Orbital surveillance satellites now exceed 1 inch resolution?

From: Robert Clark (bobbygc2001@yahoo.com)
Date: Thu Apr 26 2007 - 23:44:06 EDT

  • Next message: Russell Eberst: "2007APR26.OBS"

     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?
    
    
       Bob 
    
    ----------------------------------------------
    Orbital surveillance satellites now exceed 1 inch
    resolution. 
     
    
    The most recent public estimates of spy satellite
    resolution capabilities give them as about 10
    centimeters, 4 inches. However, it is widely known
    that the most advanced astronomical space
    observatories lag what is currently available for
    military and intelligence satellites. The Hubble Space
    Telescope for example was derived from early
    technology surveillance satellites. 
    Then since the James Webb Space Telescope has a
    segmented 6.5 diameter mirror, very likely this at
    least is available now for surveillance satellites. 
    I discussed the capabilities for such a mirror for
    space-borne imaging in the post to sci.astro below. At
    300 km altitude it would have better than 3 cm
    resolution, about an inch. Spy satellites frequently
    have elliptical orbits that can bring their altitude
    to half this at closest approach, so their max
    resolution will be perhaps half this, 1.5 cm to 1 cm. 
    The James Webb Space Telescope is however an infrared
    telescope. The question I had was whether the mirror
    smoothness tolerances required at visible wavelengths
    were available using the beryllium material used in
    the segmented mirror of the James Webb. 
    
    From this web site we may conclude that this is indeed
    possible:
    
    ESO Press Photos 34a-b/97 
    12 December 1997. 
    First M2-Unit and Beryllium Mirror Delivered to ESO. 
    http://www.eso.org/outreach/press-rel/pr-1997/phot-34-97.html
    
    The ESO's Very Large Telescope (VLT) uses 1.2 meter
    beryllium mirrors for its secondaries. This requires
    visible wavelength smoothness since the VLT will
    operate at both visible and infrared wavelengths. The
    James Webb hexagonal mirrors are 1.3 meters in
    diameter. So we may conclude beryllium mirrors of this
    size could be polished to the smoothness required for
    visible light observations.
    
    This question was raised by me in regards to
    astronomical planetary imaging: how soon could this be
    adapted to space missions to the planets? The James
    Webb telescope is a 4 billion dollar mission. However,
    a large part of this cost probably has to do with the
    fact of the high reliability required for this mission
    that has to operate far away from the Earth and
    therefore can not be serviced by human missions, and
    because of the fact the entire spacecraft's structure
    has to be optimized to keep the cryogenic temperatures
    required for the highly sensitive infrared
    observations. 
    Reductions in cost for similar sized planetary
    missions can be fueled by commercial imaging
    interests. It is clear there there would be commercial
    uses for Earth imaging at 1 inch resolution, though
    this would raise clear privacy concerns. The
    technology for producing such large foldable space
    mirrors has been patented so can now be licensed by
    commercial imaging concerns:
    
    Deployable space-based telescope. 
    Abstract 
    A large aperture light-weight space borne telescope is
    provided which may be launched by a relatively small
    launch vehicle. A 6 to 8 meter primary telescope
    composed of, e.g., 30 segments arranged in two
    concentric rings is provided. Supplemental outer
    mirror segments are stowed behind and substantially
    perpendicular to the main mirror which is usable in
    the absence of supplemental mirror deployment.
    Deployment of outer mirrors segments provides a large
    aperture telescope with a large field of view. Other
    deployable components include a secondary mirror, a
    bus, deployable with respect to the optics portion,
    and one or more sun shade sheets or panels. 
    Patent number: 5898529 
    Filing date: Jun 20, 1997 
    Issue date: Apr 27, 1999 
    Inventors: Wallace W. Meyer, Robert A. Woodruff 
    Assignee: Ball Aerospace & Technologies, Inc. 
    http://www.google.com/patents?vid=USPAT5898529
    
    
    Bob Clark
    
    
    ********************************************************
    
    Newsgroups: sci.astro, sci.physics, sci.geo.geology,
    alt.sci.planetary, 
    sci.astro.amateur 
    From: "Robert Clark" <rgregorycl> 
    Date: 10 Jan 2007 09:12:09 -0800 
    Local: Wed, Jan 10 2007 1:12 pm 
    Subject: We will soon be able to resolve Mars microbes
    from orbit. ;-)
    
    On another space oriented forum I noted: 
    
    "It took 20 years to increase the resolution by a
    factor or 10 over 
    Viking with the Mars Global Surveyor mission. But only
    10 years to 
    increase the resolution over that of MGS by a factor
    of 10 with Mars 
    Reconnassance Orbiter. 
    Could we increase the resolution over MRO by another
    factor of 10 to, 
    gulp, 3 cm per pixel in only 5 years this time?" 
    
    
    Funny though, that rather off-the-cuff estimate of
    mine is close to 
    what is possible. 
    To resolve 3 cm in the optical from say a 300 km orbit
    would require a 
    6 meter mirror. The James Webb Space Telescope will
    have a 6.5 meter 
    mirror and is scheduled for launch in 2013. But it was
    originally 
    scheduled for launch in 2011: 
    
    James Webb Space Telescope. 
    http://en.wikipedia.org/wiki/James_Webb_Space_Telescope
    
    
    So going by this rate, it'll be 3mm/pixel 2.5 years
    after that, and 
    300 microns 1.25 years after that, and ... 
    Hmm, in less than a decade then we should be able to
    resolve microbes 
    from space. 
    
    Admittedly though, the JWST is a 4 billion dollar
    mission. Also it 
    uses a beryllium metal mirror for infrared astronomy
    only. The 
    beryllium makes the mirror lightweight but it is
    unclear if you can 
    achieve the much more stringent smoothness
    requirements at optical 
    wavelengths with a metal mirror. 
    As for the data storage and transmission of the large
    files for such 
    high resolution images, data storage capacity and
    costs are doubling 
    and halving each year, respectively: 
    
    Bye-bye hard drive, hello flash. 
    By Michael Kanellos 
    Staff Writer, CNET News.com 
    Published: January 4, 2006, 10:00 AM PST 
    "Currently, NAND chips double in memory density every
    year. The 
    cutting-edge 4-gigabit chips of 2005, for example,
    will soon be 
    dethroned by 8-gigabit chips. (Memory chips are
    measured in gigabits, 
    or Gb, but consumer electronics manufacturers talk
    about how many 
    gigabytes, or GB, are in their products. Eight
    gigabits make a 
    gigabyte, so one 8Gb chip is the equivalent of 1GB.) 
    "Another driving factor in the uptake of the
    technology is cost: NAND 
    drops in price about 35 to 45 percent a year, due in
    part--again--to 
    Moore's Law and in part to the fact that many
    companies are bringing on 
    new factories." 
    http://news.com.com/Bye-bye+hard+drive,+hello+flash/2100-1006_3-6005849.html
    
    
    MRO uses the type of flash memory chips discussed
    here. 
    
    Also, interestingly NASA had planned a laser
    communication orbiter for 
    Mars for launch in 2010 before it was canceled: 
    
    Record Set for Space Laser Communication. 
    By Ker Than 
    Staff Writer 
    posted: 05 January 2006 
    02:11 pm ET 
    http://www.space.com/missionlaunches/060104_laser_comm.html
    
    
    Mars Telecommunications Orbiter: Interplanetary
    Broadband. 
    By Bill Christensen 
    posted: 05 May 2005 
    06:41 am ET 
    http://www.space.com/businesstechnology/technology/technovel_marstelecom_050505.html
    
    
    This would have allowed data transmission rates of a
    hundred times 
    greater than what is currently available. 
    
    It was the great cost overruns overruns that led to
    cancelling of the 
    Mars Telecommunications Orbiter, and great cost
    overruns also 
    threatened JWST as well. 
    That the costs for computer technology are dropping
    exponentially with 
    capacity increasing exponentially is no doubt fueled
    by the free market 
    in this sphere. 
    Conversely, that launch costs are staying static is no
    doubt because 
    the launches are controlled by large governments. When
    private 
    companies become the primary financer and purveyor of
    launches, the 
    launch costs will also drop dramatically. 
    
    
    Bob Clark 
    
    ********************************************************
    
     
    
    
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