In the Assembly and Refurbishment Facility at NASA's Kennedy Space Center, workers help guide the aft skirt for the Ares 1-X rocket as it is moved. The segment is being lifted into a machine shop work stand for drilling modifications. The modifications will prepare it for the installation of the auxiliary power unit controller, the reduced-rate gyro unit, the booster decelerator motors and the booster tumble motors. Ares I is an in-line, two-stage rocket that will transport the Orion crew exploration vehicle to low-Earth orbit. Ares I-X is a test rocket. The Ares I first stage will be a five-segment solid rocket booster based on the four-segment design used for the shuttle. Ares I’s fifth booster segment allows the launch vehicle to lift more weight and reach a higher altitude before the first stage separates from the upper stage, which ignites in midflight to propel the Orion spacecraft to Earth orbit. Photo credit: NASA/Jim Grossmann