RE: USA193 decay

From: Ted Molczan (
Date: Tue Jan 29 2008 - 22:10:37 UTC

  • Next message: John Locker: "Re: USA193 decay"

    Thomas Dorman wrote:
    > In the way the U.S. government is acting in this
    > matter and the reports of no solar panels being
    > observed. I am getting the gut feeling that this
    > satellite may have been powered by a Snap type power
    > unit.
    The apparent absence of solar panels in the brief, low-resolution imagery
    obtained to-date does not prove that they are not present. I hope that there
    will be additional opportunities to image it at closer range, between now and
    its decay from orbit.
    > Remember, no solar panels would make this
    > satellite harder to be seen which is good thing if you
    > put a spy satellite into orbit.
    Functioning solar panels tend not to reflect much light toward Earth, because
    they face the sun. In any case, solar panels or not, this object is readily seen
    with the unaided eye on favourable passes.
    Aviation Week and Space Technology has reported on a classified satellite which
    entered safe-hold mode just 7 seconds after reaching orbit, and never came out
    of safe-hold; I suspect this was in reference to USA 193:
    Entry into safe-hold so soon after reaching orbit may have precluded deployment
    of the solar-panels. Perhaps they generated some power in their stowed position,
    but insufficient to maintain the charge on the batteries.
    The late Ivan Artner and other radio monitors heard it transmit a strong signal
    on 2249.5 MHz for about 1.5 days after launch, after which it fell silent. On
    his final reception, Ivan experienced three signal dropouts of several
    millisecond duration, which may have been a sign of trouble with the transmitter
    or the power supply. All this seems consistent with failure to deploy solar
    panels, and subsequent rapid battery run-down.
    Ted Molczan
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