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 > > _______________________________________________ > Seesat-l mailing list > http://mailman.satobs.org/mailman/listinfo/seesat-l > _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l
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