Solar system

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Abstract This article reports on the initial calibration and performance of the High‐resolution Volatiles and Minerals Moon Mapper (), slated for launch on the National Aeronautics and Space Administration's Lunar Trailblazer mission. is an imaging spectrometer measuring from 600 to 3,600 nm with 10‐nm spectral sampling and 50–90 m/pixel ground sampling. The mission goal is to understand the form, abundance, and distribution of water across the lunar surface and the lunar water cycle, accomplished by measuring the distinct absorptions of water ice, adsorbed O, and OH/hydroxl while controlling for thermal effects with . also has the ability to measure mineralogical composition. has been assembled, tested and calibrated in preparation for launch and integrated on the Lunar Trailblazer spacecraft. We review the design, calibration process, results, and implications for Lunar Trailblazer science goals. We find ’s radiometric sensitivity is sufficient to confidently measure 1% differences in absorption band strengths under direct solar illumination in single pixel data. In addition, has the radiometric precision to discriminate different species of volatile absorptions at irradiances of 1 W , which will enable mapping and discriminating water ice or other volatiles within most of the Moon's Permanently Shadowed Regions using terrain‐scattered illumination. Plain Language Summary We present laboratory tests of a new instrument, the High‐resolution Volatiles and Minerals Moon Mapper (). will launch onboard the National Aeronautics and Space Administration's Lunar Trailblazer mission. It is an imaging spectrometer that will measure the spectrum of reflected sunlight in visible and infrared wavelengths for every pixel of an image. Scientists will interpret these spectra with the goal of measuring how water and ice are distributed across the lunar surface. Our laboratory tests indicate that the instrument is sensitive enough to measure small changes in the content of water on the lunar surface. We find the instrument capable of measuring areas of the Moon that are in permanent shadow using light reflected from neighboring surfaces like crater walls. Key Points has completed assembly, testing, calibration, and integration on the Lunar Trailblazer orbiter radiometric sensitivity is sufficient to confidently discriminate water ice and hydroxyl absorptions on the lunar surface performance is sufficient to measure 1% absorptions in lunar permanently shadowed regions with terrain‐scattered irradiance of 1 W

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