A satellite from Toronto-based Kepler Communications passed a bi-directional air-to-space optical communications test for the United States’ Space Development Agency (SDA).
SDA is developing the Proliferated Warfighter Space Architecture (PWSA), which is a set of low Earth orbit satellites for missile surveillance and tracking. PWSA is not only an opportunity for companies large and small in the space business, but it is also meant to be a forum for establishing standards that could be used by future space projects.
The US subsidiary for Kepler used one of Kepler Communications’ two optical Pathfinder satellites for the test, which were designed for SDA testing. The two satellites are called ÆTHER-1 and ÆTHER-2, and both launched Nov. 11, 2023 on the SpaceX Falcon 9 Transporter-9 ridershare mission.
The satellites form part of Tranche-0, which is a set of 28 satellites optimized for either transport (providing low latency military data and connectivity) or tracking of missile threats and hypersonic systems.
The test took place between a General Atomics Electromagnetic Systems (GA-EMS) optical communication terminal on an aircraft, and a Pathfinder satellite. In a statement, Kepler US officials said the demonstration is a “milestone” that is “proving the ability to establish secure, high-data-rate connectivity between airborne and space-based assets in challenging operational environments.”
“We’ve shown what’s possible when space and aviation systems work seamlessly together,” added Robert Conrad, president of Kepler US, in the same statement. He added the demonstration “reinforces how commercial space operators will be partners in delivering secure, high-throughput connectivity for the defence community and the broader commercial sector.”
The airborne terminal successfully completed the key steps of pointing, acquisition, tracking, and lock with the satellite, then verified uplink and downlink through data packet transfers, added GA-EMS President Scott Forney in the same statement. He hailed the initiative, saying it showed “our team achieved a proof-of-concept milestone.”
The test is a follow-on from previous work with the satellites on-orbit. For example, in June 2024, a test of optical inter-satellite links was performed between the two satellites. This demonstration meant to demonstrate the standards set by SDA, as well as the compatibility of Tesat SCOT80 optical terminals.
Another test was done in May 2025 with Cailabs, a French optical ground station company, for another space-to-ground optical data relay. The demonstration used one of the Pathfinder satellites, and a Cailabs ground station in Rennes, France.
Kepler officials have noted in the past that optical data – a faster type of link than the typical radio frequency (RF) spectrum satellites use – is a requirement to quickly send terabytes of data, especially in operational environments.
The company has noted that optical links have higher bandwidth and better focus than RF, but on the other hand, there are few commercial products that support optical frequencies – not to mention periodic issues with atmospheric interference as optical wavelengths are shorter than RF.
Aside from the Pathfinder satellites, Kepler Communications deployed 21 first-generation radio frequency satellites as of late 2024. They all use sun-synchronous polar orbits. The Canadian company has received funding via fundraising rounds, the Canadian Space Agency’s Space Technology Development Program or STDP, the Government of Canada’s Strategic Innovation Fund, and the European Space Agency.
As the name “Tranche 0” implies, SDA will be deploying the PWSA constellation in tranches, ranging from demonstration (Tranche 0) to autonomous operations (Tranche 4). The current phase is Tranche 1, called “initial warfighting capability”, and is set to have its first of six launches in September aboard a SpaceX Falcon 9, if the schedule holds.
Tranche 1 is a little past its initial target for deployment in fiscal 2024, but SDA has emphasized the entire PWSA should still meet its proposed 2027 date for full constellation operability. More generally, the U.S. has been pushing ahead on military spending and missile defence work while citing hypersonic missile threats from China and Russia, including a planned-for “Golden Dome” missile-defence system.
The $75 billion USD ($103 billion CAD) project is one that U.S. President Donald Trump hopes to have operational before his term ends in 2029, although some in the industry have called the four-year timeline ambitious given the scope and complexity of the project.
Related
#Kepler #satellite #passes #airborne #optical #link #test