The Microbes We Transport With Us to Mars May Become Killers

 In the H. G. Wells book “War of the Worlds,” Martians attack Earth when their planet is becoming uninhabitable due to a loss of water. Their technology is superior to ours, and we humans were not able to stop them. Finally, the assault stopped, and all the Martians died. Not because we defeated them, but because they succumbed to fatal diseases caused by Earth’s bacteria, which their immune systems couldn’t cope with.

NASA and SpaceX want to land a permanent colony on Mars. We know that planet can’t support humans directly. We will have to bring our environment with us, creating structures that can protect us from the harsh environment there.

Wherever humans go, we take with us a load of stowaways in the form of microbes, both in our bodies and on all of our equipment. Even our unmanned spacecraft are contaminated with microbes, no matter how carefully we try to keep them clean. When humans do finally reach Mars, these microbes will arrive with us.

Soil Microbes. Credit Northwest National Laboratory

Radboud University PhD candidate Tommaso Zaccaria wondered whether terrestrial micro-organisms could survive in other locations in the solar system. In space, an astronaut’s immune system becomes compromised. Several conditions of space travel contribute to that, such as the lack of a normal day-night rhythm, poor diet, disrupted gut function, DNA damage from radiation, limited social interaction, and confinement in a small space. Zaccaria asked how the microbes we carry with us to Mars will affect our health. He wondered if any microbes that survive the trip might pose a danger to humans.

Using a simulated Martian surface, he compared the microbes’ effects on our lungs with those of Earth sand. Zaccaria said, “We observed that material from Mars damages the protective layer of the lungs and causes infections. Earth material did not.”

Martian Colony. Credit NASA and JPL.

He then studied several human pathogens, including the bacteria that causes pneumonia in these same simulated Martian conditions. The bacterial cells shrank in Mars conditions, but some did survive. Human immune cells in our blood respond less strongly to shrunken pathogens. At least some pathogens we will take with us could become even more virulent on Mars.

Because of their simplicity, micro-organisms evolve far more quickly than we do. In the new conditions bacteria will find on Mars, they will likely rapidly mutate into new variants that could easily lead to a pandemic for which we have no defense.

The first human colonists traveling to Mars will face a daunting task just surviving the trip.  And once they get there, they may have to deal with a far more challenging threat from the microbes they will bring with them. And like the Martians of H. G. Wells’s imagination, they may be our own undoing on Mars.

 Each month, I write an astronomy-related column piece for the Oklahoman newspaper. After it is published there, I post that same column to my blog page.

This is reprinted with permission from the Oklahoman and www.Oklahoman.com.