image: From within the Mare Crisium impact basin, the SwRI-led Lunar Magnetotelluric Sounder (LMS) is making the first geophysical measurements representative of the bulk of the Moon. Most of the Apollo missions landed in the region of linked maria to the west (left image), whose crust was later shown to be compositionally distinct (right image) as exemplified by the concentration of the element thorium. Mare Crisium provides a smooth landing site on the near side of the Moon outside of this anomalous region.
Credit: NASA
SAN ANTONIO — March 13, 2025 —Just hours after touching down on the surface of the Moon on March 2 aboard Firefly Aerospace’s Blue Ghost 1 lander, the Southwest Research Institute-led Lunar Magnetotelluric Sounder (LMS) was activated and deployed its five sensors to study the Moon’s interior by measuring electric and magnetic fields. The LMS instrument is the first extraterrestrial application of magnetotellurics.
“For more than 50 years, scientists have used magnetotellurics on Earth for a wide variety of purposes, including to find oil, water, geothermal and mineral resources as well as to understand geologic processes such as the growth of continents,” said Dr. Robert Grimm, principal investigator of LMS and a program director in SwRI’s Solar System Science and Exploration Division. “Today, four sensors were deployed more than 60 feet away from the Blue Ghost lander at 90-degree angles — across an area about half the size of a football field — to characterize the lunar subsurface.”
Magnetotellurics use natural variations in surface electric and magnetic fields to calculate how easily electricity flows in subsurface materials, which can reveal their composition and structure. LMS will allow scientists to characterize the interior of the Moon to depths up to 700 miles or two-thirds of the lunar radius. The measurements will shed light on the material differentiation and thermal history of our Moon, a cornerstone to understanding the evolution of solid worlds.
Through NASA’s Commercial Lunar Payload Services (CLPS) initiative, LMS was delivered to the surface of the Moon as part of a 14-day lunar lander mission to help understand the Moon’s subsurface in a previously unexplored location. Mare Crisium is an ancient, 340-mile-diameter impact basin that subsequently filled with lava, creating a dark spot visible to the naked eye on the Moon.
“Mare Crisium stands apart from the large, connected areas of dark lava to the west where most of the Apollo missions landed,” Grimm said. “These vast, linked lava plains are now thought to be compositionally and structurally anomalous with respect to the rest of the Moon. From this separate vantage point, LMS may provide the first geophysical measurements representative of most of the Moon.”
The LMS payload was funded for delivery to the lunar surface by CLPS. SwRI designed the instrument, built the electronics box and leads the science investigation. NASA’s Goddard Space Flight Center, Greenbelt, Maryland, provided the LMS magnetometer to measure the magnetic fields, and Heliospace Corp. provided the magnetometer mast and four electrodes used to measure the electrical fields.
Under the CLPS model, NASA is investing in commercial delivery services to the Moon to enable industry growth and support long-term lunar exploration. As a primary customer for CLPS deliveries, NASA is one of many customers on future flights. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the development of seven of the 10 CLPS payloads carried on Firefly’s Blue Ghost lunar lander.
Watch LMS deploy sensors on the Moon here: https://youtu.be/Mxeb79E5RLY
For an overall video about LMS, see: https://youtu.be/RjizBdB7YXg?si=YxylhdLL-AjqPjia
For more information, visit https://www.swri.org/markets/earth-space/space-research-technology/space-science/planetary-science.