All that being said (and true!), you also have a very cold sink to reject waste heat to, whether you want to or not. The end result is that heating is as much

All that being said (and true!), you also have a very cold sink to reject waste heat to, whether you want to or not. The end result is that heating is as much an issue as cooling. Thus spacecraft usually wind up with blankets and radiators, both. :) Here's a detailed look at the thermal control system for the ISS, for the curious: https://www.nasa.gov/pdf/473486main_iss_atcs_overview.pdf https://www.nasa.gov/pdf/473486main_iss_atcs_overview.pdf