Simulating Rocket Trajectory Using JSBSim and Optimal Thrust Profile for Maximizing Altitude of a Sounding Rocket.

Solid rocket boosters are commonly used for launching sounding rockets due to their simplicity and power-ness. The shape and geometry of the propellant grain determine the thrust-time profile which has a significant effect on rocket performance. In practical application, the thrust profile has three typical curves; regressive, neutral, and progressive. A great deal of studies has been focused on optimizing the trajectory based on various state variables in which the profile of the thrust-time curve was not among those variables. In this research, design variables were the thrust profile, the object function was maximizing the altitude subjected to constraints of a fixed amount of fuel. The trajectory was found by solving the equations of motion. For comparison purposes, the trajectory was also found using JSBSim, an open-source flight dynamic simulator. In the results of the optimization process, the input thrust-time curve was evolved into an unusual shape, the letter "V" shaped. In this type of profile, the thrust curve starts regressively until reaches zero value at the middle of the burning time and then continues progressively until the end. This behavior can be satisfied only by two-stage boosters. Thus, these results show that two-stage boosters perform better than single-stage. The improvement is obtained by consuming the solid propellant more efficiently allowing fewer energy losses. This reason is added to the fact that two-stage boosters allow reducing the total masses due to the cassette separation. [ABSTRACT FROM AUTHOR]