"surviving orbital velocities near sea-level": How about if the tunnel was full of air moving at the same velocity as the prospective orbiter. That should give the thing some shielding at least. Or how about having a pointy armored slug (Bullet) to break up the air before the main craft comes through, reducing the drag. This would mean also that the Deceleration due to drag would ramp up slower, making 'personned' craft more workable. That said, IMH(Amauter)O, Materials Science has a long way to go before there would be a hope in hell of the ballistic orbiter becoming a reality. In addition, I can't see who would have either the cash or the inclination to build such a thing, when there are many more (and much cheaper) avenues of research to follow.
Slashdot Mirror
"surviving orbital velocities near sea-level": How about if the tunnel was full of air moving at the same velocity as the prospective orbiter. That should give the thing some shielding at least. Or how about having a pointy armored slug (Bullet) to break up the air before the main craft comes through, reducing the drag. This would mean also that the Deceleration due to drag would ramp up slower, making 'personned' craft more workable. That said, IMH(Amauter)O, Materials Science has a long way to go before there would be a hope in hell of the ballistic orbiter becoming a reality. In addition, I can't see who would have either the cash or the inclination to build such a thing, when there are many more (and much cheaper) avenues of research to follow.