Your link, I'm sorry to say, does not support the 0.85 emissivity you claimed for aluminium. Where did you get that? Your link also does not give any hint as to what temperature their source measured emissivity at. Anything can be emissive at plasma temperatures. So no. Use the engineeringtoolbox numbers, which do list treatments and temperatures. 0.2, for heavily oxidised aluminium. Z-93, as used on the ISS radiators, is rather nice, though. You should have gone with that from the start. You certainly can rotate your panels away from perpendicular to reduce insolation, but obviously that will reduce power and hash rate, while doing nothing about radiation damage or cost of now-idled capital. You are correct that we cannot perform a detailed economic analysis without a design, but I stand by my previous conclusion. We will not be commercially mining bitcoin in free space this century, and without "new physics" we won't be doing it ever. Not even with zero launch costs.

That link is for infrared thermometer readings. Hence, low temperature. It's bizarre how you are surprised by this. Anodization greatly increases the surface roughness of aluminum. This information is easy to find from lots of sources:

Gabrian

Anodized Aluminum Heatsinks: What You Need to Know - Gabrian

Heat sinks act as passive heat exchangers in many electronic devices, and many aluminum heat sinks are anodized. What benefits does anodization offer?