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Space Shuttle Return to Flight Gets a 'LIFT'
03.04.05
 
F-15B in flight during foam test If small chunks of Space Shuttle fuel tank foam insulation come off at twice the speed of sound, no one is physically there to see precisely what happens. That lack of first-hand information bothered NASA engineers who are working to safely return the Shuttles to flight, so they came to the agency's Dryden Flight Research Center for answers.

Image right: Two panels of Space Shuttle TPS insulation were mounted on the flight test fixture underneath NASA's F-15B during the Lifting Foam Trajectory flight test series.

The Dryden team prides itself on innovative flight research, and creative ways to document results. The Lifting Insulating Foam Trajectory (LIFT) flight test series at Dryden is using the research center's F-15B supersonic aircraft. It carries a special pylon, called a flight test fixture, that can shed chunks of Shuttle foam on command. Special high-speed digital video cameras trained on the pylon captured the paths of free-flying foam divots in February as researchers refined their knowledge of what to expect if this happens during a Shuttle ascent.

Part of the Space Shuttle Return To Flight team effort, these high-speed tests are showing engineers how the foam behaves; if it breaks up in the slipstream, or stabilizes, or tumbles. These traits are important to learn in order to better understand how small pieces of foam travel. A foam strike led to the loss of Shuttle Columbia in 2003. Since then, steps have been taken to minimize the chance of foam shedding during launch, but the departure of some small pieces of the insulation cannot be ruled out.

F-15B and F-18 chase aircraft in flight Image left: NASA's F-15B is shadowed by a NASA F-18B chase aircraft during a LIFT experiment flight.

Carrying the cameras, the special research F-15 records a story of free-flying foam each time a divot is ejected from the flight test fixture. The cameras can record action at the rate of up to 10,000 frames per second; by comparison, a household video camera captures baby's first steps at only 30 frames per second.


For additional F-15B photos see http://www1.dfrc.nasa.gov/Gallery/Photo/F-15B/index.html.
Video clips of the foam test and of the F-15B in flight are on http://www1.dfrc.nasa.gov/Gallery/Movie/F-15B/index.html.

Gray Creech
NASA Dryden Public Affairs