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Aeroelastic Response and Protection of Space Shuttle External Tank Cable TraysSections of the Space Shuttle External Tank Liquid Oxygen (LO2) and Liquid Hydrogen (LH2) cable trays are shielded from potentially damaging airloads with foam Protuberance Aerodynamic Load (PAL) Ramps. Flight standard design LO2 and LH2 cable tray sections were tested with and without PAL Ramp models in the United States Air Force Arnold Engineering Development Center s (AEDC) 16T transonic wind tunnel to obtain experimental data on the aeroelastic stability and response characteristics of the trays and as part of the larger effort to determine whether the PAL ramps can be safely modified or removed. Computational Fluid Dynamic simulations of the full-stack shuttle launch configuration were used to investigate the flow characeristics around and under the cable trays without the protective PAL ramps and to define maximum crossflow Mach numbers and dynamic pressures experienced during launch. These crossflow conditions were used to establish wind tunnel test conditions which also included conservative margins. For all of the conditions and configurations tested, no aeroelastic instabilities or unacceptable dynamic response levels were encountered and no visible structural damage was experienced by any of the tested cable tray sections. Based upon this aeroelastic characterization test, three potentially acceptable alternatives are available for the LO2 cable tray PAL Ramps: Mini-Ramps, Tray Fences, or No Ramps. All configurations were tested to maximum conditions, except the LH2 trays at -15 deg. crossflow angle. This exception is the only caveat preventing the proposal of acceptable alternative configurations for the LH2 trays as well. Structural assessment of all tray loads and tray response measurements from launches following the Shuttle Return To Flight with the existing PAL Ramps will determine the acceptability of these PAL Ramp alternatives.
Document ID
20050192433
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
Edwards, John W. (NASA Langley Research Center Hampton, VA, United States)
Keller, Donald F. (NASA Langley Research Center Hampton, VA, United States)
Schuster, David M. (NASA Langley Research Center Hampton, VA, United States)
Piatak, David J. (NASA Langley Research Center Hampton, VA, United States)
Rausch, Russ D. (NASA Langley Research Center Hampton, VA, United States)
Bartels, Robert E. (NASA Langley Research Center Hampton, VA, United States)
Ivanco, Thomas G. (NASA Langley Research Center Hampton, VA, United States)
Cole, Stanley R. (NASA Langley Research Center Hampton, VA, United States)
Spain, Charles V. (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 7, 2013
Publication Date
January 1, 2005
Subject Category
Fluid Mechanics And Thermodynamics
Report/Patent Number
AIAA Paper 2005-3627
Meeting Information
Meeting: 41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference
Location: Tucson, AZ
Country: United States
Start Date: July 10, 2005
End Date: July 13, 2005
Sponsors: American Inst. of Aeronautics and Astronautics, American Society of Mechanical Engineers, Society of Automotive Engineers, Inc., American Society for Electrical Engineers
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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