Observed Correlation Between Local Topography and Passive Neutron Measurements From the Dynamic Albedo of Neutrons (DAN) Instrument on the Mars Science Laboratory (MSL) Rover

• Published in: Earth and space science (Hoboken, N.J.) Vol. 11; no. 10
• Main Authors: Dibb, Steven D., Hardgrove, Craig, Lightholder, Jack, Heffern, Lena, Ehresmann, Bent
• Format: Journal Article
• Language: English
• Published: 01.10.2024
• ISSN: 2333-5084; 2333-5084
• DOI: 10.1029/2023EA003130

Abstract The Dynamic Albedo of Neutrons (DAN) instrument on the Mars Science Laboratory Curiosity rover primarily measures neutrons that have undergone interactions with rocks and materials in the rover's local environment. As the rover ascends Aeolis Mons, it may encounter more extreme local topography (e.g., cliffs, gullies, canyons). We present three parts of the rover's traverse in which local topography, expressed as the average local relief relative to the rover, is moderately to strongly correlated with an increase in passive thermal neutron count rates. These increases in count rates are consistent with results from radiation transport models of the instrument's performance near simulated topographic features. Additional DAN measurements in areas of high average local relief (>0.25 m) within 5 m of the instrument could bolster this correlation. DAN's sensitivity to topography in its passive mode could be utilized as a new measurement capability and has implications for the operation of future landed missions carrying neutron spectrometers (e.g., VIPER, MoonRanger, Lunar‐VISE). Key Points Three sections of the MSL rover traverse exhibit increased thermal neutron count rates correlated with increased average local relief The magnitude of the increase in relative neutron count rates near topography is dependent upon the source and the nearby hydrogen content Future measurements from missions with neutron instruments could use this sensitivity to measure hydration of nearby high relief features