What is the primary purpose of pre-launch checklists?

The primary purpose of pre-launch checklists is to ensure all systems are ready and functioning correctly. These checklists are critical in rocket launches because they help teams systematically verify that every component of the rocket, as well as support systems, are operational and safe for flight. By following a detailed checklist, engineers and technicians can catch potential issues before they lead to launch failures or accidents, enhancing safety and reliability. This process encompasses verifying fuel levels, electrical systems, mechanical components, and any other systems necessary for a successful launch.

The other options do not align with the main goal of pre-launch checklists. Entertainment is not a priority during a launch. Increasing the rocket's speed involves design and engineering considerations that are addressed long before the launch day, not through a checklist process. Determining the rocket’s lifespan is more about design and materials analysis rather than a pre-launch activity, as it pertains to how the rocket is constructed and its intended usage, which is evaluated over time rather than during the pre-launch phase.