North Base aka Operable Unit 10;
This site has info on it:
www.abovetopsecret.com...
Officially North Base is used for advanced propulsion research (feel free to think about hypersonic research & development when you think of North
Base), and workers are brought in via Janet Air just like the A51 workers are (yes, A51 is still an operable, viable facility).
Just for reference, Lockheed's Skunkworks and Northrop's similar secret facility are both located on the southend of Edwards.
Unlike A51, there are some parts of North Base that are actually open to public - and I might add that there are few if any reports of UFO or
unexplained aerial phenomena eminating from around that facilty.

