WASHINGTON — A laser communications terminal mounted on a twin-engine aircraft successfully connected with a satellite orbiting overhead.
In the demonstration, announced Sept. 2, an optical terminal made by General Atomics Electromagnetic Systems was mounted on a 12-inch turret aboard a De Havilland Twin Otter aircraft. While in flight, it pointed toward a Kepler Communications satellite in low Earth orbit equipped with a Tesat-Spacecom optical terminal. The airborne terminal acquired the satellite’s laser signal, locked onto it and maintained that connection long enough to exchange data packets in both directions, the companies said.
This trial which took place in July was designed to prove that optical terminals built to the Space Development Agency’s (SDA) Optical Communications Terminal (OCT) standard could communicate across vendors.
SDA, a U.S. Space Force agency, is building the Proliferated Warfighter Space Architecture (PWSA), a planned network of hundreds of satellites in low Earth orbit that will provide global communications, missile warning and missile tracking for U.S. and allied forces. A critical part of this architecture is the ability for satellites — and airborne platforms — to exchange data quickly and securely over optical links.
Unlike traditional radio-frequency communications, laser (or optical) links offer high data rates and are more difficult to jam or intercept. But interoperability has been a longstanding challenge. Different vendors have developed their own laser communications terminals, often with proprietary implementations, which can prevent seamless connectivity. SDA’s OCT standard is meant to fix that by enforcing common specifications.
“This successful space-airborne communication demonstration represents a breakthrough improvement in building a resilient space architecture. Achieving multi-vendor interoperability validates SDA’s leadership in the optical communication arena,” Gurpartap “GP” Sandhoo, SDA’s deputy director, said in a statement.
“The demonstration achieved the milestone for SDA-compatible communications across the air and space domains, but very importantly proved the robustness of the SDA standard for communications between OCT’s built by two different companies,” said Gregg Burgess, GA-EMS vice president for space systems.
This was not the first attempt. General Atomics previously tried an airborne-to-space laser communications test, but it failed due to deployment issues with the satellite involved.
Kepler deployed its first pair of SDA-compatible relay satellites last November, each equipped with Tesat-Spacecom’s Scot 80 terminals. “By pairing Kepler’s on-orbit optical capabilities with GA-EMS’ OCT, we’ve shown what’s possible when space and aviation systems work seamlessly together,” said Robert Conrad, president of Kepler US, the U.S. subsidiary of Canada’s Kepler Communications.
Under a separate SDA contract, GA-EMS is building two optical terminals for its GA-75 spacecraft, with a planned launch in 2026. These will extend the interoperability demonstrations beyond aircraft to space-based assets built by General Atomics itself.