What characteristic of the Atlas rocket's skin required it to be pressurized to prevent collapsing?

The characteristic of the Atlas rocket's skin that required it to be pressurized to prevent collapsing is its thinness. The structure of the Atlas rocket was designed using a thin-walled, lightweight configuration to minimize weight and maximize payload capacity. However, this thin skin made the rocket susceptible to buckling under external atmospheric pressure if not kept pressurized.

Maintaining internal pressure helped to counteract the external forces acting on the rocket while it ascended through the atmosphere. The design philosophy prioritizing a lightweight structure meant that the skin needed to be sufficiently supported by the internal pressure to maintain integrity during flight. This principle is crucial in aerospace engineering, as it balances the need for sturdiness with the efficiency required for successful launches.