TL;DR
A real Moon base, one people return to and live in for long stretches, needs one thing above all: power through the lunar night, about two weeks of darkness when solar panels go dead. The United States has decided the answer is a nuclear reactor, and a White House order says it should be ready to launch by late 2029. NASA and the Energy Department have now signed a 10-year deal to make space reactors. What they have not done is pick anyone to build one. The other surprises: radiation limits how long any person can spend on the surface, so the first base would be almost entirely built by robots, and a stray rocket stage has already crashed into the Moon. The Moon base has gone from vision to procurement problem.
Below the line, for paid subscribers: The full story: where it stands, how we got here and what's dated next; our Odds board on 5 milestones, starting with "NASA names a builder for its lunar reactor by 2027"; and every source.