 2003 Dec 07.70 - 07.78 UTC: NOSS trailer 0.0 0.0 0.0 4.9 v 1 71002U 03054B 03341.76414389 .00000057 00000-0 10000-3 0 04 2 71002 63.4199 290.1604 0130703 180.1208 179.9806 13.39766011 07 WRMS residuals = 0.013 deg Observation arc 2003 Dec 03.97 - 07.78 UTC: NOSS 3-2 r 10.1 3.0 0.0 3.7 v 1 71003U 03054C 03341.76053192 .00000058 00000-0 10000-3 0 07 2 71003 63.6730 289.7091 0143378 182.5667 177.4640 13.40535781 01 WRMS residuals = 0.010 deg The 0.036 s difference in orbital period between the payloads is insignificant, given our nominal measurement accuracy of 0.1 s. A number of additional manoeuvres can be expected in the coming weeks, perhaps months, until the payloads match the approximately 13.4044 rev/d mean motion of the other active NOSS triads and duos. Also, they are likely to separate their planes by about 0.2 deg. There are some notable differences between the news MOSS's first manoeuvres and those of the pair launched in 2001. Both new NOSS manoeuvred about 5 d after launch; in 2001, the leader manoeuvred 9 d after launch; the trailer, 16 d after launch. The new NOSS nearly matched their orbital periods after their first manoeuvres; the 2001 did not do so until later manoeuvres. Ted Molczan ----------------------------------------------------------------- To unsubscribe from SeeSat-L, send a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@satobs.org List archived at http://www.satobs.org/seesat/seesatindex.html
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