Mid-infrared hyperspectral imaging for Moon and beyond

The Compact Lunar Hydration and Mineralogy Explorer (CLuHME) instrument is being developed at NASA’s Goddard Space Flight Center as a mid-infrared hyperspectral imaging system to support NASA’s exploration goals for Moon, Mars, and other solid-surface bodies. CLuHME is designed for the 2.5–12 μm wavelength interval, which is sensitive to signatures of hydration by water and hydroxyl, silicate mineral features, and temperature determined from thermal emission. Modest spectral resolving power of R~100, or 0.1 μm wavelength discrimination is sufficient for solid material spectroscopy in this range. CLuHME will measure the short-wavelength hydration feature that identified mineral hydrates on the lunar surface, evaluate its association with molecular water, identify silicate mineralogy in surface operations at much finer scale than current mapping, and rapidly measure surface temperatures from the surface or from orbit. CLuHME is based on a 1000x1000 (one megapixel) Strained-Layer Superlattice (SLS) detector array, developed at GSFC to achieve high sensitivity and pixel-to-pixel uniformity with cooling to 70-100 K. CLuHME achieves spectral discrimination through a linear variable filter bonded directly to the focal plane array, minimizing optical complexity. Sweeping the field of view in pushbroom mode at a rate consistent with frame rate enables constructing a spectrum at each image pixel.