I have finally gotten comfortable with the thought that there may be a satellite directly overhead, just sitting there in geosynchronous orbit and not falling on me. But now I don’t understand why we don’t put a giant solar panel in geosynchronous orbit and run an extension cord to it. Doesn’t move, so the cord wouldn’t move either, right?
I know it won’t work, but I don’t know why. So why won’t it work?
The idea is called a Space Elevator. You can find the idea in more than a few sci-fi books. NASA’s even studied it seriously…
http://flightprojects.msfc.nasa.gov/fd02_elev.html
The page describe why we can’t build it just now, but there’s no reason why we won’t be able to before 2100 rolls around.
Well, the problem is that the cord wouldn’t be exactly orbiting except at Clarke orbit, 22300 miles out. So it would weigh on the system (very heavily indeed). One possible solution would be to counterbalance it with another 22300 miles of rigid cord extending beyond the panels.
A less expensive solution was suggested in the late 1960s by Dr. Peter Glaser. He proposed geosynchonous solar panels which would then convert the solar energy into a microwave radiation beam. That beam would then be directed to a collector on earth. The project is still being extensively studied and we may see something like this in our lifetimes.
There are, of course, problems. If human assembled, the device would cost a lot–the energy you need to get out to that orbit is fairly close to what you need to get to the moon. If remotely operated, you risk Dr. Evil gaining control of the beam and turning the residents of some city into popcorn.
Here’s a more detailed explanation.
Check out the Space Solar Power people at http://www.netdepot.com/~preble/
NASA has tried a using a tethered satellite with the shuttle to generate electricity. They, at one point considered doing something like it for the space station.
Hmm. That first link doesn’t work for some reason. Try going to http://www.spacefuture.com and pick “space power” on the left side.
If you try to do that, the first problem would be the extention cord. How can you make the cable until it snaps under its own weight? A few miles, maybe? The geosynchronous orbit is 20,000 miles up. Near the satellite the extention cord itself is almost in orbit, but that still leaves a lot of miles near the earth surface where it’s feeling a full earth gravity.
That, however, can be solved by converting the energy into microwave beams and transmitting it onto an antenna farm on earth. An antenna farm would have to be a few miles across and if you (or any creature) stay in there for too long (say, many days) you may experience health problems, but there are remote places where you could build one.
So the problem comes down to the usual one: cost. IIRC it costs $70 million or so to launch a few tons of equipment into geosynchronous orbit. Oil and coal are still pretty cheap, and there’s no way a solar power satellite can compete at this point. Maybe one day it will happen, when oil prices have gone up and launch costs have come down.
Geez, 4 replies while I was typing mine? You guys sure type fast… (or think fast, I guess, my brain seems to be the bottleneck not my fingers)