Updated elements

From: Ted Molczan (ssl3molcz@rogers.com)
Date: Wed Aug 25 2010 - 14:33:22 UTC

  • Next message: Alberto Rango: "4641 SATOBS 24 AUG 2010."

    Derek Breit, Russell Eberst, Alberto Rango, Greg Roberts, Brad Young, and I, contributed
    observations used to determine one or more of the following element sets.
    
    Russell has discovered the rocket body of Helios 2B. He reported it as an UNID on Aug 22 UTC, and
    noted its proximity to the plane of that launch. I estimated orbits based on the payload and the
    rocket, and Russell found it last night, 6.5 min late, and 2 deg off track, relative the rocket
    elements. My analysis confirmed our hunch that this is the same UNID Russell observed on April 07
    UTC, which I erroneously identified at the time as the payload. Below are all four of Russell's
    observations, with their correct IDs, in my archival format:
    
    0907302 2420 20100407 033112.76 091057+433324 6.0 6.0 0 S
    0907302 2420 20100407 033127.82 093515+402755 6.0 6.0 0 S
    0907302 2420 20100822 030152.10 211010+302836 3.5 3.5 0 S
    0907302 2420 20100825 010253.41 041659+162552 6.3 6.3 0 S
    
    Helios 2B r                                              614 X 671 km
    1 36125U 09073B   10237.02021578  .00000102  00000-0  15000-4 0    00
    2 36125  98.0401 175.1666 0040933   2.2543 357.8842 14.74859328    06
    Arc 20100407.15-0825.04 WRMS resid 0.060 totl 0.012 xtrk
    
    This orbit propagates to within a fraction of a degree of the plane of the orbit at launch.
    Near-term predictions should be accurate to within about 10 s, per day since epoch.
    
    In my recent analyses of OTV-1, I have noted a tendency toward a negative decay term of small size.
    Initially, I was reluctant to accept that, due to the short observational arc, so I forced a zero
    decay term; however, the mean motion of successive daily solutions has been decreasing very
    gradually, which is consistent with a negative decay term. At nearly 6 days, the arc is now
    sufficient to accept a negative decay term:
    
    OTV-1                                                    433 X 444 km
    1 36514U 10015A   10237.39211858 -.00002473  00000-0 -53835-4 0    05
    2 36514  39.9868 312.8221 0007860  17.7658 342.3423 15.43342168    06
    Arc 20100819.75-0825.41 WRMS resid 0.049 totl 0.011 xtrk
    
    Ted Molczan
    
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