The Lunar Trailblazer Lunar Thermal Mapper Instrument
Journal of Geophysical Research Planets American Geophysical Union (AGU) 131:5 (2026)
Authors:
Neil E Bowles, Bethany L Ehlmann, Rory Evans, Tristram J Warren, Henry H Eshbaugh, Greg King, Waqas Mir, Namrah Habib, Katherine Shirley, Fraser Clarke, Cyril Bourgenot, Chris Howe, Keith Nowicki, Fiona HM Henderson, Christopher S Edwards, Rachel L Klima, Kerri Donaldson Hanna, Calina C Seybold, Andrew T Klesh, David R Thompson, Elise Furlan, Elena Scire, Judy S Adler, Nicholas Elkington, Aria Vitkova, Jon Temple, Simon Woodward
Abstract:
Abstract The Lunar Thermal Mapper (LTM) instrument is a UK Space Agency funded infrared radiometer designed and built for the National Aeronautics and Space Administration Lunar Trailblazer mission launched in February 2025. LTM is a pushbroom imaging filter radiometer with 15 channels that cover the wavelength range from 6.25 to 100 μm with a 40–70 m/pixel ground sampling. Lunar Trailblazer's mission is to understand the form, abundance and distribution of water across the lunar surface. LTM provides an independent measure of temperature to investigate thermal effects on water's mapped distribution as well as an independent measure of surface mineralogy. The LTM instrument's 15 infrared channels include four broadband temperature sensing channels (6.25–12.5, 12.5–25, 25–50 and 50–100 μm) plus 11 additional narrow band (∼40 cm −1 ) filters from ∼7–10 μm to map and discriminate silicate composition. We review the LTM design and calibration campaign at the University of Oxford's Space Instrumentation facility and show that the instrument has sensitivity from 400 K with a Noise Equivalent Temperature Difference of <0.1 K to <1 K at 110 K for typical integration times (e.g., 30 Hz readout) from a nominal 70–130 km lunar orbit design altitude.
Plain Language Summary This paper describes the Lunar Thermal Mapper instrument for NASA's Lunar Trailblazer mission. Lunar Thermal Mapper is a thermal imaging system designed to sense the temperature and composition of the lunar surface using the thermal infrared. By sensing the temperature environment of the Moon, Lunar Thermal Mapper supports the Trailblazer's mission to map water on the lunar surface.
Key Points The Lunar Thermal Mapper (LTM) instrument will measure thermal infrared radiation from the Moon across from 400 K to <110 K The LTM instrument completed assembly, testing, calibration and integration on the Lunar Trailblazer spacecraft The LTM instrument demonstrated sensitives of <0.1 K at 400 K and <1 K at 110 K during ground testing and calibration
