The bomb-pumped laser (or in Star Wars parlance, the 'X-ray Laser') was a system proposed by the (in)famous U.S. weapons designer and physicist Edward Teller. The premise behind the weapon, like many of Teller's less-than-successful projects (including the failed first attempt at a hydrogen bomb around 1948-1952) was deceptively simple - as long as one could overlook the fairly outrageous nature of the first step in the process of its use. The system was proposed as a means of destroying ballistic missiles in flight through directed energy (a laser beam) of vast power. Essentially, the problem statement went like this.

  • In order to stop an incoming ballistic missile, the defender needed to hit it as far away as possible as fast and as hard as possible.
  • Directed Energy weapons were the best way to do this because of the very small Time of Flight and the consequent ease of aim
  • The laser/maser concept offered the best means of producing a DEW at that time
  • The problem was that contemporary lasers simply didn't have the power to produce the beam required to do this even once, much less multiple times with little to no warning.

Teller decided that the way to improve the laser's chances of destroying the missile lay in several different steps. First, the laser (and the missile) should be as far above the atmosphere as possible during the attempted intercept, both to shorten the range between them and (more importantly) have as much of the laser's path as possible avoid the interference of the atmosphere. So far, so good.

Problem two was the weakness of the beam. When coupled with the difficulty of lifting (much less basing) large installations in space and having them available at need, this (to Teller) meant that there were no available power sources which could give him the oomph required. Except one.

Teller realized that the laser mechanism itself didn't need to survive for long past the point of ignition, if the power output was high enough. Also, the higher the frequency of the beam, the higher its power. There were no methods at the time of generating higher frequency laser beams that didn't require large installations, but Teller's fertile imagination came up with one.

Why not use an atomic bomb?

The first few microseconds of an atomic explosion are characterized by an enormous wave of extremely high energy photons - X-rays. The characteristic fireball produced by an atomic explosion is, in fact, a ball of plasma that results from the atmosphere surrounding the blast becoming supersaturated with X-ray energy. That sounded perfect.

Teller's concept, in sum, was to orbit nuclear bombs in satellites, and to 'jacket' each satellite in a cluster of movable laser tubes (or 'barrels' in the gun sense). Since any incoming attack was likely to involve a number of weapons, Teller and his cronies reasoned that it would make the most sense to target a number of missiles with different laser tubes while they were in boost phase, and then upon detonation of the bomb, each laser tube (in the microseconds before it vaporized) would theoretically focus, lase and collimate the initial surge of X-rays into a beam of enormous power. These beams, despite only lasting between two and twenty microseconds in duration, would nevertheless transmit so much energy that the target would be destroyed.

Ummm....right.

As I mentioned above, the plan sounds fine until you re-examine its first step: Orbit a bunch of atomic bombs and when you suspect you're under attack detonate one or more of them. As the U.S. found out in tests over Johnston Island later on, the effects of atomic explosions in low-earth orbit (or even high orbital altitudes) are catastrophic. The EMP from such devices would thrash most of the electronic infrastructure of the area beneath its point of detonation. Furthermore, this meant placing live atomic weapons outside the direct positive control of U.S. personnel, which would leave them vulnerable to interference or misuse (remember You Only Live Twice?)

Teller's modus operandi of finding the highest-placed and most scientifically illiterate politicians culminated in his capturing the ear of Ronald Reagan. Having done spokesman work for GE, Ron was easily 'gee-whizzed' past any misgivings as to either the science or Teller's past record (although there's no record he had any), and the Strategic Defensive Initiative was born, with the bomb-pumped laser a key piece.

Actual nuclear tests were done to determine if the scheme was feasible; as far as I know, there were no results which showed that the X-ray lasers functioned. Whether that was because they didn't survive long enough or were just designed badly, we may never know. One problem with this project is the need to produce atomic explosions to test your designs, each of which is destroyed in the process...it makes the typical iterative approach to engineering design a tad pointless.

In recent years, Teller's salesmanship (and, some might say, charlatanism) have been examined in an effort to combat the continuing science deficit exhibited with shocking regularity and tenacity by some of the world's blandest and dumbest leaders. Chuck Hansen, author of U.S. Nuclear Weapons: the Secret Story, wrote in a review of a Bush-the-first era Teller biography:

A favorite Teller proposal during this period was the "nuclear bomb-pumped X-ray laser," a space-borne defensive battle station that would destroy incoming nuclear warheads high in space, which was to be ready for deployment in as little as four years. Several nuclear tests were conducted in Nevada to perfect the device; according to Teller, these experiments resulted in laser wavelengths "1,000 times shorter than lasers of visible light." Nonetheless, after 12 years of inconclusive research and the expenditure of billions of dollars, work on the X-ray laser was stopped, and a poorly conceived, shamelessly oversold high-technology project came to a fitting end as a scientific curiosity with little practical military value.

The Bulletin of the Atomic Scientists, May 1992

Teller's baby did have an effect on the world. One of the stated reasons for the enormous expenditures the Soviet Union showered on their Energia/Buran programs was the expectation that devices such as these made reuseable manned spaceflight capability imperative. Later, the Indian Government (ironically) submitted a report to the U.N. in support of the NPTwhich cited (among other things) the pursuit of such devices as a cause of continued danger from atomic research.

Although the U.S. laboratory community has been mostly wrested from Tellerite control, the example of the bomb-pumped laser is most useful to keep in mind when evaluating the proposals of future generations of weapon designers. Never mind how well a solution deals with the technical hurdles at the closing end of a problem statement; always be sure to carefully examine the beginning of the problem statement (and, most important, that which is left unsaid) before even bothering to evaluate the validity of the performance claims. Do we need this thing? Why? Will it solve problems or cause them if we bring it into existence?

As a fictionalized Jim Malone once said, "Here endeth the lesson."


http://www.nrdc.org/nuclear/endrun/er4.asp
http://www.thebulletin.org/issues/1990/d90/d90bulletins.html#anchor509008
http://www.astronautix.com/project/buran.htm
http://www.fas.org/irp/doddir/doe/pubgd.html
Directed Energy Missile Defense in Space - A Background Paper (Washington, D.C.: Ash Carter, U.S. Congress Office of Technology Assessment, OTA-BP-ISC-26 1984
http://www.fas.org/nuke/guide/india/doctrine/880000-disarm.htm

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