Why is SpaceX not using a shuttle design? From a layman's perspective, having something that basically works like an aeroplane would be much easier to get reusable, or am I missing something here?
With this variety of thing you can strap multiple first-stage rockets together, blast a great big payload into space, and then the first stages return safely for rapid re-use - while your payload stays up.
The space shuttle had a pretty small payload bay, and only came in the one configuration - no flexibility, like this provides.
Also, with a passively slowed vessel, like a shuttle, you have a huge amount of heat to dissipate, which requires thermal tiles (yet more mass and refit each launch), whereas this slows in several burns throughout re-entry, meaning that the thermal stresses are nothing like you have on a shuttle re-entry.
The Energia (Russian shuttle) program originally planned to have a system like the Shuttle with even more of the rocket returnable to launch site (boosters/core stage (Energia had the "main engines" on the tank rather than the orbiter)) but also abandoned that plan (and indeed the entire program, shortly thereafter).
Most of a rocket's travel is in a ballistic arc that's vertical at takeoff and supersonic. On the upward journey, wings are unwanted drag and weight. On the downward journey, they suffer drag heating and stress. And they don't work on planets with a lighter or no atmosphere. In theory all you have to do is fire the rocket engine that's already there with a comparatively small amount of fuel to slow it from terminal velocity (probably subsonic) to a stop exactly above the ground. We finally have the computer control systems to make that feasible.
People keep designing spaceplanes on paper, but the engines are the limiting factor there.
At the velocities rockets go, air resistance is terrible, as it grows with the square of velocity and air density.
Rockets minimize area and drag by huge amounts. This means they could carry more payload per power unit.
with the knowledge and technology we have now that means propulsive is the only way to do it
musk says of the moon, "there's are no runways and no atmosphere"
https://www.youtube.com/watch?v=SOpmaLY9XdI#t=11m30s
why colonise other planets? musk says, "planetary redundancy, backing up the biosphere..there are some risks that are just extremely difficult to mitigate and some risks which we ultimately not be able to mitigate"