What are the major systems of modern rockets?

The major systems of modern rockets include the airframe, propulsion, guidance, and control, which collectively enable the rocket to operate effectively during launch, flight, and landing.

The airframe is the structure of the rocket that provides the necessary shape and strength to withstand the forces acting on it during ascent and descent. It carries the payload and houses other systems, ensuring the rocket maintains structural integrity.

Propulsion refers to the system responsible for generating thrust, which typically involves rocket engines that burn fuel to produce high-velocity exhaust gases. This thrust propels the rocket forward and counteracts gravity.

Guidance is critical for determining and maintaining the rocket's trajectory. It utilizes sensors and computers to calculate the necessary adjustments needed to keep the rocket on its intended path.

Control systems ensure that the rocket maneuvers correctly in response to guidance commands. They adjust the rocket's orientation and trajectory by utilizing fins, gimbaled engines, or other mechanisms that affect the vehicle's motion.

The other choices do not comprehensively represent the essential systems involved in modern rockets. They may include components of the overall design but lack the structured approach that encompasses all necessary functionalities for effective rocket operation.