[ExI] SpaceX Super Heavy and Space Solar
efc at disroot.org
efc at disroot.org
Mon Oct 21 08:45:46 UTC 2024
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?
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