If you're like me (and you are sometimes) you're asking yourself why there is no new and superior replacement for a Space Shuttle that was designed in the 1970's? Well, we tried.
During the Regan era, the dream was the X-30 NASP (National Aero Space Plane) which was to use scramjets to get it up to the edge of space, where rockets would take over. I'm not quite sure what happened to this one - I think thermal management was an issue - but they are still working on the concept with the recent flights of the X-51 Waverider craft.
Then we have the X-33 prototype for the VentureStar, announced by Al Gore in 1996, . This was really advanced design. So advanced that it could not be built. It was to be a Single Stage To Orbit spaceplane utilizing revolutionary linear aerospike engines and metallic thermal tiles. To reduce weight, the carbon-fiber composite fuel tanks also served as the load-bearing fuselage. Unfortunately, trying to store liquid hydrogen in a carbon-fiber container is a bit like trying to surround a piece of jello with rubber bands. The prototype was never completed and never flew, even though we spent 1.33 billion dollars on it. However, Venture Star still lives on - take a close look at the spacecraft above Pandora in the movie "Avatar".