Multi-Constellation Networks Need Multi-Constellation Ground Stations

Rightly, the Pentagon has decided that the future of military satellite communications should not depend on one network or supplier. But putting more satellites into orbit is only half the job. The military also needs a simple way to connect to them from the ground. The U.S. Space Force is developing a Space Data Network to connect different commercial satellite systems; at the same time, the Space Development Agency (SDA) is building its Proliferated Warfighter Space Architecture (PWSA). Its Transport Layer alone will eventually include between 300 and 500 satellites in low-Earth orbit (LEO).

Cost matters, as it almost always does. Every extra piece of equipment requires space, power, maintenance, skilled people. In places where those things are scarce, establishing another satellite network can mean adding another set of equipment that has to be carried, powered and taken care of. But there are different kinds of value, and a multi-vendor system is only valuable in the broadest sense if the users can switch between networks from the ground. That this has been recognised by the Pentagon, and the SDA in particular, is to their credit. By publishing a common optical communications standard and making it available to industry, the SDA has helped establish an ecosystem of compatible optical communications terminals. Different suppliers can now build equipment to the same requirements. This is one of the foundations of interoperability within the PWSA, and a model that other military and commercial networks could follow.

The big advantage that ground equipment has over satellites is that we can change it. Once a satellite is in orbit, it’s very difficult, indeed almost impossible, to make changes to the hardware. Equipment on Earth is different: it can be upgraded, replaced, and adapted as networks change. That makes the ground the best place to address differences between satellite networks. And here, optical ground stations have a particular advantage. RF communications depend on hardware suited to particular frequency bands, such as X, Ka, or Ku. Optical ground stations, in contrast, can be designed so as to accommodate a wide range of optical waveforms without replacing the underlying optical hardware. This gives operators more freedom to connect with different satellite systems as their needs change. The differences between satellite systems thus become less important to the person trying to connect.

The goal now is to build on the interoperability that the SDA has already helped to establish in space and extend that flexibility to optical ground networks. This will become increasingly important as the Space Force explores closer links with commercial satellite systems. A flexible optical ground network could help military operators connect to new commercial constellations without having to build a separate ground system for each one. That’s not to say every network has to use the same technology; only that ground equipment should be designed to work with different systems rather than being permanently tied to one constellation.

When something goes wrong – if one network is jammed, damaged or overloaded – military users have to be able to switch to another. They may have to do so very quickly, without installing new equipment or bringing in specialist teams. The SDA has shown what the institution of common standards can achieve in orbit. There's now an opportunity to apply that same thinking on the ground. The United States is building a more diverse satellite network; a flexible optical ground network would help it make full use of that investment.

Jean-François is a physicist specializing in photonics who co-invented Multi-Plane Light Conversion (MPLC), the technology on which Cailabs was founded. Today, Cailabs develops optical communications systems for space and defense customers in Europe and the United States.

image: Secretary of the Air Force Troy Meink listens to a defense industry partner executive at a production facility in Denver, Colorado, Oct. 2, 2026. The Department of the Air Force and industry partners are working closely to develop secure and assured data transport for the joint force as a part of the Space Force’s Space Data Network (SDN) program. (U.S. Air Force photo by Staff Sgt. Jackson Manske)