Heat is a problem, but I think it is safe to say that power is a bigger one. Those big arrays are really expensive, really heavy, degrade in output over time, and have been known to fail on occasion. [0][1]

[0] https://spacenews.com/33046spate-of-solar-array-failures-on-... [1] https://sat-nd.com/failures/index.html?https://sat-nd.com/fa...