shakran

Easy explanation:

Ever take a bucket of water and swing it around really fast? The water stayed in the bucket even when it was upside down because of centrifugal force. The theory behind the space elevator is the swinging bucket on a massive scale. run a rope from the earth way out in space. The rotation of the earth swings whatever's on the end of the rope really freakin' fast. The centrifugal force makes your end-of-rope object pull tightly on the rope, which allows you to run an elevator car up and down the rope.




As for the space vehicle program, I think going back to the capsule days for manned space exploration is a mistake. The problem with the non-reuseable stuff is that every single time you go in to space you have to build an entirely new space ship. The theory behind the space shuttle is sound. After all, if you had to buy a new car every morning, you'd end up spending a fortune. But because you can use the same car tomorrow that you used today, you save a lot of money. Not only that, you figure out the individual quirks of your car - you get used to it in other words. If you replaced it every day you'd always be driving a new vehicle.

As I said the theory behind the shuttle is very sound, but the shuttle itself is too expensive and complicated, and most of it's not reuseable anyway. The tank dies right away. The SRB's (big rockets on the side of the tank) sometimes don't survive the return to earth, and even when they do they're only good for a few launches anyway. The shuttle has to be overhauled after EVERY SINGLE flight. It's insane. If commercial airlines ran like that they'd have to rebuild their 747's after one transatlantic crossing. They'd go under in less than a week.

The real answer is to design a new shuttle. Don't launch it vertically. It takes a crapload more fuel to launch vertically than it does to take off horizontally. In fact it takes so much fuel that a good portion of the fuel the shuttle uses is just used to lift the fuel. Again, insane.

Launch the thing like an airplane. Give it 2 sets of engines. Simple, PROVEN jet engines for atmospheric flight. Rocket engines that take over when the air gets too thin for the jets. You could get it to mach 3 (and probably faster -- mach 3 is just the official speed record for an airforce bird) on jets, then let the rockets take over for the final push. Bring it back to earth by slowing it down with rockets, then let jets take over once the atmosphere is thick enough and you're going slow enough again.

Redesign the heat shielding system. The tile system is great and the tiles are really cool - ever seen the demo where they glue a tile to your hand, fire a blowtorch at the other side, and your hand stays totally cool? But the problem is that the tiles just love to fall off and get damaged. A ton of tiles have to be replaced every time the shuttle comes back to earth. Figure out another way to do this. Use an ablative heat shield if you must, but preferably figure out a permanent solution - and by permanent I mean one that doesn't require major overhaul every time you make one trip.

Sure the development costs would probably be high, but it makes the most sense.