NASA is planning to send humans to the Moon again

We must know as soon as possible the difference in health of astronauts
who spend a year on the moon, in 1/6 g, against the same time spent in ISS.
Actually, theres a way to check on this sort of thing short of going all the way to the moon. We should have a space station up with a rotating section. We could confirm that 1-G of centrifugal force is as good as being on Earth (no real reason to doubt that, but theres nothing like empirical proof), and at the same time study 1/6 G and even 1/3 G while were at it. All 3 can be studied on the same structure at the same rotation rate at the same time. You just have modules at varying distances from the spin axis. It can be argued we need that testing performed before we get serious about a moonbase, because it will inform on issues of crew rotation schedules.
SSI has proposed such a structure, which they call G-lab. But so far, they havent seemed to get any serious interest.
It will be good to have the lunar base under the ground so that astronauts are fully shielded from cosmic rays.
6-9 feet of regolith should be sufficient for that.
Regards,
Mike Combs