Nearly all previous life detection instruments have looked for volatile organic compounds using a gas chromatograph–mass spectrometer, or GC-MS. The Viking landers of the 1970s, the Curiosity rover now on Mars, and the upcoming European ExoMars mission all carry these devices…
CMOLD [Complex Molecules Detector] does things a little differently. It extracts organic molecules in a liquid suspension and applies three powerful analytical techniques: (1) a microscope to look for microscale visual evidence of life; (2) a Raman spectrometer to detect atomic composition and organic molecules; and (3) a biomarker detector containing antibodies and short DNA and RNA molecules that bind to life-related compounds.
The authors claim that their new instrument is also suitable for detecting life as we don’t know it. This, of course, depends on just how alien it is. I doubt that the biomarker detector would give positive signals for a very different kind of biochemistry than we have on Earth. But the Raman spectrometer is able to detect complex organic biosignatures even if they don’t correspond to known life molecules. And the high-resolution optical microscope is an invaluable tool for looking closely at any sample.
Thus, CMOLD represents a very promising approach to searching for life on worlds like Mars and the icy satellites Europa and Enceladus, where biology, if it exists, is expected to be at least somewhat similar to what we see on Earth.