New Parts-Marking Technology Would Have Helped Investigators

A highly durable product-marking system approved for use by NASA in 2001 and currently being tested on the International Space Station would have helped investigators identify the debris from Columbia, had the technology been available when the orbiter was being built.

The 2-D marking system, called Data Matrix, is based on compressed symbology technology patented by a Canton, Mass.-based company called RVSI and released for use in the public domain.

The Data Matrix symbol is a checkerboardlike mark that's etched permanently onto a surface. The mark is scanned using a charge-coupled device or optical reader. It's similar to a bar code, but it's capable of storing up to 100 times more information than a bar code, RVSI officials said. Data Matrix symbols were designed to withstand extremely harsh conditions, said Donald Roxby, director of The Symbology Research Center, a Huntsville, Ala.-based unit of RVSI.

"Tests at Marshall [Space Flight Center] verified the mark would survive the 18,000-mile-per-hour slipstreams and temperatures in excess of 2,300 degrees" associated with orbiter re-entry, he said. "The symbols could sustain up to 30% damage and still provide 100% of the [encoded] data."

Jerry Berg, a spokesman for the Marshall Space Flight Center in Huntsville, said the organization was unable to comment because the official in charge of the Data Matrix effort was not available.

But since the 2-D etches are typically made during the manufacturing process, Roxby said, none of Columbia's parts -- except for three tiles that were recently replaced -- carried the Data Matrix symbol.

The symbols would have made it easier for investigators to identify parts of the Columbia orbiter, he added.

Data Matrix symbols of various sizes and on different materials are being tested on the International Space Station to see how well they hold up in space, Roxby said. "The last photos we saw show these marks to be still in very good condition and readable," he said.

The goal behind marking parts in this manner was to improve NASA's ability to check the manufacturing history and operational data of parts use in a shuttle, said Erin Binder, a director at Golden Valley, Minn.-based Veritec Inc., another company that has also worked with NASA to develop a compressed symbology standard for marking shuttle parts.

Unlike bar codes, which don't work on certain surfaces and can peel off, compressed symbols like Data Matrix can be applied permanently to a variety of surfaces, Roxby said.

To mark the three tiles on Columbia, small recesses were etched out of each tile and filled with a ceramic paint that would melt permanently into the tile from the heat on re-entry, Roxby said.