A few niggles.

-Interesting vibration interferrence patterns would result from all those SRB's

-Would one want to rocket straight up or use the rotation of the Earth for a launch of this size.

-No conservation of angular momentum shown in the extention/retraction of the arms.

-Interesting landing system for Mars, a glossed over issue.

It does show some thought that they're not using fission devices in the atmo. Don't get me wrong, someone want's to use laser triggered fusion, more power to them. Literally.

I've always thought Orion would be good for getting a Buzz Aldrin class Earth-Mars cycler, built BSG style in orbit, moving. Then the orbit could be maintained with more conventional, less impulsive, methods like a high efficiency VASIMR motor. Then, volatiles could be supplied in packets of ice, oxygen for breathing and hydrogen for the VASIMR, from those inevitable lunar rail guns... :)