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Forum:Exploration: Asteroids, Moon and Mars
Topic:[SLS] Marshall Space Flight Center test stands
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"The forces the tank will experience in the test stand are as close as you can get on Earth to what the tank will experience on its way to space," said Scott Chartier, primary test engineer over the stand for Marshall's propulsion systems test branch. "During the series of tests, the tank will endure up to nine million pounds of compressive, up-and-down loads, and up to 300,000 pounds of shear or 'twist' loads."

The tank of the world's most powerful rocket will be tested to the extremes before the rocket begins launching astronauts in NASA's Orion spacecraft on deep-space missions. To accomplish these SLS tests and future testing, Marshall teams designed and will outfit the stand with sophisticated fluid transfer and pressurization systems, hydraulic and electrical control and data systems, fiber optics cables and instrumentation over the next few months.

"While the SLS tank will be the first piece of hardware in the stand, this and the other new Marshall test stand can be used for a variety of vehicles and testing needs, including commercial rockets or other large spacecraft structures needed for deep space exploration," Chartier said.

The stand's location in Marshall's West Test Area was chosen to take advantage of existing infrastructure, especially nearby storage tanks for the inert liquid nitrogen that will substitute for liquid oxygen during the series of SLS tank tests. Cross-country supply pipelines will be extended to reach the stand, along with lines for other fluids, test gases such as helium and for highly purified air.

Marshall teams will also install equipment and hardware designed specifically for testing the liquid oxygen tank for the SLS core stage, which is being built at NASA's Michoud Assembly Facility in New Orleans. The test article, which includes the tank, will be produced using exactly the same materials and processes as a flight version, but with additional equipment that will simulate the tank's connections to the SLS rocket. A barge will carry the test article from Michoud to Marshall in the summer of 2017, Chartier said.

A Giant 'L' and a 'Spider'

Test Stand 4697 is shaped like an 85-foot-tall "L" with 90-foot-long arms. Three cage-like pedestals will be positioned in a broad circle on the foundation in the crook where the arms meet. When the 28-foot-diameter, 70-foot-tall test article arrives at the stand, it will be carefully lifted and then positioned inside the circle of pedestals -- there is only about a foot of clearance on the tank sides. The test article will sit atop a "spider" and special ring that will be bolted into the stand's foundation. A similar spider and ring will be mounted at the test article's top. It will take up to two months to install all the final sensors, gauges, systems, cameras and test equipment.

Above: Phil Hendrix, right, and Curtney Walters compare blueprint plans of Structural Test Stand 4697 to the nearly completed structure at NASA's Marshall Space Flight Center in Huntsville, Alabama. (NASA/MSFC/Fred Deaton)

When testing is underway in late summer 2017, hydraulic cylinders and "load lines" attached to the spiders' arms, the pedestals and the steel of the stand will push, pull and apply varying combinations of pressure to the tank, which will be filled with varying amounts and temperatures of fluid. Each test scenario and combination simulates a different phase of an SLS launch and flight, Chartier said.

And he can hardly wait to begin.

"We haven't seen this magnitude of testing since we tested the Saturn rockets and the space shuttle," Chartier said. "These test facilities will serve NASA well as we continue on the Journey to Mars. I can't wait to take my kids to an SLS launch and see the hardware we helped develop on these test stands -- sturdy stands even their generation can use as they continue exploring space."

'This Dream Will Truly Become Reality'

Phil Hendrix can't wait either. He's the Marshall Office of Center Operations facilities construction project manager for both Test Stand 4697 and for Test Stand 4693, where the SLS core stage's liquid hydrogen tank will be tested. The construction phase for 4693 will end later this year and engineers will begin outfitting its distinctive twin towers with its own range of special equipment.

Every construction milestone feels good, Hendrix said, and everyone looks forward to the start of the tank testing -- major steps toward the first flight of a complete, uncrewed SLS rocket in 2018, on a mission that will take the Orion spacecraft beyond the moon. And major steps on a later Journey to Mars.

"It's been truly unbelievable to be a part of SLS's journey. It doesn't seem real to be this fortunate," he said. "When I get to see SLS launching up through the sky, this dream will truly become reality."

Astronauts have a unique appreciation for the intricacies and role of testing. On a recent morning, just before landing at Huntsville International Airport, four astronauts in two NASA T-38 training jets banked low and slow over the construction crews finishing work on Test Stand 4697. It was a flyby salute from the men and women in the cockpits to the men and women on the ground whose work is vital to development of SLS -- the next great ship of human space exploration.

"The systems tested here will not only take humans exponentially higher and farther than these T-38's can fly, they'll propel explorers far out into our solar system, to places we've never before been able to reach," said astronaut Barry "Butch" Wilmore, who was flying one of the jets and is the astronaut liaison to the SLS program. "We look forward to the flights of the spacecraft tanks and systems that will be tested here."

Test Stands 4693 and 4697 were designed and developed by Marshall's Test Laboratory and the Office of Center Operations. The U.S. Army Corps of Engineers oversees the construction contract for the government. General contractor Brasfield & Gorrie of Birmingham, Alabama; architects Goodwin Mills and Cawood of Montgomery, Alabama; architects Merrick & Company of Greenwood Village, Colorado; steel fabricators North Alabama Fabricating Co. of Birmingham; and steel erectors LPR Construction of Loveland, Colorado expect to complete Test Stand 4693 late this year.

Robert PearlmanNASA release
Construction Complete: Stand Prepares to Test SLS's Largest Fuel Tank

Major construction is complete on NASA's largest new Space Launch System structural test stand, and engineers are now installing equipment needed to test the rocket's biggest fuel tank. The stand is critical for ensuring SLS's liquid hydrogen tank can withstand the extreme forces of launch and ascent on its first flight, and later on the second flight, which will carry up to four astronauts in the Orion spacecraft on a journey around the moon, into the deep-space proving ground for the technology needed for the journey to Mars.

"There is no other facility that can handle something as big as the SLS hydrogen tank," said Sam Stephens, an SLS engineer working on the tests at NASA's Marshall Space Flight Center in Huntsville, Alabama. "There are few places in the world like NASA's Michoud Assembly Facility that could build these things, and even fewer that can test them."

After the project began in May 2014, Test Stand 4693 changed the skyline of Marshall as its twin towers soared to 221 feet (67.4 meters). In December, contractors and steelworkers handed the stand over to Marshall engineers, who are now busy installing complex networks of cables, pipes, valves, control systems, cameras, lighting and specially designed test equipment.

"The scale and capability of this test stand are unique, and creating it has taken people from across the country, from all walks of life — concrete suppliers and finishers, steel fabricators and erectors, bolt manufacturers and more," said Robert Bobo, who manages SLS structural strength testing at Marshall. "Everyone who's touching this is proud of the Space Launch System, an American rocket that will send astronauts farther in space than humans have ever traveled before."

The stand will simulate the powerful dynamics of launch and flight by pushing, pulling and bending the SLS liquid hydrogen qualification test article, recently constructed by Boeing at NASA's Michoud Assembly Facility in New Orleans. The 149-foot-long (45.4 meters) test article consists of a liquid hydrogen tank and equipment attached at each end to simulate the other parts of the 212-foot-long (64.6 meters) core stage, the backbone of the rocket. Together, the SLS liquid hydrogen and liquid oxygen tanks will feed 733,000 gallons (nearly 3 million liters) of super-cooled propellant to four RS-25 engines, producing a total of 2 million pounds of thrust at the base of the core stage.

The liquid hydrogen tank test article will travel by barge from Michoud to Marshall. When testing begins, the tank test article will be positioned between the towers, suspended beneath a crosshead. A total of 38 hydraulic cylinders or "loadlines," each weighing from 500 to 3,200 pounds (approximately 230 to 1,500 kilograms), will be individually calibrated, outfitted with custom-built test cells to send and receive instructions and data, and then positioned at points all along the tank. At the base, 24 of the largest cylinders — 3,200 pounds each, about as heavy as a medium-sized car — will simulate the thrust produced by the RS-25 engines.

During testing, the cylinders extend and retract, pushing and pulling in different combinations against the test article, the test stand base and towers, applying millions of pounds of pulling and crushing force and up to 340,000 pounds (approximately 1.5 million newtons) of shearing or sideways force. During 30 or more test scenarios, instrumentation will capture more than 3,500 strain and detection measurements, temperatures, pressures, high-definition images and other information.

Careful attention to construction of the stand and the comprehensive testing is vital because every weld, every bolt, every connection, every measurement is important. "Everyone working on this knows that even the smallest things matter in such a big project," Stephens said.

Above: Robert Bobo, left, and Mike Nichols talk beneath the 221-foot-tall Test Stand 4693, the largest of two new Space Launch System test stands at NASA's Marshall Space Flight Center in Huntsville, Alabama. (NASA/MSFC/Emmett Given)

Nearby, similar preparations have been underway since September 2016 on Test Stand 4697, where the SLS's 70-foot-tall (21.3 meter) liquid oxygen tank test article will be anchored in the crook of the L-shaped stand's arms. Because it takes some time for the cryogenic tanks to be brought to the precise temperatures and pressures required, teams also are preparing for some round-the-clock test sessions. A tank's complete test series might take up to four months.

As the new test stands move past the major construction phase, so does the job of Phil Hendrix. He's been the Marshall Center Operations construction project manager for both stands since they were just ideas on paper in 2012, and will continue to provide support as his day-to-day focus shifts to other center operations needs and projects. As the stands took shape, Hendrix said he could see the steelworkers and welders from across the country develop a sense of mission as they worked, and all delivered.

"It really comes down to people when you need to get anything done. And I think NASA brings out the best in people," he said. "It's the sense of awe and wonder about what's out there, about exploration, imagination, pride and patriotism. It's what happens because of our mission."

GACspaceguyFantastic to see the program coming together!!

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