Only two space shuttle flights are left. That means there are only a few chances to choose music for the astronauts' wake-up calls. Normally, that music is selected by family and friends of the astronauts. But, for the end of the shuttle program, NASA is throwing it open to the public. You can vote on any one of NASA's top 40. Those are NASA favorites that were used to wake up astronauts. They include tunes from Willie Nelson, Aaron Tippin, Alan Jackson and Jimmy Buffett. There's another angle to this. NASA is accepting original songs. They'll be voted on, too.