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NASA says its plan to bring samples back to Earth from Mars is safe, but some people are concerned


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Since September, the Perseverance rover has been plowing along an ancient river delta on Mars, its robotic arms grabbing at rocks with whirling steel drill bits, scooping up soil and sucking small amounts of the red planet’s atmosphere into titanium tubes.

The plan, under NASA’s Jet Propulsion Laboratory, calls for a sci-fi symphony of technology that involves launching another vehicle to Mars to bring the unsterilized samples back to Earth, landing the samples in Utah, and shipping them to a plant that is still too safe to be built by 2033.

There, scientists will begin examining about 35 samples totaling about a pound for signs of ancient microbial life. The goal is also to understand the geology and climate of the planet and to prepare for the fact that humans will one day set foot on the red planet.

But the plan did give some members of the public who attended a public hearing on the plan a bit of intra-Galatian excitement, especially given the recent pandemic. One of them is a retired Federal Aviation Administration engineer from South Jersey who wonders what problems an unsterilized microbe from Mars might pose.

NASA’s Mars Sample Return Mission. Credit: NASA/JPL-Caltech

NASA is conducting its Mars Sample Return Mission with the European Space Agency, calling it one of the most significant missions it has undertaken.

“We also believe this is the next logical step in our quest to eventually land humans on the surface of Mars,” said Thomas Zurbuchen, an astrophysicist and chief scientist at NASA, during a virtual public presentation in May. The samples collected from the ancient Jezero river delta “are considered the best opportunity to reveal the early evolution of Mars, including the potential” for life, Zurbuchen said.

Read: NASA explains mission to bring samples of Martian soil, rock and atmosphere back to Earth

“Low probability of risk”

Some members of the public have wondered at the remote possibility that something in these samples could be alive or pose a biological hazard. They also wonder if China, which has announced a similar project, and private companies will implement security measures as tight as NASA. Elon Musk was excited about his company Space X’s plans to explore Mars, although there’s no timeline.

Public comments on NASA’s initial presentation are now closed, but a draft environmental impact statement on the mission is expected in the fall, with another opportunity for the public to comment.

The Environmental Impact Statement will consider the impacts on both Earth and Mars in terms of “natural, biological and cultural resource recovery efforts” and “human and natural environmental impacts associated with the loss of containment of Martian specimens.” investigate.

“Even if the risk is minimal”

Some people are nervous because NASA can’t say with 100% certainty that they won’t be bringing back anything alive or dangerous. Some of the 170 commenters in May identified themselves as scientists, doctors or professionals. Others remained anonymous.

One commenter wrote that all samples “should be examined off-world and remotely due to the risk of planetary contamination. Even if the risk is minimal, nothing should be returned to Earth above a 0% probability.”

Another wrote that “NASA should NOT be bringing back samples from Mars until we know more about how these samples will affect our safety on this planet.” First test for possible bacteria that will affect our health.”

Thomas Dehel of Gloucester Township, Camden County was one of the many commentators. Dehel is a retired Federal Aviation Administration graduate with a master’s degree in electrical engineering and a law degree. While not affiliated with the mission, he is a Mars fan and runs a website dedicated to the mission.

He wants NASA to proceed, but he too has concerns.

“We won’t know if it’s sterile or not,” Dehel said. “That’s my main point. We should know if we’re bringing something back to Earth, whether it’s sterile or not, to do a rough test in advance to see if there’s any sort of biological life.”

NASA counters that sterilizing samples first could destroy valuable information, such as B. Past life biosignatures. Others question why the samples can’t be taken to the International Space Station first and examined. NASA says the space station, due to be decommissioned in 2031, doesn’t have the sophisticated equipment needed for testing.

Dehel is curious as to why NASA only published notices of the May hearings in two newspapers, one in Florida and one in Utah. The agency says these newspapers are located in two key areas where the mission will take place – takeoff and landing. Separately, Dehel said the public was largely unaware, leading to low turnout at two public virtual presentations in May.

Dehel et al cite the work of Gilbert Levin, a scientist who served as lead investigator on a life-detection experiment during NASA’s Viking mission to Mars in 1976. Levin was also named as an investigator for the Mars Sample Return Mission but died in 2021 at age 97.

Levin has long claimed that tests were positive for life after Viking landers injected a nutrient solution containing radioactive carbon-14 into the surface of Mars. The belief was that any living organism would shed the isotope as part of digestion. Levin said it happened in two locations 4,000 miles apart.

Dehel wonders at the chance of bringing back a pathogen that humans are unwilling to defend.

However, NASA countered that Levin had “found a substance that mimics life, but not life”. In fact, scientists say there are other explanations for Levin’s findings now that they know much more about the chemical and mineral makeup of the Martian soil.

“Remnants of the Past Life”

Mars has a thin atmosphere, composed mostly of carbon dioxide, which is considered hostile to life. But things have been very different in the past, when water was thought to flow on its surface and a thicker atmosphere would have kept the surface warmer than the current average temperature of -81 degrees, with dips to -220 degrees.

Nathan Yee, a Rutgers professor who teaches astrobiology and has worked with NASA, agrees that it’s unlikely anything lives on or near the surface where Perseverance collects its samples.

Yee said intense UV radiation is bombarding Mars. UV radiation kills microbes by breaking down their DNA. In fact, UV sterilizers are used on Earth to kill bacteria in aquariums and drinking water. You can buy portable UV sanitizers for home use.

And unlike Earth, Mars lacks magnetic fields that can deflect solar winds, which also transport particles with dangerous levels of radiation.

Overall, Yee said it would be very difficult for life to survive these conditions. And NASA claims meteorites from Mars landed on Earth “with no adverse effects on our biosphere.”

Lee said even if microbes were found alive, it was doubtful they would pose a threat.

“There has to be a long, long time of evolution for microbes to learn how to interact and attach to animal cells, invade animal cells, and use an animal cell’s machinery to replicate,” Yee said. “It’s a very complex choreographed dance.”

However, Yee said it’s possible samples could contain “past life remnants.” He also said that recent data suggests that the deep subsurface of Mars contains liquid water and could be home to life.

More intriguing is Yee’s question: given the slim chance it will find life in a sample, what will NASA do?

NASA explains mission to bring samples of Martian soil, rock and atmosphere back to Earth

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