US Laser and Rail Gun Development News

plawolf

Lieutenant General
"Heat" in terms of solid materials is simply the motion of atomic particles. Energy imparted too rapidly to be dissipated as heat (actually vibrations in the electron lattice) cause an ablative spallation. A pulsed laser where the energy is concentrated at the leading edge of the pulse induces a mechanical effect rather than heating. For example, a 100W pulsed laser can punch holes in a quartz plate while a 100W CW laser will have no effect. One of the SDI FEL proposals was from Livermore Labs packing enough Joules of energy in a single pulse to blast a hole through anything not built like a battleship. How energy density and temporal shaping interact with materials has been studied for decades and I have never seen published data (from the laser effects and vulnerability labs in the military) so I figure it must be classified.

Good informative post!

However, the question and issue has never been one to discuss whether a mirrored surface could withstand lasers indefinitely. In order to defeat laser based missile defence, the reflective layer only needs to buy the missile the few extra seconds it needs to pass out of range of the laser or impact the target, as is the case with a point defence laser weapon.

Given that even commercially available mirrors can reflect more than 99.9% of light energy, you either need a laser 1000 times as powerful, or spend 1000 times for time hitting a target with a laser to achieve the same effect as with a target with a standard, non-reflective skin.

For a pulse laser, it still relies on energy transfer, and retention by the targeted object to achieve its destructive effect, although it should greatly offset spinning as a counter against lasers.

Thus, would you not need a laser an order of magnitude more powerful to take down a mirror shielded target compared to a normal, matt finish one?

I
 

Jeff Head

General
Registered Member
Well, the US is looking at multiple laser technologies to try and address the issues.

They are also working with charged particles.

Bottom line...stopping an RV from an ICBM is still probably a good ways off for laser technology.

Kwaig, to your point, the laser mounted on the 747 that showed itself effective, was meant to do precisely what you talk about. Destroy it during boost phase when it has a relatively thin skinned booster full of fuel.

However, stopping a more vulnerable missile that does not reenter the earth's atmosphere, but is itself usually powered right up to impact, is much more attainable and what the current technology is focusing on.

Anti-shipping missiles, land attack cruise missiles and the like.
 
I was wondering what was the
  • biggest;
  • fastest
moving target taken down by a laser so far please? I tried to find out in Internet, in the process I noticed this article (from July though):
Pentagon Eyes Airborne Lasers for Missile Defense
Please, Log in or Register to view URLs content!
 

strehl

Junior Member
Registered Member
I posted this earlier but I will flag the 7:00 thru 7:30 minute mark which shows laser effects testing on various materials. Laser coupling is nonlinear. Once a material starts to fail, the rate of further degradation accelerates rapidly.

As for a mirror coating, no coating exposed to normal air will stay above 99% as even microscopic amounts of dust and bug deposits will form absorption sites for the laser. This can be quite spectacular to watch as dust turns into little sparklers. If you examine a HEL beam director closely, you will note certain structures surrounding the output window. These are used to duct filtered, dry air (or Nitrogen) over the window surface to set up a barrier to dust and moisture. Otherwise, these windows would also fail even with their highly specialized coatings.

 

SamuraiBlue

Captain
"Heat" in terms of solid materials is simply the motion of atomic particles. Energy imparted too rapidly to be dissipated as heat (actually vibrations in the electron lattice) cause an ablative spallation. A pulsed laser where the energy is concentrated at the leading edge of the pulse induces a mechanical effect rather than heating. For example, a 100W pulsed laser can punch holes in a quartz plate while a 100W CW laser will have no effect. One of the SDI FEL proposals was from Livermore Labs packing enough Joules of energy in a single pulse to blast a hole through anything not built like a battleship. How energy density and temporal shaping interact with materials has been studied for decades and I have never seen published data (from the laser effects and vulnerability labs in the military) so I figure it must be classified.

There is no such thing as a "Mechanical effect" to a direct energy weapon since there is no mass for photons. What is happening is rapid expansion and contraction of the substrate that is being attacked by the beam of light in which the surface expands and contracts before the heat is propagated to other parts of the substrate making the point of attack to crack.
 

siegecrossbow

General
Staff member
Super Moderator
Well, the US is looking at multiple laser technologies to try and address the issues.

They are also working with charged particles.

Bottom line...stopping an RV from an ICBM is still probably a good ways off for laser technology.

Kwaig, to your point, the laser mounted on the 747 that showed itself effective, was meant to do precisely what you talk about. Destroy it during boost phase when it has a relatively thin skinned booster full of fuel.

However, stopping a more vulnerable missile that does not reenter the earth's atmosphere, but is itself usually powered right up to impact, is much more attainable and what the current technology is focusing on.

Anti-shipping missiles, land attack cruise missiles and the like.

I don't think it is feasible to use lasers to intercept incoming warheads during the terminal phase. The targets will be coming in at very high speeds and will be properly hardened against reentry heat, which makes interception difficult.
 

Jeff Head

General
Registered Member
I don't think it is feasible to use lasers to intercept incoming warheads during the terminal phase. The targets will be coming in at very high speeds and will be properly hardened against reentry heat, which makes interception difficult.
Depends on the wave length of the laser being used, and the power.

The immediate goal is to use the lasers for killing ASMs, which are a completely different matter.

Killing an RV is quite another thing...but they are testing for the possibility using various methods and a lot more power.
 

siegecrossbow

General
Staff member
Super Moderator
Please, Log in or Register to view URLs content!


Sheesh! What does it take to make the U.S. Navy happy?

Please, Log in or Register to view URLs content!
, tiny Kratos Defense & Security (NASDAQ:
Please, Log in or Register to view URLs content!
Please, Log in or Register to view URLs content!
) strapped together six commercial welding lasers, added a bit of military-industrial complex magic, and built the Navy its first working laser cannon. Unimaginatively dubbed the Laser Weapon System, or "LaWS," the new gun proved itself capable of shooting down unmanned aerial vehicles, poking holes in small boats, and
Please, Log in or Register to view URLs content!
at classified -- but "tactically significant " distances.

But apparently that's not enough for the Navy. They want a laser that's bigger. And better. (And presumably badder.) And they want Northrop Grumman (NYSE:
Please, Log in or Register to view URLs content!
Please, Log in or Register to view URLs content!
) to build it.

Introducing LaWS's bigger, badder brother
The laser that the Navy has decided to build -- and has hired Northrop Grumman to build -- is called the Laser Weapon System Demonstrator (LWSD), and it's quite a monster.

Weighing in at 150 kilowatts in energy output, LWSD will be about four and a half times as powerful as
Please, Log in or Register to view URLs content!
. According to website BreakingDefense.com, that should be enough power to "take out cruise missiles, drones, and manned aircraft at ranges of a few miles." And according to Northrop Grumman energy weapons program manager Guy Renard, all this will cost "about the price of a gallon of diesel fuel per shot" -- $2 per shot.

Getting the program up and running, though, will cost a bit more.

Building LWSD
Earlier this week, we learned that the U.S. Office of Naval Research has awarded Northrop Grumman the
Please, Log in or Register to view URLs content!
. Over the course of the next three years, LWSD will progress through three phases from design to demonstration.

In phase 1, Northrop will develop a detailed design for the weapon. Northrop will receive about 58% of the $91 million in funds budgeted for LWSD's development -- $53 million -- over the first 12 months of this work. Phase 2 would greenlight Northrop to assemble LWSD and conduct land-based test of the laser. Finally, in phase 3, Northrop would conduct at-sea tests aboard the U.S. Navy's "Self Defense Test Ship," the former Navy destroyer USS Paul F. Foster (DD 964), which serves as a floating testbed for new technologies.

Start to finish, these three Phases should take 34 months to complete.

What it means to investors
It's hard to overestimate just how important this news is for the U.S. Navy -- and not just because it would catapult the U.S. into a new generation of weapons systems, unmatched by any foe on the globe. Northrop's $2-per-shot boast -- validated by earlier testing of Kratos's LaWS, which proved capable of firing multiple 33-kilowatt shots
Please, Log in or Register to view URLs content!
-- promises to make shipborne defense against enemy missiles, drones, and aircraft extremely cost-effective.

Moreover, a warship equipped with powerful lasers, instead of powerful -- but expensive and bulky missiles and cannon shells -- would have essentially "
Please, Log in or Register to view URLs content!
" to power its weapons. It won't
Please, Log in or Register to view URLs content!
to keep it supplied with "bullets." So long as there's fuel in the tanks, the warship could remain in the fight. For that matter, freed of the need to lug around large munitions lockers stuffed to the gills with explosive ammunition, warships themselves could be smaller -- and cheaper.

These, as I say, are all benefits that laser weapons would confer upon the Navy -- but they're also strong arguments in favor of buying Northrop Grumman stock as well, because all these factors that make laser weapons so attractive to the Navy also make it a motivated buyer. The potential cost savings from a laser-armed fleet have already convinced the Navy to pay Northrop Grumman to develop LWSD -- and they will surely convince the Navy to buy these laser weapons once they've been perfected.

How many laser cannon might the Navy buy? According to Northrop, it's designing LWSD for easy integration onto the Arleigh Burke-class destroyer -- of which the Navy eventually
Please, Log in or Register to view URLs content!
. So that's at least 77 potential sales of this $91 million weapons system for Northrop. Or perhaps 154? 231? It all depends on how many lasers the Navy ultimately decides to arms its destroyers with.

Given the advantages, my guess is it's going to be a lot.

A stock for greedy investors
The world's biggest tech company forgot to show you something, but a few Wall Street analysts and the Fool didn't miss a beat: There's a small company that's powering their brand-new gadgets and the coming revolution in technology. And we think its stock price has nearly unlimited room to run for early-in-the-know investors! To be one of them,
Please, Log in or Register to view URLs content!
.
 
Top