For NASA to push its Orion spaceship past the moon into deep space on the first missions of the Space Launch System (SLS), it's going to take more than the big engines and boosters that will get it off the ground. It's going to take another propulsion system that rides along behind Orion.
This week at the sprawling United Launch Alliance (ULA) plant in Decatur, Ala., NASA took a big step toward that system it calls the interim cryogenic propulsion stage (ICPS). On Monday, ULA and Boeing turned over a full-scale model to NASA for testing.
The system, which is based on the one used on ULA's Delta IV rocket, is powered by an Aerojet Rocketdyne RL-10B2 engine fed by liquid oxygen and liquid hydrogen fuel. The engine isn't on the test model, because it isn't designed to fire.
Instead, NASA will mate the model to the adapters that will join it to Orion and the SLS booster, put the entire assembly in test stand 4699 at the Marshall Space Flight Center in Huntsville, Ala., "and vibrate, shake and rattle it," according to Chris Calfee, ICPS project manager.
What test engineers will be looking for are cracks, bends or any other signs of structural weakness or potential failure. Tests like these verify computer projections and give engineers real-life looks at entire systems as they interact.
ULA and Boeing are already working in Decatur on the flight version that will sit atop SLS when it first leaves the ground in 2018. That launch called Exploration Mission 1 (EM-1) will push an Orion with no crew out past the moon and back in the first flight test of the full SLS system.
Astronauts won't ride around the moon on SLS until EM-2 now planned for in 2021. After that, NASA will replace the entire test system with a new, custom-built and more powerful upper stage to take astronauts to Mars. Orion will make those trips, too, serving as the astronauts' ride off Earth, emergency escape cabin and splashdown ride.
"This is an incredible achievement," ULA manager John Casani told the assembled Boeing-ULA-NASA team Monday. "This is unique."
Casani wasn't talking about the basic system. ULA builds those regularly as it cranks out an average of one rocket a month for launching most of America's military and commercial satellites. He was talking about the Boeing-ULA teamwork needed to build the test model and add all of the test sensors needed in the allotted time.
Testing will start at Marshall before the summer of 2016. It will last about three months, Calfee said. No one expects problems, but any issues will be corrected in the flight version building process if discovered.