Traditional ground station systems, built around fixed, hardware-based modems, weren’t designed for this scale of satellite launching. They are expensive, difficult to adapt, and often underutilized. Terma’s Software-Defined Radio (SDR) modem is built to handle this new reality in spacecraft communication.
Traditional legacy modems ties capacity to physical boxes, which means scaling up demands you to buy and install new ones. With modern, software-defined modems, it’s different.
“You just add compute power and scale as needed. There’s no need for 20 separate legacy boxes,” explains Michael Effler, Product Manager for Terma SPECTRA.
With this in mind, we built Terma SPECTRA, Software-Defined Radio TT&C modem. The new modem makes scaling ground station much simpler and more efficient. You can add extra digitizers at the antenna site and scale up computing power in the back-end, whether on-site, as edge computing, or even in the cloud.
Terma SPECTRA has two scaling features that are important to understand:
Back-end scaling: Here the processing is handled on standard Linux servers. If more satellites need to be supported, operators can simply add more computing blades or move workloads to the cloud. Scaling is as easy as spinning up extra server capacity.
Front-end scaling: Here the modem’s digitizers connect to antennas and allows stations to grow without overhauling infrastructure. A single digitizer can already handle multiple channels, enabling communication with several satellites simultaneously.
In practice, this means one SDR modem can grow from handling a single link to managing multiple connections. And in mega-constellations, where hundreds of satellites may be in orbit at the same time, that scalability becomes essential.
Scalability ensures capacity, but flexibility makes it usable.
Every function of Terma’s SDR modem is implemented in software. Therefore, it allows to adapt fast, scales on demand and reloads the software configuration based on the mission requirements. This is much simpler and flexible than changing hardware.
Additionally, it operates natively in L- and S-band without the need for external frequency converters or intermediate frequencies (IF). This simplifies RF chain design, reduces integration effort, saves costs, and improves signal integrity by minimizing intermediate components.
While certain ground stations, designed for specific missions only, might experience underutilization of expensive ground station infrastructure, commercial ground stations always thrive for maximum utilization. Both scenarios benefit from the scaling flexibility resulting from utilization of SDR modems.
With the new system, operators can reconfigure the modem to support different satellites and missions. It reduces idle time and allows ground stations to operate as a service for multiple satellite missions. Hence, SDR enables support for various mission types, ranging from educational university satellites, legacy missions up to new mega constellations.
As Alexander Spaniol, RF Engineer at Terma, explains:
“With software-defined processing, every function is modular. You can rearrange, update, or extend each functionality by simply changing software. This enables rapid prototyping and a simple change of configuration for various satellite missions."
This approach makes it possible for operators to match the modem setup to their infrastructure and mission needs.
Beyond scalability and flexibility, Terma’s modem introduces several features that stand out in the market:
Multi-link capability: A single digitizer can support two full-duplex satellite connections simultaneously. This means more value from each unit and less hardware to maintain.
Pay-what-you-need licensing: Unlike traditional modems where you pay upfront for a full feature set, Terma allows customers to unlock only the modulation schemes and coding techniques they need. This reduces costs and lets operators scale functionality as their missions evolve.
Reliable & future proof: Through deployment of the SDR software on industry proven COTS equipment . Implementing new communications standards and modulation schemes is only a matter of updating software.
These features secure reliable communication with your spacecraft, from testing in an EGSE (RF-SCOE) up to the actual operation in a ground station.
As networks become more virtualized, cyber risks grow.
While the Terma SPECTRA SDR modem has enhanced cybersecurity features per design, we will go a step further towards advanced security based on *zero trust* principles. Every data flow and every operation must be authenticated and encrypted. This approach hardens both the payload data and the control interfaces, protecting ground stations from malicious attacks - not only from outside, but also from potential internal attacks.
As Günther Lackner, Senior Vice President for Space at Terma, explains:
“By integrating zero trust concepts into its modem and mission control systems, Terma is taking a major step towards future-proof ground segment security.”
For ground station operators, Terma SPECTRA SDR modem provides a system that grows and adapts with their missions. For organizations, it provides a cost-effective, future platform designed for mega-satellite constellations.
Combining scalability, flexibility, multi-link capability, Zero Trust security concepts, and a pay-what-you-need model, Terma’s SDR modem is laying the foundation for future software defined communication networks.