Recent observations by David Brierley and Russell Eberst reveal that the NOSS 3-4 pair have nearly completed their manoeuvres to compensate for the under-burn of the Centaur upper stage that inserted them into too low an orbit, during launch on 2007 June 15 UTC. Over the past 7 months, both spacecraft have made in excess of 50 corrective manoeuvres. Here is a plot of their manoeuvre history, expressed in percentage of completion of the altitude-raising: http://www.satobs.org/seesat_ref/NOSS_3-4/NOSS_3-4_altitude_progress_2.pdf Below are preliminary elements, based on David's and Russell's observations. The residuals are low, but further refinement in the elements is likely, as additional observations are made. NOSS 3-4 (A) 0.0 0.0 0.0 4.9 v 1019 X 1186 km 1 31701U 07027A 08043.25141745 .00000012 00000-0 20000-4 0 04 2 31701 63.4199 137.5539 0111330 143.1587 217.7154 13.41435450 04 Arc 2008 Feb 06.23 - 12.27, WRMS residuals = 0.019 deg NOSS 3-4 (C) 0.0 0.0 0.0 4.9 v 1018 X 1187 km 1 31708U 07027C 08043.25166580 .00000012 00000-0 20000-4 0 05 2 31708 63.4065 137.7264 0112790 142.1549 218.7474 13.41435895 07 Arc 2008 Feb 06.23 - 12.27, WRMS residuals = 0.033 deg The elements reveal that the inclination has been corrected; it had been about 63.35 deg; the nominal value is near 63.43 deg. Some time ago, they also manoeuvred to establish the operational planar spacing between them, about 0.2 deg. The main remaining defect is in the argument of perigee; the nominal initial value is about 180 deg; the current values are about 143 deg. I doubt this can be corrected. Currently, 07027C trails 07027A by about 21 s; eventually, this will be reduced to the nominal value of about 8 s. Eventually, the pair will manoeuvre to synchronize their mean motion to that of the other operational NOSS groups, about 13.40515 rev/d. Additional information on the NOSS satellites is available here: http://www.satobs.org/noss.html Ted Molczan ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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