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Gantry's First Splash Test Is a Booming Success
By: Jim Hodges

The principle is the same one that allows a kid to swing from a bank into a pond on a long rope hanging from a tree to beat the summer heat.

On Wednesday, the "kid" was 2,300 pounds of steel, covered in buoyant pink material normally used to wrap computers for shipping. Duct tape kept it all in place. The package hung by four short cables from its 9,000-pound Integration Platform – a steel frame – at the Langley Landing and Impact Research Facility: AKA, the Gantry.

When the frame swung back, from below the wrapped package it looked like a multi-petal pink-and-gray bow.

A long cable pulled the platform back excruciatingly, almost imperceptibly slowly. It stopped when it was 38 feet above the ground. The distance was measured by a surveyor.

First Gantry splash test.
Click to enlarge

Workers at the Gantry prepare the 2,300-pound, pink-wrapped steel to be swung and dropped into the new Hydro Impact Basin. Credit: NASA/Sean Smith

A voice came over a loudspeaker: "One minute." And then, "15, 14, 13 …." At zero, a pop indicated that a small pyrotechnic devices had cut through two steel cables between the spreader bar and frame, and it began to swing toward its target, the 20-foot-deep Hydro Impact Basin at the west end of the Gantry.

Past its deepest descent and on its way back up, the frame swung out and explosions, sounding like shotgun shells, severed bolts and threw the pink package into the basin, nose slightly down.

It didn't take much imagination to visualize a capsule full of astronauts, hanging from parachutes and hitting the Atlantic Ocean at an angle to end the return flight of a mission to Mars or an asteroid.

As the pink-wrapped package bobbed in the water, a half-dozen checklists -– the one dealing with pyrotechnics was 65 pages long – were complete. The angles and measurements drawn in black and red on test engineer Richard Boitnott’s clipboard had proved out.

Lessons were learned that will turn into improved checklists and clipboard alterations for the future.

"We wanted two things: for the pyrotechnics to work and to hit the water," said Lisa Jones, chief of Structures Testing Branch and on Wednesday, head of test safety.

"We did it. It was a success."

Eight high-speed cameras and seven high-definition cameras said so. The high-speed videos – shot at 1,000 frames per second -- will be scrutinized for a Technical Readiness Review on June 24, after which the Jones and Boitnott say they will be ready for the primary purpose of the Hydro Impact Basin: test-dropping the Orion Multi-Purpose Crew Vehicle.

"We got everything out of this we wanted," said Boitnott. "We got data. We got video. We've got to dissect this and see how it went. All of the data was in testing the gantry and the test; in effect, testing the test."

First indications were that the test graded out "A."

It was different. For one thing, it was the first time workers wore life preservers for a Gantry test.

"In the past, we would swing all the way to the ground," Boitnott explained about tests that have included aircraft, even automobiles over the half century of the Gantry's existence.

"This (with the basin) has much more mystery and possibilities. … In this case, we're not swinging into a fixed spot on the ground. We're throwing it into, ideally, a fixed spot in the pool."

Ahead are the review and then a different problem when the heavier, more sophisticated boilerplate Orion Ground Test Vehicle (GTA) is hung from the platform in 2013. Before the Orion GTA arrives the Langley-built Boilerplate Test Article (BTA) will be swung from the Gantry.

"For one thing, we'll go through a lot more instrumentation," Boitnott said. "We'll have 96 channels of data on the first three BTA tests and then 192."

The Orion GTA will have 608 channels of data. That’s going to add complexity.

"And we'll be dealing with a lot more load," Boitnott said.

At Wednesday’s end, everyone was pleased.

"This was a big step," Boitnott said. "We couldn't practice everything. We weren't practicing the pressures of 96 channels of data having to do with the impact of the water."

It's something for the coming weeks, as was something that will be more apparent to the layman's eye.

"Expect a bigger splash," said Boitnott, laughing. "A much bigger splash."

That’s because a 22,700-pound kid will be going into the pond.

The Researcher News
NASA Langley Research Center
Editor & Curator: Denise Lineberry
Managing Editor: Jim Hodges
Executive Editor & Responsible NASA Official: Rob Wyman