Simulated Lunar Surface Hydration Measurements Using Multispectral Lidar at 3 µm

Area of Science:

• Planetary Science
• Spectroscopy
• Geochemistry

Background:

• Lunar hydration (H2O + OH) signatures at 3 μm are vital for understanding water cycles.
• Thermal emission complicates accurate measurement of these hydration features.
• Orbital remote sensing is needed for global coverage and varied conditions.

Purpose of the Study:

• To assess the performance of a multispectral lidar for measuring lunar surface hydration.
• To evaluate the lidar's ability to overcome thermal emission interference.
• To determine the feasibility of using lidar for studying water generation and destruction mechanisms.

Main Methods:

• Simulated measurements using a four-wavelength multispectral lidar system.
• Utilized spectral mixtures of hydrated mid-ocean-ridge basalt (MORB) glasses and lunar regolith.
• Assessed lidar performance across various latitudes, times of day, and compositions.

Main Results:

• Demonstrated a feasible multispectral lidar system with wavelengths at 1.5, 2.65, 2.8, and 3.1 μm.
• Achieved a measurement precision of 52 ppm (1σ) or better for lunar hydration.
• Confirmed lidar's capability for uniform, zero-phase geometry measurements.

Conclusions:

• Multispectral lidar is a valuable technique for precise lunar hydration measurement.
• This method can overcome thermal emission challenges in spectroscopic analysis.
• Lidar data will elucidate OH/H2O generation, migration, and destruction mechanisms on the Moon.