Or are we assuming that STS orbiter production was accelerated in this alternate universe?
Well, the first Skylab reboost flight must take place in October 1979, so yes, STS production is accelerated in the alternate history (as noted in Section 2 of the manual under
What If?). Granted, my use of real-life mission numbers in an alterntate history was bound to create confusion, but what the hell.
Although the
Skylab Reuse Study was a serious, real-life document my history must ultimately rest on a foundation of make-believe. To save Skylab with the Shuttle (as proposed in the
Reuse Study) I had to either make belive that Congress authorized more money, allowing Shuttle development to be completed by 1979, or make believe that Sun spot activity was lower, extending Skylab's on-orbit life into the early 80s, permitting it to overlap the real-life Shuttle timeline.
In my make-believe history I decided that the actions of Congress could be more plausibly altered than the actions of the Sun. (Sure, that's a stretch.)