en.wikipedia.org
a fascinating reading and a good start to try and understand what's happening.
Here is my gut feeling about it.
To over-simplify things: by 2030 there will be kind of three major manned spaceflight programs in the USA.
- NASA lunar orbit Gateway (Artemis)
- NASA lunar surface (Artemis)
- SpaceX Mars plans
The Gateway was created by NASA to use Orion on SLS. Just like
Asteroid Redirect Mission before it.
They have no other choice than flying SLS and using it, because it was rammed on them in 2010 by Congress "Shuttle infrastructures & jobs programs" lobby.
And so they created the Gateway as a) a destination for Orion-SLS and b) a continuation of ISS legacies - international partners (ESA, Canada) and also COTS partners (SpaceX Dragon XL...).
Now, lunar surface is something entirely different. And there, NASA is going fully private and more efficient.
They have first enlisted a whole bunch of small, robotic exploration lunar landers build by startups.
And yesterday, they added SpaceX on top of that for massive crew and cargo delivery to the lunar surface: the south pole.
Meanwhile SpaceX is going to Mars without waiting for NASA: fueled by Elon $200 billion net worth, plus SpaceX, Tesla and Starlink cash cows.
In a sense, NASA and SpaceX have made an unofficial "gentleman agreement". NASA is going to the Moon, enlisting SpaceX for Artemis, twice:
Dragon XL for the Gateway cargo, and
Starship-HLS to the surface.
Meanwhile, SpaceX is going to Mars grand scale, in a whole new way much more efficient than the old Von Braun / Apollo / Paine / SEI / Stephen Baxter "Voyage" paradigm. The Starship way.