For an inherently stable rocket, where must the center of gravity (CG) be positioned relative to the center of pressure (CP)?

In rocketry, the relationship between the center of gravity (CG) and the center of pressure (CP) is crucial for maintaining the stability of the vehicle during flight. For a rocket to be inherently stable, the center of gravity must be positioned forward of the center of pressure.

When the CG is in front of the CP, it creates a restoring moment that helps the rocket return to its original flight path if it begins to tilt or yaw. This is because any disturbance that moves the rocket off its intended trajectory will cause aerodynamic forces to act on the CP, which are behind the CG, creating a torque that tends to right the rocket. The inherent design thus ensures that the forces work together to bring the rocket back to a stable orientation.

In contrast, if the CG is located behind the CP, the situation is reversed. Any disturbance could lead to increasing deviations from the flight path, making the rocket unstable and difficult to control. Hence, the forward positioning of the CG relative to the CP is fundamental for the stability and successful operation of the rocket. This concept is integral to the field of rocketry and influences design decisions to ensure safe flight characteristics.