Re: USA-193 Interception

From: Igor Lissov (
Date: Tue Feb 19 2008 - 22:04:26 UTC

  • Next message: Jeff Umbarger: "How to Check NOTAMS for USA 193"

    > At the point of collision, two objects will come together with a closing
    > speed near that of orbital velocity. The catastrophic disruption of
    > and its interceptor will produce a debris cloud spreading evenly in all
    > directions but, overall, still having USA-193's original orbital
    > characterisics.
    One year earlier a simple analysis of Fengyun 1C debris pattern was
    made. The idea was that the relative velocity distribution for debris
    may be represented as the sum of an average delta-V vector and
    a random spherically distributed component.
    Taking into account 517 pieces of debris being known at the moment
    their positions at the time of impact (22:26 UTC) were checked and
    41 objects discarded with calcualted distances more than 100 km.
    The remaining 476 pieces had average relative velocities of
    (+4.8, +34.5, +51.7) m/s (in the direction of target satellite, its radius
    vector and to the right of the flight path correspondingly). Note: the
    +4.8 m/s values was calculated for only 419 fragments with deltaVv
    less than 100 m/s.
    So I think we can expect a somewhat similar pattern in the USA-193 case.
    Of course the relative direction of the SM-3 interceptor at the time
    of collision may be another leading to different components of the
    average delta-V vector.
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