We just bought some high efficiency solar cells for our cubesat at $500 per watt.
For what it is worth, that is 1600 times more expensive than home solar panels now down to 30 cents a watt. So I plotted it:
http://aprs.org/Energy/solar/Cost-of-efficiency.png
It is interesting that we hear so much about solar getting cheaper, but in fact, the high end only gets more expensive. That is why those people who say “I’m waiting for higher efficiency” will never see it be cost effective. The space industry will always pay much,much more for just a factor of two increase, whereas the homeowner will only ever pay the cheapest. And cheap it is!
Solar power is now cheaper than a custom glass window of the same size. The cost of the solar cells is only 10% of the typical home installation (recently seen as low as $2.70/watt contractor price in PA).
Bob, WB4APR