History of the Laser
THE EVOLUTION OF THE SMART BOMB
... A Story of Technology Transfer
(Note: This story originally appeared in The Redstone Rocket 16 August 1972, pp. 1, 10-11)
The Army missile engineer takes a handful of newspaper clippings from a drawer and hands them across the desk.
"Look at this. The Air Force guided one bomb right up the mouth of a railroad tunnel," he says as he sorts through the clippings for another example.
This story is about smart bombs. All the clippings tell of the almost incredible accuracy laser guided bombs are demonstrating in the air war over North Vietnam, accuracy that the Secretary of the Air Force recently said made it possible for one tactical fighter to accomplish "what 25 might have done in the past."
The intense interest the civilian missile engineer and many of his colleagues in the research and development organization of the U.S. Army Missile Command at Redstone Arsenal have in news accounts of the combat success of the first laser guided weapons is understandable.
|
His name is David J. Salonimer. He has been working on laser guidance concepts and techniques for the Army since 1961. Many of the men who worked with him insist Salonimer was the key man in the successful effort to pioneer the concept, technology and experimental hardware subsequently used by the Air Force in the development of the laser guided smart bomb. |
|
The Army missile team makes no claim to paternity, but the smart bomb has a host of proud uncles at Redstone. Their work from the outset was aimed at laser guided weapons that could be used by the Army. In developing them, they devised and proved a guidance concept applicable to bombs, rockets, missiles, even artillery shells, then transferred what they had learned to their Air Force counterparts and assisted them in bringing along the smart bomb. How that happened provides a classic example of how problems solved by one research team can give another a running start.
Widely hailed by laymen as a potential wonder weapon almost from the moment more than a decade ago when it was first demonstrated in the laboratory, a laser converts electrical energy into a very narrow, coherent beam of light, light of extreme brightness. Despite the predictions of those who said the advent of the laser in 1960 meant a death ray lay just around the corner, there were—and still are—major technical problems involved in using lasers as weapons. Lasers are fairly inefficient devices. The early models required enormous electrical power to operate. The special properties of the laser beam, however, aroused immediate interest.
Dr. John L. McDaniel, Director of Missile Command research and engineering, recalls: "Many people in our business could see that the laser might be a way to do something. The trick lay in finding a practical application for it."
The something that interested Army missile engineers and others in the defense industry looked to be the answer to a particularly tough problem. By the early 1960s ways had been devised to guide missiles to hit tanks so long as the man who fired the missile had the tank in sight. The next step: finding a way to hit a tank when it was out of sight of the man who fired the missile.
A possible solution involved using some distinctive characteristic of the tank itself that a missile guidance system could recognize and home on, the way a heat-seeking missile steers itself to the heat given off by an airplane engine. For a variety of technical reasons, that approach failed. When it did, those working on the problem began searching for a way to mark the target. What they wanted was a means to project a distinctive signature on the tank that a missile guidance system could recognize. Radio, radar, infrared and a host of other technical approaches were tried. All failed.
Beginning in 1961, Army missile engineers at Redstone evolved a concept and theory of laser semi-active guidance. Reasoning that advances in laser technology soon might make it possible to project the laser beam over sufficient distances to meet military requirements, they proposed using a laser as an illuminator, a means to mark the target by projecting a bright spot of light upon it. If that could be done, they were reasonably sure that a seeker could be built that could see the spot on the target and guide a missile to it.
The thing looked possible on paper, but the key elements needed to make a laser guided weapon the illuminator and the seeker, had yet to be built.
In 1962 as the group at Redstone continued their investigations, the illuminator loomed as the toughest problem. Soldiers on the battlefield would need a device that could be easily moved. The portability the Redstone group knew the Army would insist upon dictated not only an operating laser but a relatively small one, hopefully a device and its related power supply that could be carried by one man.
Allan A. Norman, then a team leader in the Missile Command element charged with investigating potential future missile systems, recalls it as a time when one idea after another would be advanced, argued over and discarded. There was general agreement that to be useful to the Army, a laser illuminator and its power supply—probably batteries—would have to weigh no more than 40 pounds. Norman asked Salonimer to take a look at how that might be done.
Salonimer, then a 38-year-old general engineer with six years experience in the Army missile program, had recently completed a survey of existing and proposed missile guidance concepts. A graduate of Wayne State University, he had a solid background in electronics, circuitry and servo technology. Dr. Julian Kobler, who worked in the same group, recalls: "Dave was up to speed on current guidance technology. Beyond that, he had read every technical article on every subject he could get his hands on. He has a unique ability to synthesize a solution to technical problems by pulling together bits of diverse technology and figuring out a way to make them fit."
Synthesizing this solution took months. Often working alone for days at a time, Salonimer also drew on the specialized knowledge and skills of other members of the Missile Command research team and his widespread contacts in defense industry. He polished his evolving thoughts in the chalk board group think sessions much favored by engineers.
Of those latter sessions, Salonimer says, "You can't underestimate the importance of the devil, the guys on the negative side, who say 'That won't work and here's why.' Opposition keeps an idea alive. When everyone agrees, you run out of steam."
The original thinking had been that the laser must illuminate with continuous energy, roughly analogous to pointing a flashlight at a target, switching it one and holding the beam on the target until the missile hit. Searching impatiently for a way to get away from the large power source that approach would require with laser technology then available, Salonimer came up with the idea of pulsing the laser beam. In effect, he proposed illuminating the target with regularly spaced short bursts of very high energy. That was a way to do the job with a relatively small power source if he could find answers for a host of new problems that approach presented.
When he assumed the laser could be pulsed, Salonimer found the pieces of his technical jigsaw puzzle came together. He worked out a mathematical proof that his theory was correct.
"Dave's equations were the road map," Norman recalls. "Once we saw them, we had the way to go."
New technology of great promise attracts widespread interest throughout industry and government research organizations. By late 1962, that kind of interest had begun to accelerate laser technology. Once the snowball started downhill, the Missile Command, as the advocate of the laser guidance concept, became the focal point for ideas that poured in from everywhere.
Salonimer recalls: "People would come in and offer ideas. Some probably didn't even know that they had helped. None of us could tell you today where it all came from. We were sitting right in the middle, pulling it together, shaving off what we didn't need, urging the laser guidance concept on any one who would listen."
Some of the urging involved pointing out how laser guided weapons might be used in combat. The Army traditionally has used forward observers, men in position to see the target, to adjust the fire of cannons. Now it appeared that a forward observer, using a laser illuminator, could literally steer the weapon right to the target. If the illuminator could be made, it could be used almost anywhere; by a soldier in a foxhole, or mounted on jeeps, tanks, helicopters or airplanes. The airborne illuminator was one of many suggestions Salonimer advanced to friends in industry as he urged them to consider the feasibility of laser guidance.
The process through which weapon systems evolve from thoughts into full-scale development programs which produce usable military hardware, in the early stages, is essentially one of predict, then confirm. In June 1963, the Missile Command sought the first vital confirmations.
Autonetics and RCA received contracts totaling $156,000 to investigate different technical approaches for seekers to home on pulsed laser radiation. Within six months both the Autonetics concept using solid state devices and RCA television image tube technique had been successfully demonstrated under laboratory conditions.
As an offshoot of this effort, Autonetics also developed on its own a relatively lightweight pulsed laser that could be used as an illuminator in experimental setups.
Salonimer, one of several Missile Command engineers, who saw the crude device reflect its beam off a brick wall on the far side of a parking lot at the Autonetics plant, recalls: "At that point we knew what we wanted was within reach."
Based on the highly promising initial reports from its contractors and the results of work continuing in its own laboratories, the Missile Command now began to shift the impetus of its effort toward hardware: seekers that could be tested, first on the ground, then flown in missiles, portable illuminators that could be operated on test ranges.
In January 1964, development work on a portable illuminator got under way in the Redstone laboratories. A few months later additional contracts funded further seeker work. Awards to two industrial firms funded other possible technical approaches to the development of the laser illuminator. One of them, Martin Orlando, subsequently delivered a practical pulsed laser illuminator weighing less than 40 pounds.
Military research organizations exist to produce good ideas, but not all good ideas go on to become weapons. Once a solid technical foundation begins to support theory, other factors become increasingly important, among them: cost of the proposed weapon and what it offers in the way of improved fighting capability to the service supporting the research.
Contrary to popular belief, each military service does not jealously guard the results of its research programs from the others. In fact there is a continuous exchange of information at several levels, ranging from Defense Department sponsored tri-service working groups down to informal discussions among individuals in government laboratories and their supporting defense contractors.
Just that sort of an exchange had been going on in laser semi-active guidance with Salonimer and a colleague, Norman L. Bell, serving as the Missile Command's primary points of contact with interested groups in other services and industry research organizations. Bell recalls: "Dave organized the exchange. It was very informal but we were talking back and forth to the other people all the time to make sure that everyone knew what was happening."
Encouraged and supported by the Missile Command's pioneering work, the Air Force evidenced definite interest in laser guidance in the Spring of 1964, an interest that grew throughout the year. Bell soon found that in addition to working our potential development programs for Army laser guided weapons, he had become the Missile Command's informal ambassador to the Air Force.
The Redstone group had decided by then to persuade solid state technology for the seeker believing it offered the best approach for a high accuracy missile guidance system. The RCA image tube technique was diverted into a way to mark ground targets for pilots of attack aircraft.
By the end of 1964, sled testing on the Autonetics solid state seeker had begun at Redstone, Martin's first illuminator was nearing delivery and RCA had the target designation system ready for demonstration in an aircraft. In short, as 1965—the year of initial major commitment of American combat forces in Vietnam—began, the technology needed to make a laser guided weapon was pretty much in hand.
At the invitation of the Air Force, Bell and Salonimer attended a meeting in Orlando, Florida, in April 1965. Looking back, both men agree that session was a critical, perhaps the most critical, point in the evolution of the smart bomb.
The Air Force called the meeting to review the status of laser guidance technology and how it might be applied. In essence, the questions of overriding importance discussed in the two-day session were these: "Is the technology available now to support a development program for laser guided weapons? How can they be used in tactical air warfare?"
Bell recalls: "As it turned out, Dave and I were the only technical types in the room who could talk in terms of both the technology and how it could be used in weapon systems. We had done our homework on applications."
The two Missile Command representatives answered the first question with an unqualified yes, then outlined several weapons concepts tailored to Air Force application. In particular, they talked about the laser guided Shrike.
Looking for a relatively inexpensive missile for its own concept, the Missile Command had brought Texas Instruments Company into its effort in mid-1964, funding studies leading to integration of a laser seeker in the Shrike missile, a Texas Instruments product.
Bell and Salonimer explained to the Air Force representative at the Orlando meeting the mechanization of the laser guided Shrike, how it could be put into another missile, or a free falling bomb.
A month later—in May 1965—the Air Force formally asked the Missile Command to participate in a short and quick demonstration program to establish the practicality of laser guided bombs and their anticipated greater effectiveness. Specifically the command was asked to provide laser illuminators and operators, technical assistance and evaluation of the seeker proposals of the contractors selected by the Air Force to work on the bomb.
What the Air Force had in mind was a development program aimed at producing a relatively inexpensive modification kit to be fitted on a standard bomb, a simple seeker to home on laser illumination, coupled with moveable fins that would cause the bomb to maneuver as it fell toward the target and achieve much greater accuracy.
Able to rely on the Missile Command for illuminators—Martin had delivered one in January 1965 and had received follow-up orders from the command to build two improved models—the Air Force concentrated on the modification kit for the bomb, awarding contracts to Autonetics and Texas Instruments. The former had been deeply involved in the Missile Command's program for two years. Texas Instruments, building on what it had learned from the Missile Command during the studies on the laser guided Shrike, had submitted an unsolicited proposal to the Air Force for a laser guided bomb.
In the next 18 months with Bell coordinating the effort, the Missile Command illuminators were used by both the Air Force and its contractors in developing and testing the laser guided bomb. Salonimer and others at Redstone provided advice and assistance to the Air Force, including detailed evaluation of the contractors' technical proposals. Autonetics, with its longer experience, appeared the obvious choice. Texas Instruments offered an approach of higher risk, but potentially simpler and lower cost. Salonimer spotted that and urged the Air Force to fund both approaches. Texas Instruments eventually won the competition and went into quantity production. The Martin Company, which built the first illuminators for the Missile Command, later developed the aircraft mounted illuminators for the Air Force.
Building on the technical base developed by the Army programs, the Air Force and its contractors were able to bring the smart bomb along in a very short time. Well launched by successful demonstration in 1966 of the laser guided bomb, the Air Force went ahead in an expedited program to ready the weapons for operational use.
The laser guided weapon, as a result, saw its first combat use as a smart bomb. McDaniels explains why:
"The group working on laser guidance here at the Missile Command had been working to Army requirements, looking for a better way to fight tanks. The enemy was not using tanks in the early years of the Vietnam War. The Army had a good concept, but no targets. The Air Force, on the other hand, had targets, plenty of targets. They wanted a way to hit them more effectively. They obviously got it. The Missile Command group continued to expand laser guidance technology for application to Army requirements. That was our primary goal from the outset."
Today Salonimer can see a laser guided missile by getting up from his desk in the Missile Command research and engineering laboratory and taking a short walk down the hall. Army laser guided long-range rockets have demonstrated unprecedented accuracy. Air-to-ground laser guided missiles are fired regularly from helicopters on Redstone Arsenal test ranges.
Salonimer's mounting pile of newspaper and magazine clippings offers positive, if mute, evidence that the smart bomb had introduced a new dimension in warfare.
He feels it is just a beginning. "We've hardly scratched the surface of what can be done with laser guidance," he said the other afternoon, rapidly outlining a dozen potential applications.
Someone asked if he had ever seen a smart bomb tested. He seemed surprised by the question.
"No, I never did, but that wasn't important. We knew it would work," he said.
