Since September, the Perseverance rover has been plucking along an ancient river delta on Mars, reaching its robotic arms with whirling steel drills at rock cores, shoveling 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, including launching another vehicle to Mars to return the unsterilized samples to Earth, recovering the samples in Utah. land and take them to a safe facility to be built by 2033.
There, scientists will begin testing for signs of ancient microbial life from about 35 samples weighing about a pound in total. The goal is also to understand the geology and climate of the planet, and to prepare people to set foot on the red planet one day.
But the plan caused some members of the public attending a public hearing on the plan a bit of intragalatic agitation, especially in light of the recent pandemic. So does a retired South Jersey Federal Aviation Administration engineer who wonders what problems an unsterilized microbe from Mars could pose.
NASA, along with the European Space Agency, is conducting its Mars Sample Return Mission, 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 of science at NASA, during a virtual public presentation in May. The samples collected from the ancient river delta Jezero “are considered the best opportunity to reveal the early evolution of Mars, including its potential” for life, Zurbuchen said.
‘Low chance of risk’
Some members of the public have wondered about the slim possibility that something in those samples could be alive or pose a biohazard. They also wonder if China, which has announced a similar project, and private companies will receive as stringent safeguards as NASA. Elon Musk is excited about his company Space X’s plans to explore Mars, although there is no timetable.
Public comments on NASA’s initial presentation are now closed, but a draft environmental impact statement on the mission is expected in the fall, providing another opportunity for the public to comment.
The environmental impact statement will examine the implications for both Earth and Mars related to “remediation efforts related to natural, biological and cultural resources” and “impacts on the human and natural environment related to the loss of containment of Mars sample materials”.
‘Even if the risk is minimal’
Some people are nervous because NASA can’t say with 100% certainty that it won’t bring back something alive or dangerous. Some of the 170 commentators in May identified themselves as scientists, doctors or professionals. Others remained anonymous.
One commenter wrote that all samples “must be studied outside the world and remotely because of the risk of planetary contamination. Even if the risk is minimal, nothing should be returned to Earth with a probability greater than 0%.”
Another wrote that “NASA should NOT return samples from Mars until we learn more about how these samples will affect our safety on this planet. Test first for possible bacteria that will adversely affect our health.”
Thomas Dehel, of Gloucester Township, Camden County, was one of dozens of commentators. Dehel is retired from the Federal Aviation Administration and has a master’s degree in electrical engineering and a law degree. Although not affiliated with the mission, he is a Mars enthusiast and runs a website dedicated to the mission.
He wants NASA to continue, but he too is concerned.
“We won’t know if it’s sterile or not,” Dehel said. “That’s my biggest point. We need to know if we’re bringing anything back to Earth, whether it’s sterile or not, to do some sort of rough test beforehand to see if there’s biological life there.”
NASA argues that sterilizing samples could destroy valuable information first, such as biosignatures from a past life. Others ask why the samples cannot be taken to the International Space Station and examined first. NASA says the space station, which is expected to be decommissioned in 2031, does not have the advanced equipment needed for testing.
Dehel is curious as to why NASA posted announcements of the May hearings in just two newspapers, one in Florida and one in Utah. The agency says those papers are in two main areas where the mission will take place: takeoff and landing. Regardless, Dehel said the public was largely unaware, leading to a low turnout at two public virtual presentations in May.
Dehel and others cite the work of Gilbert Levin, a scientist who worked as the principal investigator for a life-detection experiment during NASA’s Viking mission to Mars in 1976. Levin was also named as a researcher for the Mars Sample Return Mission, but died in 2021 at age 97.
Levin long maintained 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 emit the isotope as part of digestion. Levin said that happened at two locations, 4,000 miles apart.
Dehel wonders what the odds are of bringing back a pathogen people don’t want to defend.
However, NASA refuted that Levin “found a substance that mimicked life, but not life.” Indeed, scientists say there are other explanations for Levin’s results, as they now know much more about the chemical and mineral composition of the soil on Mars.
‘Remains of a past life’
Mars has a thin atmospheric layer made up mostly of carbon dioxide and is considered hostile to life. But things were very different in the past when water was thought to flow over the 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 an astrobiology course and has worked with NASA, agrees that it’s unlikely that anything lives on or near the surface where Perseverance collects its samples.
Yee said intense UV radiation is hitting Mars. UV radiation kills microbes by breaking their DNA apart. Indeed, 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 has no magnetic fields that can deflect solar winds that also carry particles with dangerous amounts of radiation.
Overall, Yee said it would be very difficult for life to survive those conditions. And NASA claims that meteorites from Mars landed on Earth “without any ill effects on our biosphere.”
Lee said that even if microbes were found alive, it’s doubtful they would pose a threat.
“It has to be a long, long time of evolution before microbes learn how to interact and attach to animal cells, get in” animal cellsand use the machinery of an animal cell to replicate,” Yee said. “That’s a very complex choreographed dance.”
However, Yee said it is possible that samples contain “remnants of a past life.” He also said recent data suggests that Mars’ deep underground contains liquid water and may be home to life.
More intriguingly, Yee asks: What will NASA do if it is unlikely to find life in a monster?
(c)2022 The Philadelphia Inquirer
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Quote: NASA says plan to return Mars samples back to Earth is safe, but some people are concerned (2022, July 4), retrieved July 6, 2022 from https://phys.org/news/2022- 07-nasa-mars-samples -earth-safe.html
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