Kirsten Larson March 21, 2001
NASA Headquarters, Washington, D.C.
Ames Research Center, Moffett Field, CA
(Phone: 650/604-3039 or 650/604-9000)
Kennedy Space Center, FL
NEW SCANNER HELPS THE SEARCH FOR SHUTTLE TILE FLAWS
NASA workers who face the critical and often tedious task of evaluating damage to the space shuttle's protective thermal tiles now have some high-tech help in the form of a new portable, digital inspection system.
Engineers from NASA's Ames Research Center, in Californias Silicon Valley, and the Boeing Co., Huntington Beach, CA, recently delivered a hand-held laser scanner to NASA's Kennedy Space Center, FL, for evaluation.
"Tests at Ames and at Kennedy have demonstrated the scanner's ability to measure surface flaws on thermal protection tile and blanket samples," said Joseph Lavelle, Ames senior project engineer.
The shuttle's thermal tiles protect the orbiter and its crew from temperatures ranging from minus 250 degrees Fahrenheit in space, to nearly 3,000 degrees Fahrenheit during the superheated reentry. After each flight, every one of the more than 24,000 tiles that cover the shuttle's surface must be inspected.
The scanner uses a digital camera and lasers in a measurement technique called laser triangulation and is the first step toward the development of an Electronic Inspection and Mapping System (EIMS) that could aid the evaluation of the shuttle's Thermal Protection System (TPS).
"This new scanner, along with the rest of the EIMS currently in development at Kennedy, could increase the accuracy and reliability of our damage measurements," said Suzy Cunningham, Kennedy's TPS project manager. "The system could make the inspection process more efficient, which eventually could reduce vehicle turn-around time. Tile inspection is a very time-consuming process."
The hand-held instrument is a 5-inch-by-9-inch box that, when placed over a tile, measures flaws within a 3-inch-by-3-inch area. The scanner sends the data to a laptop computer. Software locates and characterizes the damage and generates a 3-D image, indicating the size and depth of the flaw. The system also contains a database of tile fabrication and maintenance information for every tile on the orbiter being measured. The latest TPS information and updates for each of NASA's four shuttles can be downloaded from a computer as required.
"A major challenge has been reducing the size of the system so it fits into small areas, such as those around the scaffolding that surrounds the orbiter during its post-landing maintenance," noted Lavelle. "With input from Kennedy engineers and United Space Alliance (USA) technicians, we have been very aggressive about making the scanner smaller."
The software also offers USA technicians various repair options. "Our California developers are writing software that integrates systems developed by Ames, Boeing Florida Operations at Kennedy, and Boeing-Huntington Beach," said Claudia Silverman, Boeing project manager at the Huntington Beach facility. "We are proud of the product and the team effort."
Lavelle said this electronic inspection technology also may have applications in other fields, such as integrated circuit inspection and in any manufacturing process that requires high accuracy.
"With the first phase of this project completed, we have already seen tremendous teamwork between NASA's field centers and the contractors," added Cunningham. "This is a clear indication of the cooperation we'll see as we develop a complete system."
Images of the scanner are available on the Internet at:
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