Toronto-based Kepler Communications notched a big win for high-speed optical data transmissions in space.
Kepler partnered with Cailabs, a French optical ground station company, for their first demonstration of a space-to-ground optical data relay. The demonstration used a Kepler optical prototype satellite in Earth orbit, which paired with a Cailabs ground station in Rennes, France.
Optical data, according to Kepler, is required to transmit terabytes of data at high speed – a rate that the available radio frequency (RF) spectrum cannot support. Most satellites today use RF communications for transferring data.
Moving to higher frequencies in RF is difficult because of the lack of commercial products at this time to support it, as well as periodic issues of atmospheric interference due to these frequencies’ shorter wavelengths. Optical beams, Kepler argues, have much higher bandwidth and the ability for better focus compared with RF.
“This is a critical milestone in creating resilient on-orbit optical infrastructure, proving our ability to leverage the power of light to improve the future of space communications,” Mina Mitry, CEO and co-founder of Kepler Communications, said in a statement.
The demonstration took place to show computability with standards defined by the U.S. Space Development Agency (SDA). SDA was formed in 2019, originally as an independent U.S. defence agency, with the mandate to deliver disruptive technologies to “warfighters” (combat-focused soldiers) more quickly than traditional Pentagon procurement practices. Today SDA is a part of U.S. Space Force, with the same mandate.
SDA is creating the Proliferated Warfighter Space Architecture (PWSA), which the agency describes as “a threat-driven constellation of small satellites that deliver critical services to our warfighters from space.” PWSA represents a large contracting opportunity for all sorts of space companies, most especially big primes focused on launching and building satellites. Due to the size and scope of PWSA, SDA is also defining standards for the satellites that will likely be followed by other space projects in the future.
PWSA will be made up of layers that are organized by function. For example, a “transport layer” has tasks that include connecting communication satellites with each other, or to ground stations. A “tracking layer” aims to sense missile threats, in connection with a “transport layer” that would assess threats and provide targeting data to warfighters.
SDA aims to deploy and advance its constellation capabilities in tranches, ranging from demonstration (Tranche 0) to autonomous operations (Tranche 4). The phase now under production, known as Tranche 1, concerns “initial warfighting capability” and is expected to begin launches in late summer 2025, according to recent SDA documentation.
This puts Tranche 1 slightly behind its aimed-for fiscal 2024 deployment date, but SDA has said it plans to keep to its 2027 date for full constellation operability. The U.S. government has said in recent years that tracking missile threats is essential given the amount of hypersonic missile activity undertaken by rivals such as China and Russia.
More generally, aside from several fundraising rounds, Kepler’s satellite communications technology has also received Canadian government support. For example, Kepler received $2 million from the Canadian Space Agency’s Space Technology Development Program or STDP. This was for on-orbit demonstration of optical and RF data relay services, including a technology demonstration of real-time data downlink and telemetry, tracking and command, according to information provided in May 2023.
Kepler also received $20 million in October 2024 from the Government of Canada’s Strategic Innovation Fund for “development of the Aether constellation and its in-orbit, high-speed connectivity network, a project valued at $280.3 million,” government officials stated at the time. This was meant to build on to the CSA’s funding, the release added.
Aether also received a contract from the European Space Agency in 2021 for 500,000€ (roughly $780,000 at current-day exchange rates.) Kepler officials stated that Aether is meant to address “limited connectivity to those space-based mission assets from the ground,” meaning moments when satellites fly between connection points at ground stations.
Aether – the second generation of Kepler satellites – aims to provide “a consistent and direct link to satellites and space-based objects”, and the two Pathfinder satellites (ÆTHER-1 and ÆTHER-2) were launched on Nov. 11, 2023 on the SpaceX Falcon 9 Transporter-9 rideshare mission. As of late 2024, Kepler has also deployed 21 first-generation radio frequency satellites. They all use sun-synchronous polar orbits and are built on a 6U CubeSat format.
A June 2024 announcement noted Kepler had successfully tested optical inter-satellite links between the two Aether prototype satellites, which was also executed for SDA compliancy.
