[ExI] Power sats and propulsion laser response

[Keith Henson]

On Sat, Dec 8, 2012 at 4:00 AM,  Adrian Tymes <atymes at gmail.com> wrote:

> On Fri, Dec 7, 2012 at 9:54 AM, Keith Henson <hkeithhenson at gmail.com> wrote:
>> At great expense and effort
>
>> the only new part is the one
>> stage of bootstrapping
>
> Can we add further stages?  Bootstrap the bootstrap of the
> bootstrap of the bootstrap?  Billion-dollar efforts may be
> "bootstrapping" compared to trillion-dollar efforts, but they're
> not the kind of thing one can just do without further planning.

The economic model already has some of this in it.  For example, the
LEO to GEO transport leg is powered first and that increases the
payload per flight from about 40% to about 65%.  Takes only about 1/10
the laser capacity needed for the boost from 26 km to LEO.

And beyond the 100 GW per year stage, the assumption is that some of
the power satellites are diverted to more propulsion lasers to get the
production rate up to one or two TW.

There is a limit on the low end because of the square/cube law.
Exactly where that is, I don't know.

The goal to optimize is getting off carbon soonest rather than
minimizing peak cost.

The whole concept needs more study and planning, certainly more than
it is possible for me to do.

The $140 B peak investment that came out of the model I ran is first
order, but I don't think I missed any of the big ticket items.  It's
also possible I was pessimistic on the cost of the lasers.

Keith