Some Experts Are Concerned With NASA’s Plan to Bring Mars Samples Back to Earth

Have there been any living things found in samples taken from space before? Critics are worried about NASA's plan to bring back Mars samples. If strict safety measures aren't in place, Mars samples could potentially cause a new pandemic.
nasa's plan

Frank Kummer writing for The Philadelphia Inquirer, has reported that some people are worried about NASA’s plan to bring samples from Mars back to Earth. Some people have asked at a hearing if there is a slight chance that something in those samples could be alive or a biohazard. Another concern is, do private companies, and China have the same strict safety measures as NASA and the European Space Agency for returning space samples to Earth?

A worried critic of the Mars Sample Return Mission

Thomas Dehel, who used to work for the Federal Aviation Administration, is interested in Mars and runs a website about it. He wants NASA’s plan to move forward, but he has his worries about NASA bringing back samples from space that are not sterile. Several critics share Dehel’s view and think tests should be done in space before samples are returned to Earth to see if there’s any life.

Mars Sample Retrieval Lander 1 Mars Ascent Vehicle Launch Illustration
NASA’s plan to return Mars samples by NASA

Dehel is curious why NASA only told two newspapers, one in Florida and one in Utah, about the May hearings for the Mars Sample Return Mission. 


NASA explained that these papers are in two important places where the mission will happen: where the spacecraft takes off and where it lands. 

Dehel said that most people didn’t know, so not many people showed up to two public presentations in May about the Mars Sample Return Mission.

Dehel wonders what would happen if the mission brings back a disease that people aren’t ready to fight.


Have living things been found in previous samples taken from space?

Dehel and others talk about the work of Gilbert Levin, a scientist that died age of 97 in 2021 and was in charge of a search for life during NASA’s 1976 Viking mission to Mars. 

Levin kept saying for a long time that tests for life were positive after the Viking landers put a nutrient solution with radioactive carbon-14 into the surface of Mars. 

NASA, on the other hand, said that Levin had found a substance that looked like life but wasn’t life. NASA relies on different expert opinions that consider other ways to explain Levin’s results now that they know much more about the chemicals and minerals in Mars’ soil.

26464 samples map cores web
Mars samples by NASA

The discussion is now closed until the fall

Whether you share the same concern as Dehel, public comments on NASA’s plan are now closed. Still, the public will have another chance to weigh in on the mission when a draft of an environmental impact statement comes out in the fall.

The environmental impact statement will investigate recovery activities concerning natural, biological, and cultural resources, as well as repercussions to both the human and natural environments linked with the loss of containment of Mars sample materials.

Mars 2020 With Sample Tubes
NASA’s plan to return Mars samples by NASA

What could go wrong with NASA’s plan?

NASA’s plan made some people nervous, especially in light of the recent pandemic, when they heard about it at an open hearing. 


Dehel wants to know what problems an unsterilized microbe from Mars might cause.

‘Low likelihood of risk’

Some people are worried because NASA can’t say for sure that it won’t bring anything alive or dangerous back from space.  Some people who wrote comments about the first consultation in May said they were scientists, doctors, or professionals.

NASA’s plan reveals that sterilizing samples first could mean losing important information, like biosignatures from past life. 


Others wonder why the samples can’t first be taken to the International Space Station and looked at there. NASA says that the space station, which will be shut down in 2031, doesn’t have the high-tech tools needed for testing.

Nathan Yee, an astrobiology professor at Rutgers who has worked with NASA, agrees that it’s unlikely that anything is alive at or near the surface where Perseverance is taking samples from Mars. Yee said that life would have a hard time living in those conditions.

NASA also says that meteorites from Mars have hit Earth “without harming our biosphere.”


Yee said they probably wouldn’t be dangerous even if living microbes were found. This is because evolution has to take a very long time for microbes to learn how to interact with and attach to animal cells, enter animal cells, and use animal cells to reproduce. On the other hand, Yee said that samples could have “remnants of past lives.”  Yee believes new information might suggest that there is liquid water deep below the surface of Mars and that it might have life.

People are curious about what NASA would do if it did find life in one of its samples. Yee has asked this question. We might not know the answer to that for a while.

Feature image credit: NASA’s plan to return Mars samples by NASA


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