NASA's JPL, Italy's Argotec Detail Plans for Near-Continuous Lunar Communcations Coverage

Scientists and engineers at NASA’s Jet Propulsion Laboratory (JPL) have partnered with a team at Italian aerospace specialist Argotec to put together an orbital satellite constellation to offer improved communications capabilities — but with a view of giving the moon, rather than the Earth, blanket coverage.

The team, which includes project manager Faramaz Davarian at NASA's end and Alessandro Balossino as the head of research and development at Argotec, is aiming to get ahead of the need for lunar missions — including, one day, moon bases and orbital space stations — to stay in contact with Earth by covering the whole of the moon's surface with reliable, high-performance connectivity available at a fraction of the power required to transmit signals directly from the moon to Earth.

The proposed solution: Andromeda, a constellation of 24 relay satellites split into four frozen elliptical orbits ranging from 447 miles to 5,027 miles above the surface of the moon. Each satellite will provide a high-performance relay service, allowing low-powered radios on the moon to send and receive messages from Earth — continuously, in the case of the lunar poles, dropping to around 79 per cent coverage at the equator.

"A shorter communication distance means a person or robot on the surface does not need a powerful terminal to maintain a low-data-rate link with Earth," Davarian and Balossino write of the project for IEEE Spectrum. "Instead, they can employ the relay satellites to bounce their signals to Earth using a small communications terminal.

"Relay satellites also mean that humans at two different locations on the surface can talk to each other without noticeable delay. Without relay satellites, a call would have to travel to Earth and back, taking about 3 seconds round trip."

At present the team is working on finalizing the design of the satellites, which will use commercial off-the-shelf hardware where possible and feature a novel metasurface antenna designed to improve performance while reducing weight and size — and which, its inventors explain, can be 3D printed — and on developing the required software for S-band, X-band, and K-band communications.

"Our proposed relay network would only be a first step," Davarian and Balossino explain. "In a more distant future, humans on the moon should be able to send and receive texts, make phone calls, and stream data at will. Similarly, robots and sensors should be wirelessly connected just like IoT devices are on Earth. Robots would be controlled remotely, and sensors would automatically upload their measured data."

More information is available from IEEE Spectrum's article.