Illustration of the Moonlander in low orbit over the lunar surface as it prepares for an automated landing. Credit: Astrium

Illustration of the Moonlander in low orbit over the lunar surface as it prepares for an automated landing. Credit: Astrium

Sen—Space giant Astrium has presented its proposals for a European mission to soft-land a probe near the Moon's south pole. A concept study produced on behalf of the European Space Agency (ESA) will be considered by a conference of ministers next month.

The Moon, once thought to be bone dry, is now known to hold considerable quantities of water, particularly in shadowed regions of southern craters that never see sunlight.

In October 2009, NASA crashed a probe, LCROSS, and its two-ton Centaur rocket stage into a 60-mile wide crater called Cabeus and detected clear signs of water in the cloud of debris that the impacts produced.

And earlier this year NASA revealed fresh evidence from its Lunar Reconnaissance Orbiter spacecraft which suggests that as much as 22 per cent of Shackleton crater’s surface is made up of ice.

On the face of it, the presence of so much water makes the south polar region an attractive destination for future astronauts and the setting up of a lunar colony.

Water will not only be vital for life but can be broken down into hydrogen and oxygen to provide fuel. Finding a local source would remove the need to ship it expensively from Earth or to try to extract it from passing asteroids.

However, the south of the Moon is a particularly rugged area and the ice could be extremely difficult to get at. Shackleton, for example, is around 3km (2 miles) deep and so its floor and steep walls are a challenge to access.

While those hurdles will need much consideration, Astrium has designed a 500 million euro unmanned mission called Moonlander to touch down near the lunar south pole and explore what is there. It was awarded the contract to be prime contractor to execute the study.

Under Astrium's proposals, a dual-stage spacecraft would be launched by a Soyuz rocket from Kourou, French Guiana, in late 2018 to land the following year. Following separation from the launch vehicle, the two components of the spacecraft, the Transfer Module and the Lunar Lander Module, will arrive in orbit around the Moon just two kilometres above its surface. The Lander Module will then detach itself from the Transfer Module and touch down near the Moon’s south pole.

If that sounds easy, it won't be. Many key technologies to allow the mission to succeed still need to be developed. The probe will need to be self aware and detect and avoid potential hazards on the surface such as boulders, craters and steep slopes. It will need a complex propulsion system and an autonomous navigation system to allow it to land gently and precisely on the Moon.

The Moonlander releases a mini robotic rover on the lunar surface. Credit: Astrium

Astrium plan to build on their success in designing Europe's Automated Transfer Vehicle (ATV) which has three times demonstrated autonomous rendezvous and docking with the International Space Station.

Dr Michael Menking, Senior Vice President Orbital Systems and Exploration at Astrium, said: “As a demonstration of technology, the ATV mission proves the skills and experience which Astrium has in automated rendezvous and docking procedures. This study’s concept is based on ATV technology, and our unique expertise will enable us to develop the key technologies essential to landing an automated vehicle on the Moon."

Safely landing is the primary objective. But once there, and using solar energy, the mission will offer the chance to do serious science by placing a number of experiments and a small rover on the lunar surface. These will provide valuable information to help plan any future manned missions.

Tests have already begun on propulsion components for Moonlander at Astrium’s Lampoldshausen facility in Germany, and navigation system hardware and landing legs have been tested at the TRON (Testbed for Robotical Optical Navigation) and LAMA (Landing and Mobility Test Facility) facilities of the DLR Institute of Space Systems in Bremen.