[ExI] SpaceX Super Heavy and Space Solar

[efc at disroot.org]

On Sun, 20 Oct 2024, Adrian Tymes via extropy-chat wrote:

> On Sun, Oct 20, 2024 at 5:00 PM Keith Henson via extropy-chat <extropy-chat at lists.extropy.org> wrote:
>       On Sun, Oct 20, 2024 at 1:28 PM Kelly Anderson via extropy-chat
>       <extropy-chat at lists.extropy.org> wrote:
>       >
>       > Has anyone run the numbers on whether space based solar makes sense yet if the Super Heavy keeps some of its economic
>       promises?
>
>       Yes.
>
>       100 tons is 100,000 kg. If a flight gets down to even $10 million,
>       that's $100/kg to LEO, double that to GEO with electric propulsion.
>       6.5 kg/kW is a reasonable number, so $1300/kW for transport, $900/kW
>       for parts and labor, plus $200/kW for the rectenna.  That adds up to
>       $2400/kW.  Divide by 80,000 to get 3 cents per kWh.
>
>       Looks good from energy return time, takes about 66 days to pay back
>       the fuel energy used to lift it to orbit.
>
>       The problem is that it takes 500 flights to build one.  A reasonable
>       construction rate of 50 a year would take 20 years to replace 1/3rd of
>       current consumption. I don't know if the atmospheric damage of 25,000
>       flights per year would be acceptable, but NOAA could answer that
>       question if asked.
>
>       The money through this program is $600 B/year.
> 
> 
> Needing that much money up front, before the program is generating revenue, makes it economically infeasible.  No one with the
> requisite finances will believe that heavily in the revenue until after a small scale prototype is demonstrating, even at
> significantly lower economic efficiency ($0.10-0.50 per kWh, perhaps). 
> 
> You may see such a prototype as "wasteful" or "wasted", and in the long run it would become obsolete.  It is a necessary expendable,
> in a sense, to get the program started.
> 
> In that light, what are the numbers for a prototype that could be built with just one Super Heavy?  The $/kWh will be worse, but you
> have an absolute maximum to LEO of 100 tons.
>

Yes! Why couldn't it be built in modules, expanding as you go?