Critical time

Including shielding Island one was to weigh between 9 and 10 million
tonnes - that would represent $100 million launch costs at $10/KG.

Don't forget though that the colony itself only weighs around 100,000
tonnes - the vast majority of the mass is shielding which consists of
the waste slag from the manufacturing process in space costing just a
few cents/KG assuming use of a mass driver from the Moon.

Anyway - the Island one idea is only one of many studied, there were
numerous scaled down versions of the island one idea. It also seems a
consensus now that it would be best to build the first SPS as soon as
possible ensuring quick economic and environmental benefits, leaving
the main colony building activities until later.

The essential thing is to get a space-based industry that uses
materials from either the moon or from Near-Earth asteroids to
produce things. After that the Solar System is our oyster.

Mark
>
> What was the estimated mass of the island one colony? It must be
remembered that
> even if launch costs from the moon + manufacturing & assembly costs
for an
> O'neill colony, are $10/Kg (1/1000th current earth launch costs,
not including
> the cost of assembly in orbit) a Billion tonne colony would still
cost $10
> trillion. This is equal to the GDP of the United States at present
levels.