General Atomics and Kepler Communications Successfully Demonstrate Air-to-Space Optical Communications Capability

GA-EMS, Kepler Achieve Air-to-Space Optical Communications Breakthrough

Multi-vendor interoperability demonstration validates SDA's open standards approach for proliferated space architecture

General Atomics Electromagnetic Systems (GA-EMS) and Kepler Communications have successfully demonstrated bi-directional air-to-space optical communications between a GA-EMS Optical Communication Terminal (OCT) mounted on an aircraft and a Space Development Agency (SDA) Tranche 0-compatible Kepler satellite in low Earth orbit, marking a critical milestone for the Space Development Agency's Proliferated Warfighter Space Architecture (PWSA).

The demonstration, conducted from late July through late August under SDA contract, achieved pointing, acquisition, tracking, and lock between the airborne terminal and satellite, then successfully transferred data packets to validate both uplink and downlink capabilities. The test utilized GA-EMS's OCT mounted on a 12-inch Laser Airborne Communication turret (LAC-12) developed by General Atomics Aeronautical Systems' Precision Pointing Group aboard a Twin Otter aircraft.

Validating Multi-Vendor Interoperability

The achievement represents more than a technical milestone—it demonstrates the robustness of SDA's open OCT standard for enabling interoperability between optical terminals built by different manufacturers, a cornerstone of the agency's multi-vendor constellation approach.

"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," said Gurpartap "GP" Sandhoo, SDA deputy director.

The interoperability validation is particularly significant as SDA has been working to establish industry-wide standards while managing supply chain challenges that have delayed Tranche 1 launches from spring to late summer 2025. The agency has once again pushed back the launch of its first batch of operational data transport and missile-tracking satellites, and is now targeting a date in "late summer 2025" to put the space vehicles on orbit.

Building Toward Operational Capability

GA-EMS's OCT is designed to scale across multi-domain communications spanning space, air, land, and sea platforms, as well as various orbital regimes. "Our OCT is designed to close a communications gap, enabling secure, robust data transfers to support tactical and operational missions," said Scott Forney, president of GA-EMS.

Under a separate SDA contract, GA-EMS designed and built two OCT systems that will fly on two GA-75 spacecraft to support future LEO airborne-to-space demonstrations for Tranche 1. Those spacecraft launch in 2026. The GA-75 is a resilient, modular half-ESPA bus design capable of supporting various communications and intelligence, surveillance, and reconnaissance payloads.

Kepler's Growing SDA Role

Kepler Communications has emerged as a key commercial partner in SDA's optical communications ecosystem. The company was the first commercial entity to successfully demonstrate SDA-compatible optical inter-satellite links (OISLs) on orbit following the launch of two Pathfinder satellites in November 2023 equipped with Tesat SCOT80 optical terminals.

In May 2025, Kepler successfully demonstrated space-to-ground optical data relay with French optical ground station company Cailabs, achieving full SDA standard data rates and acquisition in multiple scenarios. The company has also secured a position on SDA's Hybrid Acquisition for proliferated Low-earth Orbit (HALO) contract and entered into a Space Act Agreement with NASA's Communications Services Project.

Robert Conrad, president of Kepler US, emphasized the demonstration's broader implications: "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. This achievement builds on our milestone of establishing bi-directional space-to-ground communications with Kepler's SDA Tranche 0-compatible satellites and reinforces how commercial space operators will be partners in delivering secure, high-throughput connectivity for the defense community and the broader commercial sector."

Standards Evolution and Industry Impact

SDA continues to refine its OCT standards to reduce technical risk across upcoming tranches. The agency released OCT Standard v3.2.0 alongside v4.0.0, with v3.2.0 intended as the standard of record for Tranche 3, while a smaller number of terminals will comply with v4.0.0. These standards are backward compatible with previous versions and aim to ensure interoperability across vendors while enabling a robust marketplace.

The optical communications push comes as SDA works to field its first operational constellation. Skyloom completed delivery of 42 flight-ready optical communication terminals to York Space Systems for SDA's Tranche 1 Transport Layer program in March 2025, with York progressing toward an additional batch of 42 terminals for Plane 2.

Technical Heritage and Future Applications

GA-EMS brings significant optical communications heritage to the SDA mission. The company has previously demonstrated air-to-air laser communications between two King Air aircraft in 2022 and completed fully-networked demonstrations using multiple laser communication terminals spanning ground, mobile, and airborne platforms.

The LAC-12 terminal used in the demonstration provides anti-jamming communications with 300 times the data carrying capacity of conventional radio frequency satellite communications systems and provides air-to-space, air, ground, and maritime relay connectivity.

For Kepler, the demonstration advances its vision of The Kepler Network as a hybrid RF and optical constellation. The company's first tranche of optical data relay satellites is scheduled to launch in Q4 2025 and will include nine satellites and a spare in sun-synchronous orbit, with plans to expand to full LEO coverage approximately two years later.

Operational Implications

The successful air-to-space demonstration represents a critical step toward multi-domain optical communications within the PWSA. Since achieving its first successful space-to-air connect in July, SDA has repeated the experiment several times, with agency officials noting that connections are becoming more routine, exchanging gigabits of data each time.

This progress comes as SDA works to demonstrate Link 16 connectivity through its transport layer satellites, which use secure radio waves to enable real-time, jam-resistant, and encrypted communications. The optical communications layer adds another dimension of resilience and capability to the overall architecture.

The demonstration validates SDA's approach of leveraging both traditional defense contractors and commercial space companies to rapidly field advanced capabilities. As the agency prepares for Tranche 1 launches later this year and looks ahead to Tranche 2 and beyond, the successful interoperability between GA-EMS and Kepler systems provides confidence in the multi-vendor strategy underlying the PWSA.

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