Space Microbiology: Marta Cortesão

Microbiology spans many areas of study, with some focusing on microbes living in different environments, like the ocean, the desert, the soil, and…space. 

Microbes actually can survive in space.

But what types of microbes do this? And how? 

So, I talked with space microbiologist Marta Cortesão about her research and asked her these questions about microbes that live in space.

In this episode, you will learn about…

• What space microbiology is
• What kinds of microbes are in space
• Space microbes from Earth + life on other planets
• How spores help some microbes grow in space
• How to study microbes in space
• How microbes act in space conditions
• Potential for microbes on Jupiter’s moon Europa 
• Marta’s journey to space microbiology
• Marta’s Space Microbes Coloring Book
• At-home microbiology activity: Indoor Mold Scavenger Hunt

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What is space microbiology?

It all started back in the 1950s, during the Space Age, says Marta. After we started sending humans to space, we realized that “wherever humans go, microbes will also go.” So, as we learned how humans adapt to space, scientists started thinking about the microbes that go with us.

What kinds of microbes are in space?

Microbes in space fall into two categories: the microbes we take with us and microbes from space, Marta says. We know the most about the microbes we take with us and are continually learning about how they survive in space.

Microbes we take with us: Astronauts on the International Space Station have microbes on their bodies, which makes sense because we cannot sterilize ourselves. And we wouldn’t want to anyway because our microbiome is beneficial. “So,” says Marta, “as we go to the Moon or Mars, microbes will also be with us.”

Microbes from space: But then there is the possibility of microbes from space that we have yet to discover. They may be harmful, says Marta — it’s something we must be aware of as we search for them from samples from Mars or the moons of Jupiter and Saturn, and be careful in case we do find any. “We need to consider the possibility that they are harmful, at least just because we are not used to them. So maybe the shock of finding a new microbe as it is. When you put a new plant in a different country, it can also overtake the system. It will be the same with the microbes,” says Marta.

Space microbes from Earth + life on other planets

Because we have microbes all over and in us, how do scientists prevent contamination? 

Every time we send anything that will land somewhere like Mars, we must be extremely clean to ensure no microbes make their way to this other planet. If we leave them there, they survive, and later we find them, we might “discover” our own contamination. To prevent these issues, they use extensive procedures using harsh chemicals and heat sterilization to ensure the instruments and all parts of the landers will not contaminate space. The goal is the minimize contamination, because it is impossible to bring zero microbes with us, says Marta. But we need to get close. Plus, traveling through space helps with sterilization because it’s a harsh environment.

But what if we did contaminate other planets — would we be able to tell the microbes apart?

At this point, Marta says, we’re still not sure. These new microbes from space may look like the ones here on Earth. But they may also look completely different. One way to start figuring out if there’s a difference, though, would be to look at the microbe’s DNA and see how similar it is to those here on Earth. If they look a lot alike, it’s potentially contamination from Earth. 

“Personally, I think they would be similar because all of the geology and composition of the universe, at least in our own solar system and specifically, Mars, is not that different from Earth.” 

But right now, since we don’t know how to differentiate them yet, it’s extremely important to prevent the introduction of microbes to other planets. 

How spores help some microbes grow in space

The fact that we are concerned about microbes contaminating space means they can survive those conditions. But space conditions are harsh, so microbes must have ways to survive. One of the adaptations that helps them survive in space is spores. And Marta taught about this adaptation in an online course called #EUROmicroMOOC. It was the first worldwide open access microbiology course on Twitter, and Marta taught a section on Space microbiology. (MOOC = Massive Open Online Course, so it’s accessible to anyone.)

Microbes that make spores are ones that we see quite often. You may have noticed mold before in your bathrooms or on your bread. These are often Penicillium spp. These types of mold also grow in the International Space Station (ISS) due to the un-Earth-like conditions. The astronauts have to exercise to maintain their muscle strength because of the lack of gravity. And just like on Earth, they sweat. But because there’s no gravity, the sweat spreads around the ISS and gets into the walls (see a photo in Marta’s Space Microbiology lesson), which provides a great place for mold to grow. That discovery led to many other questions about how mold can grow well in those conditions in the ISS.

And that’s where spores come in. Whether they are in space or on Earth, molds produce spores that are resistant to harsh conditions. But these spores provide the means for mold to survive both inside and outside the ISS, says Marta, with lots of radiation and in a complete vacuum. The way spores protect mold is by creating a very thick wall around the cell. So, it’s like the difference between us being in the snow in a tank top, where you’re vulnerable to the cold and might eventually die, and wearing a thick jacket, where you’re protected and can survive in this extreme environment, says Marta. These mold spores do the same by creating a thick coat to protect them from space conditions.

How to study microbes in space

Figuring out the answers to space microbiology questions requires that microbiologists study microbes in these harsh space conditions. So, researchers have two approaches to their studies. “The most direct way, of course, is to send the microbes to space and see how they grow.” But it’s not feasible to send lots of experiments to space because we only have a few astronauts and it’s expensive. So, the other option is to simulate space conditions like the radiation of the sun, a vacuum, or zero gravity. 

How microbes act in space conditions

Despite the harsh space conditions, Marta says, microbes can grow almost as well as they do on Earth or better. Some increase their ability to make humans sick (virulence). But others become less dangerous. When it comes to high radiation and exposures to the vacuum of space, Marta says, they do not actively grow or grow very slowly. But that’s okay. All they need to do is to keep their DNA intact, which this slow growth state allows. And some can be “woken back up” and begin to grow again when they find themselves in ideal conditions.

Potential for microbes on Jupiter’s moon Europa

One of the most exciting parts of space microbiology is searching for life on other planets, which Marta discussed in her TEDx talk (watch it here on YouTube). In the search for microbes in space, one of her favorite places to study is one of Jupiter’s four moons, Europa. The reason being that there is a high possibility of microbial life there. “It’s very interesting because it has a massive ocean,” says Marta. An ocean or any body of water is an indicator of life because all life, at least here on Earth, requires water. “Usually, when we look for life elsewhere, we only have one example, which is us. So when we are trying to find life on other planets, we think back to life on Earth. Europa has an ocean, and it’s salty, so I’m almost 100% confident that there are some bacteria there.” The next step will be to collect samples from below the ocean’s ice crust to see if there is or once was life there.

Marta’s journey to space microbiology

Marta became interested in space microbiology through a love for SciFi when she was younger and her family’s interest in space and science fiction. Then, she discovered an interest in biology and, more specifically microbiology, appreciating that microbes are simpler organisms compared to humans but with similar mechanisms and systems. Then, she connected microbiology and space and realized people study these topics in their work. “I googled it, and somehow I found the word astrobiology, and I was like, wow, okay. It’s not science fiction. There are actual scientists studying life on other planets and how this could happen,” says Marta. That’s when she had found the perfect combination of interests to focus her career on.

Space Microbes Coloring Book

A fun project Marta did was create a Space Microbes Coloring Book. She was motivated to take this sometimes difficult-to-understand topic and make it easy for anyone to enjoy. “Microbiology is very abstract. And I wanted to make it a bit easier for people to understand and to relate to microbiology, something in our bodies, on and in and everywhere.” Creating the coloring book then led her to start the website spacemicrobes.com where she writes about her research and shares personal stories about her work. “I think it’s very important that we keep curious and learn about the world around us,” says Marta.

At-home microbiology activity

For the at-home microbiology activity, Marta shares with us an Indoor Mold Scavenger Hunt. Although mold is an organism we often see in our daily lives, consider how wild it is that mold can end up all the way on the space station. So, with this in mind — that an organism we encounter in our daily lives is that tough — let’s search for it. See if you can find it somewhere in your house. Any location with lots of moisture is likely to have mold. And because they are expert decomposers, you will find them on foods that are going bad, especially older strawberries, blueberries, or lemons. Even mold can sometimes grow on the top layer of soil on your indoor plants. I know, it’s kinda gross. But next time you find some mold, try to think about it a little differently…mold is a space traveler, a microbial astronaut.

Links & Resources

• Space microbiology: #EUROmicroMOOC (massive open online course on Twitter)
• Space Microbiology (review paper by Gerda Horneck)
• Astrobiology and the Search for Extraterrestrial Life (Coursera online course from Charles Cockell, University of Edinburgh)
• Space Microbiology | Space Microbes: In Short #1 (YouTube)
• Astrobiology: The Search for Life Beyond Earth – TEDxUniversityOfPorto (YouTube)
• Microbes in space (blog post)
• Life in extreme locations: Dr. Adrienne Kish (podcast episode + blog post)
• Space Microbes Coloring Book by Marta Cortesão

Connect with Marta Cortesão

Marta Cortesão is from Portugal and holds a Masters in Cellular and Molecular Biology (University of Porto, Portugal). She is a final-year PhD student at the German Aerospace Center (DLR) in Cologne, Germany, studying how mold adapts to space conditions. She’s passionate about space microbiology and astrobiology and loves science communication and outreach, which she does under the platform Space Microbes.

Connect with Marta Cortesão: Twitter, Instagram, website, and YouTube.