Depletion burn obs report

From: Daniel Deak (
Date: Wed Feb 09 2000 - 09:42:07 PST

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    Hi all,
    Here is my complete report for the depletion burn obs on Feb. 8, 2000.
    It was not from site 1746 but from 45.899 N, 72.433 W, 87 m.
    I was with 2 other satellite observers.
    I used a tape recorder for the timing of the events and 7x35 binoculars
    for the observation. My 20x80 were ready on a tripod but I had no time
    to use them as everything went fast for me. All times given below are UTC.
    23:14:00  Start of recording and search for the Globalstar objects using a
    Sat Spy skymap. It was already too late to acquire them in Pegasus as I
    wanted to do at first to be sure to catch the engine restart exact time.
    23:15:53  Just got my eyes in my binocs in Perseus almost overhead at the
    same time the burn was to begin. Search for the rocket stage.
    23:16:01  Acquisition of the stage. The burn was already in progress. It was
    much fainter than anticipated. As Ron Lee reported, burned liquid propellants
    produce few particulates to reflect sunlight. I noticed a brighter arc at the
    beginning of the plume while the plume itself appeared like faint parallel streaks
    emanating from the stage. It was going downward from my point of view.
    23:16:10  Plume continues to grow and stays faint.
    23:16:14  Acquisition of the 4 Globalstar satellites. They were in 2 pairs in
    line with the direction of motion and separation was about 1 degree between
    the first and the fourth. They were lower in elevation than the stage and in
    front of it.
    23:16:19  The plume was about 4 degrees in length and I saw a second arc
    emanating from the stage telling me it was the end of the burn. Shape was
    triangular with a convex base. See
    After that, I dropped my binocs to watch naked eye. The plume was not visible
    but to my great surprise, the stage was and reached mag +1 or 0 with an
    orange or gold colour at 23:16:26. The fuel dump was in progress.
    23:16:37  Shape of this much brighter plume was triangular also and was seen
    in binocs a few second after it began. It was already visible naked eye at mag
    2 or 3. So it looks like there is a 5 to 10 seconds delay before the dump
    takes place after SECO 4. Orientation was still downward but more to the
    23:16:54  The plume has reached 3 degrees as seen naked eye. It was
    moving along with the rocket and appeared oriented to the northwest. The
    trumpet shape was then evident as the fuel did not disperse as in the
    beginning of the dump.
    23:16:59  The venting stopped
    23:17:09  The venting restarted. The interruption was visible in the plume.
    See drawing at
    23:17:20  Plume has reached 7 degrees in length.
    23:17:38  Plume still visible naked eye at about 45 deg. elevation
    23:17:51  The 4 sats were engulfed in the plume that continues to grow.
    In fact, the satellites are higher. Fuel is still seen coming out of the stage
    which is getting farther and farther from the sats towards the southeast.
    23:18:28  The 4 sats are still visible naked eye at mag 3.5 to 4.
    23:18:40  Still some "fog" around the stage.
    23:19:09  Stage is now 7 degrees right of the sats. Plume remnants barely
    visible in binocs.
    23:21:19  I'm following the 4 sats and they start dimming as they near shadow
    23:21:26  The sats are no longer visible (shadow entry).
    23:21:40  End of recording.
    To resume, the obs lasted 5 min 25 sec. The fourth burn was seen except
    for the beginning and it was not visible naked eye, faint in my 7x35 but
    the start and end of the plume is noticeable by its higher brightness surely
    caused by unburned propellant.
    Five to ten seconds later, there really was a fuel dump that is spectacular to
    see naked eye and lasted for about 2 min 15 sec. Last August, this plume
    appeared almost stationnary due to its low elevation. This time it moved
    fast because we were almost right under. And the shape was more trumpet-
    like maybe for the same reason or because it lasted longer.
    I did not take positional measurements but the elset seemed to be quite
    accurate both in time and in position.
    It was a great experience and wish I could have had more time to prepare
    myself at the observation site, but my schedule was tight yesterday.
    Daniel Deak
    Drummondville, Québec
    COSPAR site 1746 : 45.8537°N, 72.4857°W, 90 m., UTC-5:00
    E-mail :        ICQ : 52770063
    Site en francais sur les satellites:
    French-language satellite web site :
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