What is a key component of an ignition system in rocketry?

An arm switch with a removable key is a key component of an ignition system in rocketry because it provides a crucial layer of safety and security during the launch preparation process. This component ensures that the rocket's ignition system can only be activated when appropriate, preventing accidental launches and unauthorized access to the ignition system. By requiring a removable key, it gives handlers a means to secure the system until they are ready to proceed with the launch operations.

In contrast, while the other options may play roles in the broader context of launch operations or site management, they do not specifically pertain to the ignition system itself. The launch site lighting system primarily addresses visibility conditions and does not influence ignition safety, automated launch controls manage the launch processes without directly igniting the rocket, and remote monitoring technology relates more to data collection and observation rather than the act of ignition itself.