Hmm, not sure if I want to get into a slanging match with a space cadet, but I'd like to point out that your link quotes the payback in energy cost of the fuel used to to launch the satellites. Not so much an apples to pears comparison as a grapefruit to raisin. Fuel cost is a tiny proportion of the cost of a launch. Must try harder.
You've been polite so far, and I appreciate honest skepticism as a counterpoint to natural enthusiasm.
I stand corrected on the cost. The Ariane 5ECA launch cost is $120M. On the other hand, SpaceX Dragon 9 is roughly comparable at $54M.
So, more realistically: If we can launch 3 million thinsats producing 4 usable watts each for $60M, that's $20 per thinsat or $5/watt. Assuming a rate of 10 cents per kWh, that takes about 5 years to pay for itself. (That's way off from what I quoted -- I think Keith was actually intending to make a case with regards to theoretical limits of rocket launching tech, not near-term costs.)
To achieve something more like $1-$5 per thinsat would require better economies of scale for launching. SpaceX is already getting really good at this kind of thing, but more demand would improve matters. So the case is stronger if mining becomes really big business (which it could, if bitcoin prices get high enough), or if bundled in with other significant revenue sources (e.g. providing cheap broadband internet for the developing world).
Another way to bring down the cost is to make much thinner sats, but combine them with space debris already in orbit. (Their minimum size is partly due to need for ballast.) Alternatively, sand launched from the lunar surface could be used. (Unlike the earth, electromagnetic launchers are actually physically plausible from the lunar surface.)
They would gather solar energy and cool by black-body radiation into space.
I don't understand how you could cool a computer chip in outer space. Theoretically, the solar panels collect the light and maintain a supply of electricity. The chips use the electricity, but expel most of the energy in the form of heat. Where does that heat go? How do you dissipate that much heat in a vacuum?
Heat naturally converts to infrared radiation. Areas of the craft not facing the sun or any other nearby radiation source can be cooled to around 2.7 Kelvin, although the speed at which they are cooled depends on emissivity of the surface and how hot they are running.
http://server-sky.com/coolinghttps://en.wikipedia.org/wiki/Black-body_radiationWhat an awesome concept. You use the electricity in space, don't try to beam it back.
I've been thinking about a self-contained unit that runs straight of a solar panel, turning the electricity straight into bitcoins without inverters or batteries or wires. This takes that concept to a whole new level.
Is there any reason they need to orbit earth? Why not put them in orbit around the sun? They can form their own mesh communication networks and work together as a phased antennae array for long distance communication.
The main reason to prefer an earth orbit is the low latency from the speed of light. Orbiting the sun could be useful for an interplanetary civilization, or if you just want huge amounts of raw processing power to do stuff that isn't timing-critical, like molecular simulations. However for bitcoin purposes you need to be able to hash a recent enough copy of the blockchain, so anything past 10 light-minutes would probably be out of the question. OTOH, we are only 8 light-minutes from the sun, so a swarm in the inner solar system could be mostly within useful range.
