"And the moon is part of that" - what he means is, further missions to the moon are part of how we achieve that.
1. He wanted them to go the moon, because we used to do that when we were great.
2. He's mad they're going to the moon, that's been done, they should go to Mars instead.
3. But they should still go to the moon.
He's unhappy because there's always more to take, and he keeps himself so in order to have a better shot at taking it.
Or the Mueller report that is 100% false and also 100% exonerates him.