Lunar Instrumentation for Subsurface Thermal Exploration with Rapidity (LISTER): A Payload on Blue Ghost 1 to Mare Crisium

LUNAR INSTRUMENTATION FOR SUBSURFACE THERMAL EXPLORATION WITH RAPIDITY (LISTER): A PAYLOAD ON BLUE GHOST MISSION 1 TO MARE CRISIUM. S. Nagihara1, K. Zacny2, P. Ngo2, L. Sanasarian2, R. Misra2, M. Zasadzien2, V. Sanigepalli2, M. Schmitt2, A. Wang2, C. Ladd2, A. Shmavonian2, P. Ng2, Y. Hwang2, W. Garcia2, J. Knorr2, R. Tuanuma2, T. Thomas2, H. Jung2, X. Estey2, T. Colen-brander2, X. Fries2, J. Emery2, N. Jeevanjee2, C. Castle2, N. Sadagopan2, T. Heiman2, E. Killian2, N. Steele2, Y. Matsuyama2, and G. Paulsen2, 1Department of Geosciences, Texas Tech University, Lubbock, TX 79409 (seiichi.[email protected]), 2Honeybee Robotics, Altadena, CA 91001. Introduction: On March 2, 2025, the Blue Ghost lander of Firefly Aerospace arrived in Mare Crisium. It was the first time a United States-based company successfully soft-landed a robotic spacecraft in the upright position on the Moon. It was also the first mission that deployed all its payload instruments as planned under NASA’s Commercial Lunar Payload Services (CLPS) program. The Lunar Instrumentation for Subsurface Thermal Exploration with Rapidity (LISTER) was one of the payloads (Fig. 1). Here we report how it operated on the mission. Figure 1. The Blue Ghost lander encapsulated in the payload fairing of Falcon 9 at the Kennedy Space Center. LISTER (magnified) is accommodated below the lander’s platform. Photo courtesy of Firefly Aerospace. LISTER Concept of Operations: LISTER measures temperature and thermal conductivity of the regolith of the landing site at multiple depths. It is designed to reach 3-m depth. The scientific objective of the measurements is to quantify the flow of heat that originates from the interior of the Moon. To achieve that objective, it is desired that LISTER penetrates deep enough (> ~1-m depth) subsurface where regolith temperature is unaffected by the insolation cycles. The heat flow is obtained as a product of the thermal gradient and the thermal conductivity of the regolith depth interval penetrated. LISTER on Blue Ghost represents the first case in which a planetary probe utilized a pneumatic excavation technique in penetrating subsurface. LISTER’s deployment mechanism is accommodated below the lander’s platform (Fig. 1). It spools out a stainless-steel tube (6.4-mm diameter) pointing downward. A jet of nitrogen gas is emitted from the leading end of the tube and blows a hole into the regolith and removes pebbles and clumps out of it (Fig. 2). Figure 2. LISTER’s pneumatic drill excavating lunar regolith simulant in a vacuum chamber. LISTER’s implementation of the pneumatic excavation technique is suited for the small lander mission in which the payload accommodation space, mass, and power is limited. A conventional rotary or rotary-percussive drill capable of reaching 3-m depth would have required a much larger, complex mechanism. It has long been a challenge for planetary scientists to design a subsurface thermal probe that can reach deep enough subsurface to sense the internal heat flow while it is compact and simple enough mechanism to be accommodated on a small robotic lander. LISTER on Blue Ghost penetrated 3 to 10+ times deeper (1 m) than any of the previous robotic penetration attempts made on the Moon or Mars regolith [1,2]. To make thermal measurements, a compact probe (“needle sensor” in Fig. 3) is attached to the gas nozzle. When it reaches a depth targeted for measurements, LISTER stops blowing gas and pushes the needle sensor into the yet-to-be-excavated, bottom-hole regolith. The needle sensor contains a resistance temperature detector (RTD) at the mid-point of the needle sensor. A spare RTD is located at the joint of the needle sensor and the nozzle. A heater wire runs along the length of the needle. Thermal conductivity is determined by heating the regolith surrounding the needle and observing how hot the needle becomes. This methodology is similar to what was done for the heat flow probe on the InSight mission to Mars [3]. Figure 3. A photograph of LISTER commencing its regolith excavation in Mare Crisium, shot by a below-deck camera of the Blue Ghost lander. The plumes of regolith were generated by the gas jet from LISTER. Photo courtesy of Firefly Aerospace. Deployment in Mare Crisium: When we deployed LISTER in Mare Crisium, cameras below deck monitored the drilling activity (Figs. 3 and 4). LISTER carried out thermal measurements at 8 depths down to 1-m depth. This was the first time a robotically deployed, planetary subsurface probe made scientific measurements at multiple depths. When LISTER reached 1-m depth, it ran into major obstacles and was unable to overcome them. Currently we are analyzing if these measurements are sufficient for quantifying the flow of heat from the interior of the Moon. Figure 4. The hole excavated by LISTER. Photographed at the end of the mission. Photo courtesy of Firefly Aerospace. References: [1] Spohn T. et al. (2022) Adv. Space Res ., 69, 3140-3163. [2] Mathew N. et al. (2025) Scientific Rep., 15, 7375. [3] Grott M. et al. (2021) JGR, 126, JE006861.