High marks

A special pigment that will turn from white to black with the application of a low-power CO

laser could be used to mark and identify mission-critical parts on NASA space shuttles.

The technology, from Cheshire-based

, is now being tested on the International Space Station (ISS) for potential use in future missions.

The technique was used to produce 2D barcodes on two small aluminium discs that were launched aboard

in February as part of a Materials International Space Station Experiment (MISSE 6). They are now sitting outside the ISS, exposed to extreme levels of UV radiation, atomic oxygen, hard vacuum and contamination before test results are revealed next February.

Mike Sorvino, Datalase laser product manager, said his company receives a monthly progress report from NASA. 'So far everything has been great,' he said.

The worst possible scenario for Datalase would be if the whole thing turned black and was unreadable, but the technology performed well under extreme UV and oxidation testing in the UK before launch. The technique has also been proven to work on US military vehicles and US Coast Guard helicopter parts.

Sorvino said the technology is preferable to stamping or etching, which can cause damage to a part. 'With current processes, parts have to be sent back and re-evaluated after marking,' he said.

The technique can be applied either during the production process or afterwards. On the production line, a computer-controlled CO

laser beam will write the required data on to the mark area, causing a chemical reaction that changes the pigment coating from white to black.

Sorvino said the company's colour-change pigment can be embedded into any type of ink. 'So if a manufacturer has an ink process to coat a part that is solvent or water-based, we can easily get our colour-change materials into that,' he claimed.

He said the technology works with an industry standard CO

laser that is not detrimental to parts and operates on a 10.6 micrometre wavelength.

The company claims that its colour-changing ink method differs from those of competitors because the change is not dependent on the application of heat. 'There are very few compounds on earth that offer this unique colour change based on laser wavelength light,' said Sorvino.

He said 2D barcodes are an ideal marking technology because it is possible to pack several hundred characters of data in a small 2.5cm x 2.5cm space which is big enough to hold all the information a mission-critical part needs.

Sorvino said NASA often requires that each metal part is not only marked with information on where it was manufactured but also from where its materials were mined.

'For example, they want to be able to tell this part was made with aluminium that came from mines in Texas and that part was made from brass from Nebraska,' he said.

Sorvino said his company is hopeful everything goes well with the current testing on the ISS because NASA's seal of approval will be good for business.

After the results are released next year, Datalase plans to market its technology to big players in the aerospace business such as Boeing and Lockheed Martin.

'We hope our data here on the earth supports that which comes back from the NASA mission,' he said. 'We would then like to move into full-scale production with the major civilian and military aerospace companies.'