Arnold Air Force Base, Tenn. -- Unlike the many long-duration tests conducted at Arnold Engineering Development Center (AEDC), the hypersonic boundary layer transition (HyBoLT) test in the center's von Kàrmàn Gas Dynamics Facility's wind tunnel B was focused in scope with a fast completion requirement. 

The NASA experiment is scheduled to launch from NASA Wallops Flight Facility, Va., late this year on an ATK ALV X-1 launch vehicle. 

The objective of the test was to assess the stability of the HyBoLT/ALV X-1 rocket during the ascent phase of the launch. "The mission of the HyBoLT payload, located on the nose of the launch vehicle is to obtain unique high-speed flight data for basic fundamental boundary layer transition flow physics," said James Pittman, the principal investigator for NASA's Hypersonic project. 

"Data for atmospheric re-entry technology will be collected on an internally carried payload called SOAREX that will be ejected during the test," added Pittman.
"The customer [NASA] wants to be sure that this vehicle will have a successful ascent to hypersonic flight test conditions," Paul Jalbert, Aerospace Testing Alliance (ATA) project engineer said. 

The vehicle was only tested at AEDC for eight hours--four hours at Mach 6 and four hours at Mach 8. The AEDC test was the first of a series of three wind tunnel test programs spanning the velocity range from lift-off to Mach 8. The test article then moved on to the NASA Langley Research Center for further testing at supersonic Mach numbers and will head to NASA Ames Research Center for transonic testing. 

"With data from three different wind tunnels, the customer can demonstrate the performance of the vehicle all the way from the ground until it leaves the atmosphere," Mr. Jalbert said. 

According to ATA Project Engineer David Yoder, one side of the wedged-shape HyBoLT payload has a rough surface, similar to the space shuttle's, and the other side has a smooth surface. 

"The customer is looking to see how the air passes over those surfaces," Mr. Yoder said. "They look to see if the air separates, if it's smooth and what sort of thing is going to happen to future high-speed vehicles."
One of the existing programs to use this kind of information is the space shuttle. 

"This information is relevant now; the top, smooth surface provides science information for future vehicles and the roughened bottom surface provides information needed now for space shuttle reentry issues," Mr. Jalbert said. 

"This was basically a science project," he said. "Small tests like this used to be more common in all the wind tunnels where a hurry-up test could be brought in; people could learn what they wanted in a hurry and keep on going." 

Mr. Yoder echoed that statement, "It was nice to see that we have the capability to do what we used to do and be just as successful."