zlacker

It makes sense to target a higher operating temperature, like 375K. At some point, the energy budget would reach an equilibrium. The Earth constantly absorbs solar energy and also dissipates the heat only by radiative cooling. But the equilibrium temperature of the Earth is still kind of cool.

I guess the trick lies in the operating temperature and the geometry of the satellites.

>>typ+(OP)
Asking for a friend (who sucks at thermodynamics:) could you use a heat pump to cool down the cold end more and heat up the hot end much higher? Heat radiation works better the higher the temperature?

>>golem1+p3
Not sure about the effectiveness of a heat pump in this use case.

>Heat radiation works better the higher the temperature?

The power output is proportional to T^4 according to the Stefan-Boltzmann law.

>>typ+(OP)
It's a minor point but the Earth doesn't radiate all of that heat to equilibrium, that's why we have climate change.

>>typ+y9
https://www.mdpi.com/1996-1073/16/10/4010

40% isn't much in the grand scheme of things, but maybe they can reach higher reduction with more research/materials. Mass and power are pretty cheap for spaceX, so shipping more solar panels and a heap pump might not be a deal breaker.

Would e.g. a reduction of 90% in radiator area change the overall picture on the overall feasibility? I think not, it would still be ludicrous, but I'd be happy to be proven wrong.

>>golem1+ND2
The radiator area is probably not what they need to worry about that much as we thought. When the energy input comes from solar 100%, they just need to optimize the ratio of the sectional area facing the sun over the total surface area of the satellite. If the ratio is low enough, like a fin or cone shaped object, it will be harder to be hot.