At the time she was flying on the Shuttle, the USAF was involved in the overall project and it was being used to lift military payloads into orbit, including some classified ones. The USAF stopped using the Shuttle after the Challenger accident.

Certain things like inertial guidance systems were (and probably still are) highly classified for a good reason: ours were great, and theirs sucked.

And how much did she know about them?

The design of the fan blades of the Rolls Royce jet engines on an A380 are a closely guarded secret and yet we allow people to fly on it without a security clearance - even people from Seattle, even Boeing employees (although they do have to sit outside!)

One of the real problems with the Shuttle is/was the cold war paranoia of Nasa. I worked on Hubble and 20years afterwards I still (as a Brit citizen) wasn't allowed inside JPL for an anniversary celebration

> And how much did she know about them?

Possibly quite a bit. Astronauts aboard the Apollo 13 had to make various repairs to different subsystems, so I would not be surprised if later Astronauts received fairly detailed information about how the entire system worked as part of their training, 'just in case'. At which point, you really don't want to have to worry about which pieces of information are safe and which are classified, or who is allowed to talk to who about what. Much easier and safer to just ensure you can give away as much info as possible to everyone involved.