air-LUSI measures the moon's spectral irradiance. Because it flies above 90% of the atmosphere in the wing pod of a NASA ER-2 (civilian U-2 variant), it can take better measurements than Earth-based instruments, which will result in better calibrations for satellites that study Earth.

Flying aboard NASA’s ER-2 airplane: New Moon-Seeking Sensor 🌛

YouTube video by NASA Armstrong Flight Research Center

And if you love NASA aircraft as much as I do, please enjoy this video about the ER-2, featuring amazing cockpit views from not-quite-space.

Suit Up and Fly High in NASA's Science Spy Plane | WIRED

YouTube video by WIRED