The Ares I-X upper stage simulator segment 7 is stacked onto segment 6.

In high bay 4 of the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida, the Ares I-X upper stage simulator segment 7 is stacked onto segment 6. The upper stage simulator comprises 11 segments, each approximately 18 feet in diameter, that will be used in the test flight identified as Ares I-X in 2009. The simulator segments will simulate the mass and the outer mold line. The upper stage accounts for nearly one-quarter of the total height of the Ares I. It will take the Ares I on the second phase of its journey from Earth, providing the guidance, navigation and control needed for the second phase of the Ares I ascent flight. Photo credit: NASA/Kim Shiflett