[The Red Zone]

Finally, you've got to figure out a way to pull the air out of your tunnel, but still allow the payload to get out safely. This means a door of some sort that has to be big and heavy enough to keep air out, but must be nimble enough to open quickly, when the payload is close to the exit.

Thin glass suffices to hold the vacuum in an electron tube at sea level. Why not a glass window that the ship smashes through?

[r9etb]

Thin glass suffices to hold the vacuum in an electron tube at sea level. Why not a glass window that the ship smashes through?

At 8 km/sec? It would make a pretty flash and you might get some shrapnel into orbit.... ;-) (And the glass would have to be thick....)