Life Support PID Control Loop Tuner (2D)

Real spacecraft life-support hardware doesn't just monitor cabin air — it closes the loop with an automatic controller that decides, moment to moment, how hard to run the CO₂ scrubber. This 2D simulator implements a genuine PID (proportional-integral-derivative) controller driving a mass-balance model of cabin CO₂: crew metabolism adds gas continuously, the scrubber's actuator removes it at a rate the controller computes from the live error, its integral, and its derivative. Push the proportional gain too high and the loop overshoots and rings; push the integral gain too high and it slowly oscillates; add derivative gain to damp the swings. A scattering dot field shows cabin CO₂ density, a spinning fan icon visualizes scrubber effort, and a live strip-chart plots the concentration against its setpoint over time — exactly the tuning trade-off real ECLSS automation engineers face. Pan and zoom the schematic freely to inspect either the cabin cross-section or the trend graph up close.