Space

From: thomsona@netcom.com (Allen Thomson)
Subject: Re: Questions on "Lacrosse" signal...
Newsgroups: sci.space.policy
Message-ID: 
Organization: Netcom Online Communications Services (408-241-9760 login: guest)
References: <5ci4rh$3hh@news.asu.edu>
Date: Tue, 28 Jan 1997 02:02:01 GMT
Lines: 92
Sender: thomsona@netcom15.netcom.com
In article <5ci4rh$3hh@news.asu.edu> aufsj@imap2.asu.edu writes:
>	As I posted earlier, I'm having doubts as to having this Lacrosse 
>business figured out.  It would be just *too* fun if they were 
>masquerading her as a DMSP or some such thing.  But now I am thinking, 
>shouldn't we know a whole lot more about the dang thing?
>
>	If it is a radar imagery satellite, then presumably it has a 
>radar on it (all those logic classes are paying off :-) ).  The thing may 
>not be turned on all the time, but every time the top dogs wanted a peek 
>at something they would have to crank her up.  I guess my question is: 
>Does anyone have any data on any signals coming from any suspected 
>Lacrosse satellite?  Has anyone collected it, be they a mad scanner on a 
>quest or an even madder scientist who thought for a moment he was in line 
>for a Nobel in radio astronomy? 
[snip]
   I'll be doing a bit of homework and arithmetic to prepare a set of
responses and semi-responses to your question, but in the meanwhile
I'm going to append a message I originally posted on 10 Jan 1997 to
s.s.p. and some other groups, but which seems to have made it only
to sci.military.moderated (my ISP's Usenet competence was particularly
low at the time).  The message is relevant because it contains what
appears to be an indication that the resolution of LACROSSE is better
than commonly believed.  The resolution depends inversely on both the 
bandwidth of the signal (for range resolution) and the target 
time-in-beam (needed for integration to form the synthetic aperture for
along-track resolution).
  BTW, a good, simple source on how to do SAR calculations is "Spaceborne 
Radar Remote Sensing: Applications and Techniques" by Charles Elachi, ISBN
0-87942-241-6.
-------------------------------------------------------------------------
                        reposted message 
   After admiring the latest Nikolayev shipyard picture at
http://www.fas.org, I happened to look at the NIIRS (National 
Imagery Interpretability Rating Scale) document (*) there, and 
noticed something interesting.  Although most of the examples in 
the NIIRS tables (**) are of generic (or mobile) things that 
might be imaged by any of a wide variety of systems, several 
aren't.  To wit, 
NIIRS  Sensor     Illustrative Capability
  2    Infrared   Identify an SS-25 base
  2    Radar      Identify large phased array radars (HEN HOUSE, DOG HOUSE)
  3    Radar      Detect stuff at an ABM fixed missile site
  4    Visible    Detect an open missile silo door
  4    Radar      Distinguish between open and closed missile garage roofs
  4    Infrared   Detect thermally active SS-25 MSVs in garrison
  5    Visible    Distinguish between SS-25 TELs and MSVs at a known base
  5    Radar      Detect missile support equipment at an SS-25 RTP
  6    Radar      Identify SS-24 launch triplet at a known location
  7    Visible    Detect details of [SS-18] silo door hinges
    Now, AFAIK, these illustrative objects exist only in the 
interior of the FEE, and are accessible only by satellite (absent 
"Aurora").  So, unless the Itek (***) authors were just kicking 
back and fantasizing about what imaginary systems might do 
against semi-imaginary targets, the tables seem to provide some 
evidence in support of the widely-held belief that the US has 
not only visual but also infrared (IR) and radar imaging systems 
on its spysats.  It also provides some upper (big is bad, small is 
good) bound on their resolutions. 
   The 0.20 - 0.40 NIIRS 7 for visible systems isn't surprising, 
as the common lore is that KH-11 and descendants can do a 
decimeter quite handily.  The radar figure of 0.40 - 0.75 is 
interesting, since most open sources give over a meter, more often 
two or so meters for LACROSSE.  IR at 1.5 - 2.5 m NIIRS 4 is 
kind of what you'd expect from a mid-IR (3-5 micron) sensor looking 
through the same aperture that yields NIIRS 7-8 at visible wavelengths.
Again, this is in accord with the canon that son-of-KENNAN/CRYSTAL has 
IR capability.  OTOH, it's incompatible with a 8-14 micron IR sensor, 
as that would require a huge primary mirror. 
(*) Cited as as an excerpt from "Imagery Interpretability Rating 
Scales" by L.A. Maver, C.D. Erdman and K. Riehl of Itek Optical 
Systems, Lexington, MA.  Unfortunately, the hyperlink to the 
original document is currently broken.
(**) NIIRS-2 => 4.5 - 9.0 m resolution; 3 => 2.5 - 4.5 m; 4 => 
1.5 - 2.5 m; 5 => 0.75 - 1.2 m; 6 => 0.40 - 0.75 m; 7 => 0.20 - 
0.40 m
(***) Itek is not unconnected to the reconnaissance world.