To keep everything under 100C (or 50C), your radiator surface area is in the same ballpark as your solar panel surface area. No laws of thermodynamics need to be broken. But you do need very low launch costs.

Edit: https://en.wikipedia.org/wiki/Planetary_equilibrium_temperat... A blackbody sphere near Earth's orbit balances out to almost exactly 0C. A sphere has about 4x as much radiating surface as capturing surface. A flat surface facing the sun that would have 2x, front and back.

ISS needs its radiators for the humans rather than for the electronics, which can run hotter than we can remain alive. However, main thing is compare them to the size of the ISS's solar panels: both are big, but similarly big.