Kepler Communications announced today that it was successful in testing optical inter-satellite links (OISL) between two data relay satellites in low Earth orbit (LEO).

The test in part was designed to showcase use of Space Development Agency (SDA) standards (PDF) and compatible optical terminals. Kepler said “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.”

Kepler launched the two Pathfinder satellites, ÆTHER-1 and ÆTHER-2, on November 11, 2023 on the SpaceX Falcon 9 Transporter-9 ridershare mission.

Kepler said the spacecraft went though “commissioning and extensive checkout” before “the optical testing campaign in recent weeks.”

They added, “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.”  

Mina Mitry, chief executive officer and co-founder of Kepler said of the tests, “Kepler is proud to make significant progress in creating the critical Internet infrastructure needed to solve compounding data needs in space. This OISL achievement is a testament to the hard work, determination, and brilliance of our Kepler team, The Kepler Network will act as a data transport layer, bringing modern Internet capabilities to space through an interoperable architecture that will revolutionize space communications as we know it.”

Kepler also 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).”

The company expects to offer initial optical services in 2025 but has not released any updates on future satellite launches for its next-generation constellation. Kepler has recently relied on SpaceX Transporter rideshare missions for launch with those satellites showing up on the manifest at the last minute.

SpaceX has two Transporter missions scheduled for the rest of this year, Transporter-11 in July and Transporter-12 in October. After that, Transporter-13 is scheduled for NET feb. 2025. Kepler has 21 RF satellites on-orbit along with the two Pathfinder next-generation constellation satellites.

The company did say it has started production on the first tranche of 10 next-generation data relay satellites.

In April Kepler signed an agreement with TESAT-Spacecom and Airbus Defence and Space as partners to develop a high bandwidth optical communications network in low Earth orbit (LEO).