I am looking for a term or phrase(3 words) that was popularized in 1979, about test pilots and the early space program. In the late 1980's it came to be used in a more general sense.

It’s an incongruous image that doesn’t seem to have any relationship to its meaning. Can you find the term?

Let me start. Strictkly off the top of my head, the first thing that came to mind was "explore the boundaries" (as in management awareness) but then I thought of "pushing the envelope". Maybe I'm way off here, but what the heck, I've started the ball rolling, so forgive me

Congrats. Colin

"Pushing the envelope" is right. Source

Well, what do you know - wasn't that a lucky guess!? I take no credit for acually knowing the answer, but reading the whole story in your linked source was educational!