Will NASA astronauts unearth microbes on Mars?

Astronauts on an upcoming crewed mission to the red planet are unlikely to find little green men, but there is compelling evidence to suggest that they may find other forms of life. If living organisms do exist on Mars, preventing cross-contamination of microbes is key to the health of both biospheres.

"Sending a human mission to Mars and returning the crew safely back to Earth is now a national goal of the United States and may occur as early as 2035," said William & Mary Research Professor of Applied Science Joel S. Levine.

Last year, Levine served on an international panel of 39 scientists to determine effective methods of planetary protection for the upcoming Mars mission. Additionally, three W&M undergraduate students performed research in a multi-year NASA atmospheric dust workshop that contributed key information to the panel for its recently published study.

"We're giving W&M undergraduates a rare opportunity to do research for NASA for their senior theses," said Levine. "These students are actively working on NASA projects, and some of them transfer into the space program."

Levine retired from his position as senior research scientist and program scientist for the Mars Scout Program at NASA in 2011, but continues to participate in NASA research while teaching in W&M's applied science department.

On April 10, Levine was honored at W&M's Celebration of the Book for his two recent works about the impact of atmospheric dust on human exploration of Mars and the moon, respectively.

Why study Mars?

The possibility of finding signs of life, past or present, on another planet has long captured the human imagination. Levine explained that for at least 2 billion years, Mars was similar to Earth. It had conditions favorable for life: a very thick atmosphere, flowing rivers and an ocean covering most of the northern hemisphere that was five miles deep.

As part of NASA's Viking mission to Mars in 1976, three experiments were conducted to search for life. Two of the experiments produced a negative response, meaning that no life was detected, but one yielded a strongly positive result, indicating the presence of life.

Researchers grappled with what to tell the public. Given the conflicting readings, they decided to report that life had not been detected.

Subsequent missions, however, have provided more information about the chemically active surface of the red planet. It turns out that hydrogen peroxide in the lower atmosphere of Mars reacts with the surface to create a veneer that likely interfered with the Viking measurements that returned negative results.

"That doesn't mean there is definitely life on Mars," said Levine. "It means that we can now explain why we didn't detect it."

If the upcoming mission does find signs of life on Mars, it will give biologists an opportunity to study life that formed and evolved independently of life on Earth, opening up new worlds within the field.

The other principal reason to study Mars is the massive shift in its climate.

"Something happened on Mars that changed the entire climate," said Levine. "It caused the bulk of the atmosphere to be lost and the disappearance of all of the liquid water."

Two of the top hypotheses are natural processes that left the atmosphere susceptible to solar wind or a catastrophic event. Researchers would like to gather more evidence to determine whether the cause is something that could affect Earth in the future.

Gases trapped in bubbles within Martian polar ice caps can provide evidence of changes in its atmospheric composition over time. Levine stated that robotic technology is not up to the task of drilling, extracting and storing ice cores for study nor is it capable of several methods of searching for fossils and other signs of life. He explained that a human presence is necessary to adequately perform these tasks. Thus, NASA is preparing to launch the crewed mission to Mars.

Avoiding the Andromeda Strain

Sending humans to Mars adds complications. One of the most pressing issues is the need to prevent cross-contamination of microorganisms between the two planets. If life does exist on Mars, organisms from Earth could affect, alter or harm it. Martian microbes, in turn, could wreak havoc on Earth.

Atmospheric dust has the potential to contribute to both forward contamination, the transport of Earth microorganisms to Mars, and backward contamination, the transfer of Mars microbes to Earth.

Levine used an example from Earth to illustrate this point. He explained that dust from the Sahara Desert can travel thousands of miles and carry living microorganisms that become viable and multiply when they settle at new sites.

Dust storms are extremely common on Mars, sometimes reaching a global level, and have the potential to contribute significantly to microbe contamination.

Levine explained that sterilization of robotic equipment is fairly straightforward and can be performed with extreme heat and ultraviolet light. Humans, however, carry microorganisms everywhere they go in the form of the microbiome, which is essential for human survival. Quarantines are an added measure that can be effective for crewed missions, and research teams are actively working to find other solutions.

Students at NASA

Undergraduate students Jason D. Nykorczuk '18, Bjorn Shockey '23 and Maximilian S. Weinhold '21 participated in the multi-year NASA workshop studying the impact of atmospheric dust on the surface of Mars. A typical day in their research included attending NASA meetings, interacting with scientists and gathering and summarizing information.

Nykorczuk currently works as a geospatial analyst, but maintains his interest in the red planet.

"Dr. Levine brings an infectious passion to studying space, particularly Mars," said Nykorczuk. "It's remarkable how many people I've run into—both at professional conferences while attending William & Mary, and professionally through my work with NASA and FEMA—that know Dr. Levine and have wonderful stories to tell about his doggedness in working towards a human mission to Mars."

Shockey, meanwhile, transitioned from studying dust-related complications on Mars to potential human impact on the moon during upcoming long-term lunar missions within the new NASA Artemis program. For his senior thesis at W&M, he received a $10,000 research stipend from NASA through the Virginia Space Grant Consortium.

"It's very rare for NASA to award a grant to an undergraduate," said Levine, "especially when it's a senior thesis or requirement for graduation."

Shockey explained that his project arose from "concern for astronaut safety due to the prevalence of space dust and potential irreversible harm to the lunar atmosphere caused by human presence."

He has been accepted to a doctorate program in Systems Synthetic and Physical Biology at Rice University and will begin in fall of 2024. Rice University is in close proximity to NASA's Lyndon B. Johnson Space Center, the home of NASA's human space missions.

"While my personal studies have transitioned, I will still be heavily involved with space applicable research in Houston at the Johnson Space Center and, of course, remain in good contact with Dr. Levine," said Shockey. "He has been a fantastic mentor and motivated my pursuit of higher education and continuous interest in planetary science and space exploration."

More information:
The Impact Of Human Presence And Human Activities On The Total Mass And Chemical Composition Of The Very Thin Lunar Atmosphere: vsgc.odu.edu/wp-content/upload … ckey_Bjorn_Paper.pdf

Provided by William & Mary