The space shuttle is a very useful vehicle, it allows for construction and maintenance of structures and equipment in space. The problem with the shuttle in its current form is that it is also the way into space. The launch system and shuttle should be separated, not combined. By separating them (Energia, Buran) not only do you have a useful space vehicle, but you also have an independent heavy lifter capable of being used for other jobs. Remove the SSMEs from the orbiter and place them under the ET, also develop a smaller capsule and supply vehicle for launch on Atlas Vs and Delta IVs. This will give our manned program the robustness needed to explore and conquer the inner solar system.