The Space Force is investing heavily in satellite laser communications before fully proving the technology works, the Government Accountability Office warned in a report published Feb. 26.
The service’s Space Development Agency is building a constellation of satellites in low-Earth orbit that will transmit data to each other and to ground and air receivers via laser, which experts say is far faster and more secure than traditional radio frequency systems.
But while SDA has only conducted a few initial trials and not met its originally planned demonstration goals, it has awarded contracts for hundreds of new satellites. That could lead to more delays and costs if SDA needs to adjust its equipment requirements on the fly and contractors have to redo their designs, the government watchdog warned.
“Without demonstrating key laser communications technology capabilities, or [minimum viable products], SDA is risking not being able to leverage past experiences into the investments either under contract or planned for in the future,” GAO wrote. “These investments are substantial—nearly $35 billion.”
SDA’s goal is what it calls the Proliferated Warfighter Space Architecture: at least 300-500 satellites that provide missile warning and tracking, communication, and navigation services for troops everywhere. But PWSA does not work without laser communications, which can transmit data 10 to 40 times faster than radio frequencies using a beam of light about 1,000 times narrower, which makes it much more difficult for adversaries to intercept.
Lasers will also make possible a mesh network where the rest of the constellation can adapt and reconfigure to route data efficiently even if one or more satellites is disrupted by systems failure or adversary disruption—it’s a key reason officials have called the PWSA the “backbone” of the Pentagon’s combined joint all-domain command and control effort to connect sensors and shooters around the globe within seconds.
But laser communications are difficult: satellites in low-Earth orbit move 17,000 miles per hour, so they have small time windows to find each other, point lasers, and maintain that laser link. Mechanical vibrations can throw off the beam, as can atmospheric conditions during space-to-surface transmissions.
GAO identified eight capabilities that SDA wants from the optical communications terminals that went on the first tranche (Tranche 0) of satellites to form the PWSA. They include establishing links between OCTs built by the same vendor in the same orbital plane, between OCTs built by different vendors in different orbital planes, and linking with ground stations.
Checking off those capabilities will help inform development of more advanced capabilities in later tranches. The problem is that SDA is already investing in the next tranches without checking off the initial capability goals. As of December, GAO found that only two of the four Tranche 0 contractors had demonstrated a total of three of the eight capabilities.
That list grew in January, when York Space Systems announced one of its data transport satellites had established a laser communication link with a missile warning/tracking satellite built by another vendor, SpaceX. But there are still gaps when it comes to demonstrating links from space to ground and between OCTs in different orbital planes.
The stymied progress led SDA to make what developers called “substantial” changes to its Tranche 0 and Tranche 1 goals, with further changes on the horizon, which could lead to confusion about what standard is most current, GAO noted.
SDA wants to use a spiral development cycle where a minimum viable product and capability informs the next phase of development, but the agency has not yet demonstrated the minimum capability of a laser-based mesh network planned for Tranche 0, GAO noted.
That hasn’t stopped SDA from awarding contracts for two subsequent tranches worth about $9.5 billion, “inconsistent with the leading practice of demonstrating the MVP before moving to the next Iteration.”
Past government watchdog reports have shown that using immature technologies in defense acquisition programs faced delays and cost overruns.
“While SDA has taken considerable steps to prioritize speed, this has had consequences,” GAO wrote. SDA is also not sufficiently communicating key test schedules or performance information to stakeholders, contractors and test officials told GAO.
The office recommended the SDA demonstrate the minimum viable product for laser communications in space in Tranche 0 and incorporate lessons learned before making launch decisions about Tranche 1 satellites; repeat the process before Tranche 2 and 3; and better communicate test plans, timelines and results to relevant stakeholders.
The Defense Department agreed with GAO’s recommendations, but it insisted SDA had met its revised minimum viable product for Tranche 0, which is to demonstrate the feasibility of developing a proliferated architecture, rather than the capability itself.
Yet the GAO argued that revising the minimum viable product is “at odds with the leading practices for iterative development.”