

So I was curious about this from a superconducting electromagnet aspect which prevented me from responding to OP on the radiation thing so thanks for getting to that.
There isn’t a way to efficiently convert heat into radiative heat fast enough to keep a superconductor cool enough long enough.
You could, theoretically, create a system that exchanges the heat through convection and conduction that then stores it in something like water. Then with the water, you pass that through fins to radiate the heat. This would give you more time with the magnet being cool enough to function.
I didn’t have any useful numbers, but it looks like at some point along the trip you’d need to disable the magnet cooling system or dump the stored water. At some point the system will just not be able to maintain the temperature.
My 8 year old still plays coloring games with Elmo on his tablet. He ain’t got no time for girls per china.