It's a bittersweet occasion, really. Space Shuttle Discovery has just returned from the unknown that we call "space," safely returning six astronauts and one zero Robonaut 2s to Earth after a 13-day mission. Discovery's legacy stretches back 27 years, compiling 39 flights during that span and making an indelible mark on the history of American space exploration. This guy is also the first shuttle to be retired after NASA was rocked a few years back by the impossible-to-ignore budget crunch, and already museums and institutes (29 at last coun
