ESTO Technology to Aid in Shuttle's Return-to-Flight
March 3, 2004 - An Earth Science Technology Office (ESTO) funded infrared-imaging technology has been selected to detect flaws in the leading edge of Shuttle wings. Originally created under ESTO's Laser Risk Reduction Program (LRRP) as a way to diagnose problems in diode laser arrays, this technology has been adopted by the Leading Edge Infrared Camera (LEIRC) Team to help inspect the reinforced carbon-carbon (RCC) panels for tiny cracks, mechanical stresses, and other defects.
Each Shuttle wing has 22 of the RCC panels, weighing about 60 pounds each, that are meant to protect the shuttle from the intense heat of re-entry. NASA officials suspect that a hole in one of these panels caused the Columbia tragedy by permitting superheated gasses to enter the left wing. The Columbia Accident Report has since recommended that NASA take a more comprehensive approach to wing inspection before flights resume.
Flaws in the RCC material are difficult to identify using convention methods such as x-ray or ultrasound. The new infrared imaging capability will greatly increase NASA's ability to discover irregularities by sensing heat absorbed by RCC panels and by measuring rates of cooling. Using this method, a flawless panel will show uniform rates of absorption and cooling while defects will stand out as spots or bands of different temperatures.