NASA’s Space Launch System (SLS), the world’s most powerful rocket, will launch crew members and massive cargo loads into deep space, including missions to Mars. But before the rocket ever leaves the ground, each part of it must undergo extensive tests to make sure it has been designed and built to withstand all the stresses of launch and space travel.
In Huntsville, Dee Vancleave, a structural test engineer for NASA, led the first set of rigorous tests for SLS components for 12 weeks between late February and May. Vancleave’s team was responsible for designing and running numerous tests on the rocket’s interim cryogenic propulsion stage (ICPS), a liquid oxygen and liquid hydrogen-based system that will provide the in-space push that the spacecraft will need to fly beyond the moon before it returns to Earth.
Her work launched the largest testing campaign for a NASA rocket since the space shuttle.
Preparing for SLS
As a senior in high school, Vancleave was asked to write an essay about what her future life would look like — and her essay included a dream of working for NASA. Clearly, she’s been on a pathway toward her current career since she was a teenager. After graduating from the University of Tennessee with a degree in mechanical engineering, Vancleave went to work for McDonnell-Douglas in 1987, the same year the company merged with Boeing.
And at Boeing, Vancleave first began working on space projects. She worked as a design engineer for NASA’s Spacelab and later as a rocket test engineer at United Launch Alliance (ULA), the Decatur-based joint venture of Lockheed Martin Space Systems and Boeing Defense, Space and Security.
“I had spent the first five years of my career as a design engineer, sitting at a desk, and when I transferred to Decatur into a testing environment, I fell in love with it, ” Vancleave says. She joined NASA in 2008 and says working there “has lived up to my dream in every way.”
Testing 1, 2, 3
When Vancleave and her team are presented with a testing project, such as testing the ICPS system, they must determine what kinds of tests should be run and figure out the logistics of how to make those tests happen.
“My job is to make sure those pieces of hardware can withstand all the pressure and stress they will endure during launch, which includes heat, loads and other types of pressure, ” Vancleave says. “We have to find ways to apply all the same stresses to the equipment on the ground, to ensure it can withstand.”
Vancleave’s team designed approximately 50 test cases for the testing series. NASA manufactured test equipment — models of the actual SLS components, almost exact to flight specifications — to be used in testing. The ICPS model (also known as test article), is about 29 feet tall and almost 17 feet in diameter and was designed and built by Boeing in Huntsville and ULA in Decatur. The other test articles included:
Core stage simulator, about 10 feet tall and 27.5 feet in diameter, designed and built at Huntsville’s Marshall Space Flight Center.
Launch vehicle stage adapter, 26.5 feet tall and 27.5 feet in diameter, designed and built by Teledyne Brown Engineering of Huntsville.
Frangible joint assembly, designed and built by Boeing in Huntsville and ULA in Decatur.
Orion stage adapter, almost five feet tall, designed and built at Marshall in Huntsville.
Orion spacecraft simulator, almost five feet tall, designed and built at Marshall.
In addition to determining which test articles would be needed, Vancleave and her team designed the tests. They included outfitting these test articles with 28 mechanical load lines, which used hydraulic pressure to push, pull and twist them. The ICPS tanks were filled with liquid nitrogen, which subjected the hardware to pressure as high as 56 pounds per square inch, and 500, 000 pounds of axial hydraulic force was applied to the entire set of equipment.
As the tests were conducted, data was recorded through 1, 900 instrumentation channels, which measured the strain on the test components, as well as their temperature, deflection and other factors. That data will be compared to computer analytics and predictions to see if the components performed as expected.
Managing Risks
Every time Vancleave and other NASA engineers conduct tests, there are always risks involved — risks of injury and property damage, as well as business risks. “When installing the test fixtures into the test stand, there are always risks to personnel and hardware, such as skin burns from the cryogenics or damage to the intricate, expensive equipment, ” Vancleave says.
To prevent problems, Vancleave and her team create an extensive risk inventory and develop processes to avoid the risks.
In addition to the potential for injury or damage, “there’s always a risk that we will complete the tests and the components’ performance won’t match analysts’ predictions, ” she says. However, during the recent tests, that was not the case.
“All the test data was positive, ” she says. “The test requesters were in the room, checking the data against their predictions, and they were very happy with all the different results.”
Next, the analysts will write test reports and make sure that all the test data lines up with expected results, and Vancleave and her team will move on to designing tests for the next stage of the rocket — the core stage engine section — moving the project another step closer to launch.
“It’s a dream come true to be able to work for NASA and do testing, ” Vancleave says. “Every test project we’re assigned presents a variety of brand new challenges.”
Nancy Mann Jackson and Dennis Keim are freelance contributors to Business Alabama. Both are based in Huntsville.
Text By NANCY MANN JACKSON // Photo by DENNIS KEIM
