The Space Development Agency demonstrated laser communications between two of its satellites for the first time recent, laying the groundwork for the “mesh network” that will link hundreds of its satellites in low-Earth orbit.
“We had the two of our tracking satellites, the SpaceX birds, using the SDA-compliant terminals built by Tesat, they were able to demonstrate that they could, in fact, do the laser communication,” SDA director Derek Tournear said at the Defense News Conference on Sept 4. “They maintained link.”
Laser communication offers significant advantages over traditional radio frequency by transferring more data faster, using less power, and needing smaller equipment. Its shorter wavelengths enhance speed and signal security, making it ideal for the high-stakes environment of space. It’s also critical for the SDA and Pentagon to realize their vision of Joint All-Domain Command and Control, by transferring data between sensors and shooters around the globe.
SDA’s standards called for the satellites to connect within 100 seconds using laser comms, with an ideal goal of under 10 seconds. In the test conducted Sept. 3, Tournear said the satellites met the requirement by linking “well under the 100 seconds,” though they didn’t hit the 10-second mark. The link did, however, remain stable for several hours. This test builds on an earlier experiment conducted by the Air Force Research Laboratory and the Defense Advanced Research Projects Agency in 2021, but using official military-grade terminals for the first time.
The laser comms test follows on previous tests by SDA to demonstrate it can use the Link 16 tactical network from space and it can detect missile launches from low-Earth orbit.
“So from my perspective, we have demonstrated all of the big rocks and burned down all of the risk for Tranche 1 and Tranche 0,” Tournear said.
The satellites involved in these demonstrations are part of SDA’s Tranche 0, which started launching last year and saw all 27 satellites reach orbit by February this year. As part of its Proliferated Warfighter Space Architecture (PWSA) program, the SDA plans to deploy hundreds of small satellites to create a resilient, interconnected network that will offer real-time data and enhanced situational awareness.
Tournear also confirmed that the initial launch of Tranche 1 satellites will start by year’s end, not this month, as previously expected.
“Sometime around the end of this calendar year, we’ll start to launch our Tranche 1 satellites,” said Tournear. “The satellites are in build, all of our transport vendors are heavily in build. Our tracking vendors are close behind them.”
However, the schedule might shift into early next year due to some remaining risks. Key issues include delays with vendors for critical components like optical communications and propulsion systems. Encryption devices, vital for satellite operations, are also on the “critical path” for delivery. Despite the National Security Agency’s best efforts to fast-track certification, any additional delays in the process or hardware production could still push back the launch, Tournear explained.
The SDA plans 10 launches for Tranche 1, aiming for a “one-month cadence” afterward, depending on payload processing facility availability. Tranche 1 will include a total of 173 satellites. The goal is to have Tranche 1 satellites operational by the end of 2025.
The agency is also working to finalize some other testing for the Tranche 0 satellites, but it may face some logistical hurdles. The testing team from the 96th Test Squadron of Eglin Air Force Base, Fla., cannot transmit Link 16 in U.S. airspace without FAA certification and also needs to pass Electromagnetic Compatibility Features validation to avoid interfering with GPS signals. As a result, the team has to conduct tests from Australia and international waters, adding both time and cost.
If all goes as planned, Tranche 0’s EMCF validation should be wrapped up by the end of the year, clearing the way for operational tests. Tranche 1 satellites, with slightly different radios, will go through similar tests, with validation expected to be completed by spring 2025.