NASA Langley Research Helps Space Shuttle Shed 32 Pounds of Foam

By Kate Shellnutt, The Virginian-Pilot, Norfolk, Va.

Jun. 15–HAMPTON — The 4.5 million-pound space shuttle Discovery will be a little lighter for its July 1 launch after having 32 pounds of foam removed from the shuttle’s fuel tank, a result of research efforts at NASA Langley.

The wedge-shaped pieces of foam that covered cables on the tank had the greatest risk of falling off during liftoff. When the shuttle Columbia launched in 2003, a piece of foam came off the fuel tank and hit the orbiter’s left wing, damaging the wing’s heat protection system. During re-entry 16 days later, the heat build up on the wing destroyed the spacecraft, killing its seven crew members.

Foam debris also fell from the space shuttle Discovery’s fuel tank during its launch in 2005, but the shuttle avoided another accident.

When the Discovery launches again in July as a part of NASA’s Return to Flight mission, it will be equipped with new safety technology developed by the Langley Research Center in Hampton.

The 34-person Return to Flight team at NASA Langley has focused on preventing foam debris from falling from the space shuttle’s fuel tank and on detecting any damage to the edges of the shuttle’s wings.

During the 14-day flight, 10 of the Langley team’s members will be at Johnson Space Center in Houston. There, the researchers will join mission support to watch and advise crew members implementing Langley’s new methods in space.

This winter, NASA Langley’s John Edwards tested the need for the wedge-shaped foam “ramps” that were originally installed to prevent the cable trays running along the fuel tanks from becoming unstable during flight.

Edwards conducted extensive computer stimulations and wind tunnel tests on the external tanks. After removing the foam from around the cable trays, he found they remained strong enough to withstand flight speeds of as fast as 17,321 mph .

“It’s a major change since last mission,” Edwards said. “It’s the first tank to fly without the ramps.”

The July launch will be the second time a shuttle uses the wing impact detection system, another program developed at NASA Langley in response to the Columbia disaster.

The system uses panels, installed along the “leading edge,” the area around the outside of the shuttle wings, that detect vibration caused by impact from debris. The panels then send signals to a wireless unit on the shuttle.

The system complements optical images collected by the spacecraft.

“Sometimes a piece of foam will fall off, and crew members will think they saw it hit the wing, but this method actually can tell if a panel has been hit,” said the system’s head researcher, Eric Madaras .

Since the impact detection system’s debut last summer, Madaras and his team have fine-tuned their software to better interpret the system’s signals. The improved software will be used on the coming Discovery mission.

The wing’s edge, where the panels are located, is tiled with a material called reinforced carbon-carbon. Tests show that tiles may splinter or crack after a severe impact, but not all damage may be visible.

NASA Langley researcher Dave Haankenson pioneered the use of an infrared camera to detect below-the-surface damage by measuring heat flowing through the tile. NASA plans to try the camera in space for the first time during Discovery’s July flight.

The camera will be used to inspect the carbon on the Discovery and on the International Space Station, where it will dock for six days.

Like the carbon material, foam on the shuttle’s fuel tanks also may have internal damage that technicians cannot see.

NASA asked its research centers to suggest a way to thoroughly inspect the foam and chose Langley’s method of using high-frequency sounds to produce internal images of the foam, said Keith Henry, the deputy of Public Affairs at NASA Langley.

The method, called terrahertz imaging, is similar to an X -ray of the foam.

* Reach Kate Shellnutt at (757) 446-2643 or kate.shellnutt@pilotonline.com.

—–

Copyright (c) 2006, The Virginian-Pilot, Norfolk, Va.

Distributed by Knight Ridder/Tribune Business News.

For reprints, email tmsreprints@permissionsgroup.com, call 800-374-7985 or 847-635-6550, send a fax to 847-635-6968, or write to The Permissions Group Inc., 1247 Milwaukee Ave., Suite 303, Glenview, IL 60025, USA.