Akash Shah analyses the necessity of HALO for NATO’s integration of space architecture. Here, he suggests that President Trump’s push for European self-reliance, data sovereignty and technical challenges could all explain the US absence from this initiative
NATO, for the most part, has treated space as a complementary domain to terrestrial military operations, supporting communications, navigation, intelligence, surveillance and reconnaissance (ISR), and missile warning. In 2019, however, it recognised space as an operational domain. The Organization is now transitioning into a new phase of space ambitions. The announcement and launch of Hybrid Alliance Layered Operations in Space (HALO) at the NATO Summit in Ankara 2026 marks a crucial step. But the absence from the initiative of the United States, a partner with the most extensive constellation of spacecrafts, is intriguing.
HALO is the next logical step after NATO’s flagship Alliance Persistent Surveillance from Space (APSS) programme. While complementary, both initiatives operate at different levels. APSS integrates data and services from national and commercial space assets into a virtual constellation, Aquila. HALO envisages the integration of sovereign, nationally controlled military satellites in a mega constellation. APSS is concerned simply with the output from space assets; HALO seeks to connect the underlying assets into a network.
The launch of Hybrid Alliance Layered Operations in Space (HALO) is a crucial step in NATO's space ambitions. But America's absence is intriguing
NATO's space capabilities have traditionally relied on the federated model. Satellites are owned and operated by individual allies, while NATO accesses their output via a joint architecture. APSS epitomises this model. The initiative achieved operational capability in December 2025, integrating commercial and national contributions into NATO’s intelligence stream and making them available for battlefield commanders. In 2026, APSS has 19 participating countries, including the US. And though it may have resolved the data-sharing problem, for a number of reasons, APSS in itself isn’t a panacea for the space integration problem.
Data may be shared through NATO’s mechanism, but spacecrafts are not interconnected. The state owns and controls satellites. Most important, however, is the discretion countries retain over shareable information. Satellite constellations are vulnerable to cyberattack, jamming and physical interference, and may lack the capacity to relay large quantities of data. Contrarily, a networked architecture like HALO could increase redundancy by distributing different functions across multiple national systems. A distributed constellation with clearly defined roles could provide reliable communication, broader coverage, faster data relay and, given the increasing contestation of the space domain, operational resilience.
A distributed constellation with clearly defined roles could provide reliable communication, broader coverage, and operational resilience
HALO is a conceptual evolution from a federated approach towards networking of spacecrafts. The distinction between APSS and HALO is from virtual constellation at the data level to operational integration at the spacecraft level. The distinction is significant when we look at it in parallel with Alliance Federated Surveillance and Control (AFSC) architecture. AFSC began development in 2026. It intends to create a ‘system of systems’ that networks multinational ground, air, maritime and space assets within the Organization. The three-tiered architecture – HALO connecting spacecrafts in a network, APSS creating a data pipeline for space-based intelligence and AFSC synergising space with the wider multi-domain surveillance network – aims to augment the cohesive operations in the long term.
Although an incremental step in the right direction, what stands out about HALO thus far is its constituent states. The initial eight participants are Canada, Denmark, Finland, Germany, the Netherlands, Norway, Sweden and Türkiye. Interestingly, the US is not currently a participant, despite previously participating in APSS and other NATO space initiatives like NORTHLINK and STARLIFT. The US possesses the largest and most sophisticated sovereign space architecture. This means it wouldn't particularly benefit from HALO for its national security needs. The initiative, however, is valuable for the Alliance, and for allies without an extensive space fleet of their own.
NATO hasn't offered an official NATO explanation as to why the US isn’t a participant country. But we could interpret it along the broader lines of contemporary NATO politics in which the US, under Donald Trump, is pushing for a more hands-on role from European partners.
As the country with the largest and most sophisticated space architecture, the US wouldn't particularly benefit from HALO. The initiative is more valuable for allies who lack an extensive space fleet
Sovereignty and information security are persistent problems. While the US already contributes to space-based surveillance and data within the APSS framework, there is flexibility in the nature and extent of data being shared with the Alliance. Integrating the spacecraft into the Alliance Framework raises different challenges, including variance in technical interfaces, classification and control of highly sensitive systems and derived information, along with a heightened risk of cyber and other means of interference. The absence of the US may therefore be a reflection, at least in part, of concerns associated with the integration of sovereign spacecrafts rather than simply sharing the selected intelligence output.
It is now time to address such concerns, particularly if they are the reason the US has opted out of HALO. In the past, allies have joined gradually. Indeed, Spain only recently became the 19th APSS participant. Regardless, HALO is a significant development in space integration into NATO’s operations.
If HALO expands and integrates with AFSC, NATO could move from a model of virtual integration of national assets towards a physically networked NATO operational architecture. That would substantially improve resilience, situational awareness and operational responsiveness in a contested space environment. But if national sovereignty, classification barriers and incompatible technical architectures prevent deeper integration, HALO could instead become another layer in NATO’s already complex federation of space capabilities.
