More than 8,000 tons of space debris endanger all space activities. Satellite operators pay more than €14 mio a year for evasive maneuvers and 1 billion USD in insurance premiums. But beside a costly thread, space debris is a valuable resource, too which does not need to be launched into space again. With affordable efforts, space debris could be transported from its orbit to the Moon for recycling to complement ISRU activities. Since the debris is picked up in orbit, small propulsion units (space tugs) are sufficient for the transport to the Moon, which are to launch cost-effectively with European rockets. Calculations from the Technical University Berlin and Orbit Recyling show, that a prize per kg of regained aluminum on the Moon of less than 150,000 euro is achievable. Orbit Recycling identified more than 130 tons of aluminum which could be regained from Ariane upper stages alone. Casting aluminum in regolith is a simple process which could be fully automated as a preparation work for human missions. This allows the manufacturing of large or fragile objects needed for any type of Moon station like walls or power lines. In addition, initial experiments show, that the material combination of aluminum and regolith has several advantages over regolith alone. Especially the heat distribution and heat capacity are dramatically enhanced, which allows the construction of a large heat storage system as a power supply for a Moon station. In the proposed co-funded research, we would like to analyze the achievable material properties of different aluminum and regolith composites. The goal should be to identify the best material ratios for the different usage scenarios like the proposed heat storage systems or for construction elements. Ideally, similar material properties like reinforced concrete will be achieved to demonstrate, that the combination of ISRU and metal (from space debris recycling) will be the perfect combination for a sustainable human settling on the Moon.
