MA-2 (rocket stage)

MA-2 functioned as the "half stage" in the Atlas's "stage-and-a-half" design, meaning they functioned as a booster attached to a central sustainer core, but did not include their own fuel tanks.^[2] Instead, fuel was drained out of the tanks of the sustainer core, until partway through the launch the booster segment was jettisoned. Similar to the booster segment on previous Atlas rockets,^[5][3] MA-2 consisted of a thrust structure with attachment points and fuel lines for two XLR89-5 rocket engines, each contained in a nacelle for aerodynamic reasons. The middle was left empty to accommodate the LR-105-5 engine of the sustainer stage. The two booster engines shared a common gas generator located at one of the engines, but separate turbopumps.^[2]

• MA-5 rocket stage