I still remember the frustration of not being able to see the other missions before finishing the previous ones.
All you had to do is start the program with "shuttle.exe/all" and all missions were available.
If you still have the program and a computer it runs on, try the following:
Start any of the missions and at 73 seconds into the mission execute a manual separation of the solid rocket boosters. Then switch to external view. It is eerie, because the program, instead of just separating the solid rocket boosters, makes the shuttle to be destroyed, and what you can see on the external view is exactly what we saw when the Challenger perished.