Survey of life in the icy crust of the ocean world

During a 2019 field test near the Greenland Summit Station, a remote observation station at high altitude, WATSON equipment will look for signs of life or biosignatures 360 feet (110 meters) below the borehole. Go through that pace. The winch that holds the drill sticks out the top of the drill tent. Credit: NASA / JPL-Caltech

One of its highest level mission goals had already been established long before NASA’s Perseverance Rover landed on the Red Planet on February 18. It is looking for signs of ancient life on the surface of Mars. In fact, the technology used in one of the scientific instruments onboard Rover could be applied to Saturn’s moons Enceladus and Titan, and Jupiter’s moon Europa.

“Patience will look for a shopping list of minerals, organics, and other compounds that could reveal the life of microorganisms when they thrive on Mars,” said Raman, an organic and chemical substance on Mars 2020. Loser Beagle, a senior researcher in scanning habitable environments with luminescence, says (SHERLOC) instruments. “But the technology behind SHERLOC, which looks for past life in Martian rocks, is very adaptable, looking for microbes and chemical components of life that live in the deep ice of Saturn and Jupiter’s moon. Can also be used for. “

Enkerados, Europa, and even the vague moon Titan, under the thick ice lining, a vast ocean of liquid water containing compounds related to biological processes, a very different environment from modern Mars. It is believed to hide in. If microbial life exists in these areas, scientists may be able to find evidence in the ice. But if it’s trapped deep in the ice, how to find the evidence?

Enter WATSON. An abbreviation for a wireline analysis tool for underground observations of the northern ice sheet, a 3.9-foot-long tubular prototype is under development at NASA’s Jet Propulsion Laboratory in Southern California. It has been combined with Honeybee Robotics’ Planetary Deep Drill, which has been successfully tested in the frigid ice of Greenland.

A smaller version of Watson will one day be able to ride a future robotic mission to explore the habitability potential of one of these mysterious satellites. The instrument scans ice to search for bio-signatures, which are organic molecules created by biological processes. If you find something, you can collect samples for further investigation in a future version of WATSON with the additional ability to collect ice from the walls of the borehole.

By using deep UV laser Raman spectroscopy to analyze the materials found, rather than immediately taking ice samples and studying them on the surface of the moon, the instrument is where they are in the context. By studying what, scientists will be provided with additional information about these samples of their environment.

Survey of life in the icy crust of the ocean world

Watson created this fluorescent map of a borehole at a depth of 307.7 feet (93.8 meters) in Greenland’s ice. The left panel shows an ambiguous mass of bio-signatures, and the right panel shows a color version of similar organic chemicals grouped together. Credit: NASA / JPL-Caltech

Mike Marasca, JPL’s astrobiologist and WATSON’s chief scientist, said: “That’s why we are developing this non-invasive device for use in ice environments. We will dig deeper into the ice, identify clusters of organic compounds (perhaps even microorganisms), and analyze them further. To be able to study them before losing them. Change the native context or its structure. “

WATSON uses the same technique as Perseverance’s SHERLOC, with some differences. One is for SHERLOC to analyze Martian rocks and sediments for signs of past microbial life that can be collected and returned to Earth in future missions for deeper research. And SHERLOC doesn’t make a hole. Another tool does that.

However, both rely on deep UV lasers and spectrometers, and if the WATSON ice cream is equipped with an imager for observing the texture and particles of the ice wall, Perseverance’s SHERLOC can be combined with a high resolution camera for rock Take a close-up photo A texture that supports that observation. The camera happens to share the same name as the prototype exploring ice: WATSON. However, in this case, the acronym stands for Wide Angle Topographic Sensor for Operations and eNgineering. (After all, an instrument with a name inspired by the famous fictional detective Sherlock Holmes should inspire references to his partner.)

Enceladus on Earth

Just as SHERLOC has undergone extensive testing on Earth before going to Mars, WATSON must do it before it can be sent to the outer solar system. To see how the device works in the icy crust of Enkerados and the cryogenic temperatures of the Moon, the WATSON team chose Greenland as the “Earth analog” for prototype field testing during the 2019 campaign. Did.

Earth’s analogs share similar properties with other parts of the solar system. In the case of Greenland, the offshore environment near the center of the island’s ice sheet is close to the surface of Enkerados, where marine material erupts from the abundant vents of the small moon and rains. On the other hand, the crushed ice at the edge of the Greenland glacier near the coast can act as an analogy to the buckled deep ice crust of Europe.

Survey of life in the icy crust of the ocean world

During field testing, WATSON and its associated drills were lowered into the borehole to a depth of up to 360 feet (110 meters). In this photo, WATSON’s optical windows allow the device to “see” the sides of the borehole. Credit: NASA / JPL-Caltech

The equipment went through that pace during a campaign to explore an existing drilling hole near the Summit Station, a remote highland observatory in Greenland. When it descended more than 330 feet (100 meters), Watson used its UV laser to illuminate the ice wall and illuminate some molecules. The spectrometer then measured their faint brilliance and gave the team insights into their structure and composition.

It was not surprising to find biosignatures in Greenland’s ice packs, but after all, the tests were done on Earth and by mapping their distribution along the walls of deep boreholes, these A new question arose about how and where the features of. The team found that microbes deep in the ice tend to aggregate in chunks rather than layers, as originally expected.

“We created the map when Watson scanned the sides of the borehole and the clustered hotspots of blue, green and red, all of which represent different types of organic matter,” says Marasca. .. “And what I was interested in was that the distribution of these hotspots was about the same everywhere we saw. It doesn’t matter if the map was created at 10 meters or 100 meters. There is none. [33 or 330 feet] Deep, these compact little chunks were there. “

By measuring the spectral signatures of these hotspots, the team teamed on aromatic hydrocarbons (some of which may be due to air pollution), lignin (compounds that help build plant cell walls), and others. Identified colors that match biologically produced materials (such as complex organic matter) Acids also found in soil). In addition, the device recorded a signature similar to the brilliance produced by microbial clusters.

Ideally, there are more tests to be done on other Earth analogs that are close to the state of other ice satellites, but the team is how sensitive WATSON is to such a wide variety of bio-signatures. I was encouraged by the crab. This high sensitivity is useful in missions to the ocean world where the distribution and density of potential biosignatures is unknown, said Rohit Burtia, a senior researcher at WATSON and a deputy senior researcher at SHERLOC at Photon Systems in Covina, California. .. “If you collect a random sample, you may miss something very interesting, but the first field test will give you a better understanding of the distribution of organic matter and microorganisms in the Earth’s ice. The crust of Enceladus. . “

Field test results published in journal Astrobiology Held in the fall of 2020, it was announced at the American Geophysical Union Autumn Conference 2020 on December 11.

Detective on NASA’s Perseverance Rover

For more information:
Michael J. Malaska et al. Underground in-situ detection of microbial and diverse organic hotspots on the Greenland ice sheet, Astrobiology (2020). DOI: 10.1089 / ast.2020.2241

Quote: Survey of life in the icy crust of the ocean world (April 7, 2021) from https: // 2021 Obtained on April 7th.

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Survey of life in the icy crust of the ocean world

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