RE: Shenzhou 5: additional pieces catalogued

From: Ted Molczan (molczan@rogers.com)
Date: Fri Oct 17 2003 - 01:53:15 EDT

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    A further search of Jonathan McDowell's indispensable Satellite Catalog yields
    evidence that convinces me that the elliptical orbit debris from the Shenzhou 1
    and 5 launches are separation motor covers.
     
    http://www.planet4589.org/space/logs/satcat.txt
    
    Consider this excerpt from the Satellite Catalog for an Iridium launch by China:
    
    
                                                   Perigee   Apogee   Inc
    S025779 1999-032C  CZ-2C Stage 2                 174      610    86.3
    S025781 1999-032E  CZ-2C Stage 2 motor cover     174      742    86.0
    S025782 1999-032F  CZ-2C Stage 2 motor cover     175      737    86.6
    S025783 1999-032G  CZ-2C Stage 2 motor cover     173      777    86.6
    S025784 1999-032H  CZ-2C Stage 2 motor cover     174      758    86.1
    
    Just as with the Shenzhou 1 and 5 launches, the covers were ejected at first
    perigee (i.e. orbital insertion) from the 2nd stage, with sufficient velocity to
    raise their apogee by 120 - 170 km relative that of the stage, including an out
    of plane velocity component sufficient to alter their inclination by 0.3 deg,
    relative the stage.
    
    I believe I can explain the out-of-plane velocity component. The separation
    motors fire shortly after the spacecraft separates from the 2nd stage. The
    in-plane component decreases the apogee of the 2nd stage, achieving the desired
    separation. To avoid the motor exhaust hitting the spacecraft, the motors are
    aimed somewhat away from the velocity vector, resulting in the out-of-plane
    velocity component of the ejected motor covers. The plane of the 2nd stage is
    not affected, because the motors are spaced symmetrically.
    
    Why 2 covers on Shenzhou 1, none on missions 2 through 4, and four on mission 5?
    I suspect four were ejected on each launch, but not always detected by
    USSTRATCOM. The objects are small and decay rapidly, so it is not difficult to
    imagine their going unnoticed.
    
    I believe that understanding the origin of the debris provides evidence helpful
    in deciding which piece catalogued from Shenzhou 1 was the 2nd stage rocket, and
    which one was the spacecraft. There was so much cross-tagging among pieces, that
    it took quite an effort to group all of the elsets by object.
    
    On that first mission, the Shenzhou did not circularize its orbit, so it
    remained in an orbit similar to that of the 2nd stage rocket; however, the
    rocket stage should have been in a lower orbit as a result of the firing of its
    separation motors, and also because of its greater ballistic coefficient.
    
    I found only one elset that could be of the intact spacecraft:
    
                                                                214 X 341
    1 25956U 99061A   99324.60834382  .00606827  83585-5  56001-3 0    60
    2 25956  42.5956  23.0886 0095292 134.3737 226.4995 16.02245812    77
    
    The epoch of this elset was for the ascending node of 14:36 UTC, which was more
    than 2 hours before retro-fire. If it can be safely assumed that the OM would
    not yet have been jettisoned, than this certainly was the main spacecraft's
    orbit.
    
    Here is the earliest one of the rocket:
                                                                206 X 335
    1 25957U 99061B   99324.48312468  .01120080  83940-5  83715-3 0    29
    2 25957  42.5973  23.8808 0096522 132.0774 228.8342 16.04716322    53
    
    Amazingly, given the rampant cross-tagging, these two elsets have the correct
    identifiers.
    
    Also, I see evidence in the spacecraft's elements of one or more small
    manoeuvres, which would make sense as part of the checkout of the new
    spacecraft.
    
    Finally, here are the first two elsets of the orbital module, cross-tagged as
    the rocket!
    
                                                                214 X 339
    1 25957U 99061B   99324.79532490  .01480763  83373-5  13432-2 0    72
    2 25957  42.5919  21.9072 0094151 132.0005 228.7773 16.02625447   106
    
                                                                215 X 339
    1 25957U 99061B   99324.91998841  .00111823  83739-5  10691-3 0    81
    2 25957  42.5967  21.1065 0092983 136.7229 224.1627 16.02406107   123
    
    Note that the epoch of the first of the OM elsets was for the ascending node at
    19:05 UTC, just minutes after retro-fire. Depending on when the USSTRATCOM
    observations were made, I suppose this could still have been the main
    spacecraft. If their practice is to use as epoch the first ascending node before
    the latest observation, then this would be the OM; if they use the nearest
    ascending node, then this could be the main spacecraft.
    
    
    On Shenzhou 2, for the first time the spacecraft circularised its orbit, but
    USSTRATCOM managed to issue at least two elsets of its insertion orbit:
    
                                                                206 X 345
    1 26664U 01001A   01009.88060300 -.00002661  84174-5 -20482-5 0    12
    2 26664  42.6086 354.6303 0104726 129.6363 231.3322 16.02871692    37
    
                                                                206 X 342
    1 26664U 01001A   01010.40241568  .00488707  83774-5  37833-3 0    62
    2 26664  42.5771 351.2888 0102358 134.0200   2.1938 16.03316553   114
    
    Here is the rocket, in its lower orbit, similar to that of Shenzhou 1's rocket:
    
                                                                206 X 337
    1 26665U 01001B   01010.37860834  .00854908  83828-5  63599-3 0    59
    2 26665  42.5762 351.4325 0098279 133.6717 227.2330 16.04483912   107
    
    On Shenzhou 3, USSTRATCOM did not issue any elsets of the spacecraft in its
    insertion orbit. Here is the first stage of the rocket:
                                                                207 X 335
    1 27398U 02014B   02085.07727699 -.00002621  82924-5 -19736-5 0    16
    2 27398  42.3957  25.7386 0096714 132.3633 228.5476 16.04519287    85
    
    On Shenzhou 4, USSTRATCOM managed to issue at least one elsets of the
    spacecraft's insertion orbit:
    
                                                                207 X 341
    1 27630U 02061A   02363.99130504 -.00002620  82868-5 -20368-5 0    19
    2 27630  42.4085 338.1747 0100490 131.4080 229.5479 16.03477566    55
    
    This was the first accurate elset of the rocket, though cross-tagged as the
    spacecraft:
    
                                                                206 X 338
    1 27630U 02061A   02364.32865137  .00788058  82648-5  58603-3 0    37
    2 27630  42.4069 336.0138 0099929 134.5463  16.8336 16.04205144   108
    
    
    On Shenzhou 5, USSTRATCOM did not issue any elsets of the spacecraft in its
    insertion orbit. Here is the first stage of the rocket:
                                                                206 X 338
    1 28044U 03045B   03288.46291200  .00131960  82982-5  10000-3 0    17
    2 28044  42.4135  27.5435 0099075 132.5549 228.3729 16.04321165    62
    
    There may be evidence of the spacecraft's slightly higher initial orbit, in the
    form of an observation from New Zealand, just 10 minutes prior to the
    spacecraft's circularization burn. The observer was puzzled as to the identity
    of a fainter object trailing behind what he beloved to have been the spacecraft.
    I am attempting to contact the observer to obtain further details, but I
    strongly suspect that the brighter leading object was the rocket, and the
    fainter one was the spacecraft. A number of people mistook the tumbling rocket
    for the spacecraft, unaware that the spacecraft was not far behind. I will post
    a follow-up if I receive any further information from New Zealand.
    
    Ted Molczan
    
    
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