Now that we know that the Centaur's orbit has been rising, I am beginning to suspect that a third NOSS may yet be deployed. Perhaps the Centaur is just outgassing or leaking, but consider the following: In terms of RAAN, argument of perigee and mean motion, the orbits of the two NOSS and the Centaur are rather similar to the geometry and altitude of an operational NOSS orbit: NOSS Leader 1 71001U 03054A 03343.77910648 .00000057 00000-0 10000-3 0 05 2 71001 63.4259 285.0442 0127151 180.9376 179.1429 13.39783980 00 NOSS Trailer 1 71002U 03054B 03343.77945003 .00000057 00000-0 10000-3 0 09 2 71002 63.4329 285.0679 0124587 180.9254 179.1558 13.39757203 08 Centaur 1 71003U 03054C 03343.77469956 -.00002230 00000-0 -38302-2 0 09 2 71003 63.6867 284.6485 0139957 183.5168 176.4888 13.40519591 02 The leader and trailer are in nearly the same plane, and have nearly the same argument of perigee. The Centaur's orbit is awfully similar to that of a NOSS outlier - its RAAN is a fraction of a degree lower than that of the leader and trailer, and its argument of perigee is a few degrees greater. The two NOSS were deployed into an orbit a few kilometres higher than that of an operational NOSS, but have made their first manoeuvres downward. The Centaur's orbit is a bit lower than that of an operational NOSS, but it has been gradually gaining altitude, apparently for about the past 6 days. The Centaur's inclination is about 0.27 deg too high, but this has the effect of causing its plane to precess 0.02 deg/d more slowly than that of the two NOSS. such that the two planes are drawing together. Initially, they were about 0.56 deg apart, but already they have closed to within about 0.41 deg, and within about 10 days, they will be at the approximately 0.2 deg operational separation between a NOSS leader and trailer and a NOSS outlier. So perhaps the Centaur's fuel-depletion burn was in fact the burn to create the separate orbit required by a NOSS outlier. IF the deployment of a third NOSS remains pending, it may explain USSTRATCOM's continuing delay in providing NASA/OIG with any catalogue entries for this launch. There remain aspects of the 2001 launch that hint at a failure to deploy a third NOSS. For example, there was the apparently botched cataloguing of objects by USSTRATCOM - reporting only one payload (USA 160), and reporting the other one as a piece of debris, and then failing to assign USA 163 and 165 to any payload. There were the 2 months of manoeuvres, which seemed to accomplish little more than to vary the two NOSS's along-track separation, perhaps suggestive of experiments to find an optimal work-around for an un-planned 2-satellite configuration. If the 2001 launch was a new design requiring only two NOSS, then why did they ultimately manoeuvre to separate their planes by the same amount as a NOSS triad - in effect forming a triangle formation with one member missing? One possible interpretation of this could be that the NRO/Navy already had years of experience operating pairs of NOSS in such orbital geometries, after the failures of single members of triads. There remain important questions to be answered abut the newest NOSS launch, Why would the NOSS outlier remain attached to the Centaur for days after launch? Does this mean that the Centaur is to perform further manoeuvres? If the Centaur's orbit is being manoeuvred, then what propulsion system is being used? Can its cryogenic propellants remain viable for days or weeks after launch? Can Centaurs be provided electrical power to operate in orbit for days or weeks, instead of the usual less than 12 hours? Then there is the matter of attitude control. Russell Eberst reports the Centaur's brightness varying regularly, with a period of 13 s, and an amplitude of about 1.5 magnitudes. Peter Wakelin has reported amplitudes of 2 or 3 magnitudes. Is this evidence of spin stabilization or of a tumble? The variation has seemed more subtle to me, but I find it difficult to concentrate on positional obs and brightness at the same time, so probably I have not been paying close enough attention to be able to comment with precision. Perhaps the Centaur is only outgassing or leaking, but I believe that we need to pay very close attention to it and the along-track space in its vicinity. 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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