[ExI] Forbes posting

Anders Sandberg anders at aleph.se
Sat Dec 1 12:57:59 UTC 2012

On 01/12/2012 07:13, Andrew Mckee wrote:
> On Sat, 01 Dec 2012 13:16:09 +1300, Keith Henson 
> <hkeithhenson at gmail.com> wrote:
>> Take solar power satellites for example. Been understood for over 40
>> years, the only reason they have not been built is that the cost to
>> lift parts to GEO is too high by a factor of about 100.
> But do the solar arrays have to be built in orbit?, what about just 
> floating them up above the clouds like the Strato Solar people propose?
> Do the numbers not work for their approach, or is there a FUD problem 
> with having a very large 'kite' floating over peoples heads?

The kite could be floating over empty countryside or lakes.

I think a big problem for space is energy conversion losses. When I 
asked Elon Musk why he didn't go for space power he did a quick estimate 
of the losses involved in converting the photovoltaic electricity into 
the right voltages needed for the microwave system. That is then 
followed by transmission and reception losses in the microwave step, 
followed by terrestrial transmission losses. All in all, they easily 
seemed to eat up the 24 hour unfiltered sunlight benefit.

Anders Sandberg,
Future of Humanity Institute
Oxford Martin School
Faculty of Philosophy
Oxford University

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