This 2D canvas simulation models a closed-loop space colony as a real coupled system rather than a scripted animation: population growth is logistic, but the carrying capacity it grows toward is set by whichever of food, oxygen or water production has the least headroom (Liebig's law of the minimum), and life-support module upgrades raise that ceiling directly. Each resource also keeps its own physical buffer that fills from production and drains with population, so a shortfall shows up first as a draining buffer and only then, once it runs low, as a real death-rate spike that pulls the population back down. Push a production slider below what the colony consumes and watch that resource's buffer collapse and the population follow; add modules or raise production and watch the ceiling โ and the population โ climb back up.