Which rocket system must be able to withstand external forces during launch?

The airframe system must be able to withstand external forces during launch because it serves as the structural backbone of the rocket. The airframe provides the necessary support and integrity to endure high levels of stress during liftoff, which includes dynamic pressures, vibrations, and gravitational forces. It must be designed to maintain its shape and prevent structural failure under these extreme conditions.

In contrast, while the propulsion system generates thrust, it does not support the rocket's structure; rather, it operates within the confines of the airframe. The guidance system is responsible for navigation and control but is not directly involved in bearing external forces; instead, it relies on the airframe for protection and stability. Finally, the payload system, which carries the cargo or scientific instruments, depends on the airframe for secure transport but does not need to withstand launch forces on its own. Thus, the function of the airframe system is vital to the rocket's ability to endure the stresses of launch.