Brian O'Leary is an American astronaut and former NASA scientist. He was born on March 5, 1940, in Kinsale, County Cork, Ireland. O'Leary earned a Ph.D. in astronomy from Princeton University and participated in several space missions, including the Mariner and Viking programs. In addition to his work with NASA, O'Leary has been involved in various scientific and educational initiatives. He has written extensively on topics related to space exploration and has advocated for the use of space technology to address global challenges. O'Leary's contributions have made a significant impact on the field of astronomy and space science.