SwRI-led Sounder Instrument Deploys Across Lunar Surface

Published on March 14, 2025 by Southwest Research Institute

Just hours after touching down on the lunar surface on March 2nd aboard Firefly Aerospace's Blue Ghost 1 lander, the Southwest Research Institute-led Lunar Magnetotelluric Sounder (LMS) was activated to deploy its five sensors. These sensors will study the moon's interior by measuring electric and magnetic fields, marking the first extraterrestrial application of magnetotellurics.

"For over 50 years, scientists have utilized magnetotellurics on Earth for various purposes, including acquiring minerals, locating geothermal energy, and understanding geological processes," stated Dr. Robert Grimm, principal investigator of LMS and a program director in SwRI's Solar System Science and Exploration Division.

The Purpose of the Lunar Magnetotelluric Sounder

The LMS's deployment consists of four sensors placed approximately 60 feet away from the Blue Ghost lander, positioned at 90-degree angles across a region that spans about half the size of a football field. This arrangement is intended to characterize the lunar subsurface effectively.

The technique of magnetotellurics involves using natural variations in surface electric and magnetic fields to assess how electricity flows within subsurface materials. This can reveal critical information regarding their composition and structure. The LMS aims to characterize the moon's interior to a depth of up to 700 miles or approximately two-thirds of the lunar radius.

The data gathered will illuminate the material differentiation processes and thermal history of the moon, providing invaluable insights for understanding the evolution of solid worlds.

Mission Overview and Significance

As a part of NASA's Commercial Lunar Payload Services (CLPS) initiative, the LMS was transported to the moon with the objective of comprehensively understanding its subsurface in a region previously unexamined. Mare Crisium, known as an ancient impact basin with a diameter of 340 miles, filled with lava flows that create a dark patch observable from Earth.

“Mare Crisium stands apart from the expansive regions of dark lava to the west, which hosted the majority of Apollo missions," Dr. Grimm explained. "The lava plains are now considered to exhibit compositional and structural anomalies concerning the rest of the moon. From this distinct vantage point, LMS may yield the first geophysical measurements that truly represent the entirety of the lunar body."

Instruments and Collaborators

The SwRI's design team built the instrument and its supporting electronics. The involvement of various organizations highlights a collaborative effort directed toward enhancing lunar exploration capabilities under NASA's visionary CLPS framework.

Notably, under this pressing CLPS model, NASA is actively investing in commercial delivery services aimed at establishing industry growth and supporting sustainable long-term lunar explorations. With this initiative, NASA serves as a primary customer for these futurist lunar pilot flights.

Conclusion and Future Prospects

The scientific initiatives supported by the LMS instrument not only underscore the potential of advanced geophysical techniques but also promise a deeper understanding of the moon's formation and evolutionary history. Future results derived from this mission will help clarify complex phenomena associated with planetary crust differentiation and the moon's thermal evolution—representing significant milestones in space exploration history.

For more detailed information on the Lunar Magnetotelluric Sounder and associated developments, please visit Southwest Research Institute’s official page.