In the missing 265 missions would be the implementation of a permanent Moon base or maned exploration of Mars for example. Or, the building of a capability to intercept asteroids or comets that threaten Earth. Or, a Holiday Inn with a fantastic view. We'll never know. It wasn't allowed to happen.
Would be interesting to know more detail of the orignal vison.
Here is how they made Tang in space. A waste of time and resouces in my opinion.
http://www.geekosystem.com/shuttle-urine-recycling/