Laser weapons pose a "lose-lose" dilemma

Laser weapons pose a "lose-lose" dilemma

Michael H. Reifer

The Electronic Industries Association (EIA) un veiled its forecast of military laser technology in October 1996 (see Laser Focus World, Dec. 1996, p. 48), and the strategy espoused in the forecast was one of "shooting first wins." This strategy is not out of line with joint military doctrine, which states [in Joint Pub 3-13, Joint Doctrine for Command and Control Warfare], "Consistent with classical military doctrine, the commander that can gather information and initiate action to affect the theater of operations quickest will have a decided military advantage."

Traditionally, that advantage is this: If the attacker can destroy the weapons of the defender before the defender has the opportunity to use them, the defender will be unable to defend and the attacker wins. In short, once all parties are armed with laser weapons, it would seem logical that "shooting first wins." However, logic notwithstanding, the possible tactics of laser weapons dictate a different answer.

The primary difference between lasers and earlier--conventional--weapons arises from a combination of two sources. First, consider how long a conventional warhead takes when transiting to the target. Some weapons, such as an artillery shell that screams as it approaches its target, provide advance warning of their arrival and thus give the intended target an opportunity to respond. With other weapons--for example, a bullet fired at close range--the speed of engagement is beyond human response time. But lasers push the engagement speed to the extreme edge of the envelope at any range. The electromagnetic pulse, flash of light, or whatever event is sensed to indicate that a laser weapon has fired, cannot transit to the target faster than the laser beam itself. Thus, with lasers, warning occurs simultaneously with being struck, and so the target has no time for firing a shot in response to the warning.

Second, consider the following. One could shoot a rigidly anchored cardboard box with a rifle, then take the two holes created by the bullet going through the box and obtain an azimuth on the direction from which the bullet came. A laser weapon is like a rifle in that each fires a highly vectored form of tightly defined energy.

Now imagine a sensor with its surface covered by a sheet capable of locating the two points at which a beam pierces it. The sensor is also continually monitoring its position (latitude, longitude, and altitude) and attitude (roll, pitch, and yaw). A device of this sort, if impacted by a highly vectored form of tightly defined energy, would be capable of pinpointing the trajectory of the energy. All of which is to say that the event of being struck can be "harvested" to provide very valuable information as to the location of the laser firing the shot (back azimuth methods of location have long been a staple of locating firing sources).

Search, aim, fire

Pinpointing the location becomes important in light of the time required for a laser weapon`s firing sequence. First, there is the search function, which requires some minimal amount of time.1 Then there is the aiming function, which also requires some minimal amount of time.2 These two delays are additive and unavoidable; they impose a minimum delay before a laser fires. Then, assuming everything works properly, a fired shot will strike its target.

A simplified scenario will now show how all this fits together. The action commences when side L launches the type of laser beam sensor de scribed above. Ac cording to the "shooting first wins" doctrine, side F fires (after, of course, searching and aiming) at L`s sensor as soon as the sensor enters F`s field of view (FOV). Again, assuming everything works properly, the shot strikes its target. From this strike, L`s sensor detects the source of F`s weapon and transmits that information to its own weapon system.3 Now L is ready to launch its own weapon. Because a firing solution has already been determined, L`s weapon can fire the moment it enters F`s FOV.4 That is, L need not expend time on searching for, detecting, and aiming at F`s weapon. But F must still search/aim/fire in order to shoot at the new target--L`s launched weapon. Thus F, because of firing first, is at a serious disadvantage.

And thus arises this basic proposition: In a laser environment, contrary to conventional military wisdom, inherent in the act of firing, the side firing first gives away very valuable information. If the side being fired on can harness that information, the firing side actually places itself in an exceptionally disadvantageous position.

While time and space do not allow a total discussion of all issues, two questions deserve answers. The first question is this: "What if F is using a mobile platform?" In that case it may be possible for L to use the information from previous F shots to make the L search volume small enough that L can still search/aim/fire when it pops into mutual FOV faster than F can search/aim/fire waiting for L to po¥into FOV.

The second question--"What if F refrains from firing?"--has two important answers. First, if L combines this laser beam sensor with its weapon, F is in a devilish dilemma: F cannot afford not to fire and yet F cannot afford to fire. Forcing the opposition to face such a dilemma is the acme of tactical doctrine. Second, to even consider an option besides shooting first must be acknowledged as an admission that with laser weapons a "shooting first wins" doctrine is flawed.

Unavoidable deductions

The one assumption that permeates both the EIA forecast and this discussion is the inevitability of laser weapons. Accepting such an assumption leads to a series of unavoidable deductions. Much research remains to be done. The first side to develo¥laser weapons will have a clear initial advantage. Such weapons will not remain the capability of a single nation.

But the point of this discussion is to raise the awareness that use of laser weapons is not risk-free. A strategy built on the idea of "shooting first wins" can be defeated by an opposition employing the tactics of harnessing the information available when a laser weapon is fired at an opposition-selected target. It is a capability we would be remiss not to develo¥for ourselves. It is also a potential opposition capability that we cannot afford to ignore in our own planning and forecasts. o

ENDNOTES

1. The search function requires scanning a large volume or area. With more scanners, each searching a smaller area, the time to scan the entire volume can be reduced, but at an added cost per scanner. Ultimately there will be some design / cost trade-off, placing a lower limit on the search time. Once the search function detects an object there may be an Identify Friend or Foe (IFF) function. For the sake of illustration it is assumed the IFF function is done concurrently with the search or aiming process so that IFF requires no additional time.

2. The time required for aiming depends on a variety of issues. For example, if the laser weapon has a barrel that requires positioning or a mirror to be angled, time for such movement must be allowed. Even if the weapon uses a phased array, which reduces the time needed to move the mass of a barrel or mirror, time is still required to calculate and set the phase of the array. Whatever the case, as with the search process, there will be a lower limit on the amount of time required to aim the weapon before it fires.

3. Jamming the communications downlink is probably not an option. The sensor may be using an infrared free-space laser communication downlink to its controller. This is a high-tech equivalent of a signalman`s flashing lam¥or blinker tube--difficult to intercept and even harder to jam, though not, one must admit, theoretically impossible.

4. Because the laser is a direct-fire (line of sight) weapon, when F is within L`s FOV, L is also within F`s FOV.