On Earth, you wake up, sit up, walk to the kitchen, turn on the tap, pour coffee, take a shower, flush the toilet, and maybe water a plant or two.
You don’t think about gravity. Or air pressure. Or heat transfer. Or fluid dynamics. They’re just there. In space, all of these things work differently.
Living in space means redesigning every part of daily life because the laws of physics that we have adapted to on Earth – gravity, atmosphere, or convection – manifest in a very different way in space.
Walking? Not Really.
On Earth, you take a step and gravity pulls your foot back to the ground. In microgravity, pushing off sends you drifting until you hit a wall. That’s why astronauts float — and why space stations have handrails everywhere.
There’s no “up” or “down,” only relative orientation. Floors and ceilings are interchangeable. And for long-term health, you need to simulate load-bearing activity just to keep your muscles and bones from wasting away.
Water: A Problem in Every State
Water clings to itself in space. There are no falling droplets, no neat streams. A drop released in microgravity becomes a floating blob. It sticks to surfaces. It doesn’t drain.
This complicates:
- Washing (everything is done with damp cloths),
- Toilets (vacuum suction replaces gravity flush),
- Drinking (surface tension keeps fluids in pouches or straws),
- Condensation (it collects in hidden places and can damage electronics),
- Showers (don’t exist — water won’t fall).
And if a pipe leaks? It’s not a puddle. It’s a hazard floating into circuits or lungs.
Heat and Air: No Flow, No Chill
On Earth, hot air rises. In space, it doesn’t. There’s no convection — only conduction and radiation. That means:
- Your laptop or body heat doesn’t “rise” — it just sits around you unless fans actively circulate air.
- Cooking is difficult, not just because of fire risk, but because heat doesn’t spread predictably.
- Radiating heat away into space is hard — which is why spacecraft have large external radiator panels.
Breathing and Pressure
Earth’s atmosphere pushes evenly on everything at sea level: 1 bar of pressure. Your lungs, your eardrums, your juice box — all balanced.
In space, you need a sealed environment pressurized just enough for survival, but not so much that structural mass becomes unbearable. Most spacecraft run at partial pressure, with high oxygen content — but that raises fire risk (like the tragic Apollo 1 accident).
Every hatch, glove, window, and suit must maintain a seal between hard vacuum and a livable bubble.
Gravity-Driven Biology
Plants grow upward because of gravity. Water percolates down through soil. Roots spread out to stabilize. In space:
- Roots get confused about where to grow.
- Water floats around the root ball.
- Soil doesn’t stay put unless contained.
- Light direction becomes the only reliable cue for orientation.
Successful space farming requires engineered substrates, moisture control membranes, and growth chambers.
What This All Means
Living in space is possible — but it’s like camping on a volcano: the environment is actively trying to unmake you.
Every routine action requires engineering and intentional design. And many of the systems we build must do the job of gravity, weather, and natural flow — things we rarely notice until they’re gone.
For entrepreneurs, designers, and researchers, this creates opportunity: to rethink, reengineer, and reimagine everything from beds to bathrooms, kitchens to gardens.
By Pedro Lacerda.
Related Links
Physics in Microgravity
Life Support and Habitat Engineering
- ESA – Micro-Ecological Life Support System Alternative (MELiSSA)
- NASA – Environmental Control and Life Support System (ECLSS)
- JAXA – Fluid Physics in Space
Food, Water & Sanitation
Historical Incidents
