The Defense Department's $11 billion effort to deploy a mega-watt
laser on a jetliner to kill ballistic missiles also could yield
a defensive weapon against low-flying cruise missiles, officials
The program, known as the Airborne Laser (ABL), is part of the
U.S. multi-tiered tactical missile defense network. The ABL is designed
to target Scud-like missiles soon after launch. The idea is to destroy
the missile and make the wreckage fall down on the country that
Other systems currently in development, such as the Army's theater
high altitude area defense (THAAD) and the Navy's theater-wide defense,
will attempt to kill enemy missiles by intercepting them in their
terminal phase, outside the atmosphere. The Army's Patriot air-defense
system and the Navy's area-wide system also rely on the hit-to-kill
principle to smash enemy missiles, but inside the atmosphere.
Some missiles have multiple warheads, or reentry vehicles. ABL
advocates contend that the only way to defeat a multiple warhead
missile is by killing it in the boost phase-before a nuclear, chemical
or biological device can deploy. That would reduce the number of
targets THAAD or Patriot would have to defeat.
Increasingly, however, U.S. intelligence officials and policy makers
also worry about the threat of cruise missiles, which fly closer
to the ground and can be guided-via coordinates determined by satellites-to
destinations hundreds, or even thousands, of miles away. These missiles
are easier and cheaper to build than ballistic missiles and could,
potentially, be armed with chemical, nuclear or biological warheads,
said Army Maj. Gen. Larry J. Dodgen, director of the Joint Theater
Air and Missile Defense Organization.
Cruise missiles, he told reporters in Hunstville, Ala., last month,
"are difficult to defend against." That is because they
fly long distances and require multiple sensors to track their trajectory
over an extended period, Dodgen explained. "We don't have a
foolproof combat identification [tool against cruise missiles]."
He also noted that current surface-to-air anti-missile systems have
"line-of-sight limitations" that hamper their capability
to intercept a low-flying cruise missile.
According to Lt. Gen. John Costello, chief of the Army's Space
and Missile Defense Command, there are studies under way to explore
possible concepts for a "national cruise missile defense."
He declined to provide details of what that system would look like.
"I have no idea," Costello told National Defense during
a briefing in Hunstville.
The Air Combat Command, meanwhile, has asked the service's ABL
program office to explore the possible employment of the laser weapon
against cruise missiles.
"We did a preliminary study, [and] we'll present that information
later this summer to Air Combat Combat," said Air Force Col.
David D. Harrell, deputy program manager for ABL.
Harrell said the goal of the study was to determine whether cruise
missile defense could become "one of the potential missions
for ABL." Currently, the ABL program is proceeding strictly
as an anti-ballistic missile system, the mission for which it was
Military Laser Projects
The Air Force, Army and Navy all started working on lasers in the
mid-1960s, so laser technology is not new, Harrell said. In November
1996, the Air Force took charge of the ABL program and awarded a
concept development contract to an industry team composed of The
Boeing Company, based in Seattle; TRW Space and Electronics Group,
in Redondo Beach, Calif.; and Lockheed Martin Space Systems, in
The word laser is an acronym for light amplification by stimulated
emission of radiation. "A laser is the most concentrated and
powerful form of light known," said Robert W. Duffner, a historian
at the Air Force Phillips Laboratory, in New Mexico, and the author
of "Airborne Laser: Bullets of Light."
In his book, Duffner explained that there are three conditions
that are necessary for "lasing" to occur. First, a gas,
liquid or solid substance is needed to produce a beam. Second, an
intense energy source-such as a chemical reaction or electricity-is
needed to "excite" and alter the condition of the selected
material. Third, a device known as a "resonator," with
mirrors at each end, is used to extract the precise optical energy
in the form of a beam.
In the late 1970s, the Air Force created the so-called Airborne
Laser Laboratory (ALL)-a modified cargo aircraft equipped with a
chemical laser, a precision pointer and tracker-designed to demonstrate
the ability of lasers to engage and destroy aerial targets. That
laser destroyed five air-to-air missiles and a cruise missile simulator,
said Harrel. "But those were much shorter distances than what
the ABL will be used for."
Although the exact range is classified, the ABL is expected to
shoot down ballistic missiles farther than 200 miles away, said
Lt. Col. Joel R. Owens, director of ABL management operations, during
an interview in Dayton, Ohio.
The killer high-energy laser is a chemical oxygen iodine system,
made by TRW. It is transported on a modified Boeing 747-400. But
that is not the only laser on board. There also are electrically
powered solid-state devices such as a tracking illuminator laser
and a beacon illuminator laser. These are made by Lockheed Martin.
The company also supplies a beam control system that helps focus
the killer laser, assists in predicting atmospheric effects on the
laser, determining the optical distortion of the beam and correcting
it, Owens explained. There is an active carbon-dioxide laser ranger,
located on top of the plane, which essentially is a modified target-acquisition
pod. It is used to determine where the missile is, where it's going
and how fast it's flying.
Program officials plan a live missile shoot-down attempt in the
fall of 2003. The program's EMD (engineering and manufacturing development)
phase would begin about six months after that, said Owens. The goal
is to field a squadron of seven ABL platforms. He cautioned, however,
that the program schedule could slip if funding were cut. For the
2001-2006 budget period, the Defense Department cut more than $800
million from the program. In fiscal year 2001, the Pentagon cut
$92 million, but Congress restored the funding.
The 747-400 frame that will become the first ABL rolled off the
Boeing assembly line last December, and was shipped to a facility
in Wichita, Kan., to undergo a 17-month modification process. Turning
the plane from a commercial jet into a weapon system involves, for
example, cutting off the nose in order to attach a nearly 5-foot
telescope turret, said Owens. The 14,000-pound turret steers and
points the laser. Another modification will be the addition of an
The crew quarters are in the front of the airplane. The crew includes
a pilot and a copilot as well as a mission commander, a weapons
officer, a maintenance technician and another crew member to handle
communications and intelligence responsibilities. The high-energy
killer laser is located in the rear of the aircraft.
The program's $11 billion price tag, Owens said, includes development
and production of two test aircraft, retrofitting those two planes
into an operational configuration, the production of an additional
five for a total of seven operational platforms, and support of
those seven aircraft for 20 years.
Owens advertises the ABL system as a good value for the money,
because it can shoot down ballistic missiles at a cost of about
$10,000 per shot, based on the price of the laser fuel. By comparison,
the new version of the Patriot anti-missile system, called PAC-3,
comes with a price tag of about $2 million to $5 million per missile.
The ABL's laser fuel is a mix of several industrial-strength commercially
available chemicals. Among them are hydrogen peroxide, chlorine,
iodine and ammonia. These chemicals are processed through a series
of identical laser modules, which act as batteries, triggering the
chemical reactions. The current ABL test aircraft has six laser
modules. The EMD version will have 14.
As far as an anti-cruise missile capability, Owens said, "what
we've found is that we can see the high missiles, but the low missiles
are harder to find." The main focus of ABL is theater missile
defense, he said, "but other things the Air Combat Command
(ACC) is having us look at include self-defense and protection of
high-value assets." That means being able to use the killer
laser to protect the ABL platform from surface-to-air attacks and
to defend, for example, surveillance aircraft such as the AWACS
radar plane or the Joint STARS target acquisition radar system.
ABL program officials briefed ACC representatives earlier this
spring on some of the findings concerning cruise-missile defense.
"The [ACC] has to decide which additional capabilities they
want us to put on the plane and the timing to do that," said
Owens. One of the potential obstacles, he added, would be obtaining
funding to adapt ABL for a cruise-missile defense role.
"We structured the program so that if they want to insert
additional mission capabilities, we could do it during the EMD phase,
and then bring out production birds with those additional capabilities,"
"It's not that we can't shoot down cruise missiles,"
said Harrell. "It's just that we can't shoot them as far away.
If they tell us to do that, we'll study it and see what it would
take, in terms of any equipment or software changes."
ABL will orbit at an altitude of about 40,000 feet. That is where
the laser performs the best, said Owens. The closer one gets to
the ground, the thicker the atmosphere, and the tougher it is to
get the laser beam through to the target. As the beam of light penetrates
the various layers of the atmosphere, it gets bent, defused and
deformed. "From 40,000 feet up, the atmosphere is thinner.
It's easier for us to get that beam through," said Owens. "That
allows us to get the most efficient use of the laser beam and use
less fuel to shoot down a missile."
Harrell agreed that the laser is more effective in the higher atmosphere.
"The ultimate is the vacuum, where the laser beams remain perfect.
But since we are going through the atmosphere, we have to apply
adaptive optics to adjust and keep the laser beam focused,"
That does not preclude being able to shoot down a low-flying missile,
said Paul Shattuck, ABL program manager at Lockheed Martin. The
answer depends on several variables, including the target geometry,
range, altitude, and weather conditions, such as the clouds in the
line-of-sight, he said. "There is nothing in the physical-mechanical
system that would preclude this type of mission."
The ABL program will be managed at Wright Patterson Air Force Base
beginning in 2004, said Owens. Late next year, the Air Force will
announce where the first squadron will be stationed.
Program officials are unsure, however, on whether a second ABL
test aircraft will be built as planned. The General Accounting Office,
the congressional watchdog agency, issued a scathing report three
years ago, criticizing the ABL program for rushing towards deployment
before the technology is fully tested. For that reason, the Air
Force decided to slow down the retrofitting of a second Boeing jet,
even though the aircraft had been purchased.
"I don't know where that [decision] is going to land,"
said Harrell. He explained that the Air Force believed it had to
buy the second jet because there was a two-year lead time to get
a Boeing airliner off the assembly line. "The plane is ready,"
he said. "If we decided to cancel the program, we could sell
that airplane because it's a commercial freighter."
The ABL is not rushing technology, he said. "We are working
on the fourth generation of the laser we'll use. Adaptive optics
have been used in observatories in the Air Force for 15 years."
The more significant hurdle, he said, is the integration. "We
are not inventing anything."
That thought was echoed recently by Gen. Michael E. Ryan, the Air
Force chief of staff. He told reporters in Washington, D.C., that
understanding the physics of ABL is not difficult, but the "big
challenge" will be integrating the laser with other critical
systems on the aircraft.