RE: Unid sat obs and orbit = 72 degree inclination

From: Ted Molczan (ssl3molcz@rogers.com)
Date: Sun Jul 15 2012 - 13:39:08 UTC

  • Next message: Russell Eberst: "2012JUL14-15.OBS"

    Kevin Fetter wrote:
    
    > As I still couldn't see any sat, that matches so far, I made some obs and a orbit.
    > 
    > 88888 99 999G   1775 G 20120715033835308 15 25 1922401+370766 37 S
    > 88888 99 999G   1775 G 20120715033919585 15 25 2007282+481934 37 S
    > 
    > I changed the cat number after, to a different value. It was suggested to me, to use a
    > certain way of numbering unid's, so I tried to do that.
    > 
    > UNID
    > 1 99201           12197.15231001 0.00000017  00000-0  50000-4 0    03
    > 2 99201  72.1531 257.9460 0009768 307.8009 100.7942 13.06430040    05
    > 
    > The orbit, shows how this sat passed across the sky.
    > Nothing I can see, in a classfd orbit, is that high up.
    
    There is no match in USSTRATCOM's public catalogue, but the inclination is suggestive of something from the 10062A
    launch. Most of the pieces are in ~630 x 655 km orbits, but the HAPS (Hydrazine Auxiliary Propulsion System) performed
    two manoeuvres with the goal of reaching at least 1200 km, at which point it deployed two ballast objects. Finally, it
    was to perform a depletion burn. The launch events are shown here:
    
    http://www.spaceflightnow.com/minotaur/stps26/images/timeline.jpg
    
    The U.N. filling is in general agreement:
    
                          Pn    Inc    Apo   Per
                          Min   deg     km    km
    2010-062H HAPS R/B   111.7  72.0  1204  1200
    2010-062J Ballast A  109.4  72.0  1204  1200
    2010-062K Ballast B  109.4  72.0  1204  1200
    
    However, circular orbits that fit your observations disagree with the initial RAAN of the 10062A plane by nearly 30 deg.
    A higher circular orbit would correct the plane problem, but would not fit your observations. Closer study of the U.N.
    filing revealed the likely solution. Notice that H, J and K all have the same altitude, but H has a greater nodal
    period, which is equivalent to a mean motion of about 12.89 rev/d. Using that mean motion, combined with a small change
    of inclination was sufficient to match the initial RAAN.
    
    Since the ballast objects are in the planned circular ~1200 km orbit, it is clear that the higher orbit of the HAPS
    resulted from the depletion burn, which in this case, raised the apogee. The following orbits fit your observations, and
    satisfy the initial RAAN constraint. They differ only in argument of perigee:
                                                           1201 X 1401 km
    1 99201U          12197.14206371  .00000013  00000-0  50000-4 0    01
    2 99201  72.1100 257.9217 0130000 355.2678   4.7145 12.89540000    07
    
                                                           1201 X 1401 km
    1 99201U          12197.14189113  .00000013  00000-0  50000-4 0    05
    2 99201  72.1100 257.9325 0130000 102.5980 258.9655 12.89540000    05
    
    Allow at least 1 min prediction time uncertainty for each day past the epoch.
    
    The 200 km difference between the apogee of the TLE and that reported to the U.N. could have arisen due a single digit
    typo.
    
    HAPS are roughly bell-shaped, about 0.7 m tall, 1 m diameter at the base, and about 0.5 m near the top. Based on those
    dimensions, the standard visual magnitude is 9 +/- 2 (1000 km, 90 deg phase angle). In the orbit of 10062H, it would
    reach mag 9 +/- 2 under ideal circumstances.
    
    Ted Molczan
    
    
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