A loop heat pipe carries heat with no moving parts: fluid boils off a capillary wick at the hot evaporator (bolted to the electronics), the vapour travels to a cool condenser on the external radiator panel and gives up its heat to space, and the liquid wicks back to start over. It is variable-conductance — a small gas reservoir expands or contracts with the fluid's vapour pressure, opening more condenser area when the component runs hot and choking it off when the component runs cold. That is a passive thermostat with no controller: hot pushes conductance up, cold pulls it down, and the evaporator settles near a fixed set-point almost regardless of what the outside is doing.
Without the loop, the component only has its own small thermal mass and a poor conduction path to fall back on. It has no way to dump a sudden solar load or to hold onto heat once the sun disappears, so its temperature tracks the raw external swing almost directly — baking in full sun and plunging in eclipse, cycle after cycle.
- Orbit period — how fast the spacecraft cycles between sunlight and Earth's shadow.
- Solar heat intensity — the external heat load hitting the evaporator face while illuminated.
- Internal electronics power — constant waste heat that keeps the passive component from ever fully freezing.
- Mode toggle — switches which trace drives the 3D model's colour and glow; both traces always plot on the chart for direct comparison.