Slashdot Mirror

There is an SULEV rated Honda Accord EX available at dealers in California now, while the Toyota Prius is not yet available (though some dealers are taking orders). The Accord isn't a hybrid and so the milage alone is nothing to write home about, but the emissions (per mile! not per gallon...) are very competitive for everything but CO2.

Some information about Honda's environmental impact can be found here at Honda's official website. A PDF file describing the SULEV spec is available from the transportation website of the Union of Concerned Scientists.

The only question is why all the other states are lagging behind California! The technology is out there, and cleaner air benefits everyone.

There is an SULEV rated Honda Accord EX available at dealers in California now, while the Toyota Prius is not yet available (though some dealers are taking orders). The Accord isn't a hybrid and so the milage alone is nothing to write home about, but the emissions (per mile! not per gallon...) are very competitive for everything but CO2.

Some information about Honda's environmental impact can be found here at Honda's official website. A PDF file describing the SULEV spec is available from the transportation website of the Union of Concerned Scientists.

The only question is why all the other states are lagging behind California! The technology is out there, and cleaner air benefits everyone.

Can NASA hold patents? I don't know, but I would think if they could, they could be pulling in alot more money from licensing technologies, giving them a bit of return on investment.

Actually, NASA does hold a lot of patents. These include things like goretex and I believe that they own the patent to velcro. They make quite a bit of money from those patents, which is good because it seems that the US Government is more interested in funding other programs like missle defence.

The only true security from nuclear weapons is their absence from the world.

Countermeasures: The Achilles Heel of Missile Defenses

All ballistic missile defenses are vulnerable to countermeasures. Despite decades of research, dealing with countermeasures remains the key unsolved--and likely unsolvable--problem facing missile defenses. It is far easier for the attacker to deploy effective countermeasures against defenses than it is for the defense to respond to such countermeasures.

It doesn't take a rocket scientist to build countermeasures. Effective countermeasures can be cheap and use simple technology--much simpler than the technology required to build long-range missiles. Among other possibilities, the attacker can overwhelm the defense; make the warhead hard to detect, leaving the defense without enough time to intercept it; or prevent the defense from identifying the true warhead. If the United States deploys a national missile defense, it must expect that any developing country that would build or buy long-range missiles to deliver an attack would also make sure these missiles had countermeasures to penetrate the defense.

Accidental or unauthorized attacks from Russia or China would include countermeasures. Russia and China almost certainly have already deployed countermeasures or could readily deploy them if the United States builds a national missile defense. These countermeasures would be equally as effective for an accidental or unauthorized launch as for an intentional attack.

The job of the defense is inherently difficult even without countermeasures. Building an effective defense against long-range missiles is intrinsically difficult even in the absence of countermeasures. First, the ground-based radar or satellite-based sensor must detect and track the attacking warhead early enough for the interceptor to reach the warhead. Second, the defense must accurately calculate the projected intercept point and launch an interceptor toward it. Third, the infrared sensor on the interceptor must detect the warhead far enough away to give the interceptor time to maneuver. Finally, the interceptor must maneuver accurately enough to hit the warhead--a small object--at a closing speed of greater than 10 kilometers per second (22,000 miles per hour). The difficulty of this task is revealed by US tests of high-altitude hit-to-kill interceptors (the type that would be used for national missile defenses) against cooperative targets: as of mid-1997, only 2 of 14 intercept attempts have been successful.

Effective use of countermeasures would make a difficult job essentially impossible. The attacker does not need to do much to make intercepts all but impossible. To defeat a defense, the attacker needs for only one countermeasure to work. But for a defense to be reliably effective it must work against all countermeasures the attacker might use, and must work the first time it encounters them. Many countermeasure techniques, each working to defeat the defense in a different way, are available and the attacker can use a combination of these. Some examples are

The attacker can overwhelm the defense. Chemical and biological warheads can be divided into many small parts--called submunitions--that can be released early in flight, just after the booster stops thrusting. This creates so many reentering targets that it overwhelms the defense and would therefore defeat any midcourse or terminal defense. Moreover, dividing the warhead into submunitions is also beneficial to the attacker because it distributes the chemical or biological agent more efficiently over the target area. US intelligence officials have stated that they believe North Korea will be able to deploy submunitions, and that this technology could be available on the world market by 2000.

The attacker can make the warhead hard to detect, leaving the defense without enough time to intercept. The infrared sensor on the interceptor, which guides it to the final intercept, detects the heat emitted by the warhead. Cooling the surface of the warhead thus makes it more difficult to detect. A small amount of liquid nitrogen in a thin shroud surrounding the warhead could cool the surface enough to reduce the distance at which the infrared sensor could detect the warhead by 10,000 times--from the hundreds of kilometers needed down to only tens of meters. The interceptor would have only a few thousandths of a second to react, in which time it could not maneuver enough to have any chance of intercepting a warhead traveling at 7,000 meters per second.

Such cooling would also make the warhead much less visible to the infrared detectors on satellite-based sensors such as the planned Space and Missile Tracking System, giving the defense less time to work. Similarly, the warhead can be made more difficult to detect by radar by reducing its radar cross-section using simple techniques such as adding a sharp nose, curving its back end, and covering it with radar-absorbing material.

The attacker can prevent the defense from identifying the true warhead. Above the atmosphere, where long-range missiles would be intercepted, objects of different weights and shapes travel at the same speed and follow the same path. This allows a missile to carry a large number of lightweight decoys to confuse the defense. Moreover, these decoys do not need to be aerodynamic and need not even look like the warhead since the warhead could also be disguised. Such decoys would force the defense either to launch interceptors at all the false targets or to wait until the atmosphere strips away the lightweight objects, by which time it could be too late to launch interceptors against the warhead.

A simple and effective countermeasure is to place the warhead in a metalized mylar balloon (similar to those sold in florist shops) and release it within a large cloud of empty balloons. Each of these targets would move at the same speed and could not be distinguished by the missile defense radar. Moreover, adding a small heater to each balloon to heat each one by a different amount would prevent infrared sensors from detecting the real warhead. And, if desired, the attacker could also add a small vibrator to the balloons to mask any small motions the warhead might cause. The lightweight balloons would be stripped away by the atmosphere late in flight, but by that time they would already have done their job.