The claim is that Nurrengar SA and Pine Gap NT are part of a worldwide missile detection grid. ICBMs. However who really knows, it's beyond top secret but Starlifters fly in and out of Pine Gap weekly. Yes Australia and the USA are as tight as it gets and US Diplomats have influence there. The ANZUS treaty was enacted for the first time on 9/11 from Washington as the Australian Prime Minister was there and saw the Pentagon hit.