Posted on 12/17/2004 6:48:56 AM PST by demlosers
One of the biggest challenges facing Lockheed Martin in its efforts to install a high-energy laser on the F-35 Joint Strike Fighter (JSF) is the question of what to do with all the excess heat generated by the system, according to the company's lead for directed energy programs.
Laser systems use electricity to produce highly focused beams of light, as well as considerable amounts of waste heat that must be dissipated. Lockheed Martin believes that a 100-kilowatt laser is the minimum power level needed to be an effective weapon for a fighter.
However, "to get 100 kilowatts of light out, you've got to put a megawatt of electrical power in, so somewhere along the way you've got to deal with 900 kilowatts of cooling," Tom Burris, lead for directed energy at Lockheed Martin Aeronautics, told The DAILY. "That's a ton, for a fighter that normally does tens of kilowatts of cooling."
To dissipate the heat, cooling loops will be employed to take heat from the laser system and transfer it into the aircraft's fuel tank, where it can be burned away.
"Just like a radiator in your car takes the heat from the cooling that goes into your engine and puts it into the air, this just puts it into the fuel," Burris said.
This process won't compromise the JSF's stealth, Burris said, because it will have no appreciable effect on its infrared signature.
"If you think about the amount of fuel onboard a jet aircraft, if you put all that heat in the fuel, you might raise it by a degree, something on that order," he said. "So in terms of signature, it has no impact."
Lockheed Martin plans to make space for the laser system by pulling out the Rolls-Royce-built shaft-driven lift fan in the Marine Corps short takeoff/vertical landing (STOVL) variant of the JSF (DAILY, Sept. 23). Within that 100-cubic-foot space, used largely for fuel storage in the other variants, the laser can draw wattage from a shaft connected directly to the aircraft's JSF119-611 engine.
Solid-state lasers, which use a solid material such as crystal or glass as the lasing medium, are the most mature and promising laser technology for this application, according to Lockheed Martin. Single-digit-wattage solid-state lasers already are commonplace on today's fighters, where they perform tasks such as rangefinding and target designation.
Over the summer, Lockheed Martin signed an agreement with the Air Force Research Laboratory's (AFRL) Directed Energy Directorate to cooperatively explore high-energy laser concepts for fighters (DAILY, June 6). AFRL will furnish the laser, while Lockheed Martin concentrates on integration into the aircraft.
Lockheed Martin anticipates the JSF using lasers against both air and ground targets, at a typical range of 10 kilometers (6.2 miles). The laser itself would be housed in a dome that would emerge from the aircraft when needed, Burris said.
"When you want to use it, you'll deploy the turret, so it'll pop out into the airstream," he said. "You'll get a target cue from somewhere, just like all weapons do. It'll slew over to where you think the target is, acquire the target, and then it'll start lasing it."
The earliest opportunity the company will have to place a high-energy laser system on the JSF will be beginning with the Block Four version around 2012, according to Burris.
Optics
The other major challenge in putting lasers on the JSF is keeping the laser beam focused properly as it passes through the turbulent air around the Mach 1 aircraft.
"That flow field around the aircraft will distort the laser beam," Burris said. "So you'll have to have some sort of system onboard ... that'll sense that distortion and then correct for it."
The solution is adaptive optics - a technology developed by AFRL that is already in use on the Airborne Laser (ABL) program and at many astronomical observatories around the world. An adaptive optics system performs real-time compensation for atmospheric distortion by using deformable mirrors that can "pre-distort" the beam in such a way that the atmosphere itself straightens it out.
The Original Story from: aviationnow.com
This is the REAL Star Wars technology.
I don't understand why air cooling, either direct or through a radiator type system wouldn't be more effective and simple than cooling throught the fuels ysstem. Moving throught the air at several hundred miles per hour ought to give enough flow to use a very small radiator for the short duration cooling would be required without significantly increasing the radar signature.
Yeah, I like the idea of burning big holes in jihadist heads in a flash.
Sounds like an idea, but the degree to which the fuel heats up will depend on the amount of fuel in the tank. Make sure you fill up the tank before blasting away with your laser.
....... by using deformable mirrors that can "pre-distort" the beam in such a way that the atmosphere itself straightens it out.
Amazing
http://www.photonics.com/todaysheadlines/XQ/ASP/url.lookup/id.5159/QX/today.htm
F-16 Pilots Join in Laser Games
Thursday, October 28, 2004
KIRTLAND AIR FORCE BASE, N.M., Oct. 28 -- F-16 pilots participating in a computerized war-game exercise this week will be armed with a simulated laser cannon developed by the Air Force Research Laboratory.
During the exercise, called Advanced Concepts Event (ACE), pilots will use the newly developed laser-armed F-16 simulator to better prepare for aerial combat once laser weapons become available. The simulator also allows Air Combat Command to develop tactics, techniques and procedures that will be needed in laser battles.
Being held at Kirtland Air Force Base in New Mexico, ACE incorporates simulators from throughout the country, networked to Kirtland. Officials said the event offers the intensity of real exercises, providing participants the opportunity to test future weapon systems in a war-games format. ACE is available to all the military services.
The F-16 laser simulator -- known as the high-energy laser (HEL) fighter -- was developed with assistance from F-16 pilots assigned to the New Mexico Air National Guard, another Kirtland-based unit.
"We started this effort nearly four years ago," said Rudy Martinez, the HEL Fighter project officer at the Directed Energy Directorate. "We wanted to merge an F-16 simulator with a laser weapon system so that a pilot could blend flying experience with the skills needed to operate a revolutionary speed-of-light weapon."
According to Martinez, "A pilot would fly his F-16 differently in a laser battle compared to a more traditional fight using guns or missiles. With guns and missiles, a pilot has to maneuver to approach a target from behind or from the side. But with a laser weapon that pilot can have more latitude. That's because the laser is mounted on a turret underneath the plane. The turret can fire the laser 35 degrees to either side of straight ahead so the pilot doesn't have to do as much maneuvering.
"Working as a team, we put together a pretty good simulator," said Martinez. "But we still needed to get it into the hands of Air Combat Command operators to get feedback on how well it works, whether it was realistic enough or not. So we transitioned it to a facility in Mesa, Ariz., called the Warfighter Training Research Division of the Human Effectiveness Directorate, which as four F-16 simulators. By loading all four simulators with our model, we were able to fly multiple, simulated, laser-armed aircraft in a single battle."
The simulators at Mesa are also more sophisticated than the ones at Kirtland; they can incorporate a 360-degree "out of the cockpit" view in their simulations.
Improvements to HEL Fighter are in the works, including more precise targeting mechanisms. A laser-armed fighter aircraft is still a few years away. Also under development are solid-state lasers in the 100,000-watt range and compact electrical sources that can power high-energy laser weapons. Until then, Martinez said, that experience will only be available through simulators like the HEL Fighter and exercises such as ACE.
For more information, visit: www.de.afrl.af.mil/pa
Heat dissipates much more effectively into a liquid than into gas.
Dissipating 900 kilowatts of heat into the air over time WOULD likely compromise the stealth of the aircraft by creating a trackable IR signature.
very cool. I think thise should be installed on the F-22 as well.
Onw problem. Putting that rasiator in a postion to take advatage of the airflow means you are putting a IR emitter in a postion to radiate into the forward arc. That's just making it easier for hostile missiles to lock on.
Big stakes for lab to build battle laser
General says he'll come up with $150 million if scientists produce mobile device within 18 months.
A two-star Army general threw down a challenge last week to Lawrence Livermore scientists: He will beat the bushes for more than $150 million if scientists can build the world's first mobile battle laser for test firing in 18 months. Livermore laser engineer Bob Yamamoto had been begging for this chance. But Livermore, specializing in nuclear explosives, never has built a full-up, firing weapons system for the battlefield.
"Eighteen months is very aggressive, and I'm saying that very politely," said Yamamoto.
On Tuesday, Major Gen. John M. Urias, the Army's chief acquisitions officer for air and missile defense, drew lab scientists and defense contractors into the hallway of an Albuquerque hotel so they could voice last-minute reservations.
Yamamoto, grinning wildly, said not a word.
The general then strode into a convention room and told 640 top U.S. directed-energy experts that Livermore's laser -- today, a profusion of wires, crystals and diodes on a tabletop -- was ready to be shoehorned into a Humvee and prove its mettle as a tactical weapon.
"We are no longer technology-limited. We are resource-limited," Urias said by phoneFriday. "I think we should charge on."
If he gets the money for Livermore and its team of defense contractors, the general suggested, the Army would get a prototype weapon that could open the military's imagination to what mobile lasers can do on the battlefield.
"I am convinced personally that the technology is evolving fast enough that we can do this," he said.
Three weeks earlier, the general donned green goggles in Yamamoto's lab and saw the world's most powerful solid-state laser drill through an inch of steel in two seconds.
"If anybody doubts what I am asserting, they need to go out to Lawrence Livermore lab and see this demo," said Urias, deputy commander of the Army Space and Missile Defense Command and acquisitions executive for Air and Missile Defense.
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The jets are mixed with air & ducted, why not the same. Besides the heat would be instantly gone, and not stored like it would be in the fuel.
I'm going to found the N.L.A.
National Laser Association.
I doubt this creates more heat than a jet engine, and they have no cooling system other that the ambient air.
900 kw = roughly 600 hairdryers. I have to beleive a jet produces more heat than that.
The short bursts of high heat flowing from the aircraft are infra-red kick me signs to a heat seeking missile.
The problem is the IR signature, not the radar signature. The laser would normally be used during an air-to-air engagement and the increased heat signature would make the JSF more vulnerable to detection and attack by heat-seeking missiles.
That said - I'm not sure how comfortable I would feel about using the laser if I knew that it was going to super-heat the fuel in my airplane.
I only read the Yamamoto part of that post at first & though it was odd the WWII Japs had a laser with that kind of capability
Warfare at the speed of light
-snip-
Experts agree battle lasers need at least 100 kilowatts of power. The Pentagon wants to see who will get to 25 kilowatts first in 2004.
Yamamoto is a veteran builder of lasers and atom smashers. Next to those, the laser weapon sitting on his lab bench is easy: It's modular. He just adds another 4-inch slab or two of manmade garnet and surrounds it with diodes. He expects to beat 25 kilowatts by Christmas and double it early next year. To reach 100 kilowatts will take more and bigger slabs.
Yamamoto's problem is heat. Lasing makes the crystals warm inside and corrupts the light beam. Eventually, the slabs can crack and shatter. They're thick and don't cool well in chilled water or gases. Livermore's laser designers had a simpler idea: Build two or more of the compact lasers in cassettes and rotate them when hot.
A leap in efficiency
But the real innovation that makes solid-state lasers worthwhile for defense are high-power diodes. Instead of using flashlamps like Maiman's ruby and the National Ignition Facility, Yamamoto's laser is pumped by more than 8,000 diodes. They're 10 times as efficient.
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