The Collaborative Research Centre (CRC) 1667 "Advancing Technologies for Very Low Altitude Satellites (ATLAS)" is focused on overcoming key scientific and engineering barriers to make Very Low Earth Orbits (VLEO), ranging from approximately 200 to 450 kilometers in altitude, accessible for sustainable satellite operations. VLEO offers significant advantages for satellite services critical to today’s knowledge, information, and communication-driven society. Additionally, these orbits offer the advantage of enabling satellite operations without exposure or contribution to the increasing contamination of traditional orbits with space debris.
However, maintaining long-term, economically viable satellite operations in VLEO presents substantial challenges due to the distinct environmental characteristics of the lower thermosphere. Notably, the high and variable aerodynamic drag in this region causes rapid orbital decay, necessitating a combination of active and passive drag mitigation techniques to sustain satellite altitude. Despite its benefits—such as the "self-cleaning" nature of VLEO through atmospheric decay—operational viability in this orbit has been hindered by short satellite lifespans.
The CRC ATLAS aims to address these challenges, bringing together interdisciplinary expertise to pioneer solutions that will enable extended operations in VLEO, ultimately unlocking the potential of this promising orbital zone.
C03: Extremely High Data Rate Communications
The subproject focuses on addressing the unique communication challenges posed by Very Low Earth Orbit (VLEO) satellites, particularly the need for high data rate links due to the reduced overpass times of VLEO satellites over ground stations. In VLEO constellations, rapid and reliable communication—both between satellites (intra-constellation links) and with ground stations or satellites in higher orbits—is essential. This communication is critical for transmitting payload data (such as sensor information, internet services, and distributed computing) as well as for supporting auxiliary functions like tracking, telemetry, and dynamic system reconfiguration.
Achieving extremely high data rates is a key requirement for applications such as the direct offload of raw sensor data (avoiding energy-intensive onboard processing) and delivering fast, global internet through a satellite-based backbone. To support these demands, this project explores high-frequency millimeter-wave (mmW) bands ranging from 40 to 110 GHz (V-, E-, and W-band), which provide the necessary bandwidth for these ultra-high data rate links.
Recent advancements in miniaturized, cost-efficient millimeter-wave monolithic integrated circuit (MMIC) technologies have made it feasible to develop compact, wideband transceivers that can meet the stringent requirements of VLEO satellite communication. This subproject aims to leverage these developments to enable the high-throughput, reliable communication systems necessary for future VLEO satellite constellations.
The project investigates several critical research questions:
- System Gain Requirements: Given the dynamic link budgets and atmospheric attenuation in VLEO, what are the necessary specifications for system gain, including output power, receiver noise, and antenna gain, to maintain high-quality links?
- Ground Station Feeder Links: What conditions must be met for mmW feeder links to ground stations to ensure compatibility with passive radio astronomy services and terrestrial communication systems?
- Performance of Key Components: What performance levels can be achieved in essential mmW analog front-end components—such as power amplifiers, low-noise amplifiers, and transponders—using advanced silicon and compound semiconductor technologies?
- Comparison with Laser-based Transceivers: What advantages do mmW transceivers offer compared to laser-based communication systems, and how might combining mmW and laser frequencies enhance transceiver performance?
Workpackage
Trade-off assessment of state-of-the-art static and dynamic link budgets for VLEO constellations
Evaluation of candidate transceiver architectures. Assessment of system relevant metrics
Design and test of key building blocks of on-board transceivers for VLEO applications
Planned Collaborations
Mark Neff
M.Sc.Research Assistant