The various effects generated by lasers find widespread applications in everyday life, including laser pointers, printers, DVD players, retinal and other medical surgical procedures, and industrial manufacturing processes such as laser welding and cutting. Researchers develop lasers as an alternative to radio wave technology to improve communication between spacecraft and the ground.
Lasers also find widespread use in military operations. One of the most famous is the Laser in the sky (ABL), which the US military planned to use to shoot down ballistic missiles. ABL involved a very large, powerful laser mounted on a Boeing 747. The program was ultimately doomed to failure due to the challenges associated with the thermal management and maintenance of the chemical laser.
A more successful military application is the Infrared countermeasures for large aircraft (LAIRCM) system, used to protect aircraft from heat-seeking anti-aircraft missiles. LAIRCM shines light from a solid-state laser into the missile sensor as it approaches the aircraft, blinding the weapon and losing sight of its target.
The evolving performance of solid-state lasers has led to an increase in new military applications. The US military mounts lasers on army trucks and naval ships to defend against small targets such as drones, mortar shells and other threats. The Air Force is studying the use of lasers on aircraft for defensive and offensive purposes.
The Russian laser
The famed new Russian laser facility is called Kalina. It is intended to blind the optical sensors of satellites that collect information above their heads and thereby temporarily blind them. As with the American LAIRCM, glare involves saturated the sensors with enough light to prevent them from functioning. To achieve this goal, accurate enough light must be sent to the satellite sensor. That is no mean feat given the very large distances involved and the fact that the laser beam must first pass through the Earth’s atmosphere.
Accurately aiming lasers over great distances in space is not new. This is how NASA’s Apollo 15 mission in 1971 meter-sized reflectors on the moon that are targeted by lasers on Earth to provide position information. Delivering enough photons over great distances comes down to the laser power level and optical system.
Kalina reportedly operates in a pulsed mode in the infrared, producing about 1,000 joules per square centimeter. By comparison, a pulsed laser used for retinal surgery is only about 1/10,000th as powerful. Kalina provides much of the photons it generates over the great distances that satellites orbit overhead. It is able to do this because lasers form highly collimated beams, meaning the photons travel parallel, so the beam does not spread out. Kalina focuses his beam using a telescope several meters in diameter.
Spy satellites that use optical sensors usually operate in low Earth orbit at an altitude of a few hundred kilometers. It generally takes these satellites a few minutes to pass over a specific point on the Earth’s surface. This requires Kalina to be able to work continuously for that long while maintaining a permanent trace on the optical sensor. These functions are performed by the telescope system.
Based on the telescope’s reported details, Kalina would be able to target an above-ground satellite hundreds of miles from its path. This would make it possible to shield a very large area — on the order of 40,000 square miles (about 100,000 square kilometers) — from intelligence gathering by optical sensors on satellites. Forty thousand square miles is approximately the area of ​​the state of Kentucky.
Russia claims it used a less capable truck-mounted laser blinding system in 2019 called Peresvet. However, there is no confirmation that it has been used successfully.
Laser power levels are likely to continue to increase, making it possible to go beyond the temporary effect of glare and permanently damage the imaging hardware of sensors. As the development of laser technology moves in that direction, there are important policy considerations associated with using lasers in this way. Permanent destruction of a space sensor by a nation can be considered an act of aggression, leading to a rapid escalation of tensions.
Lasers in space
Of even greater concern is the possible deployment of laser weapons in space. Such systems would be very effective because the ranges to targets would likely be reduced significantly and there would be no atmosphere to weaken the beam. The power levels required for space-based lasers to cause significant damage to spacecraft would be significantly reduced compared to ground-based systems.
In addition, space-based lasers could be used to target any satellite by targeting lasers at propulsion tanks and power systems, which, if damaged, would completely disable the spacecraft.
As technology advances, the use of laser weapons in space becomes more likely. The question then becomes: what are the consequences?
Iain Boyd is a professor of aerospace engineering at the University of Colorado Boulder.
This article was republished from The conversation under a Creative Commons license. Read the original article.
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