Ultraviolet Radios Beam to Life

Secret military communication scheme from the 1960s is finally practical

2 min read

The U.S. military has been chasing ultraviolet (UV) communication for decades. Now researchers say radios that communicate using UV light are finally within reach. Working with the Army Research Lab (ARL) in Adelphi, Md., these researchers are mapping out the steps needed to commercialize UV radios. They’ve reached the last piece of the puzzle: untangling the poorly understood, extraordinarily complex way ultraviolet light scatters. If they can do that, they will have unlocked the secret to a new form of non-line-of-sight communication.

Proposed UV radios communicate in the so-called solar blind portion of the UV-C band--light having wavelengths from 200 to 280 nanometers--which, unlike the sun’s UV-A and UV-B rays, is almost completely blotted out by the atmosphere. Near Earth’s ­surface, even a strong UV-C ­signal would die off within a few kilometers, as individual ­photons are picked off one by one by oxygen, ozone, and water molecules. But that attenuation also makes UVâ¿¿C radiation ideal for short-range wireless links, such as in unattended ground sensors. The U.S. military is interested in such short-range communications because they can’t be intercepted or jammed outside their intended range. What’s more, within its ­limited range the UV-C band has an inherently high signal-to-noise ratio, enabling the use of very-low-power transmitters, according to ARL scientist Brian Sadler.

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Two men fix metal rods to a gold-foiled satellite component in a warehouse/clean room environment

Technicians at Northrop Grumman Aerospace Systems facilities in Redondo Beach, Calif., work on a mockup of the JWST spacecraft bus—home of the observatory’s power, flight, data, and communications systems.

NASA

For a deep dive into the engineering behind the James Webb Space Telescope, see our collection of posts here.

When the James Webb Space Telescope (JWST) reveals its first images on 12 July, they will be the by-product of carefully crafted mirrors and scientific instruments. But all of its data-collecting prowess would be moot without the spacecraft’s communications subsystem.

The Webb’s comms aren’t flashy. Rather, the data and communication systems are designed to be incredibly, unquestionably dependable and reliable. And while some aspects of them are relatively new—it’s the first mission to use Ka-band frequencies for such high data rates so far from Earth, for example—above all else, JWST’s comms provide the foundation upon which JWST’s scientific endeavors sit.

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