NOSS 3-2 - there may yet be a third payload.

From: Ted Molczan (molczan@rogers.com)
Date: Tue Dec 09 2003 - 23:33:46 EST

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    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
    
    
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