Re: STS 107 waste water dump schedule

From: Scott D. Young (
Date: Mon Jan 20 2003 - 17:07:48 EST

  • Next message: paul: "obs 21jan"

    I'd add that the water dumps are often visible after the actually dump has
    finished... the cloud of ice crystals can take several orbits to disperse. I
    saw an ISS water dump that preceded the ISS/shuttle by almost a full minute,
    that appeared as a dramatic 40-degree "comet" following the same path.
    ----- Original Message -----
    From: "Ted Molczan" <>
    To: "SeeSat-L" <>
    Sent: Monday, January 20, 2003 3:40 PM
    Subject: STS 107 waste water dump schedule
    > Thanks to Glenn Talbert's post yesterday, I now understand that the start
    and end of waste water dumps are denoted in the flight
    > plans using the mostly opaque terms SIMO INIT and SIMO TERM.
    > Here are the currently scheduled waste water dump periods for the
    remainder of STS 107:
    >  Date         UTC
    > Jan 22   17:45 to 19:05
    > Jan 26   02:40 to 04:10
    > Jan 28   17:25 to 18:55
    > Jan 31   04:35 to 05:40
    > A waste water dump is visible to the unaided eye as an illuminated plume
    extending from the shuttle, creating a surreal looking
    > comet. The water freezes into ice crystals which reflect sunlight, so the
    phenomenon is visible only when the plume is in sunlight,
    > and the observer in darkness.
    > Please note that in the flight plan, the start and end times appear to
    fall within a 15 min range. This may have more to do with
    > having to providing sufficient space to print the words SIMO INIT and SIMO
    TERM. In any case, the above start times are the earliest
    > shown and the end times are the latest shown.
    > A quick look at the above schedule and the shuttle's predicted ground
    track indicates that North American observers will not see any
    > of the dumps.
    > On Jan 22 and 28, South Africa will have passes during water dumps, but
    both occur near sunset. The orbiter should be visible, but
    > the plume is likely to be too faint to be seen against the bright sky.
    > On Jan 31, The Mediterranean should have a great view of the final water
    dump when the shuttle emerges from eclipse at about 05:08
    > UTC. For example, Rome's pass will culminate about 40 deg in the south.
    > Observers elsewhere on Earth should run predictions to determine whether
    or not they will have favourable passes during the above
    > periods. Always use the latest shuttle elements, in case it manoeuvres.
    Also, please be aware that the water dump schedule could
    > change. The schedules are available here:
    > Ted Molczan
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