A cheap fake honey concocted from sugar would be unmasked simply by laser-scanning the carbon dioxide released from burning a few milligrams.
Seven years ago, the Rutherford Appleton Laboratory – RAL – in England embarked on a ‘blue sky’ space research project to develop a new laser technique for identifying isotopes in space.
Today’s equipment is large, bulky and stationary. Samples of, say, polluted soil must be collected in the field, put in a flask and brought to the lab for testing – clearly unsuitable for space testing.
But the new laser ‘isotope ratio-meter’ from RAL Space could change that.
Thanks to its small, lightweight, robust, highly accurate lasers, the device could be sent into space to look for trace amounts of gas in very small samples.
“You take a laser, whose optical frequency or ‘colour’ can be continuously adjusted, beam it at a gas sample, and detect the level passing through the gas,” explained Dr Damien Weidmann, Laser Spectroscopy Team Leader at RAL Space.
As the laser colour changes, the light passes straight through the sample until it reaches a particular frequency, specific to the isotopic gas, that is partially blocked.
“Each molecule, and each of its isotopic forms, has a unique fingerprint spectrum. If, on the other hand, you know what you are looking for, you can simply set the laser to the appropriate frequency.”
Further, the proportions of different isotopes tells us about the history of the formation of the molecule.
“I wanted to develop this to help gather evidence as to whether or not there was life on Mars,” explained Dr Weidmann, adding that methane in the martian atmosphere is not fully understood, and looking at carbon isotopic ratios can help to identify its origin.
“If it’s bacterial in origin, it would mean a form of life occurred on Mars.”
While not yet used in space, the approach may soon be used on Earth. Thanks to funding from ESA for a Technology Transfer Demonstration project, the potential of the technology was demonstrated and pursued.
“One thing is to develop novel technology for a specific space scope. Another is to turn it into a viable system for use on Earth, in a completely different field and with different requirement.
“The demonstrator project made it possible for us to prove its potential and to attract the interest from a company that could take it and use it for a specific application on Earth.”