I think that's an interesting idea too. Perhaps a future STS tank could have a web of carbon fibers flush with the foam surface. That might be the ultimate solution. As it stands, the odds are of another piece of lethal foam striking the orbiter are less than the odds that introducing a vastly new "safer" technology would directly (or indirectly) cause another mishap, perhaps of a different type.<br /><br />I'm going to guess that the future orbiter will be smaller, designed to carry astronauts and their supplies into space rather than large satellites, and will be mounted on top of the fuel tank and feature reusable drop away cryogenic first stage engines closely based on the current ones technology. On top of that would be a cryogenic second stage with smaller cryogenic drop away, possibly also reusable, and then a final orbit insertion and maneuvering stage that would detach and burn up before the jet engine equipped shuttle re-enters the atmosphere for maneuverable landing. <img src="/images/icons/cool.gif" />