Nimoy and other Star Trek cast members celebrate the unveiling of the NASA space shuttle 'Enterprise', 1976 NASA: NASA is mourning the passing today, Feb. 27, 2015, of actor Leonard Nimoy, most famous for his role as Star Trek's Vulcan science officer Mr. Spock. The sci-fi classic served as an inspiration for many at NASA over the years, and Nimoy joined other cast members at special NASA events and worked to promote NASA missions, as in this 2007 video he narrated before the launch of the Dawn mission to the asteroid belt.