Before the end of the week, technicians at a United States Army facility in the New Mexico desert plan to ignite a blend of exotic fuels inside a furnace akin to a rocket engine. The spectacular light energy in the inferno will be harnessed by a series of mirrors, molded by lenses into a narrow beam, and shot into the pre-dawn sky.
If all goes well, two jolts from the nation's most powerful laser will strike an aging US military satellite 260 miles above the earth.
Officials claim the test is defensive - and not aimed at creating a satellite killer that would shatter the neutrality of space and could trigger a new global arms race. But the test does focus fresh attention on the Pentagon's three-decade quest for lasers that can destroy targets on earth, in the sky, and in space.
Once ridiculed and doubted, such lasers are now seen as having growing promise by many scientists and defense experts.
And if successful, these laser weapon systems could dramatically alter the nature of warfare around the world.
Observers agree that major technical and political problems could still derail the programs, conceding that after tens of billions of dollars in research, no laser weapon is operational. But recent advances in lasers, optics, and computers, they say, make it likely that systems capable of destroying short- and intermediate-range rockets shortly after takeoff could enter the US arsenal in the next decade.
"The technology is almost certainly there," says Chris Hillman of the Center for Defense Information, a Washington think tank. "People who know seem convinced that within years, not decades, we are going to be able to do these things and do them fairly well."
"Lasers will be high payoff in the future," says Tom Meyer, deputy director of defense programs at Los Alamos National Laboratory in New Mexico, who headed laser research in former President Reagan's Strategic Defense Initiative (SDI), known as "Star Wars."
The Pentagon's laser programs enjoy strong support among congressional Republicans. In 1995, they ended a Democrat-imposed ban on firing the New Mexico-based laser - Mid-Infrared Chemical Laser, or MIRACL - at satellites. Republicans were persuaded to allow the tests, which are aimed at learning if the low-power lasers now operated by up to 30 nations could "blind" the sensors of the satellites that the US military depends on. This week's planned test has been twice delayed. It will be canceled if not held by Thursday, because the target satellite will move out of range. But the test will certainly occur in the near future.
And some GOP leaders, including Senate Majority leader Trent Lott (R) of Mississippi, are pushing for a massive hike in funds for creation of a space-based antimissile laser.
The military's laser programs are outgrowths of work than began in the 1970s and received a massive boost in the 1980s under SDI, Reagan's plan to develop a space-based shield against nuclear-missile attack.
After Gulf War, a shift in focus
In the wake of the Iraqi Scud missile attacks of the 1991 Gulf War, SDI was gutted by Presidents Bush and Clinton. They shifted resources to efforts to protect US forces in the field from short- and intermediate-range rockets. Two of these theater-missile-defense projects involve lasers.
One is an $89 million effort by the Army and the Israeli government to develop a tank-mounted system that could destroy the short-range rockets frequently fired into northern Israel by guerrillas in southern Lebanon.
The contractor, Ohio-based TRW, is scheduled to begin testing a mobile prototype next spring. A milestone was reached in February, when TRW used MIRACL and other technologies to track and destroy two rockets in flight.
Work is also progressing on the Air Force's Airborne Laser (ABL) program. It calls for equipping seven Boeing 747s with lasers capable of destroying intermediate-range missiles seconds after launch. The planes would fly above the clouds and hit missiles up to 450 miles away. The fleet will cost an estimated $11 billion to build and operate for 20 years.
Heat from the laser would detonate a missile's fuel or weaken its body until it shattered under high-speed stress. Hit in the "boost phase," the debris and warheads from the rockets would fall back on enemy territory.
Officials say TRW has made substantial progress toward developing a laser small and light enough to carry aloft, with ground tests of a near-full-scale prototype set to begin in April. A half-power demonstrator aircraft is to be built by 2002 and a full-power version by 2005, with the first fully operational planes entering service in 2007.
Although at much more modest levels than Reagan's plan, the Pentagon is still pursuing a space-based anti-missile laser system. About $28 million a year is being spent, although pressure from Senator Lott and other members of Congress could boost the budget.
A mirror capable of surviving in space has already been built and is to be ground-tested in conjunction with a high-energy laser within the next year. In the next 18 months, scientists plan to loft to the edge of the atmosphere a balloon carrying a prototype of a targeting system for tests against rockets in flight.
Air Force studies looking 30 years into the future propose a constellation of up to 28 orbiting "laser attack stations" that, in addition to zapping intercontinental ballistic missiles, could also take out short-range rockets, enemy satellites, and aircraft.
Juicing up supermarket scanners
More arcane is research on a "fotofighter," a plane whose skin would be embedded with banks of advanced versions of the tiny lasers now used in supermarket price scanners. Their beams would fuse into a single ray that could down attacking missiles and aircraft and hit ground targets.
Not everyone is optimistic that the technical barriers facing the laser programs will be overcome. These include making lasers more rugged, simpler, smaller, and more efficient than today's biggest devices. Scientists are also still trying to design systems that can prevent a beam from being broken up over extremely long distances by atmospheric distortions caused by moisture or swirls of hot air.
The administration is publicly guarded in its outlook, perhaps because the research raises serious questions about future US adherence to the 1972 Anti-Ballistic Missile Treaty, recently reaffirmed with Moscow, which bans space-based antimissile systems. "It's too soon to pronounce any verdict," says one senior official.
Others are sure that laser weapons will not work. Asserts Steve Aftergood, a defense analyst with the Federation of American Scientists: "Our political and military leaders may have been seduced by the spectacular efficiency of Hollywood lasers."
Critics cite a study, to be released shortly by the Government Accounting Office (GAO), a watchdog agency, that reportedly raises serious doubts about the viability of the ABL. It reportedly found little hope that a system that can mold laser beams to compensate for atmospheric disturbances will ever be developed.
Critics also say potential foes could develop counter-measures against laser weapons. These include missile coatings that can reflect or absorb light energy, or rockets that spin, dissipating a laser's heat. Another serious problem will be protecting the huge 747s from attacks while they linger over enemy territory close enough to launch sites for their lasers to be effective.
Scientists say the problems can be solved. Coping with atmospheric disturbances, for instance, should be overcome by refining targeting systems that use flexible mirrors that in tenths of a second can adjust the shapes of laser beams, they say. Such systems are now being incorporated in large astronomical telescopes.
Critics contend that even if the technical hurdles are surmounted, the use of laser weapons by the US holds profound political implications. Other states could begin to develop lasers for use against American satellites, setting off a new arms race, they say. Global disarmament efforts might also stall as Russia or others maintained missile forces large enough to overwhelm US systems.
"This is walking a very fine line," says Andrew Krepinevich, director of the Center for Strategic and Budgetary Analysis in Washington. "Do you pursue the research and development to position yourself if you are forced to go into space? On the other hand, some say the very fact you are doing it is provocative and will be a self-fulfilling prophesy."
Some US officials share those misgivings. Says one: "We ought to take a more careful look at the policy implications of this stuff."