March 13, 2024 — Southwest Research Institute (SwRI) has been awarded a three-year, $2,041,000 grant from NASA’s Development and Advancement of Lunar Instrumentation (DALI) program to further develop a novel ground-penetrating radar instrument. The Synthetic Pulse Artemis Radar for Crustal Imaging (SPARCI, pronounced “sparky”) instrument is designed to characterize the depth of the regolith and upper megaregolith, the upper broken-up layers of lunar crust associated with impact cratering.
SwRI is one of five teams awarded funding by NASA’s DALI program, which supports the development of instruments for future lunar missions, including Commercial Lunar Payload Services and Artemis. DALI’s goal is to develop and demonstrate instruments that are technically ready to propose for upcoming flight opportunities. These instruments must demonstrate new technologies that significantly improve instrument measurement capabilities for addressing high-priority lunar science questions.
When astronauts return to the Moon during the second half of this decade their tasks will include deploying lunar instruments and using new technology to characterize the Moon. SPARCI’s two large transmitting antennas that are 172 and 40 meters in length are designed to be deployed by astronauts. A robotic rover with much smaller antennas will then receive radar signals that penetrate the Moon’s subsurface. The ground-penetrating radar will measure the thickness and structure of the lunar megaregolith. Believed to be between 0.4 and 5 kilometers deep, the megaregolith formed just after the Moon solidified and likely experienced heavy bombardment from other objects during the early formation of the solar system.
“Learning more about the lunar megaregolith will help us gain a wider understanding of the Moon’s formation and that of similar bodies with thin, sparse atmospheres,” said SwRI’s Dr. David Stillman, the project’s principal investigator. “If we are able to pinpoint exactly where this layer begins, we can use that to create more accurate formation and evolution models.”
SPARCI’s design was inspired by Apollo 17’s Surface Electrical Properties (SEP) experiment, which collected subsurface data on the Moon while attached to the Lunar Roving Vehicle. Like SEP, SPARCI uses two stationary transmitting antennas and a mobile receiver but attached to a robotic rover instead of an astronaut-driven vehicle.
“SPARCI uses much wider bandwidth and electronics that are 50 years more advanced than the SEP, enabling both deeper and higher-resolution imaging,” Stillman said. “SPARCI will determine the thickness and density of the overall regolith, measuring the structure of the upper megaregolith and the depth of the lower regolith. This information will help advance understanding of impact processes on the Moon and other bodies that don’t have significant atmospheres. If we can pinpoint exactly where this layer below the landing site, we can use other global datasets to better constrain the structure of the megaregolith globally.”
For more information, visit Planetary Science or contact Joanna Quintanilla, +1 210 522 2073, Communications Department, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238-5166.