What is a momentary push button switch used for in model rockets?

A momentary push button switch is primarily used in model rockets for ignition purposes. When the button is pressed, it completes the circuit to the igniter, allowing current to flow and igniting the rocket motor. This is a critical component in ensuring a reliable and controlled launch, as it enables the user to initiate the launch sequence at the desired moment.

The other options presented relate to functions that are either not performed by a momentary push button switch or require different types of systems. For instance, controlling the rocket's altitude typically involves more sophisticated methods, such as altimeters or onboard flight computers, which are not linked to the simple mechanical function of a push button. Similarly, deploying recovery systems usually involves a separate, dedicated switch or electronic device designed to release the recovery system at a predefined point in the flight. Finally, measuring thrust is a process that necessitates specialized sensors and instrumentation, which are not functionalities provided by a momentary push button switch.