During a commissioning and early operations phase, Kepler established optical inter-satellite links between two Pathfinder satellites equipped with Space Development Agency (SDA) compatible TESAT SCOT80 optical terminals in low earth orbit.

The pair of satellites were launched in November of 2023 to demonstrate technology for the company’s space data relay constellation, The Kepler Network. The Kepler Network provides customers with always-available coverage in LEO, streamlining on-orbit communications with sub-second end-to-end latency, gigabit throughputs, and onboard processing to enable access to space-generated data in near-real time.

The first file transferred over the optical connection was a recent picture of Kepler’s global team gathered near its headquarters in Toronto, Canada. In the first week of testing, the company successfully sent diagnostic data between the two spacecraft, and the full link performance was demonstrated according to the SDA standard. In addition, multiple acquisition scenarios were tested, and both terminal and spacecraft performed optimally.

In addition to initial optical link commissioning, the company has demonstrated Internet Protocol (IP) mesh networking on orbit by communicating with multiple satellites in real time over a single ground link, using standard protocols including Secure Shell (SSH), Transmission Control Protocol (TCP), and User Datagram Protocol (UDP).



Kepler Communications, Inc. is a satellite telecommunications provider on a mission to build the Internet for space. Incorporated in 2015, Kepler provides real-time, continuous connectivity for space communications, abolishing barriers to make space-generated data universally available. The company is vertically integrated, with an in-house production facility allowing satellites to be designed and built on-site. The Kepler Network will initially service low Earth orbit (LEO) and plans to provide connectivity services to space missions in LEO, MEO, GEO, and beyond. Headquartered in Toronto, Canada, Kepler is building a global company to enable communications for the future space economy. To learn more about Kepler, please visit


TESAT is a world-leading manufacturer for satellite equipment. More than 1,100 employees develop, manufacture and distribute systems and equipment for satellite communications every day. The product range spans from the smallest space-specific components to modules, entire assemblies or payloads. As the world’s only provider and technology leader of in-orbit-verified optical communication terminals for data transmission via laser, TESAT has a focus on commercial and institutional space programs. Thanks to our deep understanding of market needs, customer focus and technological innovation, we offer products that contribute to sustainable development, for the people, for a better world.

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