Building Your First Space Station: Docking and Assembly Guide

A space station in KSP serves as a fuel depot, crew transfer hub, and science platform. More practically, it's proof that you've mastered docking — the most technically demanding skill the game asks of you. Don't be discouraged when your first docking attempt ends with two ships spinning past each other at 40 m/s.

Before attempting orbital docking, practice rendezvous and docking in the same orbit by launching two ships and matching their orbits manually. Understanding relative velocity is 90% of docking.

STATION CORE MODULE

Launch your station core first. A minimal but functional core:

• Mk3 Passenger Module or a stack of Mk2 Crew Cabins for living space

• 1–2 Clamp-O-Tron Sr. Docking Ports (top and bottom, plus radial ones on the sides)

• 4× Gigantor solar panels (retractable)

• 2–4 RC-001S Reaction Wheel modules for attitude control without thruster fuel

• A command module for SAS (or an OKTO2 probe core)

• Sufficient monopropellant tanks for station-keeping

Leave the core in a 200–250km circular orbit. Higher orbits are more stable long-term.

MASTERING THE DOCKING APPROACH

This is the standard approach that works every time:

1. MATCH ORBITAL PLANE: Launch your second module into the same inclination as the station. The launch window matters — launch when the station's orbital plane passes over the KSC.

2. RENDEZVOUS: Set the station as your target. Use manoeuvre nodes to bring your Pe or Ap close to the station's altitude. When within 5km, switch to "Target" mode on the navball.

3. CLOSE APPROACH: In Target mode, burn toward the target marker (pink circle). Keep relative velocity under 50 m/s until within 200m.

4. FINAL APPROACH: Switch to docking camera view (press V). Use RCS (H/N for fore/aft, I/K for up/down, J/L for left/right) to align your docking port with the station's port. Approach at 1–3 m/s.

5. DOCK: When ports touch, they magnetic-lock automatically. Cut all thrusters. Done.

The Docking Port Alignment Indicator mod (if using mods) makes docking dramatically easier. Vanilla players: enable "Docking Mode" in the RCS section and use the navball's target/anti-target markers to line up.

RCS PLACEMENT TIPS

Bad RCS placement makes docking nightmarish. Good RCS placement makes it straightforward:

• Place RCS thrusters symmetrically around the centre of mass — 4-way symmetry

• The further from the CoM, the more rotation you'll get instead of translation

• For pure translation (moving without rotating), place RCS blocks as close to the CoM as possible

• Use linear RCS ports (Vernor Engines) for high-mass station modules; standard RCS blocks for lighter vessels

If you're struggling with rotation during RCS burns, turn on "Fine Controls" with Caps Lock. It reduces thruster power and makes small corrections much more manageable.

EXPANDING YOUR STATION

Once the core is up, add modules over multiple launches:

• Science lab module (MPL-LG-2): converts data into more science passively — essential

• Fuel depot module: big LFO tanks for refuelling visiting ships

• Crew transfer hub: extra docking ports in a cross or star configuration

• Communications relay: high-gain antennae for relaying signals to distant probes

Each module is a separate launch, a separate docking. The station grows one mission at a time — which is exactly how the real ISS was built.