When using a pressure-sensor altimeter in a rocket that will not reach Mach 1, what is required?

Using a pressure-sensor altimeter in a rocket that will not reach Mach 1 indeed requires ensuring that the sensor operates effectively in its environment. In this context, drilling holes in the electronics bay for atmospheric access is crucial because the pressure-sensor altimeter measures atmospheric pressure to determine altitude. This function relies on the altimeter being able to sense external air pressure changes.

When a rocket ascends, the atmospheric pressure decreases, and the altimeter detects this change. If there are no openings for atmospheric access, the internal electronics bay would remain at a static pressure, leading to incorrect readings and potentially malfunctioning of the altimeter. Thus, creating pathways for atmospheric air ensures that the sensor can accurately measure the pressure outside the rocket, leading to reliable altitude readings throughout the flight.

Other options may suggest various modifications or precautions but do not address the fundamental need for atmospheric access necessary for the pressure-sensor altimeter to function correctly under the specified conditions.