In October 1989, she flew aboard the space shuttle Atlantis that deployed the space probe Galileo. In June 1993 she flew aboard Columbia, on the first flight of the Microgravity Science Laboratory. In June 1995 she flew on Atlantis for the first docking of a shuttle with the Russian space station Mir. Baker joined NASA as a medical officer in 1981 and was selected as an astronaut in 1984.After her 1995 space flight, Baker worked a variety of jobs at NASA in support of the space shuttle and International Space Station programs and development of the Exploration Program. She logged more than 686 hours in space before she retired in December 2011.