UNID 90079 may be 06027B

From: Ted Molczan (ssl3molcz@rogers.com)
Date: Fri Mar 14 2008 - 03:08:17 UTC

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    As discussed below, I propose that we consider re-assigning 90079 / 07859A as
    06027B / 29250, and expect to find USA 200's Centaur in a similar orbit.
    
    Peter Wakelin discovered 90079 / 07859A on 2007 Dec 25; here are the most recent
    available elements:
    
                                                          1024 X 36529 km
    1 90079U 07859A   08046.72845030  .00000000  00000-0  00000-0 0    04
    2 90079  62.3975 315.1772 7057374 274.2760  85.7241  2.17595297    00
    
    Since its mean motion was not close to the operational value for a Molniya
    payload, ~2.006 rev/d, it was obvious that it was either a decommissioned
    payload, or a rocket body. It is sufficiently bright to be either, but I now
    suspect that it is the latter, specifically, the 2nd stage of the Delta IV
    rocket that launched USA 184 (06027A / 29249).
    
    Below is USA 184's approximate orbit at its first apogee, on 2006 June 28 UTC:
    
    USA 184
    1 71001U          06179.41131020  .00000000  00000-0  00000-0 0    07
    2 71001  62.4000  47.0000 7090000 266.5070 180.0000  2.10000000    08
    
    Propagating 90079 back to the same epoch (using SDP4) yields RAAN of 48.6 deg,
    and argument of perigee of 267.2 deg, in close agreement with USA 184's orbit.
    
    The orbit of 90079 also is similar to that reported to the U.N. for 06027B:
    
    http://www.unoosa.org/pdf/reports/regdocs/ser495E.pdf
    
                          90079    06027B
    mean motion (rev/d)  2.17595  2.17588 (1440 min/d divided by 661.8 min/rev)
    inclination (deg)     62.4      62.3
    perigee height (km)   1079      1024
    apogee height (km)   36487     36529
    mean height (km)     18783     18777
    
    If 90079 is 06027B / 29250, then we can expect to find USA 200's Centaur stage
    (08010B / 32707) in a roughly similar orbit, for which I suggest the following
    search elements:
    
    USA 200 Centaur
    1 70000U          08073.46717570  .00000000  00000-0  00000-0 0    05
    2 70000  62.3000  39.5921 7035500 266.5042  17.9978  2.17588000    06
    
    Note the similarity with the payload's search elements:
    
    USA 200
    1 71001U          08073.68144909  .00000000  00000-0  00000-0 0    01
    2 71001  62.4000  39.5602 7090000 266.5070 180.0000  2.10000000    02
    
    I have assumed they are in roughly the same plane; in fact, either one or both
    planes could be out by at least a couple of degrees. I hope that at least the
    along-track spacing will be reasonably accurate.
    
    Ted Molczan
    
    
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