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Proceedings Paper

Statistical analysis and ground-based testing of the on-orbit Space Shuttle damage detection sensors
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Paper Abstract

The loss of Space Shuttle Columbia and her crew led to the creation of the Columbia Accident Investigation Board (CAIB), which concluded that a piece of external fuel tank insulating foam impacted the Shuttle’s wing leading edge. The foam created a hole in the reinforced carbon/carbon (RCC) insulating material which gravely compromised the Shuttle’s thermal protection system (TPS). In response to the CAIB recommendation, the upcoming Return to Flight Shuttle Mission (STS-114) NASA will include a Shuttle deployed sensor suite which, among other sensors, will include two laser sensing systems, Sandia National Lab’s Laser Dynamic Range Imager (LDRI) and Neptec’s Laser Camera System (LCS) to collect 3-D imagery of the Shuttle’s exterior. Herein is described a ground-based statistical testing procedure that will be used by NASA as part of a damage detection performance assessment studying the performance of each of the two laser radar systems in detecting and identifying impact damage to the Shuttle. A statistical framework based on binomial and Bayesian statistics is used to describe the probability of detection and associated statistical confidence. A mock-up of a section of Shuttle wing RCC with interchangeable panels includes a random pattern of 1/4” and 1” diameter holes on the simulated RCC panels and is cataloged prior to double-blind testing. A team of ladar sensor operators will acquire laser radar imagery of the wing mock-up using a robotic platform in a laboratory at Johnson Space Center to execute linear image scans of the wing mock-up. The test matrix will vary robotic platform motion to simulate boom wobble and alter lighting and background conditions at the 6.5 foot and 10 foot sensor-wing stand-off distances to be used on orbit. A separate team of image analysts will process and review the data and characterize and record the damage that is found. A suite of software programs has been developed to support hole location definition, damage disposition recording, statistical data analysis and results presentation. The result of the statistical analysis will provide a quantitative indication of the laboratory performance of the ladar systems in the role of through hole damage detection.

Paper Details

Date Published: 19 May 2005
PDF: 12 pages
Proc. SPIE 5791, Laser Radar Technology and Applications X, (19 May 2005); doi: 10.1117/12.609688
Show Author Affiliations
Brian H. Miles, FastMetrix, Inc. (United States)
Elizabeth A. Tanner, FastMetrix, Inc. (United States)
John P. Carter, FastMetrix, Inc. (United States)
Gary W. Kamerman, FastMetrix, Inc. (United States)
Robert Schwartz, CAS, Inc. (United States)

Published in SPIE Proceedings Vol. 5791:
Laser Radar Technology and Applications X
Gary W. Kamerman, Editor(s)

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