10 décembre 2020 | International, Terrestre

Despite progress, industry faces ‘very tough roadmap’ to field FCAS by 2040

GA is building a prototype 300-kW missile defense laser for the Pentagon and a 250-kW airborne version with Boeing.

By on December 09, 2020 at 3:04 PM

WASHINGTON: General Atomics is so confident in a unique technology they say solves the heat and weight problems found in rival laser designs that they're making it the core of two distinctly different projects.

The Office of the Secretary of Defense is funding General Atomics and two competitors to build experimental lasers able to blast out some 300 kilowatts of power – enough to burn cruise missiles out of the sky. This project is about scaling up laser power output and testing alternative technologies for the services to pick up for separate follow-on programs.

Meanwhile, Boeing and General Atomics are jointly developing a smaller laser weapon – starting at about 100 kilowatts but capable of growing to 250 kW. Unlike OSD's, this 250 kW weapon is being built at the companies' own expense, essentially on spec. (The technical term is IRAD, Independent Research And Development).

Like OSD, Boeing and GA are hoping to demonstrate technology that'll be picked up by the services for a wide range of ground- and ship-based applications: The company says they're targeting the Army's Stryker-mounted M-SHORAD and its larger truck-borne IFPC, as well as Navy shipborne models. But for the pilot project, they've set themselves a very specific and demanding technical challenge: make their laser fit aboard an airplane – and make it fire accurately from that plane in flight. (Breaking D readers will remember the Airborne Laser, a huge chemical laser on a modified 747, as well as plans to arm the Next Generation Air Dominance planes with lasers.)

Call in the “New York, New York” school of engineering: If you can make your laser work on a plane, you can make it work anywhere.

“The idea is, if we can do it for an aircraft, then it truly could be able to go on any ground or sea platform,” said GA's VP for lasers, Michael Perry. “An aircraft...has the largest constraints on size, weight, and power.”

Now, that doesn't mean getting lasers to work on ships or Army vehicles is easy. In some ways, surface platforms have a harder time: Their lasers have to penetrate the thickest, most moisture-laden layers of the atmosphere. And, Perry told me, while an aircraft in flight is constantly vibrating, you can account for that with sophisticated beam control software and high-quality aiming mirrors: That tech is tricky to build, but not bulky to install once you've built it. By contrast, a laser installed on a surface platform has to handle sudden, massive jolts as the warship crashes over a wave or the truck drives over a ditch, and that requires shock absorption systems, which are bulky and heavy.

(While General Atomics and Boeing haven't said what aircraft they're planning to test the laser aboard, given the fact that Perry thinks extensive shock-absorption will be unnecessary, that suggests it isn't going to be a fighter jet or anything that makes violent high-gee maneuvers. That's in line with Air Force Special Operations Command's longstanding interest in putting a laser cannon aboard their AC-130 turboprop gunship).

So GA's major focus in this project seems to be proving how compact their technology can be. Smaller size is a big advantage of the GA approach, Perry said, which they refer to as scalable distributed gain.

Fibers, Slabs, & Distributed Gain

What is a “distributed gain” laser, anyway? In the Wild West days of Reagan's Star Wars program, the Pentagon looked into lots of ways of powering lasers, from literal nuclear explosions – an idea called Project Excalibur – to massive vats of toxic chemicals, like the ones that filled the converted Boeing 747 that became the Airborne Laser. The real progress, however, has come with so-called solid state lasers: They pump light into a crystalline “gain medium,” which then amplifies the power of that light (hence “gain”), until it's released as a laser beam. But there are two main ways of building a solid-state laser:

  • A slab laser, as its name implies, uses a single big chunk of crystal as the gain medium. This gives you a single coherent beam of laser light. The problem with slab lasers is heat buildup. The bigger you make the slab, the further the distance from its core to the edges, which means it takes longer to disperse waste heat, which can build up and damage the system. (You may recognize this from high school physics as a manifestation of the square-cube law). So slab lasers tend to require cooling systems, which are bulky and heavy.
  • A fiber laser, by contrast, uses lots and lots of fiber-optic cables as gain media. Each individual fiber is very thin, and you can leave space between them, so it's easy for them to disperse waste heat. The problem with fiber lasers is the act of combining the beams. The bigger you make the laser, the more fibers you need – a 250-kW weapon might take 100 fibers, Perry said – and each fiber produces its own, weak laser beam, which you then have to combine into a single, powerful beam. Beam combination systems tend to be expensive and complex, not to mention (surprise!) bulky and heavy.

General Atomics' distributed gain laser tries to strike a balance. Instead of a single big slab, you have several smaller slabs, each of them thin enough to disperse heat quickly. But instead of each of these slabs producing its own beam in parallel, which you then have to combine, you connect them in serial. The initial light source goes into the first slab, which magnifies it and shoots it into the second slab, which magnifies it still more. In theory you could have a third slab as well, even a fourth and fifth, though that's not what GA is building here. (They don't have to be lined up end to end, because you can use high-quality mirrors to bounce the light around a corner).

“It is a series of slabs,” Perry told me. “The single beam passes through them all, as opposed to being separate lasers.”

The advantage of distributed gain for high-power lasers is that you need neither the extensive cooling systems of a slab laser, nor the exquisite beam-combination systems of a fiber laser. “It's pretty compact,” Perry told me. “If you came out to see if you would be surprised at how short it is.”

That said, there is a minimum length for a given amount of power output. That's why General Atomics couldn't fit the same 300-kW weapon they're building for OSD onto Boeing's aircraft (again, they're not saying what that aircraft is), which is why that version had to be scaled down to 250 inches.

“The problem we have is, the 300-kw architecture is about 18 inches longer then the 250,” Perry said ruefully. “Believe it or not, as painful as it is and as frustrated as I am, I cannot eke out another 18 inches of length... The platform can't even give us another 12 inches.”

It may be frustrating for Perry and his team to build two different versions of their lasers, rather than build two identical copies of the same thing – but the exercise could help prove to potential customers just how adaptable the basic design can be.

https://breakingdefense.com/2020/12/general-atomics-new-compact-high-powered-lasers/

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  • New National Guard medical helicopter unit set to deploy

    12 juin 2018 | International, Aérospatial

    New National Guard medical helicopter unit set to deploy

    WINDSOR LOCKS, Conn. (AP) — The Connecticut National Guard's newest unit, which has spent the past two years training with new, specialized helicopters, will deploy soon to provide care and transport to the sick and wounded in support of military operations in southwest Asia. "To receive your first medical evacuation aircraft in 2016 and be fully prepared for a deployment less than two years later is a testament to the hard work and dedication of those in our aviation community," Maj. Gen. Thaddeus J.Martin, adjutant general and commander of the Connecticut National Guard, said in a statement ahead of a sendoff ceremony last month for the aerial medical evacuation unit, officially known as Detachment 2, Charlie Company, 3rd Battalion, 126th Aviation Regiment. The detachment, based in Windsor Locks and commanded by 1st Lt. Matthew Barringer of South Glastonbury, doesn't officially deploy until later this month. It represents a new capability for the National Guard. It received the first of three Blackhawk helicopters specifically outfitted for medical evacuation in the spring of 2016, even before becoming a fully operational unit in the fall of 2016. Thirty members of the detachment are deploying and will spend about a year providing aeromedical evacuation, en-route critical care and medical support while transporting patients. Five of the members deploying are women. The unit will join the 70 guardsmen from Connecticut already deployed in support of operations around the world. While deployed, the unit will be on 24-hour standby, and operate in shifts. A crew of four — two pilots, a crew chief, and a flight paramedic — can transport up to six patients at a time on one of the Sikorsky-built HH-60M Blackhawk helicopters. The helicopters have been specially outfitted for aerial medical evacuation and will be stocked with medical supplies like ventilators and IVs. The crew also has the capability to do procedures on board such as put in a chest tube. "We're almost a flying hospital," said Chief Warrant Officer Jonathan Behuniak, 28, of Unionville. From the time a call comes in, they have less than 15 minutes to grab supplies, get to the aircraft and take off to aid a patient, who could be a member of the U.S. military or coalition forces, contractors, and even military working dogs, Behuniak said. Through training, they've been able to get that number down to nine minutes. "There are a lot of computers that need to start working, so as fast as the aircraft will let us take off, we can take off," Behuniak said. The benefit of a medevac unit, he added, is the ability to get a critically wounded patient to a hospital within so the so-called "golden hour," which greatly increases a patient's chance of survival. A 2015 study involving the Army, Texas A&M University and the University of Texas Medical School at Houston found that getting wounded troops to hospitals in less than an hour, along with improved care on the battlefield and in medical helicopters, saved hundreds of lives. "There's a wide spectrum of care an injured person can receive on this aircraft," said Sgt. Ryan Will, 28, Manchester, a flight paramedic. "It's very comprehensive care as well." Flight paramedics like Will and Staff Sgt. Trevor O'Neill, 27, of Greenwich, have gone through extensive training and are nationally registered paramedics. Both are also civilian paramedics. Members of the unit underwent a range of training to prepare them for the conditions they'll encounter overseas. They trained at a facility in Rhode Island that can simulate desert conditions. Anticipating mountain peaks of 13,800 feet, some pilots went to Colorado for training to get an understanding of how air density affects a helicopter's rotor system and the ability to fly. Last week, they trained with members of Air National Guard's 103rd Airlift Wing, practicing loading and unloading patients onto the helicopters, and simulating different missions where the two units would cross paths. "There are a lot of gravity and effects that are placed on the patient that there aren't normally on the ground, whether that be from high maneuver turns or simply just taking off and landing. Things like vibrations can really make a patient uncomfortable and these are things they have to know when they're giving us patients," said O'Neill, one of the flight paramedics. There was strong interest in joining the unit, which represents a new capability for the Connecticut National Guard. Second Lt. Brett Boissonneault, 25, of East Hampton, was handpicked out of flight school to be part of the unit. "It's a great opportunity to be part of an important mission where we're saving people every day, helping people every day," he said. https://www.sfchronicle.com/news/article/New-National-Guard-medical-helicopter-unit-set-to-12984985.php

  • USAF Logistics Chief Raises Urgent Warning On Surge Capacity | Aviation Week Network

    29 avril 2021 | International, Aérospatial

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  • New, Low-Cost Air Force ISR Drone Prototype Flies 2.5 Days

    16 décembre 2019 | International, Aérospatial

    New, Low-Cost Air Force ISR Drone Prototype Flies 2.5 Days

    The Air Force Research Laboratory believes it's on to something when it comes to long-endurance drone flight. By THERESA HITCHENS WASHINGTON: While other commercial and military drones have flown longer, the two and a half day flight of the Air Force's latest unmanned aircraft prototype this week does represent a kind of breakthrough for the US military: proving that commercial technology can be adapted to build affordable long-endurance and highly capable surveillance drones. And the Air Force Research Laboratory (AFRL) in Dayton, Ohio is convinced that the new, autonomous Ultra-Long Endurance Aircraft Platform (Ultra LEAP) will be able to stay in the sky for longer in future flight tests. “Developing a UAS with this level of endurance is an incredible achievement for future warfighting and battlefield success,” said Paul Litke, the AFRL project engineer for Ultra LEAP. In an Air Force announcement yesterday, Litke explains that since the system employs many commercial off-the-shelf components, Ultra LEAP will dramatically reduce the costs for high performance intelligence, surveillance and reconnaissance (ISR) drones. The “2.5-day Ultra LEAP mission is a significant milestone in solving the tyranny of distance problem for ISR systems,” said Dr. Alok Das, director of AFRL's Center for Rapid Innovation (CRI). “It will provide immediate benefit to our warfighters while at the same time paving the path for future low-cost, multi-day endurance ISR systems.” Ultra LEAP is based on a commercially available “sport-class” commercial airframe — sport aircraft cost anywhere between $20,000 and $140,000. An AFRL spokesman told Breaking D today that the service could not release the name of the company providing the chassis “for security reasons.” The basic airframe was souped up by AFRL to carry a “customizable suite of ISR tools” that feature “secure, easy to use navigation employing anti-jam GPS and full global operational access via a satellite-based command and control and high-rate ISR data relay link.” The aircraft body was further “converted to a fully automated system with autonomous takeoff and landing capabilities,” the press release said. The high level of automation it provides will enable greatly reduced operator training requirements for the Air Force. Smaller support crews will also lead to lower operating costs, according to AFRL. “As the Air Force balances current readiness with long-term modernization, Ultra LEAP represents an affordable approach that supports both existing and future force needs,” said Maj. Gen. William Cooley, AFRL commander, adding that the “enhanced UAS capabilities along with the cost savings offers the military a winning solution.” The Ultra LEAP effort evolved from an earlier AFRL experiment, just called LEAP but with the A standing for aircraft, started in 2016. Then AFRL Commander Robert McMurry testified to Congress in September 2016 that the program, managed by CRI, was designed to provide “a revolutionary, low-cost, low acoustic signature, persistent aerial ISR capability to address Combatant Command and U.S. Special Forces ISR gaps by converting a proven, fuel-efficient Light Sport Aircraft into an UAS.” Four of the original LEAP aircraft were deployed in early 2016 in conjunction with Special Operations Command, he said. McMurry added that “LEAP significantly bends today's ISR cost-performance curve and enables needed counter- insurgency capability and ISR capacity at a fraction of the cost of comparably performing systems.” The original LEAP was capable of missions up to 40 hours and has completed more than 18,000 combat flight hours. Using the same commercial customization strategy as the original LEAP, CRI developed Ultra LEAP from concept to first flight in less than 10 months, the AFRL release explained, and the system could be ready for operational fielding as soon as 2020. The Air Force is interested in developing a range of long-endurance ISR drones, and in August 2018 issued its Next Generation Intelligence, Surveillance, and Reconnaissance Dominance Flight Plan. The plan sets out the service strategy for “a shift from a manpower-intensive permissive environment to a human-machine teaming approach in a peer threat environment.” For example, the Air Force issued a $48 million contract to Boeing's Aurora Flight Sciences subsidiary for its Orion drone in January 2018. Orion has an endurance of 80 hours. In May of this year, AFRL worked jointly with Lockheed Martin to enhance its Condor eXtended Endurance and Payload (XEP) — improving its endurance from two hours to four. The team also improved the small drone's fuselage to accommodate multiple payload types, according to a May 22 Lockheed Martin press release. The current record for the longest flight time by an unmanned aerial vehicle is held by the pseudo-satellite (an airframe that flies very, very high in the stratosphere) called Zephyr, developed by Airbus Defense and Space. It flew for more than 25 days in the fall of 2018. The US military's most famous drone, the armed MQ-1 Predator made by General Atomics, has an endurance of 40 hours. https://breakingdefense.com/2019/12/new-low-cost-air-force-isr-drone-prototype-flies-2-5-days

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