Re: Orbital surveillance satellites now exceed 1 inch resolution?

From: GlocalNet (bg_26934@glocalnet.net)
Date: Tue May 01 2007 - 05:33:40 EDT

  • Next message: David Brierley: "DMB Obs April 30-May 1"

    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
    >>
    >>
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