CATS (Cloud-Aerosol Transport System)

The Cloud-Aerosol Transport System (CATS) is a lidar instrument developed by NASA Goddard Space Flight Center and hosted on the International Space Station (ISS) External Payload Facility.^[1][2] CATS uses elastic-backscatter lidar to profile clouds, aerosols, and particulate matter in the atmosphere. The instrument simultaneously transmits at three wavelengths: 1064 nm and 532 nm are cited in agency documentation from cats.gsfc.nasa.gov,^[1] while eoPortal records the full 1064/532/355 nm three-wavelength configuration.^[3] Laser 2 incorporates an injection-seeded design that enables High Spectral Resolution Lidar (HSRL) capability at 532 nm.^[3] A 60 cm telescope diameter is reported by eoPortal.^[3]

CATS draws heritage from the CALIOP instrument on CALIPSO. The low-inclination ISS orbit enables measurements over tropical and subtropical latitudes, complementing the high-latitude coverage of polar-orbiting instruments.^[2][3]