Harmon Everett wrote:

Its going to be unrealistic for a long long time. The "plentiful and
cheap" materials in orbit is not going to happen for decades if not
centuries.

Oh, say two or three decades, if we decided to make it a priority.

O'Neill's argument was that the moon's low gravity and lack of atmosphere made
horizontal electro-magnetic launch of raw material off the surface possible.
And that such EM launch would be many orders of magnitude cheaper than launch
via rockets.


--


Regards,
Mike Combs
----------------------------------------------------------------------
We should ask, critically and with appeal to the numbers, whether the
best site for a growing advancing industrial society is Earth, the
Moon, Mars, some other planet, or somewhere else entirely.
Surprisingly, the answer will be inescapable - the best site is
"somewhere else entirely."

Gerard O'Neill - "The High Frontier"