Airborne Laser
Assessing Recent Developments
and Plans for the Future.
by Colonel Robert McMurry
We have made some pretty amazing progress in the airborne laser since my first run through the program. I arrived at the airborne laser for my first stint there in 2002 and was there until the middle of 2005. I have been gone for about three years. I came back to the program in May and as a person who is well-informed on this program, I was frankly pleasantly surprised at the amount of progress that we had made in this technically demanding area.
The airborne laser is the air-based component of the ballistic missile defense sys-tem and it is focused on acquiring, tracking, and killing ballistic missiles in their boost phase. The system is a highly modified 747-400 aircraft. It is obviously deployable and mobile and its focus, as part of that ballistic missile defense system, is to protect the U.S., deployed forces, U.S. allies, friends and areas of vital interest from ballistic missile attack. It is a directed energy program and the leading edge in that arena.
BOOST PHASE
We are a boost phase system. The system works by detecting the missile plume and then tracking the missile while it is boosting. The engagement sequence is important for later discussion, so I will go through that very briefly now.
Essentially as the missile clears cloud break, infrared sensors that have a 360-degree view around the aircraft detect the missile plume and guide a tracking laser to the missile that then tracks the hard body of the missile. We track with a second solid-state laser on the system and illuminate that. The laser then measures the atmospheric distortion between us and the missile.
In effect, by measuring that atmospheric distortion, we now have the “prescription” of the atmosphere. Then we distort the high-energy laser beam before it leaves the aircraft in such as way as to use the atmosphere of the lens to refocus the beam onto the missile. This sounds like science fiction and cosmic can’t-be-done stuff, but it is actually done quite often in astronomy and has been demonstrated in several areas. We have demonstrated all of these phases through flight tests and I will talk a little bit more about that later. The atmosphere then refocuses the beam to create a coherent focus spot on the missile. The energy on the missile generates a crack in the missile and under pressure, the missile falls apart; it comes unzipped. That sequence begins and runs all during the boost phase and it happens very quickly.
TEAM EFFORT
We have what I consider the A-Team playing on this. We have the best contractor team I could think of to put the airplane and the battle management system together and the overall integration is led by Boeing out of Seattle. Mike Rinn is our program manager. The laser modules themselves are built by Northrop Grumman Space Park in Redondo Beach. Guy Renard is the program officer there. The beam control system is built by Lockheed Martin- Sunnyvale and Mark Johnson is the program manager there. These companies have worked as professionally and as competently as I could possible hope for in terms of their cooperation in bringing about an integrated system that functions as a weapons system.
The legacy of the system is one of weapons system planning. While it is a demonstration program, a development program, for the Missile Defense Agency in the sense that we are working very hard to prove this capability, it is not really a laboratory program. It has its roots in our relationship with air combat command and we have air combat command folks here today. From the very beginning, we have looked at this system as a deployable operational asset for combatant commanders and as we bring this thing together, it brings a significant operational capability to the combatant commander that does not exist today.
BACKGROUND
We began the program in 1996 and again those roots were with a very tight relationship between the program office and air combat command. We were looking from the beginning to deployability and operational utility of the system in theater. Its focus originally was theater ballistic missiles because of the outflow from Desert Shield/Desert Storm and the Scuds. It is a fact, though, that there is nothing inherent in the ABL requiring it to be directed just against theater missiles. The ABL is effective against all classes of missiles it can reach.
We basically spent 2000 to 2003 building and integrating the system. In 2004 and 2005, a couple of key events took place. The first is that we actually got the laser in its six-module configuration in a 747 fuselage. That was no small feat and was a significant achievement for the team. While we had tested each component of the laser in-dependently, we hadn’t integrated and done so in its intended environment. We did that; we also got back into flight tests to put the optical system in flight at that time. As we completed that, we had a second phase of low-power testing.
I will define some terms to make sure we are clear on them. “High-power” involves the six-module megawatt class laser. “Lowpower” is all the other lasers on the system and the optical control systems associated with controlling the high-power beam and getting it to the target. The high-power testing up to this point has all been ground tested. We have successfully fired and tested the laser some seventy-plus times in a 747 fuselage on the ground. For the low-power system we have done both passive flight testing, to prove that the sensors and systems can detect and acquire targets in flight and track them, and active flight testing, in which the system detects the missile.
Remember I said the engagement sequence is then to engage the missile with solid-state lasers that detect the missile body and measure the atmospheric composition. Using a low-power surrogate high-energy laser, in 2007 we demonstrated the complete tracking and engagement sequence with a non-cooperative target—a Big Crow aircraft with a plume emulator. Basically you have to detect the plume, so we have to have some-thing to simulate it; we are obviously not going to set the airplane on fire. We had an emulator here that looked like a plume for the infrared system to track and it picked up. Then the sequence is that the target eliminator finds the nose of the missile and the beacon puts a spot on that. We measure the distortion from the atmosphere and then put a surrogate high-energy laser on that missile body (obviously moving at a slightly different rate than you would see in a normal missile) and compensated that low-energy beam all through it.
We completed all of that testing in 2007. This was the first time to catch a non-cooperative target and show all of that engagement sequence all the way through. This is obviously not a boosting ballistic missile, so the question is whether the turret can do the kind of things that we need to track the rate of climb of a ballistic missile. We actually tested that using an F-16 in a zoom climb near the airplane and demonstrated that we had all the slew rates and the tracking loop rates that we needed to engage a missile.
PATH FORWARD
We talked about the timeline. So where are we now? The answer is that we are moving into the critical flight testing of the fully integrated system. We are at present integrating the laser. We have completed the activation of the laser at Edwards Air Force Base on the flying aircraft. That is probably not the right phrasing; the aircraft is actually on the ground, but it is the aircraft that will be in the flight test.
We are beginning the ground testing of that laser. To test the laser on the ground actually requires a test of full vacuum, so there is a significant test infrastructure set up at Edwards Air Force Base. We began vacuum loads testing and we actually finished the test on that last night. The first step is to prove that the vacuum system works and that we understand what it does to the airplane. We will then go through chemical flow testing and what we call an “all systems blow down.” We will do everything that the laser requires except flowing the last chemical to make it lase. Then we will finally move very quickly from that, assuming that everything is in good working order. We crawl, walk and run. We step carefully to make sure that the chemical flow is all safe and that everything is working. Then we will lase the laser on the aircraft onto a calorimeter that is actually on the aircraft.
In fact, that is one of the first knowledge points that weare trying to get done this year: the airborne laser is to actually lase in the flight test aircraft into the calorimeter. After that, the next step, and probably the most significant emotional event this year for us, would be to take that laser past that calorimeter, through the entire beam control system and out the nose of the turret. That will be the first time that we have exposed that optical train to the megawatt class laser and that should happen in the next few months. Talking about how the system engages—when you see the missile tracking and the high-energy laser looking at the target without the tracking loops closed, you see a very fuzzy picture. What I have seen of the video of it, it is very difficult to see the high energy laser on the target at all. It is very shadowy, a little bit of light that plays across it.
What you see is the Surrogate High-Energy Laser (SHEL) with only one of the major tracking loops closed. As the final tracking loop closes you see the spot focus improve dramatically. As that composition is put into the control, you see this cloudy illumination with the laser shift to a very tightly focused beam. These pictures were observed at the aircraft; they are not simulated. They were actually measured by the Big Crow aircraft which had cameras on the wing that registered what we saw on the spot there. It is real data and you can fly it at significant operational ranges. As we got through that system, we saw that we were ready for the integration that we are doing now, so we will move pretty quickly through the summer.
There are a number of things that folks have said, such as this is too hard to do. And to be frank, it has been harder than people thought it would be. I think that is a fair point. We have taken a little bit longer in each phase than we would like. And people have said that we are not going to be able to track it, we are not going to be able to compensate for the atmosphere, we are not going to be able to provide the kind of control mechanisms needed to point this beam accurately and to put energy on a missile in an effective way.
What I can tell you is that step by step we have proven those statements incorrect and proven that we can do this and that the system has demonstrated every step of the sequence except the final “can we shoot it down?” So that is where we are. Every bit of that engagement sequence that I have talked about has been demonstrated in flight tests and under realistic conditions, with the exception of firing the high-energy laser in flight. The highenergy laser has been fired on the ground in a 747 fuselage in test conditions over 70 times. It is repeatable and it generates the kind of energy that we expect. The surrogate high-energy laser that we used in the low-power test has proven controllable.
Our job at this point is to put this high-energy laser into the aircraft, which we are doing and activating now, put it in flight, and begin a progressive set of tests to demonstrate the capabilities to guide and control the laser to a boosting target and then destroy it. There is a series of tests that will begin with return to fly in the early 2009 time frame. The target is the demonstration of a shootdown of a foreign material asset threat-representative system in the August time frame.
I have come through very different acquisition programs in the last few years, some in very good shape, some in not so good shape. What I would tell you from examining this program right now is there is always risk in a program like this. Some of this stuff we just haven’t done before. If you know somebody who has put a megawatt class laser into a 747 and shot down a boosting missile, send him on over! It hasn’t been done; it is a first-of-a-kind activity.
In assessing a program as a program manager or an acquisition professional, my job is to look at the risk in the program. I have seen programs over my stint that were optimistic to the point of painful; they were just pie-in-the-sky and 17 consecutive miracles have to occur to get there. That is not the case here. I have looked at this schedule and the plan is coherent. The risk in the schedule is manageable and while there is a significant opportunity for discovery, in particular as we send that high-power beam through the optical train all the way through the turret, we are not looking as something that is a pie-in-the-sky wish list at this point. What we have here is a coherent, well thought out, deliberate crawl, walk and run type program that is getting to the run stage. ♦
Colonel Robert McMurry recently spoke at the George C. Marshall Washington Roundtable on Science and Public Policy. The Roundtable examines scientific questions that have a significant impact on public policy and seeks to enhance the quality of the debate on the growing number of policy decisions that look to science for their resolution.
McMurry is commander of the Airborne Laser Program Office at Kirtland Air Force Base, New Mexico. This mission of this wing level organization is to demonstrate the capability of the ABL to shoot down a ballistic missile in its boost phase. This is his second tour with the missile defense agency; in previous assignments he was the F-16 system program manager and the vice wing commander for Space Based Infrared Systems.