Flagship Scenario
The 150 Human Test
What does it actually take to keep 150 regular people alive in space? Regular people. Not astronauts. Just humans.
The Scaling Ladder
A group of 9 people works completely differently than a group of 150. Each time the population grows, the old rules stop working and new problems show up. Here's how that plays out at four scales.
9
People
The Crew
Everyone knows everyone. The chain of command is obvious. When someone has a problem with someone else, they deal with it face to face. This is the scale of the ISS, submarine patrols, and Antarctic winter-over stations. It's the only scale where we actually have solid data on how people hold up. For a 180-day mission, here's what 9 people consume: ~2,960 lb of oxygen, ~6,750 lb of water (assuming 93% recycling), and ~2,920 lb of food.
25
People
The Platoon
Subgroups start to form. You don't talk to everyone every day anymore. Unofficial leaders pop up alongside the official ones. Cliques happen. Some people know things other people don't, and that gap matters when specialists hold knowledge nobody else has. The consumable numbers for 180 days: ~8,235 lb O2, ~18,750 lb water (at 93%), ~8,100 lb food.
75
People
The Community
You can't know everyone personally anymore. You need actual governance. You need rules about who gets what. You need a way to settle disputes between people who barely know each other. At 75, the "we're all one crew" feeling breaks down. You're running an organization. The 180-day consumable load: ~24,705 lb O2, ~56,250 lb water (at 93%), ~24,300 lb food.
150
People
The Colony Seed
This is Dunbar's number. It's roughly the most people who can all know each other personally. Past 150, you have strangers in your own population. Factions stop being a possibility and become inevitable. Military-style command won't cut it here. You need politics. And here's what they eat and breathe over 180 days: ~49,410 lb O2, ~112,500 lb water (at 93%), ~48,600 lb food. Total: ~105+ tons.
What the 150 Human Test Tracks
Oxygen, water, and food. Actual mass at each population level, calculated from known per-person rates. These are the numbers that determine how big your ship has to be.
Psychological timeline at each scale. When does novelty end? When do factions form? How does scale change the curve?
How many hours per day go to exercise, medical checks, and keeping the hardware running? This tells you how much of the crew's time is spent just not dying.
If one person dies, one system breaks, or one skill disappears, does the whole mission collapse? The answer changes at each population level.
At what group size does "the commander decides" stop working? When do you need actual laws, elections, and courts? And how do you prevent a dictator in a place nobody can leave?
Where does one failure trigger the next? How many systems deep does a single breakdown go before it stops?
Why 150?
Because 150 is roughly where a crew turns into a society. Below that, you can run on personal trust and informal rules. Above it, you need institutions, written agreements, and a way to settle disputes that aren't between people who already know each other.
If a habitat can hold 150 ordinary people for a year without breaking, you've answered the colony question. See what the numbers look like at full scale.