What does "total impulse" of a motor measure?

Total impulse refers to the cumulative measure of the thrust produced by the rocket motor over the entire burn time. It is a critical parameter in rocketry that combines both the force exerted by the motor and the duration for which this force acts. This is expressed in newton-seconds (Ns) and is central to understanding how much propulsive capability a rocket has.

The total impulse allows rocketeers to assess how much change in velocity (or "delta-v") the rocket can achieve, which directly impacts the rocket's ability to ascend to a certain altitude, reach its intended flight trajectory, and carry its payload effectively. The relationship between total impulse and thrust is key, as it demonstrates that simply having high thrust levels is not enough; the thrust must also be sustained over an appropriate time period to achieve meaningful performance.

By understanding this concept, one can gain insights into the design and operational capabilities of rocketry, making it a fundamental aspect of effective rocket planning and performance evaluation.