Space psychology research on ISS crews, Antarctic winter-overs and other isolated-and-confined-environment (ICE) analogs consistently finds that morale does not decline steadily — it follows a distinctive curve first named the third-quarter phenomenon (Bechtel & Berning, 1991): high spirits early on from novelty, a slow decline through the middle of the mission as monotony and sensory restriction accumulate, a nadir around the third quarter, then a genuine lift in the final stretch as the crew anticipates returning home.
This simulator drives each crew member's stress level si ∈ [0,100] with a per-day differential update built from three well-documented drivers:
ds/dt = k_iso · (1 − e^(−t/τ)) adaptation/monotony load, saturates ~3 weeks in
− k_coh · cohesion team-building & structured activity countermeasure
− k_sup · cohesion·(1 − delay/22) real-time family & flight-surgeon contact
− k_ret · max(0, (t/T − 0.85)/0.15) anticipation-of-return relief, final 15%
Longer Earth communication delay (up to ~22 minutes one-way at Mars's farthest point) throttles the third term directly — real-time counseling becomes impossible and support falls back to slower, asynchronous messages, a documented behavioral-health risk for Mars-class missions. Group morale is 100 minus the crew average of si; the cohesion index falls as individual trajectories spread apart, reflecting fraying group dynamics rather than any single person's mood.
- Crew size — more people means more individual variability (independent noise per astronaut) averaged into the group readout.
- Mission duration — stretches or compresses where the third-quarter nadir and the end-of-mission recovery fall in real time.
- Cohesion activities — the flight surgeon's main lever: shared meals, exercise pairing, structured recreation.
- Comm delay — models a Mars-distance mission, where the isolation itself gets psychologically harder to counteract.
This is a simplified computational model built to reproduce the qualitative shape NASA behavioral-health researchers report, not a validated clinical instrument.