> For this purpose "country" has to be interpret as stepping on any land outside of the US.
"Land" is legally (and generally) defined as pertaining to planet earth. In this case the crew did not step on any land outside of the US. The moon does not have land.
I wrote in general and generic terms. Apollo 11 demonstrated that one can "set foot" on the Moon. So don't call it 'land' if that creates issues with existing laws and treaties on property rights but the point remains.
"Land" is legally (and generally) defined as pertaining to planet earth. In this case the crew did not step on any land outside of the US. The moon does not have land.