Colloquially, and on the internet, it is now being referred to as the "Bedrest Study" because some newscasts and blogs found the bedrest portion amusing. What it boils down to is finding ways to keep humans healthy in space for longer periods of time, so we can survive on a possible moon base, and hopefully make it to Mars. The only way to do that on earth is lie down until your muscles and bones mimic what happens in space. See the new links for photo galleries and articles to the right if you are curious about the details -- or feel free to ask questions. I had a million myself at the beginning!
Here is another colorful pamphlet, front and back, for the Johnson Space Center. It sure changed a lot over the years! Definitely worth the visit if you are ever in the neighborhood.
