On 8/24/2010 6:39 AM, Pat Flannery wrote:

And it's got around the chance of flying in its finished form that
Dyna-Soar did. :-D

To explain that - Orion is too heavy as presently designed to get into
orbit on either a Delta IV Heavy or Atlas V Heavy.
Once the Ares 1 booster goes bye-bye, Orion has nothing that can carry
it into orbit; and Ares 1 is dead - so you now have a spacecraft that
can't be launched on any existing booster.

Pat