The security airlock is the entry point to a rocket. Everything from the outside environment
that wants to enter a rocket, needs to go through its hatches and pass all their security checks.
Whenever a hatch needs to cross-check information with or needs to ask for
permission at mission control, it uses the communicator to contact and speak with it.
A hatch isolates the airlock from the outside environment and only grants entry
after all its security checks are passed. Otherwise it remains shut and denies access.