Closed-Loop Life Support Sustainability Index (2D)

Loop Closure — Recycling Efficiency

Water loop

Water recycling 92%

Oxygen loop

O₂ / CO₂ recycling 85%

Solid-waste loop

Waste recycling 60%

Crew size 4

Live Readouts

Sustainability index

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Resupply / year

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Mission day

Cumulative resupply lifted

0 kg

How it works

Every consumable loop (water, oxygen/CO₂, solid waste) has a recycling efficiency r ∈ [0,1). Each mission day, a crew of N consumes a fixed mass per loop; a fraction r is reclaimed and re-enters the loop, and the remaining (1−r) is a permanent loss that has to be lifted from Earth (or mined in-situ) to keep the crew alive:

daily loss_i  = consumption_i × N × (1 − r_i)
annual resupply = 365 × Σ daily loss_i

Sustainability Index = 100 × ( 1 − Σ consumption_i(1−r_i) / Σ consumption_i )

Consumption rates used here are real per-crew-member design values: water ≈ 3.6 kg/day, oxygen ≈ 0.84 kg/day, solid waste ≈ 0.5 kg/day. Because the loss term is linear in (1−r), the last few percentage points of closure matter far more than the first — going from 90%→99% water recycling cuts annual resupply mass by 10×, which is exactly why ISS's water recovery system pushes past 98% and why a multi-year Mars mission cannot tolerate anything below the high-90s without an enormous resupply budget.

Sliders — set each loop's recycling efficiency and the crew size; the mass-balance math and the ring animation update live.
Rings — particles orbit each loop; on every lap a share proportional to (1−r) turns red, breaks away to the resupply pod, and is counted into the cumulative total before a fresh particle re-enters the loop.
Reset Mission Clock — zeroes the elapsed mission day and cumulative resupply counter without changing the sliders.

Water loop O₂/CO₂ loop Waste loop Lost → resupply pod

Mission day 0
Index —