- 3735 - LIFE - Are we alone in the Universe? An answer to that age-old question has seemed tantalizingly within reach since the discovery of ice-encrusted moons in our solar system with potentially habitable subsurface oceans. But looking for evidence of life in a frigid sea hundreds of millions of miles away poses tremendous challenges.
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--------------------- 3735 - LIFE - Are we alone in the Universe?
- The science equipment used must be exquisitely complex yet capable of withstanding intense radiation and cryogenic temperatures. The instruments must be able to take diverse, independent, complementary measurements that together could produce scientifically defensible proof of life.
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- To address some of the difficulties that future life-detection missions might encounter, scientists have developed “OWLS“, a powerful suite of science instruments unlike any other. Short for ‘Oceans Worlds Life Surveyor“, OWLS is designed to ingest and analyze liquid samples. It features eight automated instruments that, in a lab on Earth, would require the work of several dozen people.
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- OWLS combines powerful chemical-analysis instruments that look for the building blocks of life with microscopes that search for cells. One vision for OWLS is to use it to analyze frozen water from a vapor plume erupting from Saturn’s moon Enceladus.
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- In June, 2022, after a half-decade of work, the project team tested its equipment, currently the size of a few filing cabinets, on the salty waters of Mono Lake in California’s Eastern Sierra. OWLS found chemical and cellular evidence of life, using its built-in software to identify that evidence without human intervention.
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- The science autonomy software on JPL’s OWLS tracks particles as water flows past the microscope, using machine-learning algorithms to look for evidence of lifelike motion.
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- A key difficulty the OWLS team faced was how to process liquid samples in space. On Earth, scientists can rely on gravity, a reasonable lab temperature, and air pressure to keep samples in place, but those conditions don’t exist on a spacecraft hurtling through the solar system or on the surface of a frozen moon. So the team designed two instruments that can extract a liquid sample and process it in the conditions of space.
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- Since it’s not clear what form life might take on an ocean world, OWLS also needed to include the broadest possible array of instruments, capable of measuring a size range from single molecules to microorganisms. The project joined two subsystems: one that employs a variety of chemical analysis techniques using multiple instruments, and one with several microscopes to examine visual clues.
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- Water ice and vapor are seen spraying from Saturn’s frozen moon Enceladus, which hosts a hidden subsurface ocean. OWLS is designed to ingest and analyze liquid samples from such plumes. OWLS’ microscope system would be the first in space capable of imaging cells. It combines a digital holographic microscope, which can identify cells and motion throughout the volume of a sample, with two fluorescent imagers, which use dyes to observe chemical content and cellular structures. Together, they provide overlapping views at a resolution of less than a single micron, 0.00004 inches.
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- This microscope system has no moving parts. It uses machine-learning algorithms to both home in on lifelike movement and detect objects lit up by fluorescent molecules, whether naturally occurring in living organisms or as added dyes bound to parts of cells.
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- To examine much tinier forms of evidence, OWLS uses its Organic Capillary Electrophoresis Analysis System (OCEANS), which essentially pressure-cooks liquid samples and feeds them to instruments that search for the chemical building blocks of life: all varieties of amino acids, as well as fatty acids and organic compounds.
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- The system is so sensitive, it can even detect unknown forms of carbon. Like a shark that can smell just one molecule of blood in a billion molecules of water, but this will also tell the blood type. It would be only the second instrument system to perform liquid chemical analysis in space.
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- “OCEANS” uses a technique called “capillary electrophoresis“, that is running an electric current through a sample to separate it into its components. The sample is then routed to three types of detectors, including a mass spectrometer, the most powerful tool for identifying organic compounds.
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- These subsystems produce massive amounts of data, just an estimated 0.0001% of which could be sent back to faraway Earth because of data transmission rates that are more limited than dial-up internet from the 1980s.
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- So OWLS has been designed with what’s called “onboard science instrument autonomy.” Using algorithms, computers would analyze, summarize, prioritize, and select only the most interesting data to be sent home while also offering a “manifest” of information still on board.
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- Are some of these other planets habitable? Is there defensible scientific evidence for life rather than a hint that it might be there? That requires instruments that take a lot of data, and that’s what OWLS and its science autonomy is set up to accomplish.
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- November 7, 2022 LIFE - Are we alone in the Universe? 3728
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