A Canadian space agency satellite that measures global ozone processes. It was launched on 12 August 2003 from NASA's Vandenberg air force base in California. It is in a low polar orbit of 650 km and travels around the Earth 15 times a day. SCISAT helps scientists improve their understanding of the depletion of the ozone layer, with special emphasis on changes occurring over Canada and in the Arctic.

SCISAT's primary instrument is a Fourier transform spectrometer and another is named MAESTRO (Measurements of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation). The mission was expected to last two to five years, but it remains operational as of 2017.