Quick answer
Plan the new room with placeholders, install floors and exterior walls while the old hull still contains atmosphere, then connect power, lighting, and life support before opening the interior wall. Every addition changes mass and flight performance, so finish with a low-speed maneuvering and docking test.
Build in a safe order
- Pause and mark the room footprint with construction placeholders.
- Install floors, exterior walls, and the new room's outer door or airlock boundary.
- Add conduit and connect essential power, atmosphere, lighting, and control equipment.
- Confirm the extension is sealed before removing the old exterior wall that separates it from the cabin.
Systems to plan before decoration
- Power generation, storage, conduit routes, and emergency isolation.
- O₂ supply, N₂ pressure, CO₂ removal, temperature control, alarms, and vents.
- RCS or torch propulsion, fuel storage, navigation, sensors, and docking access.
- Repair access, storage density, crew paths, hygiene, sleep, and fire response.
Do not confuse a complete room with a flyable ship
A larger footprint affects docking cost, while extra structure and cargo increase mass. More mass means slower acceleration unless thrust grows with it. Keep clear access to critical parts and test the ship before committing to an interplanetary route.
Post-build flight check
- Verify pressure, temperature, power, fuel, alarms, and control access while docked.
- Undock with clearance and test rotation plus low-throttle translation near the station.
- Measure how much distance the heavier ship needs to cancel relative and cross velocity.
- Perform one controlled docking before loading valuable cargo or beginning a long route.
Sources used