One of NASA's Space Shuttle Return-to-Flight (RTF) efforts has been to develop thermography for the on-orbit inspection of the Reinforced Carbon Carbon (RCC) portion of the Orbiter Wing Leading Edge (WLE). This paper addresses the capability of thermography to detect cracks in RCC by using in-plane thermal gradients that naturally occur on-orbit. Crack damage, which can result from launch debris impact, is a detection challenge for other on-orbit sensors under consideration for RTF, such as the Intensified Television Camera and Laser Dynamic Range Imager. We studied various cracks in RCC, both natural and simulated, along with material characteristics, such as emissivity uniformity, in steady-state thermography. Severity of crack, such as those likely and unlikely to cause burn through were tested, both in-air and in-vacuum, and the goal of this procedure was to assure crew and vehicle safety during reentry by identification and quantification of a damage condition while on-orbit. Expected thermal conditions are presented in typical shuttle orbits, and the expected damage signatures for each scenario are presented. Finally, through statistical signal detection, our results show that even at very low in-plane thermal gradients, we are able to detect damage at or below the threshold for fatality in the most critical sections of the WLE, with a confidence exceeding 1 in 10,000 probability of false negative.
Implementing Recommendations of the Columbia Accident Investigation Board: Development of On-Orbit IR Thermography
2005
11 pages
Report
No indication
English
Quality Control & Reliability , Manned Spacecraft , Space shuttle orbiters , Aerospace safety , Thermography , In-flight monitoring , Wings , Leading edges , Carbon-carbon composites , Cracking(Fracturing) , Damage assessment , Columbia(Orbiter) , Accident investigation , Accident prevention , Vacuum tests , Space environment simulation , Impact damage
COLUMBIA ACCIDENT REPORT: Investigation board makes many recommendations
Online Contents | 2003
Columbia Accident Investigation Board
NTRS | 2003
|Columbia Accident Investigation Board Report
NTRS | 2003
|Columbia Accident Investigation Board. Volume One
NTIS | 2003
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