Re: Orbital surveillance satellites now exceed 1 inch resolution?

From: Robert Clark (bobbygc2001@yahoo.com)
Date: Tue May 01 2007 - 12:08:15 EDT

  • Next message: Robert Clark: "Re: Orbital surveillance satellites now exceed 1 inch resolution?"

     My reading of the discussion on the topic is that a
    big reason why this was believed to be debris or a
    decoy was because of its unusually light weight for
    its size.
     This could be explained by the great reduction in
    weight a beryllium mirror allows. The James Webb Space
    Telescope  has a mirror that weights half as much as
    the Hubble mirror but has a collecting area 6 times as
    great. So this means a reduction in weight to area by
    a factor of 12 in regards to the mirror. The mirror
    makes up a big part of the weight though not all of
    course for a imaging satellite.
    
    
      Bob Clark
    
    --- Björn Gimle (GlocalNet) <bg_26934@glocalnet.net>
    wrote:
    
    > 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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