Re: "Stealth" satellites

Allen Thomson (
Sat, 13 Jun 1998 15:20:38 -0700 (PDT)

I've waited a bit before replying to this thread in order to try to 
answer various people's questions and comments in one message. The 
topic is a bit peripheral to the charter of SeeSat, but the 
questions were asked here and the amateur observers' community has 
been highly involved in tracking classified satellites, including the 
putatively stealthy ones.  I'll take the liberty of posting this long 
reply, but suggest that follow-ups be via e-mail. 

>Date: Tue, 09 Jun 1998 15:48:56 -0500
>From: Dave Mullenix <>
>The Manchester Guardian article on spy sats has this interesting
>Since writing his controversial report, says Thomson, it's become clear 
>that the US has tried to hide some of its satellites. Starting in 1990, 
>four satellites have "disappeared" from the view of amateur trackers. 
>Thomson suspects that the satellites use stealth technology, and have 
>been moved to higher orbits. 
>Can anybody tell us which four satellites have "disappeared"?  

As Sean Sulliven suggests below, the prime suspects are AFP-731 and 
the three NOSS 2 A objects. 

I wrote up a note on these a while back -- it needs some updating,
but may still be of some use:

Also of possible relevance are

>Also, any 
>ideas on what the "stealth" technology would be?  I assume they have 
>something better than black paint to play with.  I wouldn't think that 
>the aircraft stealth technology would work too well, though.  That seems 
>to mostly involve not creating surfaces that reflect radar waves 
>directly back to the transmitter.  That won't work for visual sighting 
>because the "light transmitter" is the sun and the "light receivers" are 
>our eyes and there's usually a very wide angle between the two. 
I think you're guilty of an excess of rationality here. :)  Stealth 
in space, whether optical or radar, is likely to depend primarily on 
the same reflective principles as aircraft radar stealth. Absorptive 
materials will play perhaps a supporting role in places where there 
need to be penetrations of the reflecting shield, suppression of 
creeping waves, etc.  The implication of this is that, as in the 
aircraft case, you have to have a very good idea of where the threat 
receivers are so that you can arrange to steer "nulls" at them (or, 
to phrase it differently, send their "line of sight" out into 

This is, as you suggest, particularly problematic in LEO, since the 
amount of solid angle containing potential receivers is large, and 
making an error can turn your stealthy reflective surface into an anti-
stealthy flare producer.  I've been told by some former NRO contractors 
that this is what happened to AFP-731: the operators had been assured 
that there was no detection threat except a few radar and optical sites 
in the USSR, and so they nulled those out -- giving Western European and 
UK observers a nice show. Oops.  (This, BTW, was not the fault of the 
operators, but the result of some fairly spectacular malfeasance among 
the people who were supposed to be providing threat analyses, plus lack 
of due diligence on the part of the program office.)  Among the 
advantages of going to higher orbit is the smaller solid angle 
containing potential observers you need worry about. 

For one example of how a stealth satellite might look, see .
There are obviously other ways to do it, such as rigid reflective 

From: "Lloyd Verhage" <>
Date: Tue, 9 Jun 1998 16:02:51 CST6CDT
> The Manchester Guardian article on spy sats has this interesting
> paragraph:
>What kind of paper is this?  Do they tend to focus on liberal or
>conservative issues?  The reason I ask this is the next statement.
> Since writing his controversial report, says Thomson, it's become clear
> that the US has tried to hide some of its satellites. Starting in 1990, 
> four satellites have "disappeared" from the view of amateur trackers. 
> Thomson suspects that the satellites use stealth technology, and
> have been moved to higher orbits.
Is stealth a conservative vs liberal issue? If so, I'd assume the 
liberals are pro-stealth, as it was Jimmy Carter who gave the 
go-ahead on the B-2.  :-)  As I understand it, the Guardian (UK readers 
please correct me if I'm wrong) is center-left, but is one of the 
principal and most respected newspapers in the UK.

>I don't see how this makes sense.

Hopefully, this note will help make things clear, or at least 

>It seems to me that Thomson has an axe to grind.  

Well, I do have some concerns about the way our satellite reconnaissance
systems have been designed. See .

>Correct me if I'm wrong, but once a satellite ias up, no 
>one is going up to modify it.  

You're wrong.  See the patent referred to above.

>Also, spy satellites work best in low orbits where their resolution 
>is best. 

Only if resolution is the principal figure of merit. Since Desert Storm, 
things like dwell time and coverage have come to be regarded as of equal 
if not greater value in military situations.  Going higher helps with 
both of those -- and, as mentioned above, it does help with stealth by 
reducing the solid angle of the earth as seen from the satellite. 
One meter resolution is good enough for many military needs, and an
optical system that can do 10 cm at 500 km range can do 1 m at 5000 km.


>Or perhaps the satellites have reentered the atmosphere.  

That can't be ruled out, although a half-dozen people with various
connections to the programs have said that they haven't (at least
as of a few years after launch). But maybe they were just foolin'.

>In this case I would suspect that Thomson is being less than honest. 

If I knew they'd reentered around the time of their disappearances,
it would be dishonest.  However, all the information I have is to the
contrary.  But I could, of course, simply be mistaken.
>These comments set off my baloney detector.

A baloney detector is a very good thing to have in this wicked world,
but one should take care that it's properly calibrated.

>But I'm sure I'll be corrected if I'm wrong. :)

De nada.

>Beinging satellite watcher
Persist! It's a great hobby. 

>Date: Tue, 09 Jun 1998 18:42:11 -0500
>From: Dave Mullenix <>
>I thought I got the URL for the spysat article from this mailing list,
>but so many haven't heard of it that I guess I got it somewhere else.
>Here's the URL for the article I mentioned regarding the stealth sats:
>It's from the English newspaper, "The Guardian".  The article is about
>how India and Pakistan avoided American spy satellites while preparing
>for their recent underground nuclear tests.  The lines about four spy
>satellites vanishing were a minor aside in the main story.  

Duncan Campbell (the author) got the disappearing satellite stuff
from the messages referenced above. I just told him that yes, I still 
thought that what's in them is valid.


>I've since had messages saying that there's no such thing as stealth
>tactics for satellites, but I highly doubt this.  

You're right, the message-writers are wrong -- see the patent referenced
above.  Also, it's now documented that that stealth for reconnaissance
satellites was under consideration back at the dawn of the spysat era.

>From a formerly secret document of 8 January 1963, declassified by
the NRO on November 26, 1997:

   SUBJECT : 9-10 January Meeting On Satellite Vulnerability

   1. The vulnerability meeting on 9-10 January should result in two 
   fairly well detailed programs. One would be directed specifically at 
   the "C" [i.e., CORONA] vehicle.  The second would be a broad, long 
   term program of a more fundamental nature, aimed at providing the 
   basic data we will need for succeeding systems and for more 
   sophisticated approaches with the current system. 

   2. "C" Vehicle Program

     a. ---
     b. S[E?S? copy unclear]D should undertake an extensive program
        of cross section reduction and concurrent decoy design. At 
        the same time they should investigate scintillation 
        techniques to confuse radar signatures. (This may be 
        particularly suitable for "J" which will scintillate 
        naturally for part of its lifetime.) 
     c. We should develop, test and maintain as shelf items one or
        more hardened models of the "C" mission. Such models would 
        incorporate cross section reduction techniques, decoys, 
        shielding and other countermeasures...

   3. Broad Program
       A great deal o basic work needs doing. The following, surely, 
   is just a partial list. 

     a. --
     b. --
     c. --
     d. Methods of reducing optical cross sections.
     e. Radar cross section study, low cross section shapes, 
        absorbers signal attenuation and modification, scintillation 
        techniques, flush mounted antennas.
     f. --
     g. --
     h. Study and development of capability to hide among existing
        space objects.

                                           [Signature censored]
                                           Development Division

                                      [Office of Special Activities -
                                       Deputy Directorate of Research]
                                      [[Central Intelligence Agency]]

>I'm sure there are plenty of things that can be done to make satellites 
>harder to spot both visually and via radar.  


>I was just hoping that someone on this list would have some suggestions 
>of how to do it.

Hope the above helps.

>Date: Tue, 9 Jun 1998 19:51:34 -0400 (EDT)
>From: Sean Sullivan <>
>I don't know which satellites Thomson has in mind, but the obvious four
>candidates are the A objects from the three NOSS block-2 launches, plus
>the STS-36 payload.  


>The latter object was found (by accident - it turned
>up as an unid much later) but it did disappear for a long time.  

And then it disappeared again, possibly to a higher orbit where
it's subsequently escaped the notice of the amateurs.  Whether 
other, non-amateur observers have spotted it is a fascinating 
question.  See the "Disappearing Satellites" note referenced above. 

>The A objects associated with the NOSS-2 launches are more mysterious; 
>I have seen one of these objects (90-050A) through heavy clouds, but it
>maneuvered and was not seen again (my obs was probably *before* deploy
>of the NOSS cluster, so it may have been a single package at the time.

I agree.  Enough people in the know have been sufficiently outraged 
by the AFP-731 episode that they've been willing to talk. 
Consequently, I think I have a pretty good idea of what happened and 
why (not a pretty picture). 

But there's a lot less buzz going around about the NOSS-2 A objects, 
only a couple of reasonably credible assertions that yes, they did
go to higher orbits in the 1000x10,000 km range. I assume that 
either they worked more or less as planned, or, disappointingly, 
really aren't very interesting.  The only puzzling part about the 
"worked as planned" hypothesis is why they drew attention to 
themselves before performing the disappearing trick. 

>To throw out some half-baked ideas, the Molniya-like inclination of the
>NOSS clusters suggests the possibility that the mystery A objects are in
>some kind of eccentric orbits with fixed perigee latitude.  

Absolutely -- that makes all the sense in the world, and also applies
to AFP-731 (I talked about that some in the "Spysats going higher" 
note).  Interestingly, the new Russian spysat Arkon-1 is using such 
an orbit, so maybe they have also decided that dwell time and 
coverage are sometimes to be preferred over resolution. 

>I have also
>heard the idea floated that they may be hiding in "debris fields" from
>some breakups (seen but not recognized as interesting).  

Yes, see last item in the 1963 CIA memorandum.  Trying to look like 
a smallish piece of junk is probably intrinsically less demanding on 
signature reduction techniques than trying to disappear altogether.  
When I looked at this possibility a couple of years ago, it turned 
out that the objects associated with USA 40 aren't a bad 
match to the hypothesized final NOSS 2 A and AFP-731 orbits. 

>I personally
>think that these A objects are among the most interesting DOD mysteries.
One of the reasons satellitology is fun.



Reports of stealth satellite programs go way back. It's true that 
newspaper reports don't constitute proof of much of anything, but 
when they come from generally well-respected reporters, they do 
deserve some attention. 

   Smaller Spy Satellites May Give U.S. Stealth Capability Over 
   Trouble Spots  
   The Washington Post, February 01, 1998, FINAL Edition 
   By: Walter Pincus, Washington Post Staff Writer
   Section: A SECTION, p. A09

   A new generation of small intelligence satellites, planned to be 
   launched beginning in 2003, is expected to give U.S. analysts almost 
   constant overhead images of specific trouble spots anywhere in the 
   world, according to administration and congressional sources. 

   Some of the new vehicles may be equipped with stealth technology so 
   they cannot be tracked by radar, several sources said. But other 
   sources doubt a way has been found to prevent detection of the 
   satellites, a feat the CIA and Pentagon have been trying to 
   accomplish since the 1960s. 

   Keith Hall, director of the National Reconnaissance Office (NRO) 
   which buys and flies the satellites, would not discuss stealth 
   capability in satellites. 

   Other sources on Capitol Hill and within the intelligence community 
   said the existence of the technology in satellites is one of the 
   closest-held secrets in government. 

There was a similar article a decade earlier,

   U.S. Designs Spy Satellites To Be More Secret Than Ever
   by William Broad
   The New York Times
   November 3, 1987

   [I can't locate the text right now, but it said, in the context
   of bigsats rather than Pincus' smallsats, that the US was trying
   to stealthify satellites.]

plus reports from 1984 that the Long Duration Exposure Facility included 
stealth materials in its experiments: 

   Shuttle Challenger Launched Toward Swashbuckling Adventure 
   Astronauts Scheduled to Retrieve and Repair Damaged U.S. Satellite in 
   The Washington Post, April 07, 1984,
   By: By Thomas O'Toole, Washington Post Staff Writer
   Section: A, p. 02

   "Sources said Stealth material must be tested in space because the 
   Air Force is considering development of Stealth satellites and even 
   Stealth shuttle craft that could fly in orbit undetected by Soviet 
   ground radar." 

And, (finally!) SDIO seems to have thought it was worth looking into:

   Stealth Satellite Test Conducted 
   Defense News
   September 25, 1989, p.2

   The Strategic Defense Initiative Organization announced last Friday 
   that it had quietly launched on Sept. 4 and Sept. 11 two rockets to 
   test stealth features for U.S. satellites. The suborbital satellites 
   [sic] launched in the $6.6 million Starmate experiment were tracked 
   by radars, as well as infrared, ultraviolet and visible sensors in 
   their brief 10 minute flights. The rockets were launched from Kauai 
   Test Facility in the Hawaiian Islands. The information will be used 
   to increase the survivability of U.S. satellites, which face threats 
   from Soviet ground- launched interceptors and from future space-
   mines and directed energy weapons, DoD officials say.