Blue Origin's lunar lander mockup is ready for NASA Artemis astronaut training
A notional illustration of a moon base. (Image credit: NASA) GOLDEN, Colorado – Here on Earth, centuries of accumulated engineering knowhow, hard-learned lessons, and societal evolution have shaped a robust framework of building standards that govern how we build and maintain buildings today.But now, as humanity prepares to put in place a "sustained presence" on the moon, how do we guarantee the safety and integrity of structures built in an environment for which no such tradition exists?At the 26th Space Resources Roundtable held June 2-5 on the campus of the Colorado School of Mines, one expert says what's needed is a lunar building code, the development of specific design criteria for the moon.What's shaking? Both NASA and China's space agency are planning to build habitats, landing pads, equipment shelters, and tall towers on the moon. But all that construction could be off to a shaky start, suggests Nerma Caluk, an engineer and lunar specialist for Skidmore, Owings & Merrill, an architecture and structural engineering firm in San Francisco, California.Caluk said there's a need to leverage terrestrial building experiences."On Earth, structural systems rely on strong gravitational acceleration to resist seismic lateral forces through both foundation friction and overturning stability. However, on the moon, the gravitational field strength is reduced to just one-sixth of Earth's surface gravity," Caluk told Space.com.Because seismic inertial forces are governed purely by a structure's mass rather than its weight, the lateral demand on a structure remains fully active while its gravitational restoring capacity is substantially diminished, Caluk added."Low-profile surface structures risk translational sliding across poorly characterized regolith interfaces, while taller vertical structures face significant overturning vulnerability, as the moon provides only a fraction of the gravitational restoring moment available in a terrestrial seismic environment," said Caluk.Here on Earth, structural engineers routinely design typical building systems to yield, crack, and sustain permanent inelastic deformation during a design-level seismic event.They intentionally leverage "inelastic energy dissipation" as the primary mechanism for managing seismic demand, Caluk said. But this design philosophy is fundamentally incompatible with a crewed lunar environment, she said.Take for example a hatch distortion or pressure seal misalignment. They constitute a mission-critical failure, and any structural breach risks catastrophic depressurization, said Caluk. An artist's rendering of a NASA Artemis moon base with development underway. (Image credit: NASA)A group taking on the challenge of shaping guidelines on the building of lunar infrastructure is the aerospace division of the American Society of Civil Engineers.The group's technical committee on space engineering and construction has crafted "Infrastructure Engineering, Design, Analysis, and Construction (LIEDAC) guidelines" for the moon, Caluk said, to tackle seismic issues imposed by moonquakes.The LIEDAC guidelines, Caluk said, characterize the unique lunar hazard environment, classify operational consequences through a risk-categorization hierarchy, and establish target performance objectives "so that safe commercial development can proceed on a defensible technical basis."Inherent uncertaintiesCaluk also outlined a "Response Spectrum Analysis" supported by NASA Small Business Technology Transfer funding that looked at the inherent uncertainties of the lunar subsurface.The output of the analysis has developed criteria emphasizing the necessity of a local geotechnical site investigation for all structures, regardless of their seismic design category."These investigations are critical for identifying and mitigating risks such as seismic slope stability, seismically induced total and differential settlement, and other geotechnical hazards that may be triggered or amplified by moonquake groun
