[ExI] Thoughts on Space based solar power (risks)

Paul D. Fernhout pdfernhout at kurtz-fernhout.com
Sat Nov 22 13:32:28 UTC 2008

hkhenson wrote:
 > I don't see any reason some hundreds to a thousand power sats and
 > rectennas would be any more brittle than the current situation.
 > Rectenna goes out, there are several feeding that section of the grid.
 > Power sat dies, there are spares.  Should be more robust.  The only
 > common mode would be a big solar flare wiping out the PV cells.  For
 > other reasons I doubt PV cells will be used anyway.

There is the risk of failure of capital concentration. Put all our eggs in 
the SPS basket (and launched from Earth, not built in space) and we may have 
to stop investing in renewables on Earth. That is a big risk.

Then there is common mode failure. They may all be subject to the same 
attack via their control signals. Or they may be all easily targeted by a 
military strike or terrorists. Or they may all be shattered in a chain 
reaction from orbital debris (there is a lot of junk up there already ready 
to go).
"The Kessler Syndrome is a scenario, proposed by NASA consultant Donald J. 
Kessler, in which the volume of space debris in Low Earth Orbit is so high 
that objects in orbit are frequently struck by debris, creating even more 
debris and a greater risk of further impacts. The implication of this 
scenario is that the escalating amount of debris in orbit could eventually 
render space exploration, and even the use of satellites, too prone to loss 
to be feasible for many generations."

Then there are unknown physical effects of long term space operations and 
material degradation in space, which are much bigger unknowns that ground 
based operations.

But the bigger point is even with thousands of rectennas, you still need a 
grid to distribute the power. If people can soon generate their own power at 
a lower price than maintaining the grid, then who are your customers? Even 
if you get big industrial customers, home use will drive falling renewable 
costs. Then competing will be hard on a price basis. So there is a 
fundamental economic business model risk.

--Paul Fernhout

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