This is a 1:15 scale model of one of five versions of the Delta IV expendable launch vehicle, one of two families of rockets that have carried all medium and heavy U.S. government payloads to space since 2006. Since its creation that year, United Launch Alliance has built and launched Delta IVs.

There are three classes of Delta IVs: one medium, three medium-plus(+), and one heavy. This model is a Delta IV Medium + (5,4). The first digit in parenthesis represents the payload diameter in meters; the second digit, the number of strap-on solid rocket boosters. All Delta IVs use the same first and second stage engines and many other components.

United Launch Alliance built and donated this model to the Museum in 2011.