Mission specialist is an astronaut trained to do a specific task on a United States space mission. Such a task might be conducting a scientific experiment or taking part in extravehicular activity (EVA) by working outside the spacecraft. Engaging in extravehicular activity is sometimes called spacewalking. Spacewalks are undertaken to perform tasks such as construction or maintenance on the spacecraft or other orbiting satellites . Many mission specialists are scientists, including astronomers, oceanographers, and biologists. A few have been middle or high school teachers, selected to help educate students from orbit. The title of mission specialist was first used for space shuttle missions.
Mission specialists spend years learning how to operate and maintain spacecraft systems. A specialist then trains with the other astronauts assigned to the same mission. The crew trains in the specific tasks they will carry out in space.
Mission specialists have conducted biological experiments on themselves and their crewmates. They do so to learn how the human body adapts to being in space. This information may help future astronauts survive long space missions. Some mission specialists have tested new kinds of equipment for use in space. Much of the equipment used on the ISS was tested in this way. Mission specialists and Russian cosmonauts have built most of the ISS. The job has required over 150 spacewalks and much delicate and demanding work with robotic arms. Mission specialists have captured malfunctioning satellites in space for repair. They have also launched new satellites, among them the Hubble Space Telescope . Mission specialists visited the Hubble five times to repair broken parts and to install upgraded equipment.
