Launch is due at 12:05 PM GMT on Thursday lunchtime.
The Orion Capsule will be lofted on the huge Delta IV Heavy rocket, so its going to be spectacular.
There is a 60 percent chance the weather will hold up for the first, uncrewed test of the space capsule.
Orion is a return to the “capsule on a rocket with parachutes” design of Apollo, but it’s substantially bigger. 5 meters across at the base, versus just under 4 for Apollo, and it’s taller as well. That actually is a huge difference. Orion has a pressurized volume of nearly 20 cubic meters versus just over six for Apollo. Its planned to eventually carry four to six astronauts. Apollo carried three.
The planned mission profile is to orbit the Earth twice, heading up to an altitude of about 5,800 kilometers. The mission should take about four hours from launch to splashdown.