Discovery ventured back to space while two shuttles sat grounded due to the infamous liquid hydrogen leaks during the summer of 1990. The shuttle lifted off at 7:47 a.m. on October 6, 1990 to send the Ulysses solar observatory on its journey to the polar regions of the sun. The mission was headed by Dick Richards, with pilot Bob Cabana, mission specialists Bill Shepherd, Bruce Melnick and Tom Akers.