An Ultra-Compact Imaging Spectrometer for the Lunar Surface: Enabling Volatile Mapping and Unraveling the Moon's Geologic History

Goals & objectives: The proposed project will advance an ultra-compact shortwave infrared imaging spectrometer (UCIS) for use on future lunar surface missions, including expected commercial lander ventures. UCIS will be developed to address science knowledge gaps about the abundance and sources and sinks of lunar volatiles and provide key knowledge about possible in situ resources for future human exploration. UCIS is currently TRL4 for these objectives on a landed lunar mission based on its (1) spectral range, (2) lunar surface environments, and (3) onboard processing to maximize return of surface information to Earth. We will develop these three areas, raising UCIS-Moon to TRL6 so that it may be proposed in response to future announcement of a landed lunar flight opportunity. We will maintain its low volume, mass and power requirements to be suitable for diverse landed platforms. Approach & methodology: UCIS is currently capable of collecting spectra to 2600 nm. For this work, we will upgrade the spectrometer detector and thermal system to extend the spectral range to 3600 nm. The extension to 3600 nm is critical to detect, attribute, and map lunar water resources -- specifically, the form, abundance, spatial distribution, and temporal variability of lunar OH species, molecular H2O, and water ice – as well as organics. In addition to volatiles, the extended wavelength range to 3600nm will enable UCIS to detect organic material that may be present, delivered to the moon via impact of external, organic-rich solar system objects. UCIS will maintain its capability to map the mineralogical composition and geologic context of the lunar surface, unraveling the geological history at unprecedented spatial scales (meters to microns depending on optics). We will also develop new on-board analysis to enable return of high value spectra while reducing the volume of transmitted data. We will adapt existing algorithms based on (1) endmember detection and (2) fitting continuum-removed absorptions. These can identify unanticipated materials and detect known high-value target signatures, respectively. Prioritized downlink of key spectra and derived maps will ensure fast, efficient landed operations. Onboard analysis will enable investigation lifetimes as short as one lunar day while still obtaining full maps of the landing site. Finally, we will develop the UCIS instrument to operate in the challenging thermal lunar surface environment. Temperatures on the surface of the moon can range from approximately 100 – 400 K, and reach even lower temperatures of ~30 K on permanently-shadowed lunar ice deposits. We will mature the UCIS thermal design to operate in this wide temperature range while maintaining excellent signal-to-noise-ratio and sensitivity. A high precision mode will be included to allow useful measurements from terrain scattered light in permanently shadowed regions. Reasons proposed work is within scope of program element & why program is most appropriate: This work is within the scope of the DALI program because it seeks to mature lunar science instruments that support NASA’s broader lunar exploration goals, including human exploration and in situ resource utilization (ISRU) as well as lunar science. We will mature the UCIS instrument from a TRL4 to TRL6 to operate in the lunar environment, extend its wavelength range to answer high priority lunar science and ISRU questions, and add onboard analysis to support high yield during short-lifespan missions. The full range spectroscopy of UCIS-Moon is required to identify and quantify the surface abundance of lunar surface volatiles and their geologic context for future in situ resource utilization objectives. DALI is the most appropriate program element because the work proposed is specific to advancing lunar science via an instrument suitable for a lunar lander, including those of commercial providers. More »