SwRI sends first instrument to the Moon to study its interior

SwRI sends first instrument to the Moon to study its interior
by Clarence Oxford
Los Angeles CA (SPX) Jan 14, 2025

Through NASA's Commercial Lunar Payload Services (CLPS) initiative, Southwest Research Institute (SwRI) has developed the Lunar Magnetotelluric Sounder (LMS) to explore the Moon's interior structure and composition by measuring its electric and magnetic fields. The LMS instrument, set to launch aboard Firefly Aerospace's Blue Ghost lunar lander on January 15, 2025, marks the first time an SwRI instrument will operate on the lunar surface.

"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 at SwRI. "The LMS instrument will be the first extraterrestrial application of magnetotellurics."

NASA's Artemis program aims to establish a sustainable human presence on the Moon through increasingly complex missions. LMS plays a vital role in a 14-day lunar lander mission designed to investigate the Moon's subsurface in a previously unstudied location.

The mission will target Mare Crisium, a 350-mile-wide ancient impact basin filled with lava that forms one of the Moon's dark, prominent features visible from Earth. Early astronomers mistook these dark areas, known as "maria," for seas. Mare Crisium stands out as it is isolated from the vast, interconnected lava plains in the Moon's western regions, where most Apollo missions landed. This vantage point may provide geophysical data more representative of the lunar interior as a whole.

Magnetotellurics, the primary method employed by LMS, relies on natural surface electric and magnetic field variations to assess subsurface material properties. By measuring electrical conductivity, the instrument can reveal the temperature and composition of materials up to 700 miles beneath the surface, approximately two-thirds of the Moon's radius. These insights are expected to advance our understanding of the Moon's material differentiation and thermal history, which are key to comprehending the evolution of rocky planetary bodies.

LMS uses cables equipped with electrodes that extend 60 feet at right angles to each other, measuring voltages across pairs of electrodes similarly to a conventional voltmeter. A magnetometer, deployed on an extendable mast to minimize interference from the lander, complements these measurements. The data will provide a vertical profile of electrical conductivity, offering valuable clues about the Moon's interior composition.

"The five individual subsystems of LMS, together with connecting cables, weigh about 14 pounds and consume about 11 watts of power," Grimm explained. "While stowed, each electrode is surrounded by a 'yarn ball' of cable, making the assembly roughly spherical and about the size of a softball."

The LMS project received funding through NASA's CLPS initiative. SwRI led the instrument's design, built the electronics box, and oversees the scientific investigation. NASA's Goddard Space Flight Center contributed the magnetometer for magnetic field measurements, while Heliospace Corp. provided the magnetometer mast and four electrical field electrodes.

Under the CLPS framework, NASA collaborates with commercial partners to advance lunar exploration and stimulate industry growth. By positioning itself as a primary customer, NASA encourages future flights with multiple stakeholders. Marshall Space Flight Center in Huntsville, Alabama, manages the development of seven out of ten CLPS payloads aboard Firefly's Blue Ghost lunar lander.