Planetarium exhibit
Docking, berthing, and propellant
How a vehicle joins the International Space Station, and which ships move propellant into station tanks.
Docking
The vehicle flies itself in. Soft capture, then hard capture, then the hatches open.
the ship flies itself in
- IDA-2 — Harmony forward. NASA Docking System. Crew Dragon and Starliner. the ship flies itself in
- IDA-3 — Harmony zenith. Second NASA Docking System port.
- Prichal — probe-and-drogue under Nauka. Soyuz and Progress. the Russian docking hook
- Poisk — probe-and-drogue on Zvezda’s zenith. the Russian docking hook
- Rassvet — probe-and-drogue under Zarya. the Russian docking hook
- Zvezda aft — probe-and-drogue on the service module’s aft port. Soyuz and Progress. the Russian docking hook
Berthing
Canadarm2 captures the vehicle. The crew bolts it to a Common Berthing Mechanism. That is not docking.
the arm catches the ship and the crew bolts it on
CBM berthing was the path for older cargo vehicles. The SSRMS is jointed on the station model.
Capture sequence
Approach. The vehicle holds on the docking axis.
the ship flies itself in
Propellant
- Progress transfers hypergolic propellant (UDMH / NTO) into the Russian segment through the docking interface. the cargo ship that also fills the Russian tanks
- Crew Dragon does not transfer propellant into station tanks. people and cargo; it does not fill station tanks
- Cygnus can reboost by firing its own engine while berthed. The propellant stays aboard Cygnus. a push from the ship’s own engine; the propellant stays aboard Cygnus