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![[F]](_images/site.gif) New York Times on the Web Forums  Science
Keywords: optics
 | Missile Defense #6413 - rshowalter
Jul 2, 2001 03:53 pm
Indented question set #1: "what do you mean exactly by "see"? --see what? -- see how well?.. | | | Missile Defense #6407 - gisterme
Jul 2, 2001 02:25 pm
rshowalter 6/30/01 8:01pm rshowalter wrote: "...Note especially: " For example, Ted Postol of MIT, among others, argues that NMD cannot discriminate between reentry vehicles and decoys (e.g., balloons) that are designed to confuse defenses.6 This was a problem that also dogged the Nixon-era ABM. The technology was different but even the corporate contractors that devised the ABM system believed that its radars could not differentiate between decoys and reentry vehicles." As you should know by now, Robert, the flight profile of an ICBM can be broken down into three general phases: 1) The boost phase where the reentry vehicle(s) and decoys ride atop a huge flaming rocket that is vulnerable to attack by satellite based lasers or kinetic projectiles or even aircraft based lasers. Tracking of ICBM boosters would most likely be accomplished by satellite based infrared sensors that are known have far better resolution than radars... | | | Missile Defense #6231 - rshowalter
Jun 28, 2001 03:28 pm
Subject to some rules of checking that we're getting close to here -- where engineers outside the security vail can "count miracles that DOD has to solve" -- it is getting harder and harder to maintain that the missile defense programs have anything worth doing. Really good people are working their hearts out, on jobs that they can't do -- and forced to lie about it (or, at the least, to deflect attention from fundamentals.) Whether money is being stolen or not -- it sure is being wasted. For example, the "space based lasar" program -- for missile defense - is VERY far fetched when you look at Space Telescope resolution, and consider the much higher levels of resolution the program has to ask for technically -- for control systems, optics, and radar resolution and a stack up of related reasons ... | | | Missile Defense #6149 - gisterme
Jun 27, 2001 02:06 pm
rshowalter wrote: "...The artificial intelligence efforts funded by the military have been dominated by a "connectionist" or "parallel distributed processing" paradigm that was showing severe limits by the late 1980's..." Why would any very complex level of AI be needed to track a ballistic missile? As dirac says, the "B" in ICBM stands for "sitting duck". ICBM payloads follow a nice parabolic trajectory once the boost stage is over... | | | Missile Defense #6145 - gisterme
Jun 27, 2001 01:05 pm
rshowlater wrote: "...The resolution of an electro-optical system depends on many things, but is limited by wavelength -- and radar waves are MUCH coarser than light waves. The resolution of the best radars may, therefore, be much worse than the angular resolution of Space Telescope..." WRT radar, don't forget that the USAF now uses ground based radar to track orbiting objects down to a size of about 1" in diameter. However, infrared sensors like those that would likely be used to track rocket boosters use wavelengths much shorter than the optical and therefore have much better theoretical resolution than optical sensors... | | | Missile Defense #6130 - rshowalter
Jun 27, 2001 09:39 am
I can't prove that something doesn't exist beyond a wall - without getting a look. And so "we have it, but it is classified" is an answer that cannot be proven wrong, in the most direct possible ways. Some facts are useful as guides to the possible, however... | | | Missile Defense #6059 - rshowalter
Jun 26, 2001 12:35 pm
I'd like to repeat the posts that ended this thead on June 24th.
MD5978 rshowalter 6/24/01 9:00pm ....
MD5979 rshowalter 6/24/01 9:01pm
MD5980 rshowalter 6/24/01 10:21pm
Let me add a fact that I believe a loyal United States citizen should be permitted to post... | | | Missile Defense #6025 - dirac_10
Jun 25, 2001 05:01 pm
smartalix - 02:47pm Jun 25, 2001 EST (#5999 of 6024) I asked dirac those same questions, and he dismissed them. The fact is that we currently do not have the neccessary skill in optics to maintain a beam that tightly over a long distance in atmosphere. As a matter of fact we do... | | | Missile Defense #5999 - smartalix
Jun 25, 2001 01:47 pm
I asked dirac those same questions, and he dismissed them. The fact is that we currently do not have the neccessary skill in optics to maintain a beam that tightly over a long distance in atmosphere. In addition, the inverse-square law dictates that the farther the beam has to go, the weaker it gets... | | | Missile Defense #5995 - rshowalter
Jun 25, 2001 12:30 pm
smartalix , you're an optics jock, aren't you (you edit a magazine that sometimes deals with lasars, as I recall?) If I remember, the lasar "hot spot" to take out a ballistic missile on boost phase has to be on target for the order of a second (ON THE SAME SPOT) -- would you care to comment on how "easy" it is to get that resolution (say 1 cm) over the distances involved, from a moving platform (plane or satellite) shooting at a moving target? If the distance is 100 km, isn't this a target of 10e-7 radians diameter, that is moving ? Shot at from a moving platform with some degree of vibration and "unwelcome motion" to be compensated for?.. | | | Missile Defense #4892 - dirac_10
Jun 12, 2001 02:22 pm
rshowalter - 03:15pm Jun 12, 2001 EST (#4890 of 4891)Amazing how innocent those that post on the missile defense forum are. Well, I'm here to inform... Absorbtion problems?.. | | | Missile Defense #4659 - dirac_10
Jun 9, 2001 11:50 am
smartalix - 12:08pm Jun 9, 2001 EST (#4658 of 4658) BS, Dirac. Actually P.A.M. but whatever... | | | Missile Defense #4658 - smartalix
Jun 9, 2001 11:08 am
BS, Dirac. We have yet to display consistent intercept with a missile under any circumstances. Even the antiquated Scud managed to get past the Patriot system (akin to the Aegis system which is also presented as a missile-intercept system) consistently enough to demonstrate the insanity of relying on such a system to protect against nuclear attack... | | | Missile Defense #3060 - gisterme
May 2, 2001 06:25 pm
rshowalter wrote: "...And missile defense, to be any good, has to handle the hardest interceptions, under the noisiest conditions, that an adversary can arrange. As the brits would say" " It is just not on." ... The BRITS!.. | | | Missile Defense #3049 - rshowalter
May 2, 2001 05:38 pm
Radar engineering, for instance, has been going on for a long time. And there were very good, motivated people in it, very early. Order of magnitude resolution breakthroughs, dealing with targets built to be hard to measure, are going to be hard to come by... |
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