[ExI] EP, lasers and power satellites

Keith Henson hkeithhenson at gmail.com
Fri Mar 2 15:11:00 UTC 2012

Robert Wright was my first introduction to Evolutionary Psychology.
He is now an editor at The Atlantic and wrote this piece:


I responded in the comments section:

Robert, I have been a fan since _Moral Animal_, cited you a number of
times and have a couple of EP publications, though my degree is in

I would like to suggest a different way, expensive, but much less so
than a war with Iran.  It also provides a solution to energy and
carbon and, unlike a war, it could make enough money to pay off the
national debt, including that needed for Social Security. It even
makes synthetic gasoline for a dollar a gallon.

Long term, solar is the best energy source.  It's hard to use because
it is intermittent.   Dr. Peter Glaser suggested in 1968 that we go
into space (geosynchronous orbit) to collect energy and send it down
by microwaves similar to those communication satellites use.   The
problem is the high cost of shipping millions of tons of parts to GEO.
  Google seth potter boeing power satellite for one of the studies
showing the cost would be around a dollar a kWh given current
transport cost.

We need power at two cents per kWh to make synthetic fuels.  If you
analyze the contribution to cost of space transport, it has to get
down to around $100/kg to GEO.  I don't think that can be done with
chemical fuels.  The SpaceX Falcon Heavy is 40 times too expensive.

Beamed energy propulsion is a different matter.  Instead of getting 1
or 2% of a rocket liftoff mass to orbit as payload, the higher exhaust
velocity from laser heated hydrogen will allow 25% payload and a fully
reusable first stage.  It looks easy to get a cost reduction from over
$10,000 a kg to under $100.  The reason this has not been proposed
before is that the big solid state laser diodes and multi kW fiber
lasers are just coming on the market.

While they make it possible, it's still expensive in parts and the
cost to lift an initial seed laser to GEO.  I estimate the cost to be
between$50 and $100 billion.  That's less then the space station,
about the same as the F-22 and much less than the Iraq War.

So how does laser propulsion keep us from worrying about Iran?  In
addition to propelling rockets to space by heating hydrogen, they can
_melt_ rockets or aircraft being used to deliver nukes.  The SDI
software was repurposed to kill mosquitoes.  Google jordin kare
mosquito laser for the story.  We can repurpose it back to its
original use, after killing a few million mosquitoes it should be
reliable.  Done with Manhattan project type of management, it could be
ready before Iran could make nuclear bombs.

Given that the alternate is a war with Iran, I don't think anyone is
going to be concerned about putting propulsion lasers in space that
are not intended as weapons even though the could be used that way.

Between drones and Hellfire missiles, the US already has the ability
to fire on even our own citizens anywhere in the world.  A propulsion
laser is in the same class as a Hellfire missile so it isn't going to
make things any worse.

If you want to read a slightly out of date longer version, Google
Henson Oil Drum.


More information about the extropy-chat mailing list