CGRO Re-entry!

From: Steve Walter (
Date: Sun Jun 04 2000 - 02:08:28 PDT


    Hi All ...
    Word has it that CGRO actually re-entered at 06:13z [2:13am ET], over 
    the Pacific southeast of Hawaii.
    The operations-side of things was VERY smooth, with very few concerns.
    The third burn this evening went off well.  The subsequent (low) 
    perigee passing got the attention of the attitude-control guy, who 
    stated that there were obvious aerodynamic torques with thrusters 
    firing (essentially continuously) -- and that he hoped we would not 
    have to do this again on the next orbit.
    Burn #4 also went smoothly, and we transitioned to the desired 
    parking attitude for the ride down to the ocean.   We were each 
    looking at our individual subsystems to try and detect anything 
    anomalous.  However, it winds up that there was VERY little to catch 
    ... at the very end, we had a minute or so of detectable attitude 
    control errors and rates diverging (confirmation that CGRO was 
    tumbling due to atmospheric drag overcoming the thruster control), 
    and 1 report of temperatures jumping 40-degrees F.   [I could not 
    confirm this on my own temperature display page.]   Then, we lost 
    telemetry -- and had to await NORAD confirmation of re-entry, which 
    came by 6:18z.
    We were all quite pleased -- but amazed -- that things went so smoothly.
    Tho a shame that we had to kill off science operations -- this was 
    still a neat -- and GREAT learning -- experience!
    Steve Walter
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    This archive was generated by hypermail 2b29 : Sun Jun 04 2000 - 02:08:15 PDT