Critical time

> With
> abundant and cheap lunar
> materials, available in high earth orbit, entire
> fleets of ion-driven Mars bound
> ships, could be constructed.

Looking just a little bit further into the future it
is likely that a lunar mining or space manufacturing
facility would have, attached to it, multiple research
operations. Although no one really considers anyone
to 'extract' any He3 from the moon any time soon, it
is possible that this form of fusion reation will be
utilized for an interplanetary rocket. I don't think
we will discover any energy benefits from fusion too
soon, but we will likely use an extremly powerful
fusion rocket to travel around quicker.