Jeffrey Alan Hoffman, Ph.D. (born November 2, 1944) is an American former NASA astronaut and currently a professor of aeronautics and astronautics at MIT. Hoffman made five flights as a space shuttle astronaut, including the first mission to repair the Hubble Space Telescope in 1993, when the orbiting telescope's flawed optical system was corrected. Trained as an astrophysicist, he also flew on 1990 Spacelab shuttle mission that featured the ASTRO-1 ultraviolet astronomical observatory in the shuttle's payload bay. Over the course of his five missions he logged more than 1,211 hours and 21.5 million miles in space. He was also the first Jewish Astronaut, and the second Jewish man in space after Boris Volynov.