ETH Zurich researchers, led by Johan Robertsson, have come up with a creative way to study the Moon’s interior. They’re using fibre‑optic cables as distributed seismic sensors.
By turning a long fibre into thousands of tiny vibration detectors, scientists hope to build a dense, high‑resolution seismic network on the Moon. This could open up new insights into its structure, history, and maybe even resources.
DAS on the Moon: a new kind of seismic network
This method, called DAS, uses lasers that send pulses down a fibre. Tiny imperfections in the fibre scatter light back to an interrogator.
The returning signals let the cable act like thousands of evenly spaced vibration sensors along its length. That means much more spatial coverage than traditional seismometers can offer.
A rover could unroll kilometres of lightweight fibre across the lunar surface. That would give far more detail than anything we’ve managed on past missions.
How distributed acoustic sensing works on the Moon
Lab tests at Los Alamos used crushed basalt to mimic lunar regolith. Researchers saw that thicker cables laid on the surface can pick up seismic signals almost as well as buried ones.
This is pretty encouraging, since the Moon’s lack of atmosphere means surface deployment might avoid the wind noise that often messes with DAS on Earth.
Simulations are helping scientists figure out how the fibre couples to the lunar ground in low gravity. They’re also predicting how cables will respond to seismic waves on the Moon.
These models help forecast how long DAS arrays might perform and guide how data could be interpreted to image the subsurface.
Active seismic imaging and mission‑level benefits
Besides just listening for moonquakes and impacts, spacecraft landings and takeoffs could actually act as active seismic sources. It’s a bit like using medical ultrasound to see inside the body.
The DAS cables would record waves from these events, giving a dynamic look at what’s hiding beneath the surface.
The fibre network might also help measure how much lunar dust rocket exhaust kicks up. That info could help mission planners reduce dust risks during landings and operations.
What DAS could reveal about the Moon’s interior
Long DAS arrays could pick up tidal stresses and even the Moon’s normal modes. That could really expand what we know about internal lunar dynamics.
This technique might help researchers study lava tubes, find safer landing spots, and maybe even locate shallow water resources. All of that could support a longer human presence on or near the Moon someday.
Key potential benefits in bullet form
- High‑resolution imaging of the lunar interior, including mantle and crustal structure
- Detection of tidal stresses and normal modes to understand lunar geophysics
- Mapping of lava tubes that could shelter future bases
- Identification of favorable landing sites with better risk profiles
- Assessment of subsurface water resources for in‑situ resource utilization
- Quantification of dust dynamics from rocket exhaust to improve mission safety
Challenges, next steps, and the path forward
The concept is compelling, but a bunch of challenges stand in the way before anyone can pull off a full lunar DAS deployment. Deployment logistics need real solutions—autonomous rovers and landers have to lay down and protect kilometres of fibre in some of the harshest conditions imaginable.
The lunar environment throws everything at you: wild temperature swings, radiation, micrometeoroid impacts. These could easily mess with fibre durability or degrade data quality. And then there’s the tricky business of interpreting seismic signals up there. Scientists need better models for how the cable couples with the lunar ground, plus a clearer sense of how the regolith interacts with the cable during different seismic events.
Still, the research hints at a future where fibre‑optic networks and DAS might just turn the Moon into the most densely instrumented seismic lab away from Earth. If this works out, it would add a new layer to what we get from traditional landers, maybe revealing details about the Moon’s interior, its hidden resources, or even the risks and opportunities for long-term exploration.
Here is the source article for this story: Imaging Moon’s Interior With Fibre-optics