DM-F3 / Delta 3 RB - Who is Who ?

From: Harro.Zimmer (Harro.Zimmer@t-online.de)
Date: Sat Aug 26 2000 - 06:53:47 PDT

  • Next message: Wayne Hughes: "Re: Obs 26 Aug 2000"

    During an attempt to estimate the lifetime of the recently launched Delta III
    dummy payload (DM-F3) and its RB I found this strange discrepancy:
    
    Payload: Zylinder 4348 kg, 1.7 x 2.0 m : Ballistic coefficient (B): 503.4
             under the assumption of a Drag coefficient (D): 2.2. The international
             designation and the Catalog number: 2000-048A - # 26475 (DM-F3)
    
    RB:      Zylinder 2476 kg dry mass, 4.0 x 8.0 m, B: 71.7  also under the assump-
             tion of D: 2.2. International designation and catalog number:
             2000-048B - #26476.
    
    Now the problem: For the nearly identical orbits the RB must have a very much 
    larger drag then the massive and small payload. But the last released ELSETs
    shows a reverse behavior:
    
    Catalog number            Epoch            ndot         Bstar
    26475                     00238.369...     0.00108719   0.25111e-002
    26475                     00238.122...     0.00101159   0.24834e-002
    
    25476                     00239.115...     0.00003254   0.84746e-004             
    25476                     00238.266...     0.00002080   0.58611e-004
    
    My preliminary conclusion: SpaceCom has misidentified the objects. #26475
    is the RB and #26476 is the dummy payload. I think it would possible to
    make a final decision based on visual observations.
    BTW: My calculations based on a random tumbling of the objects. But also if
    you assume a specific attitude the conclusion remains unchanged.
    
    Harro
    
    Harro.Zimmer@t-online.de
    Berlin, Germany
           
    
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