Massive radiators. In this photo[0], all of the light gray panels are thermal radiators. Note how they are nearly as large as the solar panels, which gives you an idea about the scale needed to radiate away 3-12 people's worth of heat (~1200 watts) + the heat generated by equipment.

[0] https://images-assets.nasa.gov/image/jsc2021e064215_alt/jsc2...