Johnson Space Center is home to America's program for human spaceflight. It houses NASA's mission control center, which directs space shuttles, both past and present. The old control room is where flight directors heard Apollo 13's, "Houston, we've had a problem." From the new mission control, Johnson scientists manage all astronauts aboard the International Space Station.
Along with directing, Johnson tests equipment for human spaceflights. It has several temperature-controlled vacuum chambers, one large enough to fit parts of a space shuttle, meant to simulate the conditions in space. Space suits and tools for spacewalks go in and, hopefully, work [source: Dean].
Astronauts also train at Johnson in a pool unfit for the Olympics. The pool, called the Neutral Buoyancy Lab, has mock-ups of the International Space Station and the Hubble Space Telescope inside. Astronauts from all over the world suit up, dive in and practice -- space walks, telescope repairs or installing parts on their new home among the stars. In fact, all International Space Station astronauts trained there [source: Jeffs].
Start at the privately owned Space Center Houston. For $90 and your advance reservation, guides will lead you on a five-hour tour of the Johnson facilities, where you can roam the Apollo mission control room. Sit in the flight director's chair? Don't mind if you do. You can also peer through windows into the new mission control, stand at the entry of the largest vacuum chamber and a walk a catwalk over the pool [sources: Space Center Houston "Level 9 Tour," Space Center Houston "Ticket Prices," Moore].
After gas and a well-spent $90, is your wallet feeling a little empty? Don't worry. The next stop is free.