A recent news report about US laser weapons developments states:
An airborne laser weapon dubbed the “long-range blowtorch” has the added benefit that the US could convincingly deny any involvement with the destruction it causes, say senior officials of the US Air Force (USAF).
US weapons laboratories compete fiercely for funding from the military. A branching network of fractal complexity, like the root system of a tree, spreads out from the main cascades of funds issuing from the Pentagon: army, navy, air force; and these economic rivers break up into filaments nourishing major weapons laboratories, within which the filamentation process continues as departments, projects and groups each compete with sibling administrative units at their level of the hierarchy, for funding. This filamentation of competition extends to the individual level, it is a dog-eat-dog careerist system.
Each competitive unit, from the individual on up to the military services each produces advertisements, in the form of presentations, journal articles, white papers, fact sheets, and official testimony, to toot its horn and solicit funds. This activity is ongoing, frenzied, and produces an enormous quantity of hyperbole every year. The most fanciful, dramatic and ominous claims about weapons and systems under development (perhaps “being marketed” is a better phrase) are produced as examples of this hyperbole. As in all advertising, the purpose of the hype is to get the attention of a “sugar daddy,” who might then listen to your pitch long enough to buy something from you.
The people working on the Advanced Tactical Laser (ATL) at the US Air Force Research Laboratory at Kirtland Air Force Base, in Albuquerque, New Mexico, clearly think that funding officials higher up the food chain will see “plausible deniability” as a worthy feature of their product. The group working on chemical lasers since the 70s must keep advancing the technology to stay competitive relative to alternative weapons systems (e.g., RPVs, described later), and they must invent rationales for government and military policy-makers to favor their products and methods. Hence, they have invented the claim that firing an infra-red (IR) chemical laser, mounted in a cargo airplane about 10 km to 20 km from its target on the ground, can be done without detection, and hence the perpetrators — the US military — would have “plausible deniability” of responsibility for the attack. Reliable sneakiness is seen as desirable, a selling point.
Is it undetectable? A kilowatt-power, infrared (invisible) laser beam delivering the heat equivalent of a “blowtorch” to a small spot on a target, from an airplane at 10 km distance, would be very difficult to detect if unanticipated. If you expected this type of attack, you would probably have radar detectors scanning for the presence of Hercules C-130H aircraft, IR sensors scanning the low-level atmosphere for scattered IR laser light, trace-gas (Raman spectroscopy) scanners for detecting the chlorine and iodine chemical scent trail of the attack airplane, and you would shield your high-value targets with ample heat-absorbing material (i.e., burying them if possible). However, many targets would remain at risk. They could be everyday people or objects elevated to momentary importance during the course of a crisis, for example your diplomatic (spy) or military (or insurgent) personnel, transport equipment: troop carriers, vans, food and supply trucks, ammunition transports, mobile communications and tracking electronics units, artillery pieces, boats; and they could be civilian infrastructure deemed fair game by the US attackers. Perhaps we can think of the ATL as the equivalent of a US soldier with the destructive power of an automatic rifle or flame-thrower, with global-positioning-satellite (GPS) guided accuracy (assuming the GPS coordinates of the target are known), and with a 10 km stand-off distance. Since the power delivered to the target is less than that of aerial (gravity, dropped) and missile-carried bombs, the ATL people find it useful to claim their system produces “less collateral damage.” So, think of it as possibly reliable remote-controlled assassination and sabotage.
There is certainly some substance to the claims, but these “stealth” features would not be foolproof, nor always easily applied. There is a great deal of coordination that must occur to use this weapon system. As noted, the GPS location of the target must be known, and this becomes complicated with a moving target. The dose delivered to the target will depend on the distance to the aircraft, and on atmospheric conditions (scattering and absorption of the laser light). The attackers would want to be sure to deliver enough power to cause a disruptive effect sufficient to their purpose. The aiming of the beam and positioning of the airplane are simultaneous dynamic processes, so a quantity of fancy military computers and electronics will be in play (which is involved but routine now in the high-tech military). Confirmation of the kill would require separate surveillance systems or discretely positioned personnel.
A competing technology would be the look-down, shoot-down aerial drones (remotely piloted vehicles, RPVs) used extensively by US forces in Iraq and Afghanistan, and by the Israelis. The drones are much closer to the action, though they can be much smaller than a C-130H, and they use old-fashioned bullets, bombs and missiles; only the control is far away. So, drones may not afford “plausible deniability” when used in densely populated areas (too many witnesses).
The ATL is a chemical laser; brief descriptions of the laser and its chemistry are given by internet articles “chemical oxygen-iodine laser (COIL)” , and “Iodine“. First, chlorine gas and hydrogen peroxide are combined (2Cl + H2O2 => 2HCL + O2), and this produces hydrochloric acid and oxygen molecules in an excited state. The hydrochloric acid then reacts with sodium hydroxide (HCL + NaOH => NaCl + H2O) to neutralize the acid and form saltwater). Finally, iodine is introduced, which reacts with with the excited oxygen, which then gives off its excess energy as infra-red photons. This occurs in a chamber with infra-red mirrors, which is the laser cavity from which the beam is cast. My description of the chemistry is grossly oversimplified (since I am not a chemist), there will be many reactions occurring between all the possible byproducts, and there will never be a complete depletion of chlorine and hydrochloric acid, nor a complete transformation to pure saltwater and oxides of iodine. There will be a toxic stew in need of chemical reprocessing, to clean it up for reuse or disposal. The ATL airplane will be carrying tanks of chlorine gas under high pressure and high purity hydrogen peroxide; both are significant explosion hazards.
The ATL is one of many weapons development projects that suckle for decades on the tits of the national treasury, sustaining the career ambitions of technocrats and weapons laborers, and sometimes advancing complex products into the inventories of the military services. The actual military value of any such system is defined by the magnitudes and range of the threats it is intended to remove, and the reliable ease-of-use of the technology. Whatever the actual utility (to the military) of any such system, it is never as fantastic as its many commercials claimed it would be. Given the witches’ brew that must be airlifted to produce the ATL infra-red beam, one might well ask, is this a weapon system of plausible utility?
MANUEL GARCIA, Jr. is a retired physicist. E-mail = firstname.lastname@example.org