It is "generally" agreed that what amateurs have observed is a decoy. See http://www.satobs.org/seesat/Dec-2005/0052.html and the Reply liked from there! ----- Original Message ----- From: "Robert Clark" <bobbygc2001@yahoo.com> To: <SeeSat-L@satobs.org> Sent: Tuesday, May 01, 2007 3:54 AM Subject: RE: Orbital surveillance satellites now exceed 1 inch resolution? > Thanks for the informative response. > > Your description on this page of the "Misty" > satellite gives it as one of the lightest satellites > for its physical dimensions: > > USA 144: The Mystery Deepens - Flash Timings Needed. > "SRP Analysis Reveals Area to Mass Ratio. > SRP analysis has yielded an accurate estimate of the > object's area to mass ratio - more precisely, its kA/m > value - area to mass ratio multiplied by a constant > which accounts for its shape and reflectivity. > The value of k can be between 1 and 2. A value of kA/m > of about 0.135 m^2/kg appears to account for the > object's historical rates of orbital decay. > Assuming k = 1.5, then A/m = 0.09 m^2/kg - at least an > order of magnitude greater than that of most payloads > and rocket bodies. For comparison, consider: > > Compton GRO 0.004 m^2/kg > Hubble ST 0.006 m^2/kg > UARS 0.007 m^s/kg" > http://www.satobs.org/seesat/Aug-2002/0045.html > > This passage describes it as having a large surface > area for the given weight. But note this means it also > has a very low weight for its given surface area. > A key feature of the James Webb Space Telescope is > also its low weight for the size of its mirror. This > is because of its beryllium mirror which allows very > thin mirror blanks. > So this low weight of the Misty satellites is > consistent with ligthweight, segmented beryllium > mirrors. > > > Bob Clark > > > > --- Ted Molczan <molczanssl@rogers.com> wrote: > >> Robert Clark asked: >> >> > I copied below a post I sent to some space >> oriented >> > discussion lists about the possibility of large >> segmented >> > mirrors being used on surveillance satellites. One >> objection >> > to this idea was that satellites large enough to >> have mirrors >> > this size, 6.5 meters, would have been noted by >> amateur >> > satellite watchers. >> > Have there been cases where a satellite was >> > *inexplicably* brighter than expected? >> >> No. Four satellites of KH-11 lineage are in orbit, >> tracked fairly regularly by >> hobbyists. One or two Misty satellites (essentially >> stealthy versions of KH-11) >> may also be in orbit, but there is no way to be >> certain because they intended to >> be nearly invisible, and seem pretty effective doing >> so. >> >> If technological advances of the sort you describe >> are going to appear in IMINT >> satellites, I believe they are more likely to do so >> as part of the FIA (Future >> Imagery Architecture) program, which is believed to >> be years away from >> operational launches. >> >> An apparent FIA technology development satellite was >> launched in 2006 Dec, from >> VAFB, aboard a Delta II, into a 58.5 deg, 370 km >> orbit. Reuters has reported >> that the satellite is related to the FIA optical >> program, but that it failed >> soon after reaching orbit, apparently due to a >> faulty computer. Hobbyist >> tracking to-date has detected no orbital manoeuvres, >> without which, the >> satellite will decay by about 2008 Feb. >> >> By the way, in your post, you mentioned that spy >> satellites frequently have >> elliptical orbits, and can lower their orbits to 150 >> km at closest approach. The >> KH-8 film-return satellites operated with a perigee >> of about 130 km +/- 10 km. >> The last of those orbited in 1984. >> >> KH-8's direct successor, the KH-11, was introduced >> in 1976, and approximately >> doubled the perigee height to about 280 km +/- 20 >> km, enabled by doubling the >> diameter of the primary mirror compared with that of >> the KH-8. >> >> Although KH-11 and its successors are manoeuvrable, >> they do so infrequently >> (several times per year), and only to counter the >> effects of orbital >> perturbations, mainly drag and solar gravity. I am >> not aware of any instance of >> their having dropped their perigee below >> approximately 260 km. The satellites in >> the eastern KH plane tend to raise their perigee as >> they age, up to about 330 >> km. In recent years, those that have remained in >> orbit after the launch of their >> successors, have operated with a 400 km perigee. For >> some reason, the western >> plane KHs generally have maintained the 280 km >> perigee, even in retirement. >> >> Ted Molczan >> >> > ------------------------------------------------------------------------- >> Subscribe/Unsubscribe info, Frequently Asked >> Questions, SeeSat-L archive: >> http://www.satobs.org/seesat/seesatindex.html >> >> > > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! 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