Updated elements of USA 193

From: Ted Molczan (ssl2molcz@rogers.com)
Date: Mon Feb 18 2008 - 15:00:02 UTC

  • Next message: joglekar of kothrud: "visual obs from Pune,India"

    Brad Young and Paul Sventek have reported positional observations. There is a
    problem getting Paul's messages to the list, so he reported his obs off-list:
    
    WGS84 observation position 35d 42.70N, 97d 39.78W gps elevation 1111' (just
    northwest of Oklahoma City, OK)
    time: 18 Feb 2008, 00:57:54.4 UT
    J2000.0  5h 37m 58s  +21d 26' 28" (near zeta Tau)
    
    Here it is in IOD format:
    
    29651 06 057A   9999 P 20080218005754400 17 15 0537580+212628 99 S
    
    In addition to the positional observations, I have made use of a couple of
    images. The first one was imaged on 2008 Feb 17, I estimate near 02:33:30 UTC,
    and is available here (registration may be required to access it):
    
    http://www.bautforum.com/astrophotography/70430-decaying-spy-satellite-usa-193-i
    ss-cross-heart-orion.html
    
    Note that the likely site coordinates of the above are shown in the message
    header.
    
    The second one was imaged by Oscar A. Rodriguez on 2008 Feb 17, I estimate near
    19:00:10 UTC (site coordinates are on the image):
    
    http://satobs.org/seesat/Feb-2008/0310.html
    
    The images are not accurately timed; therefore, I could not include data from
    them in the differential-correction; however, they do provide a superbly
    accurate record of the path among the stars, so I used them as a sanity-check of
    the differential-correction. As a result, I am more confident in the shape and
    orientation of the orbit, which should reduce track errors, compared with my
    epoch 08048 elset.
    
    USA 193          5.0  2.5  0.0  4.3 v                    250 X 257 km
    1 29651U 06057A   08049.03290930  .00227439  00000-0  27958-3 0    02
    2 29651  58.5131  39.7259 0005095  99.1484 261.0195 16.07330305    09
    Arc 2008 Feb 11.46 - 18.04, WRMS residuals = 0.1 deg
    
    Predicted arrival times tonight are uncertain by at least 10 s; track
    uncertainty is 0.2 deg. 
    
    Rate of altitude decrease is about 1.3 km/d (kilometres per day).
    
    Using the above elements and a 10.7 cm solar flux of 70, Satevo v0.51 estimates
    decay from orbit on 2008 March 15. The uncertainty is at least several days.
    
    Definition of 2-line elements format:
    
    http://spaceflight.nasa.gov/realdata/sightings/SSapplications/Post/JavaSSOP/SSOP
    _Help/tle_def.html
    
    Ted Molczan
    
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