NASA uses "terrestrial" in the sense of "not in low earth orbit." And they're a government agency. I'm not a bit surprised to find they classify people according to the project they work on, using clumsy language. (The terrestrial experiment involved this much money, so many people, that much equipment. Was Ed one of the terrestrial people? No, Ed is still working on the space station.) Someone hacking in to read a bit out of context might conclude Ed was of non-terrestrial *origin*, rather than recognizing he was just doing a job with non-terrestrial focus.