What is the relationship between center of gravity (CG) and center of pressure (CP) for a stable rocket?

For a stable rocket, the center of gravity (CG) must be located in front of the center of pressure (CP). When CG is positioned ahead of CP, it creates a restoring moment that helps the rocket maintain its intended flight path.

If the rocket tilts during flight, the aerodynamic forces acting at the CP will create a torque that pushes the rocket back to its stable position, effectively righting itself. This arrangement is crucial for stability; if the CP were to be in front of the CG, the rocket could become uncontrollable and may end up tumbling or veering off course due to the aerodynamic forces acting to exacerbate any tilt rather than correct it.

In contrast, saying that CP must be in front of CG results in a configuration that is inherently unstable. Additionally, the other options present incorrect or irrelevant conditions regarding the relationship between CG and CP. Thus, the correct relationship as established by aerodynamics and rocket stability principles is that CG must always be in front of CP for optimal stability during flight.