Spacefarers from all countries are required to have college educations, along with professional experience in their fields as a prerequisite to joining a space agency. Pilots and commanders are still expected to have extensive flying experience whether in commercial or military flight. Some come from test-pilot backgrounds. Often, astronauts have a background as scientists and many have high-level degrees, like Ph.Ds. Others have military training or space industry expertise. Regardless of their background, once an astronaut is accepted into a country’s space program, he or she goes through rigorous training to actually live and work in space. Most astronauts learn to fly aircraft (if they don’t already know how). They also spend a lot of time working in “mockup” trainers, particularly if they’re going to be working aboard the International Space Station. Astronauts flying aboard the Soyuz rockets and capsules train those mockups and learn to speak Russian. All astronaut candidates learn the rudiments of first aid and medical care, in case of emergencies and train to use specialized instruments for safe extravehicular activity. It’s not all trainers and mockups, however. Astronaut trainees spend a lot of time in the classroom, learning the systems they will work with, and the science behind the experiments they will conduct in space. Once an astronaut is chosen for a specific mission, he or she does intensive work learning its intricacies and how to make it work (or fix it if something goes wrong). The servicing missions for the Hubble Space Telescope, the construction work on the International Space Station, and many other activities in space were all made possible through very thorough and intense work by each astronaut involved, learning the systems and rehearsing their work for years ahead of their missions.