so this mostly turns to dust as it hits the end of the tunnel. oh, my gosh. dramatic music now, where were we? oh, yeah! 500 miles an hour. so now you're going about as fast as a jet. the actual projectiles and the spinning arm are made of carbon fibre — pretty much the only substance that can withstand the forces involved. 700 miles an hour. and in order to spin up to nearly 1,000 miles an hour today, this entire chamber needs to be a near vacuum, and that's why we can hardly hear anything. system is supersonic. if this were full of air, we'd get a sonic boom on every single revolution. you can hear a little bit. can you hear it? just a little bit? a little bit of vibration too. arming system... here we go. so he's doing the launch sequence now. ten... nine, here we go.