Total impulse is an important parameter of a launch vehicle and is simply the integral of the force over time
where is the burn time and is the average force over . The force from the rocket motor can vary substantially with time. Usually, a larger total impulse means a physically bigger rocket, but note that it does not mean a larger force or a longer burn time. Putting more fuel and oxidizer into a rocket means increasing the total impulse.
This article is part of a pre-course program used by NAROM in Fly a Rocket! and similar programs.