ECHOES Digital Sky Demonstrator delivers groundbreaking results for air traffic management

In December 2025, the ECHIES Digital Sky Demonstrator concluded after nearly four years of collaboration, achieving what many considered a major step forward for aviation. The project successfully demonstrated that VHF voice and data communications could be delivered from space-a concept that had never before been proven in a real-world setting.

The project involved more than 200 professionals, directly and indirectly, drawing on the combined expertise of industry, ANSPs, research organisations, and technology providers, all working together to align innovation with real operational needs.

Thanks to close collaboration among the consortium and contributors as well as the co-funding of CINEA - European Climate, Infrastructure and Environment Executive Agency with the backing of SESAR JU , ECHOES turned an ambitious idea into operational reality.

Following the successful launch of two demonstrator satellites, IOD-1 and IOD-2, real-time trials with the participation of several airlines, CSPs, and ANSPs were conducted within the framework of the project. These trials focused on the operational performance of the technology and its integration into real ATM systems, validating the concept in a live environment.

A project built on collaboration

Throughout its lifecycle, ECHOES brought together a strong and diverse consortium, united by a shared goal: to prove that space-based VHF communications for ATM are not only possible, but operationally viable.

ECHOES stands as a clear example of what European collaboration can achieve when industry, ANSPs, research organisations, and institutional partners work hand in hand. The project benefited from continuous engagement across the ATM ecosystem, ensuring that operational, technical, and regulatory perspectives were all embedded. This collaborative approach ensured that validation activities reflected real scenarios in a solution shaped with - and for - the ATM community.

Members of the project during the Partners and Contributors Meeting held at Lisbon on May 2025.

Milestones of the project

Frequency approval

In December 2023, the International Telecommunication Union World Radiocommunication Conference approved the spectrum allocation for future space-based VHF communications services (voice and data) and surveillance for air traffic management. This approval is a fundamental enabler for the final solution, providing the regulatory foundation needed to move from demonstration to real-world application.

The work developed within ECHOES played a key role in this process, delivering essential data, insights, and inputs that supported the studies and helped demonstrate that space-based VHF services can safely coexist with existing aeronautical communications.

The first satellite in orbit

The launch of IOD-1 (In-Orbit Demonstrator-1) on March 14^th 2025 marked a turning point for ECHOES. As the project's and SESAR SJU's first satellite, IOD-1 took the concept of space-based VHF communications into orbit, enabling the first demonstration activities.

Loud and clear: The first-ever satellite-based VHF voice communication

With IOD-1, the team achieved a world first for aviation: a conversation between a pilot and an air traffic controller in real time using VHF signals transmitted from space. The demonstration took place only two months after IOD-1's launch, during tests conducted within the framework of ECHOES over the Atlantic Ocean. A pilot exchanged real-time voice messages with an ENAIRE air traffic controller at the Canary Islands Area Control Centre, using standard VHF procedures. The system was tested under real operating conditions, with the support of several airlines including Air Europa, Iberia, TAP Air Portugal, Plus Ultra, TUI and Vueling.

Second satellite in orbit

The launch of IOD-2 on June 23rd built directly on the success of the first demonstrator. With broader capabilities, IOD-2 expanded the scope of in-orbit testing and amplified the tests with ANSPs, CSPs and airlines.

Unlocking VHF Data-Link from space

The validation of space-based VHF voice was only the beginning. ECHOES achieved another world first with the validation of VHF data communications via satellite. VHF data plays a key role in many ATM functions, from controller-pilot data link communications to trajectory management and system-to-system information exchange, enabling clearer, more efficient, and less congested communications for ANSPs, CSPs, and airlines.

These demonstrations confirmed that both voice and data services can be delivered reliably from space, opening the door to more resilient and seamless communications for air traffic management, particularly in remote and oceanic regions.

Project officers witness live trials

ECHOES also welcomed project officers from CINEA and the SESAR Joint Undertaking to the ENAIRE Control Centre in Gran Canaria, one of the key operational sites for the project's flight trials. During the visit, they witnessed a live space-based demonstration activity. The visit highlighted the full operational reality behind ECHOES: the infrastructure, systems, procedures, and people working together to make the solution possible.

A validated, mature solution reaching TRL 7

ECHOES has reached Technology Readiness Level 7 (TRL 7), which confirms that the space-based VHF solution is no longer just a concept and has been demonstrated in an operational environment.

Achieving TRL 7 means that the technology has been implemented, integrated, and tested under conditions that closely mirror real ATM operations. The trials captured actual procedures, performance requirements, operational constraints, and real-world use cases, providing robust evidence of the solution's reliability.

In a safety-critical domain like aviation, reaching TRL 7 is essential: it builds confidence across ANSPs, airlines, CSPs and regulators, and signals that ECHOES has delivered a solution ready to progress toward certification, standardisation, and eventual operational deployment. Additionally, it turns the project's vision into a tangible, operationally relevant reality for the whole industry.

End users' perspectives

The project's results generated a strong and tangible impact among future end users of the solution. Pilots, air traffic controllers, and airline operations managers who participated in the trials highlighted the clear benefits of space-based VHF communications, particularly in terms of coverage and continuity of service.

From the cockpit to the control room, feedback consistently pointed to the easy integration of the solution as well as the quality of the communications exchanged. In a video created within the framework of the project, end users gave their first-person testimony. Watch it here.

Closing a chapter, opening the next

To close the project as it deserved, Startical, the project leader, organised the ECHOES final event, held in Madrid and online on 17 December 2025. The event was a moment to reflect, connect, and look ahead. Partners and contributors came together to review key results, share lessons learned, and discuss how ECHOES outcomes can support future ATM developments.

Demonstrations, technical insights, and open discussions reinforced a common message: the work carried out in ECHOES does not stop here. Its results feed directly into ongoing conversations around how the space-based VHF solution can make aviation safer and greener, opening the door to the next chapter of connected, global air traffic management.

More about ECHOES