HU-25
HU-25 Guardian

The Geostationary Trace gas and Aerosol Sensor Optimization (GeoTASO) is an airborne pushbroom spectrometer developed by Ball Aerospace with support from NASA’s Earth Science Technology Office. GeoTASO measures nadir backscattered solar radiation in the ultraviolet (290-400 nm) and visible (415-695 nm) spectral ranges. These measurements can be used to determine atmospheric aerosols and trace gases, including ozone, formaldehyde, and nitrogen dioxide. GeoTASO has a spatial resolution of approximately 250 m by 250 m and an integration time of 0.25 seconds.

The High Altitude Lidar Observatory (HALO) is an airborne lidar system developed by NASA's Langley Research Center. HALO operates at four wavelengths (1645, 1064, 935, and 532 nm) and combines Differential Absorption Lidar (DIAL) and High Spectral Resolution Lidar (HSRL) to measure lidar backscatter and depolarization ratio. It provides vertical profiles of aerosol and cloud optical properties, atmospheric water vapor, and methane at a data rate of 2 Hz. HALO has a nominal spatial resolution of 12 km horizontally and 315 m vertically at an altitude of 10 km.

The GEOstationary Coastal and Air Pollution Events (GEO-CAPE) Airborne Simulator (GCAS) is a push-broom airborne instrument with two spectrometers. Developed by the Radiometric Calibration and Flight Development Laboratory at Goddard Space Flight Center (GSFC) as a simulator for the GEO-CAPE mission, GCAS measures atmospheric trace gases and ocean color. The first spectrometer operates in the ultraviolet to visible (300-490 nm) range for air quality observations of nitrogen dioxide (NO2), ozone (O3), formaldehyde (HCHO), and other trace gases. The second spectrometer operates in the visible to near-infrared (480-900 nm) range to measure ocean color. GCAS has a typical spatial resolution of 250 m across track and 500 m along track at an altitude of 9 km, with a frame rate of 12 Hz.