[ExI] Trying for a minimum technical comment

[Keith Henson]

It would be a huge job, but there is at least one way to end the use
of fossil fuels, the rise of CO2 in the atmosphere and climate change
to whatever extent humans are  responsible.

At huge effort using conventional rockets or rocket planes we build
one solar power satellite in geosynchronous orbit and equip it with
propulsion lasers in the place of a power transmitting microwave
antenna.

Fly space planes such as the proposed Reaction Engines Skylon high and
fast, above the clouds and track the vehicle with the propulsion laser
focused on hydrogen heaters.

The higher performance of heated hydrogen in comparison to chemical
combustion gets the cost to lift power satellite parts to GEO down
from current cost by a factor of around a hundred.

That makes power from space less than half the cost of power from coal
and the energy payback is two months, ten times shorter than solar
power on the ground.

With only modest diversion into more propulsion lasers the project can
triple the number of power satellites produced every year.  Starting
from one hundred GW per year, seven to eight years after start, it
takes less than twenty years from deciding to do it for humanity to be
off fossil fuels, because this energy sources is so much less
expensive.

Power that cheap can be use to make carbon neutral synthetic gasoline
for a dollar a gallon.

There may be other ways to solve the problem, but there is at least one way.

There is lots more for people who can handle tedious engineering details.