Hypersonic Strategies Part 7; Directed Energy Weapons

This is a continuation of Hypersonic Strategies Parts 1 – 6.

(Defense News Daily) Pentagon terminates program for redesigned kill vehicle, preps for new competition. Quoting,

“Ending the program was the responsible thing to do,” Mike Griffin, undersecretary of defense for research and engineering, said in the statement. “Development programs sometimes encounter problems. After exercising due diligence, we decided the path we’re going down wouldn’t be fruitful, so we’re not going down that path anymore. This decision supports our efforts to gain full value from every future taxpayer dollar spent on defense.”

The cancellation is fully justified. The reasoning is explored in U.S. Hypersonic Strategies Part 2; Board Game for a Rainy Day and U.S. Hypersonic Strategies Part 3.

Now we turn to directed energy weapons, beginning with the laser. Lasers are mysterious, photogenic, and according to some wags, “the weapon of the future — and always will be.” My treatment of the EKV in Parts 2 and 3 had all the delicacy of a WWE body slam. There is no need to slam the laser, because there isn’t the presumption that it actually works against missiles. There is a lot of hope that it will. I don’t want to squash hope. Hype should be countered; cautious hope is reasonable.

The hype began with H.G. Wells’ The War of the Worlds, in which the invaders possessed heat rays. Auric Goldfinger’s laser helped it along.  It’s just a movie prop, but the Prima Power video is no joke.  The Warcom video is even better. Note:

  • The laser head is a fraction of an inch from the steel, versus a great distance for missile interception.
  • The laser beam heats the steel. If the steel  could reflect the beam, it wouldn’t cut.
  • The laser spot is about 1/32 inch wide. This cannot be maintained at distance. When the beam spreads, cutting power diminishes, eventually to zero.
  • Both companies are multinational; the bulk of manufacture may be in China; this level of technology has already disseminated.

The purpose of this article is to present the aspects of lasers that pertain to missile defense, without the distraction of the fascinating physics. The interests of a missile defense program rest in a few facts:

  • A laser beam is the most parallel light beam that exists. It spreads the least with distance.
  • If a beam is the-most-parallel, not just decently parallel, it comes from a laser. Theory allows no alternative. If it’s not parallel, it doesn’t come from a laser.
  • Even laser beams are not perfectly parallel, which means they spread with distance.
  • Air weakens laser beams, absorbing, distorting, and spreading them. They travel best in space.
  • The frequency, the “color” of the beam, is determined by the application, and how efficient the “color” is to make. Infrared is the usual choice.
  • The more powerful a laser is, the shorter the lifetime. A pulse can be so powerful, the focusing lens falls apart.
  • Lasers make very inefficient use of power for resulting destructive effect. A black powder  musket is much more efficient. But lasers are cheaper per shot than other modern munitions.

An empty soda can in the path of an Avangard warhead would destroy it. A laser beam can be so aimed. Combined with the eerie videos,  our fascination is explained. Laser beams defy the limitations of physical objects. But they come with new limitations. Compare:

  • Atmospheric vulnerability. An antiaircraft bullet isn’t weakened by a cloud; a laser is.
  • Shots per kill. An antiaircraft gun, even a sophisticated Phalanx CIWS, requires many shots to kill. Because a laser beam can be precisely positioned, a laser requires just one shot.
  • Size/power limitation. The power of  a naval laser weapon is restricted by available electricity.  The power of a land forces laser is limited by the weight and bulk of the power supply.  By comparison, a gun-weapon needs little power.
  • Current lasers are effective only against small, agile, “soft” targets, such as drones and helicopters, with vast per-shot savings over anti-missiles.  The AN/SEQ-3 Laser Weapon System claims hard kill only at low altitude.
  • Gun-type weapons and missiles can be made to knock a hole in anything.
  • Hypersonic warheads and re-entry vehicles  have some natural resistance to lasers. They could be designed for more.

For the energy used, the laser delivers less punch  than collision with a dense, heavy object. Even a pickaxe beats it. Next, we’ll run some numbers and see why this is so.

Next: Comparison with a pickaxe. In the meantime, polish your technique.

 

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