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."
How big is this deal? The Orion is the biggest bet on getting humans to Mars. Thursday's unmanned test flight will send Orion 3,600 miles up into space, 15 times higher than the International Space Station, to test the riskiest parts of the craft—a new launch abort system, computers being subjected to high levels of radiation, the largest heat shield ever made, a parachute system that will have to slow Orion from 20,000 mph to zero in 11 minutes, and a new manner of ocean recovery being handled by the U.S. Navy.