What does a barometric altimeter measure?

A barometric altimeter measures altitude based on changes in air pressure. As a rocket ascends, the atmospheric pressure decreases, and the altimeter uses this change to calculate the altitude. The principle behind this measurement is that the air pressure at higher altitudes is lower than at sea level, so by measuring the current air pressure and comparing it to a standard value (usually at sea level), the altimeter can determine how high the rocket is.

This device is crucial in rocketry, as it allows for accurate tracking of altitude during flight, which is essential for understanding performance and parameters such as the rocket’s apogee. In contrast, the other options relate to different measurements that are not the focus of a barometric altimeter's functionality. For example, measuring speed or temperature are functions typically executed by different instruments. Similarly, monitoring fuel levels is managed through other specific sensors designed for that purpose.