Is there available breakdown of the heat balance of the International Space Station?

In particular:

  • How much heat is produced?
    • by direct warming by sun
    • by warming of solar panels (heat for the sake of energy production)
    • by life support systems
    • by present humans
  • How much heat is radiated away?
    • via active cooling (heat radiators)
    • through other surfaces

The mentioned categories are just examples what I understand under the breakdown, a breakdown into different categories will also be very interesting.

  • $\begingroup$ Heat production by direct warming by sun and by presence of astronauts will not be constant over time. $\endgroup$
    – Uwe
    Commented Feb 10, 2019 at 18:14
  • $\begingroup$ Yes, I know it is necessarily a simplification. But maybe breakdown for average situation would be available, or it would be possible to obtain ranges for some of these? $\endgroup$
    – Irigi
    Commented Feb 10, 2019 at 18:18
  • $\begingroup$ Are you talking about the interior of the ISS (the habitable volume) or something else? $\endgroup$ Commented Feb 10, 2019 at 18:25
  • 1
    $\begingroup$ Yes, about the pressurized habitable volume. $\endgroup$
    – Irigi
    Commented Feb 10, 2019 at 18:28
  • $\begingroup$ Heat produced by warming of solar panels is conducted to the pressurized habitable volume only in a very, very small amount. $\endgroup$
    – Uwe
    Commented Feb 10, 2019 at 21:27

1 Answer 1


On the US Operating System side:

The External Active Thermal Control System has two independent loops, each of which can reject up to 35 kW, for a total of 70 kW.

enter image description here

The EATCS provides heat rejection capabilities for all U.S. pressurized modules and the main power distribution electronics on S0, S1 and P1.

Additionally there are 4 PhotoVoltaic Radiators (PVRs) which cool the solar array power generation systems. Each PVR can reject up to 14 kW.

enter image description here

Total heat loads must remain less than the capabilities of these loops in order to control the internal temperature.



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