[en] SCISAT-1, also known as the Atmospheric Chemistry Experiment ( ACE), is a Canadian satellite mission for remote sensing of the Earth's atmosphere. It was launched into low Earth circular orbit ( altitude 650 km, inclination 74 degrees) on 12 Aug. 2003. The primary ACE instrument is a high spectral resolution (0.02 cm(-1)) Fourier Transform Spectrometer (FTS) operating from 2.2 to 13.3 mm ( 750 - 4400 cm(-1)). The satellite also features a dual spectrophotometer known as MAESTRO with wavelength coverage of 285 - 1030 nm and spectral resolution of 1 - 2 nm. A pair of filtered CMOS detector arrays records images of the Sun at 0.525 and 1.02 mu m. Working primarily in solar occultation, the satellite provides altitude profile information ( typically 10 - 100 km) for temperature, pressure, and the volume mixing ratios for several dozen molecules of atmospheric interest, as well as atmospheric extinction profiles over the latitudes 85 degrees N to 85 degrees S. This paper presents a mission overview and some of the first scientific results.