Observing the "extreme" perigee of 20698

From: MALEY, PAUL D. (JSC-DO) (paul.d.maley1@jsc.nasa.gov)
Date: Mon Mar 06 2000 - 08:49:47 PST

  • Next message: Jim: "Re: SkyMap downloads"

    Last week I attended a conference in Albuquerque, New Mexico from March 1-3.
    Before leaving Houston, I ran predictions for a number of visible satellites
    and found that the perigee of the auxiliary motor 20698 was oddly positioned
    just to the west and south of the city. The interesting thing about the
    motor is that its RCS is about 1 meter squared which was similar to that of
    the recently decayed STARSHINE.  I sent an email to Alan to find out the
    decay date of this object to see if the decay was close at hand. Luckily it
    was not. 
    
    But the mean motion was indeed increasing gradually, so I had to run
    continuing elsets to verify whether the perigee was really where it was
    supposed to be due to its low altitude. In fact, QUICKSAT produced altitudes
    ranging from 123 to 132 km (77 to 83 miles) altitude on the mornings of both
    March 2 and March 3. The first opportunity was far to the west but a storm
    moved in and clouded over the whole area. Luckily the sky cleared late on
    March 2. I did not have a PC with me so I resorted to finding a public
    library that had an internet connection so I could try to get the latest
    TLEs from OIG. Yet, when I got on the machine I found the language was
    entirely in Spanish and the Gateway PC did not have DOS! I finally had some
    elsets faxed to me and located a PC belonging to a conference attendee.
    Elsets showed that the perigee was gradually rising but the lighting was
    going to be marginally perfect. Earth shadow exit point was anti-sun 43
    degrees above the west north west. I decided to drive 48km (30 miles) south
    to Belen where the motor was to fly directly overhead. I had seen this motor
    before at a range of 3200km where it was magnitude 9.8, so I had estimated
    that it could be as bright as +3 at perigee. 
    
    As the pass time of 12h52m UT on March 3 approached I found a dirt road
    1.6km (2 miles)west of the interstate highway at Belen. Rats were seen
    scurrying across the road in the darkness so I made sure to position myself
    on top of the rental car. Stars to  magnitude 4 were faintly visible, and
    the thin crescent moon appeared low in the east as dawn was starting to
    creep in. Just prior to 12h53m a white dot at magnitude 3.5 shot out of the
    earth's shadow in Ursa Major. It gradually brightned to +3 before fading
    quickly at the zenith. It was visible for about 16 seconds and I was able to
    use my Sony camcorder to record part of its flyover [to be shown at EUROSOM
    4, whenever that is]. This morning I queried existing historical elsets on
    OIG and it appears the actual height was more like 147km (92 miles) or so.
    Either way, the experience was very exciting and this is the lowest I have
    ever seen an object that was still in orbit.
    
    Paul
    
    -----------------------------------------------------------------
    Unsubscribe from SeeSat-L by sending a message with 'unsubscribe'
    in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org
    http://www2.satellite.eu.org/seesat/seesatindex.html
    



    This archive was generated by hypermail 2b29 : Mon Mar 06 2000 - 08:49:45 PST