Monday, January 22, 2007

Nuclear Missiles

Recently the State Department announced that Iran is at least ten years away from building a nuclear bomb. This is absolutely false; Iran has already built as many as 75 nuclear fission warheads. Evidence of this will be presented after we have finished accumulating the necessary background in this and the next few postings. The State Department's misleading statement arises from a failure to lay out the technical aspects of the issue in a way that the American public can understand. For instance, if the State Department is using the term "nuclear weapon" as a nickname or euphemism for "thermonuclear weapon," then technically they are right; it will probably take Iran a decade to produce a thermonuclear bomb. But Iran already has an atom bomb; the kind of device that was used to destroy Hiroshima or Nagasaki at the end of World War II. Such a device could easily destroy Manhattan or Washington D.C.

In this posting, we will lay out the vocabulary and concepts that you will need to understand these issues.

Nuclear Fission Warheads
A nuclear fission warhead gets its immense power from the breakdown of uranium or plutonium nuclei when bombarded by neutrons. In 1945, the United States detonated the world’s first fission weapon. It was called an “atomic bomb” or “atom bomb.” Before ballistic missiles, an “atomic bomb” was really a bomb: it was actually dropped from an airplane. Nowadays, the term, “atomic bomb,” usually refers to a nuclear warhead in the nose cone of a ballistic missile or a cruise missile. A more proper name for such a weapon is “nuclear fission warhead.” This precision of naming matters because there is another type of nuclear warhead, variously called a “hydrogen”, “thermonuclear”, or “fusion” warhead, that is much more powerful.

It took the United States three years to develop the first atomic bomb. Israel developed a bomb in 18 years. Iran has had 27 years; their nuclear weapons program began in 1979.

Nuclear Fusion Warheads
A nuclear fusion warhead gets its power by driving together pairs of hydrogen nuclei to produce helium nuclei. A nuclear fusion warhead is also called a “hydrogen” or “thermonuclear” warhead. Before ballistic missiles, this weapon was known as a “hydrogen bomb” or “H-bomb.” A nuclear fusion warhead can be a thousand times more powerful than a nuclear fission warhead. In fact, you need a nuclear fission explosion to drive together large numbers of hydrogen nuclei. (In the vocabulary of the early Cold War, you need to set off an A-bomb in order to detonate an H-bomb.)

On May 29, 2006, Sadat Hosseini, the head of the technical department of Iran's Nuclear Research Center, announced that Iran has been conducting research into nuclear fusion for the past five years. Nuclear fusion technology can only be used for two things: producing electrical power and making a thermonuclear warhead. But no one has yet succeeded in making cost-effective electrical power from nuclear fusion. This means that Iran's fusion research can only have been directed at making a nuclear fusion warhead: a hydrogen bomb.

Triggering a Nuclear Explosion
A fission warhead, or a fission explosive designed to trigger a fusion warhead, can be detonated in one of three ways:

• By slamming together two sub-critical masses of enriched uranium or plutonium.

• By compressing a sub-critical mass of plutonium until its density becomes critical.

• By firing a stream of neutrons at a sub-critical mass.

A critical mass is an amount of uranium or plutonium large enough and dense enough to trigger a nuclear chain reaction. A chain reaction occurs when uranium or plutonium atoms break down and emit subatomic particles, notably neutrons. These neutrons then collide with and break down other atoms, causing more free neutrons. The breaking up of atoms in this way produces large amounts of energy that are quickly converted into heat. The heat is so intense that it vaporizes all matter in its vicinity, and sends out a tremendous shock wave. The devastation caused by a nuclear explosion is caused by the intense heat, the shock wave, electromagnetic radiation, high-energy subatomic particles, and radioactive nuclear waste materials that disperse at high speeds all over a city.

Delivering a Nuclear Warhead
A nuclear warhead can be delivered to its target in one of three ways:

• By secretly transporting it into a city, and then detonating it locally or remotely.

• By placing it inside a bomb, and dropping the bomb upon the target. (This is now sometimes referred to as a gravity bomb.)

• By placing it in the nosecone of a missile and firing the missile at the target.

The first option — manual delivery — has recently garnered much attention in the press and in fiction, especially in recent movies and television programs. However, transporting the components of a nuclear bomb by hand is difficult, delicate, and dangerous, especially from outside the target country. The Soviet Union is reputed to have built dozens of suitcase-sized atomic bombs. But these weapons are not city-killers; they are too small.

The second option is no longer viable against a modern state. Western countries and many others have radar and missiles that can detect and destroy an approaching bomber. However, the advent of stealth technology, which effectively renders a stealth jet invisible to radar, may bring back the threat of the nuclear gravity bomb.

Therefore, the main nuclear threat today comes from ballistic missiles and cruise missiles that have been specifically designed or altered to contain a nuclear warhead.

Ballistic Missiles
A ballistic missile is a rocket which, after an initial powered flight upward, continues on to its target under the influence of gravity, alone. (The first ballistic missile, the V-2, was invented by the Nazis.) An intercontinental ballistic missile (ICBM) is one that can fly between 2,000 and 8,000 miles. Long-range ICBMs have to pass up through the earth's atmosphere, travel through space, and then reenter the atmosphere in order to reach their targets.

It took the United States 14 years to develop its first ICBM. Iran didn't bother to develop its own ICBMs: it simply bought and copied them:

• Iran purchased between 90 and 100 SCUD-B short-range missiles from North Korea. The North Koreans built a rocket plant near Isfahan so that Iran could mass-produce its own copies of this missile. The Iranians are now building copies of the SCUD-C, known in Korea as the No-Dong, probably at the same factory. The No-Dong missile can reach Turkey and Saudi Arabia.

• More ominously, it bought ICBM-class liquid-fueled engines from Russia, and solid-fueled engines from China; it was not difficult to wrap Iranian-made rocket housings around them. Iran is developing at least one long-range ballistic missile that can reach the United States. In this design, four Russian RD-216 booster rockets are strapped together to form the first stage of the missile. A Chinese-made rocket is used for the second stage.

Cruise Missiles
A cruise missile is designed to fly hundreds of miles at low altitude, changing its path as needed to avoid obstacles and detection, and deliver a payload at a precise target location. (It is possible to program a cruise missile to fly into one particular window in one particular building.) Cruise missiles require advanced computer technology packed into a very small space. It would be difficult for Iran to develop the engineering capability to build cruise missiles; so they’ve bought it instead:

• In January, 2004, the United States Congress learned that Iran was acquiring cruise missile technology from Pakistan.

• On January 28, 2005, Ukraine announced that an earlier Administration had illegally sold 12 Soviet KH-55 “Granat” nuclear-capable cruise missiles to Iran. The KH-55 can carry a 200-kiloton warhead. The Iranians have reverse-engineered the missile and are now mass-producing copies of them at the Khaibar missile base in Karaj.

In recent years, there has been a blending of missile technologies: some cruise missiles can now reach targets that at one time could only be reached by ICBMs; some ICBMs can now alter their flight paths before they drop on a target.

Missile Defense Systems
The United States and Canada are protected from long-range bomber and missile attacks by an array of detection and defensive systems. One of them, administered by the North American Aerospace Defense Command (NORAD,) was designed to deter attacks from over the North Pole from by the Soviet Union. Such systems now protect the entire North American continent from attacks from afar.

The Pentagon claims that we can shoot down incoming ballistic missiles. But I doubt that we have a complete missile defense shield. If we did, it would be common public knowledge. Otherwise its existence could not act as a deterrent to other nuclear powers. (Israel does have a missile defense shield; it consists of Israeli-designed Arrow Interceptor missiles.) If we do not have a missile shield, Iran can strike us at will with ballistic missiles. So can China, the Russian Federation, and other nuclear powers. But as we will see, unlike these other countries, Iran has everything to gain by striking us, and little to lose.

Moreover, these Cold War-era missile defenses are only effective against large ballistic missiles. Such missiles typically have to ascend into space before they can fall on a target. This makes them relatively easy to detect, gives the target population hours to take shelter against the explosion, and allows us to counterattack by launching our own long-range ballistic missiles before the incoming rockets can destroy them on the ground.

But our Cold War-era missile defense plans did not foresee the advent of cruise missiles. A cruise missile can be launched at sea level, and can be programmed to fly so low that our defensive radar systems cannot see it. On September 11th, 2001, a key part of al-Qaeda's strategy was to fly the hijacked planes down below the radar line so that no one could see where the planes were heading. If we cannot detect a slow-flying jumbo jet, then we cannot detect a small missile traveling faster than the speed of sound.

Mutual Assured Destruction
During the Cold War, the United States and the Soviet Union had enough ICBMs to destroy each other. Both countries could also detect an incoming strike, and counterattack before the enemy's missiles reached their targets. The result was a tense stand-off that, fortunately, forestalled a nuclear war. This policy was referred to as "mutual assured destruction," for if one side attacked, the other would be destroyed, too.

Today, in the Middle East, there is a scaled-down version of the mutual assured destruction policy in place between Iran and Israel: if Iran launches a nuclear attack on Israel, Tehran will be destroyed. At least one Israeli submarine is on patrol at all times in the Indian Ocean in order to do this.

Mutual assured destruction works if the two rival nations are roughly equivalent in power. But the safety afforded by mutual assured destruction does not apply when one of the rivals is significantly bigger than the other. Such is the case between America and Iran; simply put, we have much more to lose than Iran does.

Therefore, while it is folly for Russia to attack us, and folly for Iran to attack Israel, it is not folly for Iran to attack us; they have much to gain and little to lose. They have fewer cities than we do, and many of their people are still living as their ancestors did in the Middle Ages; on family farms in small communities, or with small herds of domesticated animals on open land. On the other hand, by attacking America, Iran would gain enormous and instantaneous prestige throughout the Muslim world.

No comments: