Mini-constellations – smaller satellite networks typically numbering from a few to a few dozen spacecraft – could accelerate the deployment of new technologies in orbit by adopting a fundamentally different design philosophy than traditional approaches.

Rather than forcing payloads to conform to standardized satellite buses, manufacturers like Space Inventor are building configurable platforms that adapt to evolving payload requirements. According to SpaceNews, this approach is proving especially valuable for operators developing thermal imaging, space domain awareness, and in-orbit servicing capabilities.

Payload-first design: a different approach

The traditional satellite industry has long faced a familiar tradeoff. Engineers must often begin designing the satellite bus before every detail of the payload is finalized. Lock in the design too early, and the payload may need to conform to the bus. Allow the payload to evolve, and the bus may require extensive – and expensive – redesigns.

Space Inventor, a Danish manufacturer, is taking a different approach. When the European thermal-imagery company constellr began working with Space Inventor on its next generation of satellites, the requirements for the payload's size, weight and power were still evolving. Rather than demanding the payload fit a standardized bus, Space Inventor adapted its BIG CAT 600 bus as constellr's requirements changed.

"We needed a platform built around the payload, not the other way around," said Marius Bierdel, constellr's co-founder and vice president of program management. "Space Inventor's system-level approach means our thermal sensors perform exactly as designed once they're in orbit."

Modular design and in-house manufacturing

Space Inventor's BIG CAT family – which includes the BIG CAT 100, 300, and 600 platforms – is designed around modularity rather than fixed specifications. If a mission suddenly needs more power, improved pointing performance, or a new communications capability, Space Inventor can often accommodate these changes by swapping out bus modules rather than redesigning a spacecraft from scratch.

Critically, Space Inventor manufactures nearly all of its components in-house at its factory in Aalborg, Denmark – with the exception of propulsion systems. This control over design and supply chain reduces exposure to volatility and enables rapid iteration.

Consider a printed circuit board. If a new requirement calls for a modified PCB, Space Inventor can update the design, machine a revised housing, assemble the new component and test the change – all under the same roof. According to Jan Smolders, the chief commercial officer at Space Inventor, such a change ordered from an outside supplier might take about six weeks. Space Inventor can make the same change in roughly one week.

"Because we make everything in house, we can easily add new modules to facilitate changing requirements, very fast," Smolders said.

Space Inventor also maintains a stock of its components, allowing next-day shipping. This reduces the risk that a small component or supplier delay holds up spacecraft production.

Advantages for mini-constellation operators

For mini-constellation operators, this model makes it easier to change later satellites based on lessons learned from earlier ones. Unlike megaconstellations numbering in the hundreds or thousands, mini-constellations can target specific geographies or niche capabilities, making them well-suited to fields where technology is advancing rapidly.

The philosophy of iteration is especially helpful in rapidly changing fields such as thermal imaging, space domain awareness and in-orbit servicing. It also means Space Inventor can avoid locking in a design around requirements developed years before launch.

Military and defence applications

Space Inventor has also adapted its configurable approach for the defence community. Rather than only offering military customers a satellite bus, the company can pair a BIG CAT platform with a mission-specific payload to provide a turnkey system.

The company's defence-specific Apex Predator series includes BC Lynx and BC Leopard, two turnkey surveillance solutions built on its BIG CAT platform. Lynx is designed to detect radio-frequency emissions, geolocate their source and identify activity that may warrant further investigation. Leopard can then be tasked with capturing high-resolution optical or thermal imagery in the same area.

Space Inventor has developed a business case for detecting and investigating maritime activity in the heavily trafficked Baltic Sea, bordered by NATO members and Russia. There, Lynx satellites can identify anomalous RF emissions that could reveal dark vessels or help locate sources of GPS spoofing, then cue a Leopard satellite to collect additional intelligence.

"For the cost of one or two F-35s, you can actually get the intelligence to tell those planes where to go," Smolders said. "Affordable, proven ISR capability is ready to deploy in Europe today, with Space Inventor at the forefront of turning that capability into operational missions, but the decision-makers need to know about it."