All of these designs have heritage. The X-38 drew from the design experience of the HL-20. Ultimately all of these vehicles can be traced back to the X-20, Dynasoar and X-15. The X-38 was sized to be carried in the cargo bay of the Shuttle. I personally think the X-38 was inappropriate as a rescue vehicle. For emergency escape from the ISS, a capsule like what was shown in the very first episode of Star Wars (the thing that carried C3PO and R2D2) would be the best bet (KISS = "Keep It Simple Stupid"). People would counter argue that an escape system needs cross range capability. That's an utterly lame argument, IMHO. A life boat for an ocean freighter or luxury liner is designed to only save the crew and not provide real transport capability.

Concerning NASA management: Don't look for rationality. Unlike NACA of the 1930-1950s or NASA of the 1960s, the NASA of today has no real overall objective, e.g. send people to Mars. NASA is like a leaf floating down a stream being buffeted about by short term political and financial considerations. It will continue to be that way until we have a President who gives a damn about the Space Program. The first and last President who did give a damn about the Space Program was Lyndon B. Johnson. Contrary to myth, Kennedy was not really interested in the Space Program and only saw it as a propanganda exercise against the Russians and also a neat photo opportunity for himself to pose with astronauts and aerospace engineers.

Gary