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Objectives
The Data Relay Constellation (DRC) aims to significantly enhance satellite communications by deploying relay satellites that function as “ground stations in space”.
Its primary objectives include establishing European sovereignty in the manufacturing and operation of satellite communication infrastructure, thus reducing reliance on external entities. The project seeks a tenfold improvement in satellite telecommand and telemetry (TC/TM) capabilities, targeting at least 90% connectivity availability and minimal latency (<120 seconds nominally).
Additionally, the DRC is designed to revolutionise Earth Observation (EO) data transfer, ensuring continuous connections with speeds of 2.5 Gbps or higher. By combining optical inter-satellite links and robust Radio Frequency (RF) links (S-band, K-band), the constellation provides reliable, efficient, and rapid data relay, significantly shortening the decision-making loop for Earth observation applications.
Ultimately, the DRC fosters independent European capabilities, strengthens critical satellite infrastructure, and enhances responsiveness in satellite-based missions.
Challenges
Key challenges of the Data Relay Constellation include achieving reliable optical inter-satellite links and ensuring continuous high-speed communication despite satellite movement and alignment complexities. Managing signal interference, particularly with RF (S-band, K-band), presents technical hurdles.
Additionally, deploying strategically positioned ground stations globally requires addressing geopolitical, regulatory, and logistical challenges. Balancing cost-efficiency, technology maturity, and maintaining European sovereignty in space-based communications infrastructure adds complexity.
Lastly, ensuring compatibility and interoperability with existing and future satellite systems, while meeting ambitious latency and availability targets (>90% connectivity, <120-second latency), is critical.
System Architecture
The architecture of the Data Relay Constellation (DRC) consists of an integrated network comprising space, ground, and user segments. The space segment features node satellites in low Earth orbit, equipped with Optical Communication Terminals (OCTs) compliant with Space Development Agency standards, and robust S-band and K-band RF links. These satellites communicate with client satellites and each other via high-speed Optical Inter-Satellite Links (OISLs) at ≥2.5 Gbps, providing reliable data relay and minimal latency.
The ground segment includes a global network of strategically placed optical and RF ground stations, ensuring continuous connectivity and data throughput. These stations connect seamlessly to a centralised Mission Control Centre (MCC), responsible for satellite operation, monitoring, dynamic routing table management, and system optimisation.
The user segment provides an intuitive web interface and API, enabling efficient scheduling, monitoring, and management of satellite communications and data flows.
Collectively, this integrated architecture ensures continuous, high-speed connectivity, dramatically reduces communication latency, and improves data relay efficiency. The DRC’s system design addresses connectivity bottlenecks in traditional satellite communications, supporting real-time mission-critical decision-making and ensuring European sovereignty in satellite infrastructure.
Plan
The project plan follows structured phases:
- Phase A (Conceptual Design): Mission definition, system architecture, preliminary risk assessment (Milestone: System Requirements Review – SRR).
- Phase B (Preliminary Design): Subsystem specifications, technical trade-offs, and preliminary testing plans (Milestone: Preliminary Design Review – PDR).
- Phase C (Detailed Design): Final subsystem engineering, prototyping, and validation testing (Milestone: Critical Design Review – CDR).
Phase D (Assembly, Integration, and Testing): Manufacturing, subsystem integration, system-level testing, and launch preparation (Milestone: Launch Readiness Review – LRR)
Current Status
The Data Relay Constellation (DRC) project is currently in Phase B (Preliminary Design). Phase A was successfully completed, defining clear mission objectives, requirements, and initial architecture. Payload preliminary design is actively progressing and set for completion by June/July 2025, while platform design activities are on track, targeting completion by October/November 2025. Presently, subsystem technical trade-offs, risk mitigation, and validation simulations are underway. Preparations for detailed subsystem engineering and prototyping (Phase C) are about to commence, positioning the project for smooth transition toward detailed design and eventual operational deployment.
