MOST

MOST (Microvariability and Oscillations of Stars) was a Canadian (CSA) satellite designed to detect minute variations in the light of stars to study their seismology (asteroseismology), which requires viewing stars for much longer periods of time than can be afforded with major telescopes such as the Hubble Space Telescope (HST). It was launched in 2003 in Russia and featured a 15 cm telescope viewing 350 nm to 700 nm waves. It operated until it failed in 2019.