Next-Generation Life Detectors Are On the Way

Scientists are coming up with non-destructive, non-contact, and highly efficient ways to look for biology on other worlds.

Some day soon, we may be able to quickly scan the Martian surface for signs of life.

Several promising new tools for astrobiology are in the works, according to presentations at this week’s Lunar and Planetary Science Conference in Texas.

One intriguing example is the “Standoff Biofinder,” which is based on the principle that many biological materials exhibit a short-term fluorescence effect that can be distinguished from the natural luminescence of many minerals. Specifications for an early prototype of this instrument were published in 2016, and since then the biofinder has been tested and proven able to detect both current and fossilized life. A research team led by Anupam Misra from the University of Hawai’i at Manoa used it to produce a color fluorescence image of a rocky area that showed green plants as bright red due to the plant’s chlorophyll. Microbes were displayed in various colors, including green, purple, while, blue, and red. Thus, the instrument is in principle able to provide a first glimpse of microbial diversity—even though more research has to be done on what color corresponds to which type of microbe and biomarker.

Testing of the instrument’s ability to detect fossilized organisms was led by Tayro Acosta-Maeda of the University of Hawai’i. He found that younger fossils tend to show a stronger fluorescence than older fossils, and that the biofinder is able to identify putative fossils as much as 2.2 billion years old.

Let’s hope this methodology is developed further, so it can be employed on future life-seeking missions. Much work still needs to be done, including developing a spectral library to rule out false positives. Such a library would have to include the fluorescence and luminescence signatures of all potential biomolecules and minerals that might be detected on an alien world. This would be even more challenging if the extraterrestrial life turns out to be based on a different type of biochemistry, in which case the signals would likely be ambiguous. But non-Earthlike biochemistry would be a huge challenge for any life detection method.

A “standoff” biodetector like this would have many advantages. Not only is it non-destructive, the information can be obtained from a distance, since the instrument would be able to scan an area of about 300 square meters in just 10 minutes. Any scientist planning a future mission to Mars, or to icy worlds such as Europa, would be thrilled to have such a device.

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