you want to find “forces” to apply to a dynamical system so that you steer it in behaving the way you want. it can be as simple as asking “what are the forces that I need to apply so that it eventually goes to a place I want it to”. In general applications are in the domain of optimal control theory which also requires to minimize a certain function while you are controlling the system. So then the questions become

1- Can I find external influences such that I can force this system to end up there

2- What is the minimal cost way I can force this system to end up in there

In the example of a rocket it could to reach a certain speed or a certain location (both can be seen as subsets of the coordinate,speed phase space which is where the dynamical system evolves) while minimizing fuel usage