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