Pentagon’s Top R&D Chief Throws Cold Water On Laser Missile Defense Aspirations

Aviation Week's Defense Editor and good friend of The War Zone Steve Trimble posted the comments from Under Secretary of Defense for Research and Engineering Mike Griffin on Twitter on May 20, 2020. Griffin had disclosed these details at the Washington Space Business Roundtable, which is being held this year via a remote video conference due to the COVID-19 pandemic.

"As a weapon system to equip an airplane with the lasers we think necessary in terms of their power level …and get them to altitudes where atmospheric turbulence can be mitigated appropriately, that combination of things can’t go on one platform," Griffin said. "I’m extremely skeptical that we can put a large laser on an aircraft and use it to shoot down an adversary missile even from very close."

What Griffin is talking about here is how laser beams inherently become more diffuse as they extend further from their source, as the light particles pass through the elements of the atmosphere and otherwise getting beaten about by other environmental factors, such as turbulence in the air, all of which reduces their power and accuracy. Increasing the power and otherwise focusing the beam, such as adaptive optics, as well as simply employing the system at higher altitudes where the air is thinner, can help mitigate these issues. Unfortunately, in turn, this generally increases the size and power requirements of the overall system. 

There have been significant developments in miniaturizing solid-state lasers for years now, resulting in experimental weapon systems that are compact enough for aircraft and helicopters or for small ground vehicles to carry. These have shown themselves to be capable of shooting down small drones, rockets, and missiles.

Shooting down a ballistic missile, especially larger intermediate or intercontinental range types, is a much different affair. In the 1990s and the 2000s, the Air Force and the Missile Defense Agency (MDA) notably tested a laser-armed Boeing 747 airliner known as the YAL-1, which cost billions to develop and was canceled in 2011 after the Pentagon determined it could only knock down ballistic missiles at extremely close ranges during the initial boost phase of flight. 

During that stage of flight, the missile is moving slowest and its rocket motors are burning brightly, making it easier to detect and track and more vulnerable to attack. However, at that point, it is also likely flying over an enemy's own heavily defended territory, making it difficult to get close to it.

However, the YAL-1 Airborne Laser system employed a massive chemical oxygen-iodine laser (COIL). MDA has been working on an unmanned successor to the YAL-1 for boost-phase missile defense using a more advanced and far more compact solid-state laser weapon since 2015. Two years later, Lockheed Martin, Boeing, and General Atomics got their first contracts to develop Low Power Laser Demonstrators (LPLD) to explore the feasibility of the concept. 

MDA gave Lockheed Martin $30 million and Boeing and General Atomics each $29 million in additional funds to perform critical design reviews of the beam control systems in their respective designs in March 2019. Griffin is now saying that, at least so far, and possibly based on data from those and other design reviews, a more advanced airborne solid-state laser weapon that is viable for missile defense still remains elusive.

These comments are especially notable coming from Griffin who has been an outspoken advocate for directed energy weapons development, even including notoriously complex particle beam systems, for decades. This traces back to his work on the Reagan-era Strategic Defense Initiative (SDI) missile defense effort, better known by the nickname "Star Wars."

“We should not lose our way as we come out of the slough of despondence in directed energy into an environment that is more welcoming of our contributions," the Undersecretary had said in remarks at the 2018 Directed Energy Summit in Washington, D.C. "We should not lose our way with some of the other technologies that were pioneered in the ’80s and early-’90s and now stand available for renewed effort."

It's also interesting to note that Griffin had announced that the Pentagon was putting its plans for a space-based particle beam weapon on hold in September 2019. He specifically said that this decision would allow for the refocusing of funding for that project to support other work on lasers. 

The idea of using laser directed energy weapons for ballistic missile defense is unlikely to go away completely, either. A space-based system, something that MDA has also been exploring, would have few, if any of the issues that ground-based or airborne designs face when operating within the Earth's atmosphere. France also has plans for satellites carrying laser weapons to defend other assets in space against potential threats, further indicating that there is a broader view that these kinds of systems in orbit would be technically capable of providing useful capabilities, at least in principle.

"Directed energy weapons (high energy lasers or particle beam) or space-based interceptors provide the best overall hope of a hard kill" against future hypersonic weapon threats, as well, according to a March 2020 report from the NATO Science & Technology Organization. "These systems will need to be refined and be made operational, within the appropriate policy and legal constraints, if effective defensive countermeasures are to be deployed over the next ten years."

It's possible that the lasers that MDA has been development so far might still have some value when combined with a penetrating unmanned aerial vehicle that can more readily get close to a launch site and in certain specific situations, including against launches of only a small number of missiles by a rogue state, such as Iran or North Korea. This would still be a capability with only limited applications.

Griffin may just be speaking about the present state of the applicable technologies, or he may even be being deliberately misleading to confuse America's opponents, as well. There is always the potential that advances in the future could make the idea of an airborne laser ballistic missile defense system more practical broadly, just as improvements in solid-state designs have made them viable short-range defense systems against various small aerial threats, as well as artillery rockets and smaller missiles.

Whatever the case, Griffin has raised some clear concerns about the value of MDA's current work on airborne laser missile defense, at least in the near time.

Contact the author: joe@thedrive.com