To plan space settlements, scientists redesign concrete

Can we construct with off-world materials?

In 1969, as Neil Armstrong stood on the lunar surface, a new era of space exploration began—or so we thought. After a fifty-year hiatus, we’re preparing to step onto the Moon and Mars with an even more ambitious goal: this time, we are going to stay. But once we land on new worlds, how will we build infrastructure to withstand their extreme environments?

The pathway to space colonization seems clear: build rockets for transport, orbital habitats, landers for surface missions, and machines to construct permanent settlements on new worlds. Timeline for this audacious endeavor? Mere ten years—a blink of an eye — to make leaps in civil engineering, construction, and manufacturing.

Use what you have on hand

As space colonization inches closer to reality, nations and private firms race for technological dominance. NASA’s nearly $100 billion Artemis program, China’s lunar ambitions, and SpaceX’s private-sector push are all advancing breakthroughs in materials and manufacturing methods to withstand radiation, extreme temperatures, vacuum, and low gravity.

On Earth, concrete is typically made by combining sand and gravel aggregates with binders like cement paste (a mix of water and limestone- and clay-based cement powder). However, transporting these materials off-world is impractical, with launch costs ranging from $2,720/kg (SpaceX Falcon 9) to ~$43,157/kg (NASA’s SLS), and even higher beyond Earth’s orbit.

Designing permanent space infrastructure requires balancing these costs with maximizing In-Situ Resource Utilization. To reduce costs, Lunar and Martian regolith (loose rock debris from meteoroid impacts and radiation) could serve as aggregates or even bases for cement-like binders.

Thus, “space concrete” and its manufacturing must endure harsh conditions beyond the safety of landers. Gravity on Mars and the Moon is lower than on Earth (38% and 17%, respectively), atmospheric protection from radiation is minimal, and temperatures fluctuate drastically (on the Moon’s equator, from 121°C by day to −133°C at night).

Current research efforts focus on improving mechanical strength, durability, and radiation shielding in concrete made with lunar or Martian soil. Several variations show promise. A 2024 review of extraterrestrial construction highlights geopolymer concrete as a strong contender due to its lower water and energy requirements, fast setting, and chemical stability. A 2023 study, found that lunar-like sand can be mixed with sodium hydroxide, or lye—an industrial chemical used in soap and cleaning products—to produce high-strength geopolymer cement with radiation shielding. Another 2024 study, shows highland lunar regolith as particularly suitable for the task.

Space concrete: not so concrete

Major challenges remain. Lunar soil’s heterogeneous composition complicates achieving a consistent mix. Even less is known about Martian soil, with samples to return post-2030. Binding agents like leading space geopolymers still need water, requiring bases near water sources, alternative hydration methods, and closed-loop water retention. Moreover, these materials have only been tested on simulants of Apollo-era Moon samples and Mars’s Curiosity rover data.

Traditional production methods fail in space: microgravity disrupts mixing, near-vacuum weakens materials, and extreme temperatures cause cracking. To tackle this, researchers are optimizing concrete curing in lower-than-Earth gravity. NASA’s Microgravity Investigation of Cement Solidification project studies cement hydration and hardening on the ISS under simulated lunar and Martian gravity. Returned concrete samples show increased porosity affecting density and strength—calling for further study.

For all this excitement, off-world construction remains a distant vision without scalable breakthroughs in materials. Mission safety still demands extensive research and testing —even as some in the industry lightheartedly reference the “one-way trip” mindset of such high-risk ventures. And the clock is ticking. On February 26, the House Committee on Science, Space, and Technology reaffirmed support for NASA’s lunar ambitions—while demanding higher speed. The next decade will determine whether space colonization takes its first real step or remains stuck on the launchpad.