What structure is described as housing the missile separately from the launch facility?

The correct choice refers to a structure known as a missile silo. A missile silo is specifically designed to house intercontinental ballistic missiles (ICBMs) safely and securely, ensuring that the missile is protected from outside threats and environmental factors while it is not being launched. This type of structure allows the missile to remain underground, minimizing the risk of detection and damage.

The silo's design means that the missile is separate from the launch facility, which includes the necessary command and control systems for the launch process. This separation enhances security and efficiency during both peacetime and potential conflict scenarios.

Other structures mentioned, like the Vertical Launch System and Ground Launch System, incorporate missiles into their launch mechanisms, rather than housing them separately. An Underground Bunker, while providing protection, generally serves a broader purpose for various military operations rather than specifically for missile storage and launch readiness. Thus, the distinct feature of the missile silo as a dedicated facility for storing missiles separately from their launch operations is what makes it the correct answer.