The possibilities, he said, include electromagnetic guns for aircraft and land vehicles, airborne lasers to blast missiles and hostile aircraft, transport airplanes capable of taking off and landing like helicopters, and advanced unmanned air vehicles for strike missions and reconnaissance.

"This is all long time-scale stuff," said Mark. "It's not going to happen tomorrow."

That's only to be expected, he went on. "We need a long-range view--20 years into the future," he remarked at a Nov. 4 session of the Defense Writers Group in Washington, D.C.

On other topics, Mark said he believes the Joint Strike Fighter will be an enormous, long-running program, would like to see the US build "a lot" of F-22 fighters, and has "no worries" about the ultimate success of USAF's airborne laser project. Mark also said he doubts that the Air Force's B-2 stealth bomber will be the last of its venerable breed. [For Mark's comments about bombers, see "Mission to Mach 5," by John Tirpak.]

Mark in July became DDR&E, making him the chief technical advisor to the Secretary of Defense and Undersecretary for Acquisition and Technology. He oversees the priorities, programs, and strategies of Pentagon research, development, test, and evaluation.

A veteran scientist and engineer, Mark has seen more than a few high-technology weapon cycles come and go.

Mark graduated from the University of California, Berkeley, in 1951 with a degree in physics. He immediately entered national security research and engineering-first at MIT (1951-54), where he received a Ph.D., and then at Berkeley and Lawrence Livermore National Laboratory (1955-69). He served as director of NASA Ames Research Center in California (1969-77), where he supervised the Pioneer planetary exploration program and launched the Bell XV-15 tilt-rotor aircraft program.

Mark's Washington service began in 1977, when he became undersecretary of the Air Force and, at the same time, director of the National Reconnaissance Office. As head of NRO, he managed the nation's classified satellite reconnaissance program. He then served two years as Secretary of the Air Force (1979-81), then became deputy administrator of NASA. From there, he went on to become chancellor of the University of Texas System in 1984.

Thus, for nearly half a century, Mark has had a ringside seat for some of the nation's greatest technological triumphs--and he has been in the ring for more than a few of them.

Science and Technology Research

Mark believes the United States, by embracing emerging technologies and properly funding their development, could again enjoy dramatic advances in military capabilities.

The goal: Ensure that the United States retains worldwide technological supremacy and acquires weapons that can be used in a wide variety of operations.

He warned that paying for such developments will be a grave challenge given the Pentagon's limited funding and its wide range of priorities. Congress boosted the Pentagon budget for this year but the services are struggling to meet their needs.

Mark believes it's time for a shift in science and technology emphasis.

"Information technology is obviously something that has enjoyed a great deal of attention in the last 15 years," he said, pointing out that he was personally engaged in early work in the field during his stint at NASA-Ames. "I've watched this thing grow for a long time. However, I think that we now need to change some priorities. ... The commercial sector does a lot of information technology that we can use. My own feeling is that we need to look at new weapons-particularly weapons for troops in the field. ... And we need to do that with a long-range view."

Mark pointed out that some of the most vital weapons are quite old. Case in point: thermodynamic military guns.

"I believe that electromagnetic guns could very well be a decisive weapon 20 years from now," said the DDR&E. "We are not anywhere close to fielding any, but ... trying to define the problems and then solve them is what [the Defense Advanced Research Projects Agency] and the military services should be sponsoring."

Why would the US military want electric guns?

"The normal [gun] is ... a thermodynamic engine. ... You can't shoot a bullet out of the barrel at a velocity much faster than the speed of sound inside the barrel. ... In order to get higher muzzle velocities, you can't use a thermodynamic engine. Electromagnetic acceleration doesn't have that limit."

Why would one want higher muzzle velocities?

Today, said Mark, the international market can provide tanks bearing explosive-reactive armor that can defeat current anti-tank weapons. The way to defeat this armor will be with hypervelocity rounds with enough energy to pierce it in milliseconds, said Mark. Researchers are now engaged in high-profile work to develop a workable rail gun for armored vehicles and even aircraft, a task that requires major breakthroughs concerning power sources and rail life.

"We now have a gun that can do 10 shots," said Mark. "You want guns that have 100 or 200 shots."

Heavyweight VTOL?

Mark said that, in the US research base, there are "probably half a dozen weapons developments" he would like to bring higher in priority.

Among them: research aimed at developing a transport with Vertical Takeoff and Landing capabilities. Essentially, said Mark, the aim is to create a giant tilt-rotor, a larger version of the V-22 Osprey now being built for the Air Force, Navy, and Marine Corps.

"I would put the air transportation at a very high level of priority," said Mark. "One of the things we are looking at over a very long time scale is ... a Vertical Takeoff and Landing airplane that is the same size as a C-130 or C-17. Right now, we don't know how to do that."

Such an aircraft would need highly advanced variable-length propellers made of superstrong and superlight materials.

"Is that possible?" he asked. "Sure; we didn't know how to put slats on wings either in the early days of aviation and today it is done as a matter of course. It is a lot of hard materials research, basic research, how do you move the blade in and out? How do you do it reliably and how do you do it 100,000 times?"

Mark also noted that the basic M-16 rifle actually was designed in 1945 and has been in wide use for three decades. Mark said US troops need a more accurate, longer-range weapon.

"Can we build an infantry weapon today that is lighter than the M-16, has double the range, and better accuracy?" Mark inquired. "I asked that question four years ago at the Army Science Board, we did a study, and the answer is, 'Yes, you can,' and there are now people looking at advanced concepts. I think something is going to happen in that area in the next five years. That could be a decisive advantage."

Joint Strike Fighter

Mark, who has decades of experience with tactical fighter aircraft programs, said he is optimistic the Joint Strike Fighter will live up to advance billing.

"We have many missions for airplanes," said Mark. "You can design a program-not an airplane, a program-that can do all of those missions.

"Now, you remember we did that back in the 1960s with something called TFX [Tactical Fighter Experimental] that became the F-111. There, the notion was, 'Is there one airplane that can do all the missions?' And we got the answer to that one: There is not. That is why I use the word program rather than airplane."

Mark thinks the JSF will succeed because times have changed.

"The question you should ask is: 'What can we do now that we couldn't do in the 1960s?' " said Mark. "That is the real issue, and the answer to that is the following: We now have four or five orders of magnitude more in computer capacity than we had then.

"If you apply that to the design process of airplanes, you can do many, many [more] design iterations than we used to have. So, you can, from a common framework, put together, in a modular manner, different kinds of airplanes. ...

"We have a carrier version, a land-based version, and [a] VTOL [version]. When I first saw this, I said, 'Gee whiz, can you guys really do this?' It took me awhile to come to the conclusion that you indeed can make a good stab at it."

Mark referred specifically to a common cockpit for three different configurations, common engines, and so forth. However, he said the key is more sophisticated design engineering.

"When I was supervising things like that," said Mark, "you couldn't do as many trade-off analyses as you can do now. Literally, today, one engineer, sitting at a computer screen, can do trade-offs that it took 100 people to do 20 years ago, when I was in the business. That is a major difference."

F-22 Fighter

Mark is impressed with the capabilities of the new Air Force air superiority fighter, the F-22 Raptor, and would like to see the US build "a lot" of them, but he cannot confidently predict a final outcome regarding the size of the program. The production run will hinge to some extent on the success of the JSF program, he observed.

"We have two airplanes flying," Mark said. "We are learning about how that machine works. I hope we build a lot of them, but I don't know right now. There obviously have to be trade-offs between the F-22 and the JSF. But none of these things are firm yet because they are still 10, 12, 15 years in the future.

"History says that all these things [completion of the current fighter programs] will get done. When we started the F-4 [Phantom fighter], it started out as a carrier airplane. We were going to build 500 because, at that time, the Navy had enough carriers to handle 500. [Does] anybody know how many we finally built? ... I remember when they rolled out the 4,000th airplane in St. Louis. I can't predict what will happen." [Production actually surpassed 5,000.]

Mark turned aside criticism of the F-22's currently high unit cost. He suggested that the number had been artificially inflated by political decisions reducing the numbers of aircraft to be purchased.

"When you look at ... cost per aircraft, you have both a numerator and a denominator," he said. "You can run the cost per aircraft up by changing the numerator or ... the denominator. I would guess that the cost per aircraft of the original F-4 was pretty high, [but,] by the time we shut down the line, we could stamp them out like cookies and they were cheap."

The Airborne Laser

Mark said he believes a bright future lies ahead for the Air Force's Airborne Laser, one of the service's top programs.

Fueling Mark's optimism about the system are a number of major advances in adaptive optical technologies. These new types of technologies, when incorporated in actual systems, will allow operators to finely focus powerful laser beams on a moving target and thereby destroy it. The problem in the past always has been that atmospheric turbulence would disturb the beam being propagated.

Indeed, Mark embraced the airborne laser concept decades ago. In 1967, as a member of the Air Force Scientific Advisory Board, he and others promoted the idea, and the Air Force did put a large carbon dioxide laser on a KC-135.

"Basically, we solved part of the atmospheric turbulence problem," said Mark. "We did the wind tunnel tests on that airplane at Ames. ... We learned how to shoot the beam through the boundary layer on the airplane and that was really the biggest problem that we had in the beginning. So we solved that problem."

Mark asserted that engineers long ago solved the airborne laser's fire control problems, noting that, in 1983, "we shot down five Sidewinder missiles with it."

The real remaining issue, said Mark, is making sure that a laser has sufficient range to be militarily useful. Here, he said, there is great cause for optimism.

"What has happened since 1983 to give us confidence that we can get the range?" asked Mark. "The answer is: adaptive optics. We are now in a position where we can structure the mirror-which is really the [basic] element of the gun-to be compatible with the atmospheric turbulence along the path.

"The way you do that is you shoot out a laser beam to measure the turbulence, and you adjust the mirror so it gives you a plain wave front which keeps the beam together.

"We have just finished, in Texas, at the McDonald Observatory, a large telescope, 10 meters in diameter, which uses adaptive optics to do astronomy. I was out there in July when we turned it on. ... There is a little switch on the console that controls the telescope. We focused it on a star and [we got] a fuzzy image, ... and then you tweak the switch and turn on the adaptive optics and it focuses on the point.

"That is the secret. Adaptive optics will make this thing work. No matter what the atmospheric turbulence is, you will know how the beam has to be shaped in order to beat it. ... I don't have worries about this. A lot of people have worries, but I don't, because I've seen it."