An Italian receiver to be installed on the Moon to test future lunar communications LuGRE, lunar connection tests

by Giulia Bonelli

Following the success of the Artemis 1 mission, the return of manned missions to the Moon is drawing closer with the goal to establish a long-term human presence on our satellite. In addition to the scientific and technological challenges regarding the safety of future lunar crews, the project will require the development of reliable lunar telecommunication capabilities, enabling astronauts to live, move and work on the Moon while keeping in constant contact with each other and with Earth and enjoying the support of several robotic and automated systems. In this respect, the European Space Agency has been working for several years now on the so-called Moonlight project, which envisages a constellation of lunar satellites that would provide navigation data on our satellite, a kind of lunar GPS. The Lunar Pathfinder satellite, scheduled to launch by the end of 2024, will be the first step in this direction.

In the meantime, final trials are being conducted to ensure future lunar connectivity. Italy is a key player with LuGRE, a joint ASI-NASA research and technological development project, which is designed to use the GPS and Galileo signals on the Moon. The project is part of the Artemis program initiatives and the corresponding Italy-US agreements.

LuGRE, which stands for Lunar GNSS Receiver Experiment, is a Software Defined Radio (SDR) Receiver operating on a dual frequency and dual constellation. It will travel to the Moon as a payload aboard the Blue Ghost 19D lander, manufactured by Firefly, a US company, for NASA's Commercial Lunar Payload Services (CLPS). In recent weeks, the Italian Space Agency, ASI, and NASA have formally delivered the Flight Model of the full LuGRE payload (receiver and antenna) to Firefly to start the integration process. Nine other scientific and technological experiments will be aboard the lander together with LuGRE. The payloads will be delivered to the Mare Crisium region of the Moon in June 2024.

"The goal of LuGRE is to travel as far away as possible from Earth and be delivered on the lunar surface in order to collect GPS and Galileo measurements in transit between Earth and the Moon. GPS and Galileo signals are designed to be delivered on the surface of our planet but not outside its orbit," said Mario Musmeci of the Engineering Department of the Italian Space Agency (ASI) and coordinator of engineering activities for the ASI-NASA Artemis partnership program.

Musumeci also said that: "To date, NASA has been experimenting with signal reception at a maximum distance equal to 30 Earth radiuses, that is approxi- mately halfway between the Earth and the Moon. Picking up the signal on the Moon, or even making a specific positioning on our satellite, as we do with our smartphones, is a great challenge since this experiment has never been carried out before."

Developed for ASI by Qascom, a company located in the Veneto region, LuGRE is a device no bigger than 25 centimeters with a mere 1.5 kg weight and equipped with highly sophisticated miniaturized technology featuring truly innovative processing algorithms, and designed to capture, track and process GPS and Galileo signals while traveling to the Moon, in cislunar and lunar space.

"Once the lander is on the Moon, we’ll wait for NASA's go-ahead to turn on our receiver on the Moon,'" said Musmeci."We will have 14 days, that is one lunar day, to try to capture, and analyze the GPS and Galileo signals, whose power when they reach Earth is about one-millionth of that of mobile phone signals. The signal will be extremely weak on the lunar surface, and could be confused with background noise. It is a bit like trying to hear the music of an entire orchestra standing in the street, outside the concert hall, through a tiny slit, and with all the background noise of the city. This is the spirit with which we will embark on the Earth-Moon journey to try and intercept the GPS and Galileo signals."

It is a highly complex technological challenge, that aspires to add yet another fundamental building block in the construction of the future lunar communication system. LuGRE will make it possible to understand how the GPS and Galileo systems could be used also for manned lunar missions, for lunar satellite constellations and, in general, for the entire architecture now being developed for the Artemis program.

In his final comments, Musmeci said: "This is not just a technological experiment. Its goal is to characterize the signals now being used by satellite navigation for a future system in orbit around the Moon. The Artemis program envisages a lunar space station, the Lunar Gateway, which will orbit the Moon. A lunar base is scheduled to be built at the south pole of the Moon. Several landers will go back and forth from the lunar surface.

The entire infrastructure will need to be supported by a complex communication system, enabling interconnection between its different elements and with the control centre on Earth.

They will need navigation, positioning, and timing services to synchronize all the different activities. Therefore, navigation services are key for future human habitation on the Moon.

And this is why with LuGRE we plan to start testing lunar connectivity.