While the initial solids will have five segments—a design ATK developed for the terminated Ares I crew launch system—the company's advanced design will revert to the four-segment configuration used on the shuttle.

“We took advantage of the maximum transportable size available to us, and the other elements of the system—the composite cases, which allow for higher internal pressures, and that yields higher performance,” says Charlie Precourt, vice president and general manager of ATK's space launch division. “Fundamentally we wanted to minimize the processing time at the Cape, so you have one less assembly function. Intuitively you can see that you minimize to some extent a failure mode by removing one joint, and then you take advantage of other means to manufacture that and processing that in a more efficient way.”