Space Station Life Support Monitor - 2D Spin Gravity, Coriolis and O2/CO2 Balance Lab

Presets

Live readouts

Graphs

Experiments

Spin: release the ball at different heights and switch between the rotating and inertial viewpoints. Life support: start from "Crew only" and see how many hours the cabin has, then add the scrubber, plants or the electrolyser one at a time.

Numerical checks

running...

How to use

Use the experiment selector or a preset. In spin mode a ball is released from rest relative to the floor; in the rotating view it is deflected, in the inertial view it simply flies straight. In life support mode set the crew, the cabin volume and the hardware and watch the gauges; the time scale runs hours per second. Space pauses, R resets.

The science

Spin gravity. A floor at radius R turning at angular speed omega must accelerate the people on it toward the axis, so they feel a push of g_eff = omega^2 R, omega = 2 pi (rpm) / 60, rpm(1 g) = (60 / 2 pi) sqrt(g / R) A 224 m wheel needs 2.0 rpm for 1 g. Gravity falls linearly toward the axis, so a head at 1.8 m is lighter than the feet by 1.8/R: 0.8 % at R = 224 m but 4.5 % at R = 40 m.

Coriolis. In the rotating frame a body with velocity v feels a = -2 Omega x v - Omega x (Omega x r). A ball released from rest relative to the floor is moving at omega r0 in inertial space and goes straight; the floor turns under it by omega t - atan(omega t) while it falls for t = sqrt(R^2 - r0^2) / (omega r0). The simulator integrates the rotating-frame equations (RK4) and compares them to this exact geometry. Walking spinward at speed u weighs (1 + u / omega R)^2 times as much.

Air balance. Cabin air is an ideal gas, p = n R T / V at 294 K. The crew uses about 0.84 kg O2 and exhales 1.04 kg CO2 per person per day (respiratory quotient 0.9), scaled by the activity factor. A scrubber that processes Q m3/h with efficiency eta removes (Q eta / V) n_CO2 (up to its capacity); plants fix 0.78 mol CO2 and release the same O2 per m2 per day at full light, limited at low CO2 by pCO2 / (pCO2 + 0.05 kPa); an electrolyser makes P eta / 474 kJ mol O2 per second (water splitting needs 474 kJ per mole of O2); leaks lose all gases in proportion; makeup gas restores 101.3 kPa with a 79/21 mix.

Health thresholds used for the status line are coarse: pO2 below 16 kPa is hypoxia, above 30 kPa raises fire risk; pCO2 above 0.7 kPa gives headaches, above 3 kPa is dangerous. They are teaching values, not medical limits.

Honest simplifications. The wheel is a rigid ring with a flat floor (no atmosphere drag on the ball, which would partly carry it along); gases mix instantly; no humidity, trace contaminants, temperature control, nitrogen or food loop; plant yield is a constant per square metre; the electrolyser's hydrogen is simply discarded.

Checks run in the page. The rotating-frame ODE against the exact inertial geometry (landing lag and fall time); 1 g spin rate; CO2 mass balance with no scrubber; scrubber equilibrium against production / k; an electrolyser sized to the crew keeping O2 constant.