[QUOTE=Canadian Army;56353]The Enterprise (OV-101) was constructed without engines or a functional heat shield, and was therefore not capable of spaceflight. Originally, Enterprise had been intended to be refitted for orbital flight, however, during the construction of Columbia (OV-102), details of the final design changed. Refitting Enterprise for spaceflight would have involved dismantling the orbiter and returning the sections to subcontractors across the country. As this was an expensive proposition, it was determined to be less costly to build the Challenger (OV-099). Similarly, Enterprise was considered for refit to replace Challenger after the latter was destroyed, but Endeavour (OV-105) was built from structural spare parts that had been ordered by NASA as part of the construction contracts for Discovery (OV-103) and Atlantis (OV‑104).
Which is why I would be partial to the USAF taking control of the Enterprise and rebuilding it for military flights into orbit.
I agree the Soviet shuttle program would not have been cancelled and US DoD and NASA were working on a number of Space Shuttle replacements, and the European Space Agency could build the Hermes Spaceplane. But who would fly them? Most pilot astronauts come from military background, which means as soon as the war starts, the military is not going to release any pilots for astronaut training and some point they are going recall all military personnel serving as astronauts. What you would see is switch to unmanned rockets or the Shuttle-C (
https://en.wikipedia.org/wiki/Shuttle-C)
There is less distinction in the Soviet space programme between military and civilian (if any) than in the American space programme. In wartime NASA's funding and activity would be curtailed if not stopped all together, and the shuttle programme could very well be placed under USAF control for the duration.