No more radio silence behind the moon? This is the solution

Recently, the world held its breath for forty minutes as the Orion capsule disappeared behind the Moon during the Artemis 2 mission. During this period, no communication was possible between the crew and Earth. The Moon’s immense mass blocked all radio signals. For technicians on Earth, these are the most nerve-wracking moments of a mission. The risk is high when astronauts are completely on their own without support from mission control. The European Space Agency (ESA) plans to change this in the future. With the ambitious Moonlight program, Europe is building a communication network that will make the Moon accessible anytime, anywhere.

The terrifying silence of the far side

The Goonhilly Earth Station in Cornwall recently played a key role in tracking the Orion capsule. For the first time in decades, this station tracked a spacecraft with people on board heading toward the Moon. Matt Cosby, the station’s technical director, described the tension that comes with the loss of the signal. When a capsule dips behind the moon, it disappears into what is known as a communication shadow. For forty minutes, no data transmission or voice communication is possible. The technicians in Cornwall can only wait and hope that everything goes well. Only when the spacecraft reemerges on the other side is the connection restored. This period of uncertainty is currently unavoidable due to the direct line of sight required for radio waves. This is acceptable for a short test flight, but for complex operations it poses an unacceptable risk.

A sustainable infrastructure for the Moon

NASA and other agencies are working on the construction of a permanent lunar base. For a sustainable presence, a reliable 24-hour connection is essential. This applies not only to the visible side of the Moon, but also to the far side. Scientists are very interested in exploring these unknown areas. However, without a communication network in orbit around the Moon, these areas remain dangerous and difficult to reach.

ESA’s Moonlight program is specifically designed to overcome this barrier. The goal is to create an infrastructure comparable to commercial networks on Earth. As a result, future missions will no longer need to carry their own heavy communication equipment. They can simply “log in” to the European network to send data back to Earth.

The technology behind the Moonlight network

The Moonlight program was officially launched during the International Astronautical Congress in 2024. The core of the system consists of a constellation of five satellites. One satellite is specifically designed for high-speed data communication. The other four satellites are intended for navigation services. This network spans a distance of approximately 400,000 kilometers between Earth and the Moon. To ensure the connection, three special ground stations are being built on Earth. One of the key partners in this project is Telespazio, which leads an industrial consortium.

The network’s initial focus is on the Moon’s south pole. This area is strategically important due to the presence of water ice in deep craters. Water is a crucial resource for producing fuel and oxygen. The satellites ensure that landers and rovers in this rugged terrain always know their exact position.

Phased Rollout

The first major step is the launch of the Lunar Pathfinder in 2026. This satellite will serve as a precursor and conduct the first communication tests. Initial operations of the full Moonlight network are scheduled to begin in 2028.

A year later, in 2029, the first tests for international collaboration are planned. ESA is working closely with NASA and the Japanese organization JAXA. Together, they have established the LunaNet framework. These are global standards that ensure different systems can communicate with one another. It is comparable to the roaming agreements between mobile providers on Earth. This allows an American rover to use a European satellite without any issues.

The entire system is expected to be operational by 2030. This coincides with the planned increase in the number of lunar missions. It is expected that more than 400 missions will travel to the Moon over the next twenty years. By then, a universal network will no longer be a luxury, but an absolute necessity.