That somehow, someone in NASA will find a way
to use space shuttles to haul up moonbase modules
into LEO, where they'll rendezvous & linkup with
"hopefully" reusable OTV's
that will boost them towards the moon.

The modules might go up by the shuttles.
And the unmanned OTV's might be launched into
LEO by Atlas-V Heavy-Lifters [already in NASA's inventory]
and DELTA-IV Heavy-LIfters [capable of parking 26 metric tons
in LEO].
Of course, to make a "reusable" OTV, one that can be
returned from the moon and refueled in LEO (Low-Earth-Orbit), would
probably require it to use hypergolic propellants [UDMH-N2O3].

Jacob

"This world has enough for everyone's need, not everyone's greed."

MAHATMA GANDHI.