NATO’s Ankara Summit in July marked a significant advancement in interoperable, multinational satcom systems with the announcement of the Hybrid Alliance Layered Operations in Space (HALO) initiative. Looking up at a sky full of satellites, governments are asking how to harness new and existing capabilities to form a coherent, hybrid network.

Government programs for hybrid, interoperable satcom include Europe’s sovereign commercial-government constellation IRIS², the U.S. commercial-military Space Development Network (SDN) and NATO’s multinational Arctic military satcom program NORTHLINK. HALO, launched by Canada, Denmark, Finland, Germany, the Netherlands, Norway, Sweden and Türkiye, envisions multinational data transport and missile tracking to improve “connectivity and integration of sovereign, nationally owned and controlled military satellites into a networked mega constellation,” according to a release.

Initiatives to pool owned satellite resources “reflect a political reality, [that] sovereignty over space assets remains non-negotiable,” said Arthur Kvalheim Merlin, VP of KSATlite, KSAT’s ground-as-a-service business for commercial smallsats. That political reality is “colliding with an operational reality, which is that no single nation’s fleet is resilient or large enough on its own,” he told Constellations.

Programs like HALO and NORTHLINK represent a change in architecture from traditional capacity arrangements, like NATO’s Satcom Services 6th Generation (NSS6G) government lease program or its Project 7 commercial lease framework. Building on the foundations of dedicated bandwidth agreements, satcom delivery is shifting toward networkization and interoperability within the ground segment and network control infrastructure, not just in orbit.

“The differentiator isn’t so much the satellites themselves anymore, it’s the ability to orchestrate them,” Alix Rousselière, Novaspace strategy consultant for satcom and the ground segment, told Constellations. “The materialization of these multi-network, multi-orbit dreams really comes down to the ground segment. It’s the network that makes the dream work.”

The challenge of interoperability lies more in data and software than antennas and hardware, said Merlin, noting that standardized interfaces, data formats and orchestration logic “are the real bottleneck, not RF hardware.”

In a statement to Constellations, NATO Communications and Information Agency (NCIA), which leads digital transformation and technology procurement for the alliance, acknowledged that future allied satcom will require a combination of modern ground infrastructure and software-defined technologies. Specifically, these include multi-band, multi-orbit terminals, common service management and orchestration capabilities, automated resource management as well as virtualized network functions, digital modems and cloud-based architecture for flexibility and vendor diversity.

“As NATO’s operational environment evolves, the challenge is not simply increasing satellite capacity, but ensuring sovereign, Allied and commercial capabilities can operate together through a secure and interoperable communications architecture,” said an NCIA official.

As eight nations begin the exploratory period for HALO—and more may join—the next steps will be to frame the multinational architecture and develop requirements around core functionalities, cost and scope. According to a NATO official, the transport layer will be the first phase of HALO’s development. This will be built “from scratch—connecting to existing as well as future national assets and capabilities,” including ties with other national initiatives, like the U.S military’s Proliferated Warfighter Space Architecture (PWSA).

Aggregating Demand and Requirements

As an aggregator of demand across 32 nations and a setter of standards and requirements, NATO has powerful leverage to both drive interoperability and steer the commercial market. Industry players are tracking increased government demand for hybrid space architectures, combining commercial solutions and sovereign control.

According to Michèle Beck, Telesat’s senior vice president of Canadian sales, governments “are increasingly looking for sovereign-adjacent solutions.” Such systems tend to be lower cost, have less operational complexity and offer greater resilience in contested space.

“Recent conflicts have reinforced the need for communications architectures that can continue operating even when assets or infrastructures are disrupted or compromised. At the same time, nations need to share data and coordinate operations with allies at a pace and scale that wasn’t required a decade ago,” Beck told Constellations. “That is pushing governments toward architectures that are distributed, interoperable, highly resilient and designed to operate seamlessly across coalition partners’ networks and infrastructure.”

Telesat, which was recently awarded a 2.3 billion CAD ($1.6 billion) Arctic satcom contract, is planning a 44% expansion of the Lightspeed LEO network to 225 satellites. The Arctic contract, under the Enhanced Satellite Communications Project – Polar (ESCP-P), covers Mil-Ka-band capacity for the Canadian Armed Forces, with support for requirements that can also serve the broader needs of allies. Lightspeed, scheduled to deploy in Q1 2028, will provide a global, dual-use architecture.

Sovereignty and Control in Shared Infrastructure

In addition to aligning technical requirements, multinational, hybrid satcom systems raise thorny questions about ownership, operational control and sovereignty. While the answers are largely political, industry has a role in reducing operational friction.

“The key question is not simply how many satellites you have, but how you assure the service and control the data,” Steve Mills, Eutelsat’s vice president for global government, told Constellations.

Eutelsat has seen strong demand from government and defense customers for multi-network, multi-orbit architectures, with total government services revenues up 17.7% year-on-year. The company deploys data sovereignty schemes to secure shared infrastructure and has invested significantly in ground infrastructure security over the last 18 months.

Merlin emphasized the preeminent need for security, encryption, segmentation and access control for multinational networks, noting these features must be designed in “from day one,” not added later as an afterthought.

“Governance is often just as hard as the engineering,” he warned. “[D]eciding who tasks what, in what priority order, under what crisis conditions, is the part that sinks multinational programs as often as technology does.”

Sovereignty and related issues of space data sharing remain a point of contention among allies, particularly the United States. Despite public statements about loosening classification constraints with trusted allies, the U.S. military continues to face “persistent challenges related to information sharing” with partners and allies for joint space operations, according to a recent government report.

“The word sovereign gets floated around very easily, but it really comes down to who controls what layer of the stack,” Rousselière said. “Who controls the network? Is the orchestration centralized? Is there some kind of federation? Can sovereign users retain certain aspects of mission control while leveraging commercial infrastructure?”

NATO currently employs a federated approach for its Alliance Persistent Surveillance from Space (APSS) program, aggregating intelligence, surveillance and reconnaissance data from commercial and government sources. According to a NATO official, a federation scheme “is one of the options on the table” for HALO. Though satcom presents unique challenges, APSS offers a framework for a shared, hybrid ecosystem among allies.

5G MILSATCOM?

As the largest global consumers of satcom and satellite services, militaries have an outsized role in shaping specifications and standards. Industry leaders say this creates a push-pull relationship between government requirements and commercial innovation. Governments must navigate the tension between market creation and over-standardization, while industry must balance private-sector agility against market fragmentation.

“If governments want to enable coalition operations, hybrid architectures and multi-orbit networks, industry needs a clear understanding of the standards and interfaces those systems will be expected to support,” said Beck. Transparent requirements make it easier for industry to invest capital and build to scale, she added. “At the same time, it’s important to avoid a future where every nation develops its own unique framework or technical standard.”

As 5G becomes the de facto open architecture for satellite operators and service providers, its benefits are increasingly relevant to the defense sector. Earlier this year, NATO formally adopted a 5G Standardization Agreement (STANAG), defining core procedures, interfaces and protocols for military-grade 5G-enabled infrastructure. While there was no mention of satcom in NATO’s announcement, the standardization of 5G Non-Terrestrial Networks (5G NTN) makes 5G MILSATCOM a likely next step, said Stuart Daughtridge, vice president of advanced technology at Kratos and director and chair of the Digital Intermediate Frequency Interoperability (DIFI) Consortium.

For hybrid MILSATCOM, building on commercial 5G is “in some ways easier” than other networking methods, Daughtridge said. “You’re not innovating a new capability. The technology is done. There’s a clearly defined standard. You may still do Mil5G at the waveform level, but your backend, roaming, how you come into the network, that is all handled through 5G standard systems.”

Widescale industry adoption of 3GPP’s 5G NTN standards created a common language between satellite operators and the broader telecommunications industry, said Rousselière. “It reduced uncertainty and … it really encouraged investment. We’re seeing massive investment from both terrestrial and satellite players. That has really been driven by this confidence boost and the standards that underpin it.”

Open Standards, Open Markets

Beyond 5G, industry adoption of DIFI has had a similar effect of opening the market by shifting away from proprietary vendor solutions. As a common standard for digitizing and transporting analog intermediate frequency signals, DIFI “creates a robust supply chain for the user community,” said Daughtridge.

Defense organizations like NCIA and U.S. Department of War agencies joined DIFI in large part “because it’s the only way to ensure interoperability and avoid vendor lock,” Daughtridge said. A more diverse vendor base is becoming increasingly important as agencies prioritize joint operations and move toward distributed, software and cloud-native architectures.

An NCIA official cited DIFI as an example of the agency’s support for open, standards-based approaches that “promote interoperability, flexibility and vendor diversity while reducing dependence on proprietary solutions.” DIFI standardization also reduces the cost and complexity of integrating multi-vendor equipment, the official added, and enables the transition to software-defined or virtualized ground for hybrid, multination, multi-orbit and multi-band satcom.

Merlin explained that without common standards, there is no way to effectively scale a multinational network. Without standardization, interoperability becomes a “bespoke integration nightmare” with point-to-point interfacing between every pair of systems driving cost and schedule.

In addition to practical economics, standardization is also vital to resilience. Failover across constellations and orbits can be automated and handled seamlessly when there’s a common baseline for terminals, waveforms and data formats.

Interoperability as a First Principle

The satcom industry is once again undergoing a shift in how service is provided, moving from sovereign, centralized capacity leasing schemes to federated, hybrid models built on network flexibility and secure multi-tenancy. In response to demand for these capabilities and the movement toward common standards, industry is reshaping satcom systems from the ground up.

“There’s a lot of discussion about hybrid and multi-orbit architectures, but the reality is that interoperability must be engineered from the start,” said Beck. “It requires shared standards, aligned security frameworks, and networks that are designed from the outset to work together.”

Establishing a baseline of standards, protocols and interfaces is increasingly a first principle for shared infrastructure. IRIS², which has faced criticism for a slow start, but was designed from the outset to support secure, 5G-standards-based communication and data services, is a core example of interoperability as a starting point.

“[IRIS²] reflects a broader European objective: strengthening European strategic autonomy through shared sovereign infrastructure,” said Mills. “[I]t highlights that sovereignty and interoperability can go hand in hand, particularly when programs are designed to leverage both public-sector objectives and commercial expertise.”