Say the word "astronaut," and you'll immediately conjure up visions of heroes and heroic feats: Alan Shepard and Virgil Grissom successfully completing suborbital flights; John Glenn orbiting Earth aboard Friendship 7 in a historic five-hour flight; Neil Armstrong stepping down from the lunar module ladder onto the moon's surface; and Jim Lovell stabilizing the Apollo 13 spacecraft after an explosion a little more than 55 hours into the flight.

But being an astronaut is not all glamour and glory. And very often it's not about being in space. In fact, the most time spent in space by one astronaut -- Sergei Krikalyov -- is just more than 803 days. That works out to be just shy of 2.5 years. When you consider most people spend 30 to 35 years in their professional career, 2.5 years doesn't seem that impressive. What do astronauts do with the rest of their time?

Well, most American astronauts are civil servants, which is what the federal government calls its employees. As civil servants, they have to attend meetings, go to training sessions and write reports -- just like any other office worker. They do, however, possess some specialized skills unique to their trade. And they enjoy, albeit rarely, opportunities to travel and work in space. From that perspective, you might say astronauts are regular, ordinary government employees who get to travel extensively, both around the world and in space.

But first, let's start with the basics -- what exactly is an astronaut?

Video Gallery: Astronauts Becoming an astronaut takes extensive training. This video clip from NASA will tell you more about what it takes. How do astronauts learn to deal with zero-gravity environments? This video from Discovery Channel will show you. What projects will future astronauts tackle? Some think they'll be heading to Mars. Learn more in this NASA video.