"If we find out there’s water on the Moon, and we want to do more extensive operations on the Moon to go explore that, we have the ability with Deep Space Gateway to support an extensive Moon surface program," he said. "If we want to stay focused more toward Mars we can keep that."
It has been a long time since NASA, especially its chief human spaceflight official, talked openly about an "extensive Moon surface program." However after six months of a new presidential administration, the agency realizes that its destination may well change. Therefore its leadership is keeping the decision about destinations open, be it the surface of the Moon or Mars.
The reality is that NASA may not be able to go either place unless something changes. The agency doesn't have the funding to build a large lunar outpost if it must rely on the Space Launch System—which will only fly about once a year, at a cost of more than $1 billion. Mars landings, clearly, would cost even more with the big, expendable rocket approach requiring five or more launches per mission.
Another, less costly option is having the freedom to rely much more heavily on partly or completely reusable launch and in-space transports systems being built by SpaceX, Blue Origin, and United Launch Alliance. Politically, so far any reliance on commercial companies for deep space exploration has been a non-starter in Congress. But that could change, as Vice President Mike Pence has been making some noise about increasing commercial partnerships at NASA. "The truth is that American business is on the cutting edge of space technology,"