Spacesuit Liquid Cooling Garment Simulator

Astronaut Activity Level

LCVG Controls

Coolant water flow 2.0 L/min

Sublimator feedwater 3.0 g/min

External heat load 0 W

⚠ Core temperature rising toward heat-stress limit — increase coolant flow or feedwater.

❄ Loop water near freezing — sublimator may ice-block. Reduce feedwater or flow.

Live Readouts

Core body temp

37.0 °C

Loop water temp

15.0 °C

Heat picked up

0 W

Heat rejected

0 W

How it works

An EVA spacesuit's Liquid Cooling and Ventilation Garment (LCVG) is a stretch garment sewn with ~90 m of narrow tubing that carries chilled water against the astronaut's skin, picking up metabolic heat. The water then flows to a sublimator, where feedwater ice sublimates straight into the vacuum of space, rejecting the collected heat and re-chilling the loop.

C_core·dT_core/dt = Q_met + Q_env − UA·(T_core − T_water)
C_water·dT_water/dt = UA·(T_core − T_water) − ṁ_feed·L_subl

UA(flow) = UA_max·(1 − e^(−flow/flow_ref))   [coolant heat-pickup effectiveness]
Q_reject = ṁ_feed · L_subl                    [L_subl ≈ 2834 kJ/kg for ice → vacuum]

Activity level — sets metabolic heat production Q_met, from ~117 W at rest to ~700 W during heavy EVA work.
Coolant water flow — how fast water circulates through the LCVG tubing; more flow raises the effective heat-transfer conductance UA between skin and loop, up to a saturation limit.
Sublimator feedwater — the ice-water flow fed to the sublimator plate; it sets the maximum heat-rejection rate via the latent heat of sublimation.
External heat load — radiant/conductive heat gained (sunlit, +) or lost (shade, −) through the suit's multi-layer insulation.

Real EVA suits (Shuttle/ISS EMU) reject up to roughly 2000–2800 W this way; running short on feedwater or throttling coolant flow too low lets core temperature climb toward heat-stress limits, while over-cooling can chill the loop toward freezing and risk blocking the sublimator's pores with ice.

Cool coolant (from sublimator) Warm coolant (heat picked up)

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