If all goes according to plan, a capsule designed to carry humans will rocket up from Florida at 7:05 a.m. ET on Thursday, and go higher than any such craft has flown in more than 40 years.

"Tomorrow is giant. It's a huge day for us," said NASA Administrator Charles Bolden, a former astronaut. Standing in front of the Orion spacecraft sitting atop a powerful Delta IV rocket, together stretching 240 feet into the sky, Bolden told a crowd of international media, "I've become accustomed to saying it's a 'BFD.' If you don't know what that is, then I'll let somebody else explain it to you."