Two new studies from Los Alamos National Laboratory suggest that simple fibre-optic cables laid directly on the lunar surface could revolutionise how scientists measure seismic activity on the Moon. The research challenges the assumption that traditional seismometers are the only effective way to detect moonquakes.
The Moon has a lot of seismic activity, but deploying traditional seismic sensors like seismometers is extremely difficult and costly, according to Carly Donahue, the lead scientist on the research. The fundamental limitation of seismometers is their fixed location; they gather excellent data from one spot, but monitoring a wider area requires deploying multiple instruments at considerable expense.
Using a robot or rover to launch fibre-optic cables across many kilometres on the surface of the moon without burying them and still getting useful data offers a fundamentally different approach. This technique, called distributed acoustic sensing (DAS), turns a single cable into thousands of virtual sensors.
What the lab tests revealed
The first study examined whether cables would need to be buried to function effectively. On Earth, fibre-optic cables must be buried because even low windspeeds shake the fibres, making it difficult to extract useful data from the noise. But the Moon has only a thin exosphere, which could lead to improved signal quality for surface-draped optical fibres. When researchers tested cables at various depths in a lunar regolith simulator, burial depth did not significantly impact the clarity of the signal. This is a significant finding, as it avoids the logistical nightmare of digging trenches across the lunar surface.
The second study explored which cable characteristics matter most. Stiffer, thicker cables and continuous ground contact improved signal strength. This creates a practical trade-off: mission planners must balance better signal quality against the weight penalty of heavier cables being transported to the Moon.
Understanding the science
DAS uses the tiny internal flaws in a long optical fibre as seismic sensors. An instrument called an interrogator at one end of the fibre sends laser pulses down the cable that are reflected off the fibre flaws and bounced back to the instrument. This transforms what appears to be a simple cable into a sophisticated detection system spanning kilometres.
For lunar exploration, this matters enormously. Because the moon lacks tectonic plates, moonquakes are triggered by forces such as Earth's gravitational pull, meteorite impacts and extreme temperature swings. Understanding the frequency and distribution of these quakes helps scientists map the Moon's interior structure, particularly the core, which remains a subject of active research.
Beyond seismology
Beyond academic curiosity, moonquakes pose practical hazards. Particles blasted from the lunar surface when a rocket takes off or lands could move at speeds of about 2 kilometres per second and cause damage to equipment or man-made structures on the moon, but there is little current knowledge of how far those particles travel. Fibre networks deployed away from landing sites could monitor how widely debris disperses, offering early warning of hazards to future bases.
This technology has proven applications on Earth as well. On Earth, surface-deployed fibre can track groundwater movements and underwater seismicity. It also keeps tabs on vessel traffic, wildlife movements, and even shifting Arctic ice. Openreach, the UK telecoms firm, recently demonstrated using fibre networks to detect leaks in water supply pipes through the vibrations they create.
The convergence of these advantages suggests that fibre-optic seismic networks will play a central role in the next generation of lunar exploration. Whether supporting human settlements or robotic missions, the technology offers a pragmatic solution to one of space exploration's persistent challenges: gathering dense, reliable scientific data in harsh environments where traditional methods strain against logistical and cost constraints.