Named in honor of Riccardo Giacconi {1931– }, since 1981 the first director of the Space Telescope Science Institute. After serving as a research associate in the cosmic-ray physics group at Indiana University, and then briefly at Princeton, in 1959 he joined American Science and Engineering, where he began work on X-ray astronomy. His team there developed grazing-incidence X-ray telescopes, and in 1962 they discovered Sco X-1, the first known X-ray source outside the solar system. This was followed by the orbiting X-ray observatory UHURU, which made the first surveys of the X-ray sky. Joining the Harvard-Smithsonian Center for Astrophysics in 1973 as associate director for high-energy physics, Giacconi led the construction and successful operation of the powerful X-ray observatory HEAO-2, also known as Einstein, which made detailed images of X-ray sources. (M 16884) _ _.