Want to become an astronaut? It's not going to be easy — and the demands are as much mental as they are physical.
1) Do you have a bachelor's degree in engineering, biological science, a physical science or mathematics?
If not, you'd better go back to school. Films such as "The Right Stuff" portray the original group of astronauts as daredevil test pilots, but the fact is that six of the seven Mercury astronauts who went into space during the early 1960s had degrees, mostly in aeronautical engineering. Neil Armstrong had a master's degree before he walked on the moon, and Buzz Aldrin a doctorate.
2) Are you an American citizen?
This one's kind of a no-brainer, but some shuttle astronauts were born overseas and became naturalized Americans before going into space. Citizens and subjects of other countries have gone into space aboard American craft — for example, Canadian Julie Payette currently on her second shuttle mission — but are certified as astronauts by their own national space agencies.
3) Are you in good physical shape? Do you possess good vision and blood pressure? Do you stand between 5-foot-2 and 6-foot-3?
You've got to pass a NASA "space physical," which the space agency says is similar to a military or civilian flight physical. Vision needs to be 20/100 or better in each eye, correctable to 20/20 — LASIK and other surgeries are now OK. Your blood pressure should be 140/90 or better in a sitting position. And NASA doesn't want anyone who's too short or too tall.
4) Can you swim?
If not, learn. You've got to go through military water training as an astronaut candidate, as well as become SCUBA certified to prepare for spacewalk training, much of which takes place underwater. In your first month of astronaut training, you're going to have to swim 75 meters (246 feet) while wearing a flight suit and sneakers.
If you want to become a shuttle pilot, you've got to meet all the above requirements AND have logged 1,000 hours of flight time as a jet pilot.
There's also a loophole: Some spaceflyers are technically not astronauts. Rather, they're "payload specialists," who are responsible for a certain item or system that's central to a mission.
These include scientists and engineers, naturally — and while these individuals don't go through the two-year astronaut candidate training, they do have to meet the physical requirements and swim training as outlined above.