Subject: Re: Iraqi ASAT From: thomsona@netcom.com (Allen Thomson) Date: 1995/08/22 Message-Id: <thomsonaDDqCvJ.I8E@netcom.com> Newsgroups: sci.space.policy,alt.war,alt.politics.org.cia in <41b6kp$cjk@clarknet.clark.net> < johnpike@fas.org> (John Pike) wrote: >prb@clark.net (Pat) wrote: >>... look at higher orbits (Get above the AA fire), >Well, you start to run into aperture problems, in that the current KH >would seem to me to start to run into resolution problems above ~5000 km. True, the 2.5 to 3 meter apertures thought to characterize current US spysats give "only" one meter resolution at 5000 km. This is just fine for the majority of tactical and strategic reconnaissance requirements, as witness the choice of one meter resolution for Helios. Even 1.5 - 2 meters, corresponding to 7,500 - 10,000 km altitude and a 2.5 m aperture, is still quite usable for many purposes. A 2-meter Russian picture of San Diego, for example, shows identifiable aircraft at the airport, boats and ships, even buses on the highways. High orbits can improve dwell times, and even, if made elliptical, help the absentee ratio which John rightly emphasizes as being a big problem for tactical use of small constellations of LEO satellites. As noted earlier on some of these newsgroups, a November 1994 Aerospace America article by the DDCI strongly implies that higher altitudes for imaging satellites of more-or-less the present design is the way the NRO is planning to go if it hasn't done so already. Whether migrating to higher altitudes would be much direct help in avoiding any but the most primitive ASAT threats is a question which should be studied. >>make satellites more stealthy (Hard to see, hard to hit) >Don't bet on it. You could paint them black to reduce the optical >signature, but then it stands out like a sore thumb in infra-red, and the >thermal control problem would be pretty intense [which is why they have >those nice shiny gold/mylar thermal control reflectors which make them so >visible at optical. It is really very hard to see just how one would put >meaningful radar absorbing material on these things, particularly since >countour control would be pretty hard to do.... Actually, if you're concerned about avoiding detection by monostatic radars of VHF and higher frequencies, simply hiding behind a reflective plate tilted to direct the return away from the radar should work pretty well. That applies to optical detection too, if you cant the plate so that the observer's line of vision is reflected out into space. You can see the effect in some of the pictures and paintings of HST being deployed: the flat, shiny sunscreen on the front reflects space and looks, surprise!, like space. Full body absorptive stealth has its problems in both radar and visible light -- remember that the Moon is as reflective as asphalt -- and has been used to date apparently as an adjunct to reflective designs. Otherwise F-117s and B-2s wouldn't look the way they do. Things may change with the march of technology, but it appears as if reflective principles are still on the top of the stealth designers' toolkit. The real difficulty with stealth in LEO, I think, is that all stealth vehicles which have been revealed to date _are designed and operated to be stealthy against specific kinds of sensors encountered in specific geometries_. This is probably a fatal problem for low-orbiting satellites, at least if they are supposed to stay hidden for long periods of time. If we only had to worry about a few, well-located and well- characterized sensors -- for example the big Russian space surveillance radars -- there might a chance to "fool all of them all of the time." That, however, is far from being the actual situation. For a LEO satellite, a large fraction of the sky (the disk of the Earth, ignoring the possibility of space-based detection systems) is the possible location of a wide and ill- understood collection of sensors. Moreover, the satellite is illuminated from a variety of directions over a very wide range of frequencies and reflects or reradiates that energy in ways which are difficult to predict and control. As Greg Canavan at LANL has succinctly put it,* "Observables can only be reduced by so much for low-altitude satellites, which are continually observed from many angles with many phenomenologies." So even if a system designed and operated so as not to be spotted by the Russian radars worked as intended, it would still be at risk of detection by Russell Eberst and his binocular- wielding friends, people doing radar and optical orbital debris surveys, asteroid inventory projects, bistatic intercept off radars and commercial transmitters, et lengthy cetera. Add to this the ever-present danger of HUMINT compromises, and the wisdom of depending on stealth to protect big, expensive, not- easily-replaceable satellites becomes dubious indeed. Expendable tactical satellites would be a different matter, of course. In that case, the purpose would be to buy time, not immortality, and stealth might well be a very useful component of the satellite's capabilities, along with a certain amount of maneuverability. Covert launch would be nice also, which is one reason I hope Pegasus gets over its current problems. The potential utility of stealthy tacsats has not escaped foreign analysts; in the summary of an analysis of U.S. satellite reconnaissance during Desert Storm,** a Russian writer notes Factors which can lower the tendency of satellite reconnaissance to reveal military operations and intent are the use of Stealth technology (especially for small satellites), active maneuvering and orbital servicing [I'm not sure how "orbital servicing," orbital'noye obsluzhivaniye" is supposed to fit in]. >>make them more maneuverable (New engines, new ideas) >Well, the "KH-12" would seem to already have a fair amount of push-water >on board [~10klb out of 40klb] but do the math -- this is enough for a >few days of sky-dancing, or one giant leap to a ~5000 km orbit from >nominal 800 km, but it really isn't going to help much in a multi-week >attrition campaign. One of the big problems with maneuver as a protective measure is simply going to be getting warning and characterization of an attack in time to command the appropriate maneuvers. Direct- ascent ASATs aren't all that easy to detect and track. And, as you say, a satellite can carry just so much gas, so it can't afford to react to every false alarm or perform anticipatory maneuvers too often. >>or make them more economical. >Well, one out of four ain't bad [the other three solutions all tend in >the other direction], but there is no such thing as a cheap satellite -- >some are only more expensive than others. >>s/c can be cost effective if they are built cheap >Well, do the math -- in general: > unit cost absentee Cost/effectiveness > ratio >S/C $100-2000 M 1:10 0.01 to 0.001 >UAV $ 10-20 M 1:1 1.00 I'm not sure I understand your Cost/effectiveness calculation, so just one comment on spacecraft cost: if there's a reason why a 1-m resolution optical spysat needs to cost more than a few tens of millions of dollars when procured in quantity, it's escaped me. IMHO, this is one area where the much-esteemed market forces would do wonders if the NRO were to join the country. >>it's jus the NRO >>has trouble with a s/c that doesnt cost a billion dollars. > Their deformations make things even worse than they have to be, but >the problem has more to do with their institutional imperative to get >folks hooked on their toys than with their refusal to build cheap toys. Well, sure: any business wants to be a monopoly -- just ask Citizen Gates. There are excellent reasons for legislation against this practice, and it would be a good thing if the same reasoning that led to those laws were to be applied to the black world. >>however to data, s/c survivability has been greater then aircraft >>survivability. >And the issue at hand is whether this is a permanent operating factor. Nothing is forever. * An Entry-Level Conventional Radar-Driven [sic] Rocket Anti-Satellite" by Gregory H. Canavan Los Alamos National Laboratory LA-UR-91-4122 ** "O demaskiruyushchikh priznakakh kosmicheskikh sredstv razvedki" "Reconnaissance Satellite Operations as Indicators of Military Intent" (Lit: On the Revealing Characteristics of Space Reconnaissance Means) by Major L.N. Doda Voyenna mysl' (ISSN 0236-2058), No.10, 1992, pp. 42-47 and inside back cover.