Army Maj. (Dr.) Francisco Rubio waves as he is introduced as one of 12 new astronaut candidates at NASA’s Johnson Space Center in Houston, Texas, June 7, 2017. After completing two years of training, the new astronaut candidates could be assigned to research missions aboard the International Space Station, on launches from American soil aboard spacecraft built by commercial companies or on deep-space missions aboard NASA’s new Orion spacecraft and Space Launch System rocket. NASA photo by Bill Ingalls