{Spam?} Re: OPS 8180 (RADCAT) 1972-076A

From: Ralf Vandebergh (ralf.vandebergh@home.nl)
Date: Mon Aug 09 2010 - 10:24:57 UTC

  • Next message: Michael Boschat: "What satellite was this?"

    Analysis of incoherent radar signatures of a tumbling rotationally symmetric
    satellite:
    (full article not available):
    http://adsabs.harvard.edu/abs/1982STIN...8328049G
    
    See also my own optical OBS taken last July:
    
    http://img256.imageshack.us/img256/5315/radcat10071821142429c.gif
    
    http://img830.imageshack.us/img830/3162/radcat10071823142729t.jpg
    
    
    Ralf Vandebergh
    
    
    
    ----- Original Message -----
    From: "Ted Molczan" <ssl3molcz@rogers.com>
    To: <SeeSat-L@satobs.org>
    Sent: Friday, August 06, 2010 5:29 PM
    Subject: RE: OPS 8180 (RADCAT) 1972-076A
    
    
    > Brian Webb asked:
    >
    > > I have two questions about OPS 8180 (RADCAT) 1972-076A:
    > >
    > > 1. When this spacecraft was launched in 1972, was there any information
    > > publicly available about it? What did the TRW Space Log say about it?
    >
    > I do not know how much information was made public in 1972; the 1987
    edition of the TRW Space Log
    > does not name or describe the object.
    >
    > > I have the impression that it was an unclassified payload with a highly
    > > specialized purpose that would not have been of much interest to the
    public.
    >
    > I agree; it is a radar calibration target.
    >
    > Two Radcats were built; the first one was lost (along with many other
    payloads) in a launch failure
    > on 1968 Aug 16 UTC; see Jonathan McDowell's launch log for details:
    >
    > http://www.planet4589.org/space/log/launch.html
    >
    > The second one was launched on 1972 Oct 02 UTC. USSTRATCOM's catalogue
    number is 6212. The COSPAR
    > designation is 1972-076A.
    >
    > > 2. Are there any detailed drawings or photos of this satellite available
    on the Internet?
    >
    > A drawing appears in the 1971 report, "RADCAT Radar Measurement Program",
    available here, scanned
    > into a 26 MB pdf:
    >
    > http://handle.dtic.mil/100.2/ADA036305
    >
    > The drawing is in Figure E-1 on page 241 of the pdf, which I have
    extracted and provided below:
    >
    > http://satobs.org/seesat_ref/misc/72076A_dwg.jpg
    >
    > On pg. 240 of the pdf, Radcat is described as, "an 8 foot cylinder with
    2:1 oblate spheroidal ends".
    > Based on the dimensions given in Figure E-1, its overall length is 10 ft
    (3.05 m), and its diameter
    > is 4 ft (1.22 m).
    >
    > NOTE: The SI dimensions derived from the report, solve a long-standing
    problem in the R.A.E. Table
    > of Earth Satellites 1957-1989, which describes Radcat as a cylinder, 12.2
    m long and 3.05 m in
    > diameter. Those dimensions never made sense, and now it is obvious that
    they arose from some sort of
    > garbling of information, whereby 10 times the diameter became the length,
    and the length became the
    > diameter.
    >
    > Observed Optical Characteristics
    >
    > Russell Eberst has reported 57 observations of Radcat since my
    correspondence with him began, in
    > 1989, which I have used to determine its standard visual magnitude, per
    the following plot of
    > magnitude normalized to 1000 km range vs. phase angle:
    >
    > http://satobs.org/seesat_ref/misc/72076A_std_mag.pdf
    >
    > The standard magnitude is 5.7 +/- 1 (1000 km, 90 deg phase angle).
    Coefficient of phase is 0.017
    > mag/deg.
    >
    > In its present 470 km circular orbit, the object reaches magnitude 3.7 +/-
    1 when observed at high
    > elevation, and well illuminated.
    >
    > The object was steady in brightness in each one of Russell's 57
    observations. The PPAS record of 18
    > observations, which spans 1973-2005, is in agreement. The PPAS archive is
    available here:
    >
    > http://www.io.com/~mmccants/bwgs/index.html
    >
    > Ted Molczan
    >
    > _______________________________________________
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    >
    
    
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