I think the temperature at that altitude is ideal for mining (It also bears the risk of the equipment freezing!). Now if only we could stick together a couple of S9's and hook them up to a little solar power generator in there... That would be even more amazing!
Hook it on what?
Temperature in space close to Earth is around 10 Celsius, there is no risk of freezing and without air there is actually no air convection and heat is lost through radiation....it gets complicated.
But that balloon was flying in the stratosphere and at those levels the average is -20-10 C.
...
Really? Haven't you heard of portable solar power generators? Here, let me show you the Google search results for that:
https://www.google.com/search?q=portable+solar+power+generator
And 100,000 feet above the surface level is not by any means "close to Earth" AT ALL!
And there is a REAL risk of equipment freezing at that altitude, because temperature is around -50° Fahrenheit or less (-46° Celsius) up there, not "-20-10 C."
Unprotected electronic devices in general (and mining rigs in particular) are not designed to operate at those temperatures.