[ExI] [wta-talk] MIT boffins crack fusion plasma snag

John K Clark jonkc at bellsouth.net
Mon Dec 15 17:40:02 UTC 2008

"hkhenson" <hkhenson at rogers.com> Wrote:

> The current best estimates are in the $350 billion range.  Of course that
> assumes the project were done in a more permissive legal environment, say
> China.  The big ticket items are either a partial space elevator (rockets
> up to the end about one earth diameter out) or a 4 GW laser for the pop up
> and push transport system.  Both need to be sized to about a million tons
> per year if power sats are going to replace fossil fuels over a 30 year
> span.  I don't have a figure on the partial elevator, but the laser
> transport system (under $100/kg to GEO) looks like $40 billion for the
> lasers (at $10/watt) $20 billion for the mirrors in GEO and $20 billion
> for the pop up rockets that loft 50 ton laser stages to 260 miles.

The trouble is that we live in a era where a simple attack helicopter or
even a Tom Cruise movie can end up costing two or three times what was
predicted, and you're talking about Space Elevators (made of who knows what)
and continuous duty 4GW Lasers. Is it any wonder that few can take your
financial estimates seriously?

Everybody thought the Space Shuttle would make it cheap to get into space,
it's reusable after, but those estimates were off by at least an order of
magnitude. We'd have been better off sticking with the 40 year old Saturn 5.

I don't think anybody will be convinced by paper and pencil stuff, you need
actual hardware that produces usable energy where the path to scaling up the
pilot plant is clear, and that will take many many billions of dollars.

> Well, if you or anyone else who groks high school physics and can follow
> the math wants to help reduced the skepticism, try going over the figures
> in the web sites I have posted here.

The problem is not physics, the problem is economics.

  John K Clark

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