Pine Gap is a telemetry site. It's used to maintain contact with polar satellites while they're over the southern hemisphere. There is no effective infrastructure to do anything nefarious out there. This is one reason American involvement has dropped ; the proliferation of space-based relay systems has deprecated its utility. The US has many similar facilities worldwide but the Australians have always had an itch about Pine Gap because it's a visual and geographic reminder that they're our bitch. It's funny. There is more nefariousness at LAAFB, which is off Sepulveda and shares parking with LAX. It was at LAAFB that a 22 year old kid discovered that US espionage was being used to influence Australian elections in favor of the US. But what the Australians protest is US involvement in other countries, not their own.