Spaceships dock by using a probe and drogue system for initial alignment, followed by retraction to create a sealed connection.
Here's a more detailed breakdown:
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Initial Approach: The approaching spacecraft, typically the one taking the active role, navigates towards the target spacecraft or station. Precise navigation and relative velocity control are crucial.
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Probe and Drogue System:
- The active spacecraft extends a probe. This probe is a protruding mechanism with a capture latch.
- The target spacecraft or station has a drogue, which is a cone-shaped receptacle on its docking port.
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Capture: The probe on the active spacecraft is guided into the drogue on the target. The latch on the probe engages, capturing the drogue.
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Alignment: Once the probe has captured the drogue, it initiates an alignment process. This ensures that the docking ports of both spacecraft are perfectly aligned.
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Retraction and Sealing: The probe then retracts, pulling the two spacecraft together. As they are drawn closer, docking rings on each vehicle engage, creating a structural connection and an airtight seal.
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Hard Dock: After the initial soft dock, a process called "hard docking" occurs. This involves extending latches and bolts to rigidly connect the two spacecraft, establishing a strong and secure interface.
In simpler terms, imagine throwing a rope (the probe) with a hook on the end into a hoop (the drogue). Once you've hooked it, you pull the rope to bring the two objects together.