OAO-2, nicknamed Stargazer, was NASA’s first successful cosmic observatory and the second Orbiting Astronomical Observatory. Launched on 1968-12-07, its Celescope and Wisconsin Experiment Package made the first orbital stellar observations in ultraviolet light, catalogued thousands of UV stars, and studied planets, galaxies, comets, and interstellar extinction above Earth’s atmosphere.
Alerts are unavailable because this mission is no longer active.