Pre-Phase A Mission Report
Master of Science in Space Engineering
University of Pisa Academic Year 2023/2024
HERMES is a commercial constellation of four satellites operating in a southern Halo orbit around the Earth–Moon L2 point (EML2). The mission provides:
- Continuous, high-data-rate relay communications between Earth and the lunar far side
- A Lunar Navigation Satellite System (LNSS) for precise positioning of rovers, landers, and future infrastructure
- Support for upcoming lunar missions (NASA Artemis, CNSA, ISRO, ESA, and private operators)
- Data rates up to 5 Gbps (Moon → spacecraft) and 1 Gbps (spacecraft → Earth)
- Continuous visibility of both Earth and the lunar far side
- Scalable architecture with potential for expansion
The system consists of four identical satellites placed in a southern Halo orbit around EML2, with a Z-amplitude of approximately 25,000 km.
- Minimum number of satellites required for reliable LNSS triangulation
- Excellent geometric dilution of precision (GDOP)
- Reduced station-keeping requirements
- Heritage from missions such as Queqiao, LUMIO, and EQUULEUS
- Orbital period: ~15 days
- Optimized for central and southern far-side coverage, with emphasis on the lunar South Pole
Each satellite has a dry mass of approximately 200–290 kg and includes:
- 9 primary antennas (Earth- and Moon-facing panels) + 8 redundant antennas
- COTS patch arrays (S, X, Ka, and L bands)
- LNSS navigation signal generation using atomic clock technology
- Chemical propulsion (hydrazine) for halo orbit insertion
- Electric propulsion (Krypton Hall thrusters) for station-keeping
- 4 reaction wheels
- 16 × 1 N hydrazine thrusters
- Pointing accuracy: ≤ ±5°
- ~2.5 m² GaAs solar arrays
- Two 200 Wh Li-ion batteries with thermal heaters
- Passive thermal control using MLI and aluminized Kapton
| Parameter | Value |
|---|---|
| Dry mass (per satellite) | 200–290 kg |
| Propellant | ~76 kg |
| Peak power | 900–1030 W |
| Lifetime | ≥ 7 years (+50% extension) |
| Launcher | Falcon 9 (2029) |
| Estimated total cost | ~1 billion € (10-year mission) |
The HERMES architecture is designed for scalability:
- Addition of 4+ satellites in a northern Halo orbit
- Increased coverage and redundancy
- Enables:
- Lunar GPS-like navigation
- High-bandwidth lunar communications network
- Continuous support for lunar bases
Report/— Full Pre-Phase A report (PDF + appendices)Poster/— Mission poster
Last updated: May 2024