Does the shuttle fly ahead of the ISS?

From: Walter Nissen (
Date: Wed Dec 04 2002 - 11:59:23 EST

  • Next message: John locker: "STS 113 latest keps ?"

    With powered vehicles much is possible, but very little of that is
    This is the scenario which has repeated many times:
    When launched to the ISS, the shuttle enters an orbit very similar to
    that of the ISS.  But this orbit is lower and, thus, faster.  So as the
    shuttle approaches the ISS, during overflights, the ISS will be seen to
    be leading the shuttle.
    When leaving the ISS, the shuttle often performs a fly-around in the
    immediate vicinity of the ISS.  You would need a telescope to separate
    the images.  Then she again enters a lower and faster orbit.  So then,
    during overflights, the shuttle will be seen to be leading the ISS.
    Propagation from typical elsets, such as is obtained from Heavens-Above,
    does not refute this scenario.  Great care is required to analyze the
    detailed meaning of elsets, which are somewhat deficient because they
    presume unpowered flight and somewhat inaccurate when applied outside a
    limited-duration interval of time.  An elset intended for a day may be
    quite different than that intended for a month.
    Any variation from the scenario described here would be of very high
    interest.  But it is not helpful when observers (or kibitzers) post
    spurious "results" of propagation based on disparate elsets.
    As I understand it, no actual variations were noted for STS-113.
    Last evening, during a 32-degree altitude pass here, the dynamic duo
    were, anomalously, invisible naked-eye, but very bright in binoculars.
    I cannot offer an explanation for this.  It was very much unexpected.  I
    recall a discussion with Jay Respler about whether EGP should be
    included in his list.  I've never seen it naked-eye.  But from seeing it
    in binoculars from horribly polluted sites, I am under the impression it
    should be easy naked-eye from a dark site.
    Careful observations demolish unwarranted assumptions.
    Walter Nissen         
    -81.8637, 41.3735, 256m elevation
    Wouldn't a conservative be _opposed_ to experimentation on his only
    available atmosphere?
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