Lunarcrete

Lore & Background

Lunarcrete would use lunar regolith as aggregate, with cement manufactured from lunar rock high in calcium content. Water would either be supplied from off the Moon or produced by combining oxygen with hydrogen from lunar soil. In 1986, Lin et al. used 40 g of lunar simulants to produce lunarcrete, curing it with steam on a dry aggregate/cement mixture. That lunarcrete withstood compressive pressures of 75 MPa and lost only 20% of that strength after repeated vacuum exposure.

In 2008, Houssam Toutanji and Richard Grugel used a lunar soil simulant to test sulfur-based lunarcrete, which required no water. The sulfur, obtainable from lunar dust, was heated to 130–140 °C. After 50 temperature cycles from −27 °C to room temperature, the simulant lunarcrete withstood 17 MPa, potentially raised to 20 MPa with silica reinforcement.

Casting lunarcrete would require a pressurized environment to prevent water sublimation. Proposed solutions include steam injection or a pressurized fabrication plant. Lunarcrete lacks tensile strength, but lunar glass or imported Kevlar could serve as reinforcement. David Bennett noted that lunarcrete production would require less energy than steel, aluminum, or brick, and that it absorbs gamma rays and is unaffected by extreme temperature variations.

Reader's Guide

Lunarcrete represents a key concept for in-situ resource utilization on the Moon, potentially lowering the cost of lunar construction by using local materials. The idea has evolved through multiple proposals, including water-based and sulfur-based formulations, each with trade-offs. Sulfur concrete avoids the need for precious water but offers less radiation protection and is vulnerable to high lunar surface temperatures. AstroCrete, using human serum albumin as a binder, offers another alternative for both Moon and Mars. While no industrial-scale production has occurred, small-scale tests with actual regolith and simulants have demonstrated feasibility. The concept remains hypothetical but influential in space architecture and planetary construction planning.

Did You Know?

• Sulfur-based lunarcrete, tested in 2008, required heating sulfur to 130–140 °C and withstood 17 MPa after 50 temperature cycles.
• AstroCrete uses human serum albumin from blood as a binder and can achieve compressive strengths up to 40 MPa with added urea.