Crews rehearse Launch Abort System stacking with Orion

Though stacking the real thing for a Space Launch System mission is still a few years off, engineers said performing the task now, using the same procedures and demands that will accompany the actual assembly, helps them anticipate difficulties ahead of time.

The practice also keeps the crane operators proficient in handling spacecraft components that must be moved gingerly and placed precisely. The exercise took place inside the Vehicle Assembly Building, or VAB, at NASA's Kennedy Space Center in Florida using the same equipment and operators that stacked space shuttles for launch.

"The breakover, taking the LAS from horizontal to vertical, is not as easy as it sometimes seems, but the VAB guys are exceptional, they are really good at what they do so they really didn't have a problem," said Douglas Lenhardt, who is overseeing the Orion mock-up and operations planning for the Ground Systems Development and Operations program, or GSDO.

During missions, the LAS will be ready to ignite its solid-fueled engines and lift the Orion and its crew away from disaster in the unlikely event that the booster fails during the first part of launch. Its design is similar to that used during Apollo launches, though the LAS is larger than the escape rocket used before. A test flight in 2010 saw the LAS produce 500,000 pounds of thrust, about the same as the Titan II rockets that launched Gemini spacecraft into orbit.

As powerful as it is for an escape rocket, the LAS's power is a fraction of the overall thrust the Space Launch System is designed to produce to lift Orion into orbit and then propel it to deep space.

The LAS stacking topped off a mockup Orion and service module that has been standing at the north end of the transfer aisle in the VAB for several months. It will remain there so engineers and designers can continue to refine their plans for the spacecraft as it evolves from a concept that exists only on a computer screen to a spacecraft carrying humans into deep space.

"The number one thing people say about real hardware is, the computer-aided design (CAD) model doesn't do it justice," Lenhardt said. "Things seem to almost always work on a CAD mode. Real-life, things don't always work perfectly and that's why it really does help having a physical model."