Each of the 64 hull panels is its own lumped thermal node solving a real energy balance every frame:
C·dT/dt = α·S·max(0,n·s)·A·[sunlit]
+ Q_internal/N
- ε·σ·T⁴·A
where S = 1361 W/m² (solar constant), σ is the Stefan-Boltzmann constant, α/ε are the coating's absorptivity and emissivity, n·s is the cosine of the sun-incidence angle on that panel's own outward normal, and Q_internal/N spreads the crew-and-equipment heat load evenly across all panels — exactly the ~100 W per astronaut plus onboard electronics described in the source article.
- Eclipse — the station's circular orbit passes behind Earth's shadow cylinder once per orbit; every panel's solar term drops to zero and only internal heat plus its own radiative loss remain, so the whole hull cools fast — this is the "-150°C in shadow" swing.
- Inertial-fixed attitude — the hull keeps one fixed orientation in space, so the same panels always face the sun and the same panels stay in permanent radiative shadow: a large steady hot/cold split.
- Barbecue roll — slowly spinning the whole hull about its long axis (as Apollo and Soyuz crews did) cycles every panel through sun and shade, averaging the temperature and shrinking the hot/cold spread.
- Coating — a high-ε white paint dumps heat fast (bright, but a good radiator); low-ε gold foil (MLI) barely radiates at all and mainly reflects incoming sun, which is why it runs hot in sunlight and stays warm in eclipse.
Real hardware relevance: this is the same lumped-node radiative balance used to size ISS radiators, spacesuit MLI layers, and satellite thermal-control coatings — just accelerated from a 92-minute real orbit to a few seconds so the swing is visible live.