Atlas

In front of the museum is an Atlas missile.

According to Chuck Walker's Atlas: The Ultimate Weapon, the Atlas is vehicle 8A, "reconfigured to Atlas D configuration." Being research & development models, relatively few of the Atlas A through Atlas C series were manufactured (the Atlas D was the first operational version).

As part of this reconfiguration, a center engine was added (the Atlas A had only the two outer booster engines, lacking a center sustainer engine). This missile is also fitted with what appears to be a Mk. 4 reentry vehicle; the Atlas A was fitted with a dummy nosecone and aerodynamic probe with an angle-of-attack sensor.

I think it would have made a more interesting display to have kept the Atlas in its "A" configuration (plus, the dummy sustainer engine leaves something to be desired).

In addition to the lack of a center sustainer engine, the booster engines on the Atlas A were among the first models of rocket engines produced by Rocketdyne. They were uprated versions of the engines manufactured for the cancelled Navaho program, and where conical, rather than bell-shaped. Later Atlas models had improved with the familiar bell shape. This Atlas has the conical engines. If I would have noticed this fact when I visited, I would have taken more detailed photos of these boosters.