I always wondered this as a kid, and have never been able to find a straight answer to this question. I especially began wondering this immediatly after the Challenger disaster.
Could the Space Shuttle Enterprise have been converted to being a flight worthy shuttle? I know it was never intended too, only to be used for landing and aerodynamic tests, but would it have been easier to retrofit the Enterprise and bring it out of retirement? Or would it have even been possible in the first place? I know it was donated to the Smithsonian before the accident, but it could have been brought out if need be, couldn’t it?
The shuttle Endeavour was built as a replacement for the Challenger after it exploded. I think if it had been easier to refit the Enterprise they would have done so.
Don’t know if it could have been refitted for service (I assume not, or they wouldn’t have built Endeavour instead), but ISTR Enterprise originally was to have been a working shuttle, but President Carter cut the funding for the shuttle program, so NASA could only afford four working shuttles instead of five.