Astrobiology Revealed #38: Celia Blanco

on astrobiology in human space exploration

by Aubrey Zerkle

In this Q&A, we asked Celia Blanco about the paper she recently coauthored, “The Case for Integrating Astrobiology Before, During, and After Crewed Space Missions.” Celia is a Ramón y Cajal Research Fellow at the Centro de Astrobiología (CAB, CSIC-INTA), in Madrid, Spain. She’s also affiliated with Blue Marble Space in the U.S. Celia discusses the possibilities and challenges of incorporating astrobiology into human space missions and envisions how humans and robots might best work together. (This interview has been edited for length and clarity.)

I read on your website that you describe yourself as a “theoretical physicist fascinated by astrobiology.” How did you come to connect these fields, and what types of questions do you tackle?

Like many of us, I blame a good teacher for all of it. Mine was Isabel Gonzalo Fonrodona, who taught a course called Molecular Interactions during my physics degree. She told us about chiral molecules. For those who might not know, these are molecules that come in two versions made of exactly the same atoms, connected in exactly the same way, but arranged in space as mirror images of each other. Our hands are the classic example: they have the same fingers in the same order, yet no matter how you turn them, you can’t stack your left hand perfectly on top of your right. Chiral molecules work the same way, and that small difference in shape matters a lot, because molecules in living things fit together like a hand in a glove, and a right-handed glove won’t fit a left hand. She also told us that life almost exclusively uses ‘right-handed’ sugars to build nucleic acids and ‘left-handed’ amino acids to build proteins, and we still don’t really know how that happened or why.

I immediately became fascinated by this topic, and shortly thereafter, I had the chance to pursue a PhD on this very subject at the Centro de Astrobiología (CAB, CSIC-INTA), building mathematical models to try to identify chemical processes that could explain how biological homochirality came to be. I did my work under the supervision of Dr. David Hochberg, who is the second person to blame for my love of astrobiology. From there, it all just happened very organically.

In the paper you recently coauthored in Astrobiology, you argued that human space exploration is changing the landscape of astrobiology. What new scientific connections or directions are you most excited about?

I think the most exciting part is the flexibility that human exploration can offer. So far, we’ve mostly worked with data and samples from robotic missions designed years before launch, with little room to change course once they were underway. Once a crew is living and working on the Moon, we will be able to adjust our experiments as we go and follow up on surprises right away.

On a more concrete level, I am excited about the prospect of new environments in which to do science. For example, the lunar south pole offers partial gravity, higher radiation exposure, and more extreme temperature conditions than the ISS. Basically, it’s a completely new natural laboratory to investigate aspects related to microbial survival and contamination.

In an earlier work, we mapped how space settlement topics overlap with astrobiology. For example, life support connects to habitability, space mining connects to sample return, the ethics of settlement connects to the ethics of contact, and so on. Honestly, many of these links weren’t obvious to me until we put them side by side.

What do you think are the most daunting challenges astrobiologists will face in implementing these connections, in the scientific, political, and/or operational realms?

Scientifically, I’d say contamination is the most daunting challenge, hands down. Humans are pretty good at carrying microbes everywhere, so once a crew starts building habitats in an environment, that environment will change, most likely permanently. And unfortunately, some of the environments targeted for future human exploration are also among the most promising places to look for signs of past or present life; if we don’t characterize them before human activity begins, we may never know what was there originally. I’d say astrobiology is the field that has the most to win from crewed exploration and also the most to lose.

Politically, I think the main problem is that the rules haven’t kept up with how quickly space exploration is changing, with more countries and private companies planning or aspiring to head to the Moon than ever before. The Outer Space Treaty (1967) requires countries to avoid harmful contamination of other worlds and adverse changes to Earth’s environment from extraterrestrial material. But it doesn’t define specific thresholds or procedures. The detailed guidance comes from COSPAR, which is scientifically respected but not legally binding. Unfortunately, the Artemis Accords, which have attracted a growing number of signatories, don’t create new legally binding obligations, and the China-Russia lunar program (ILRS) has outlined general principles for cooperation, but its detailed governance framework hasn’t been made public. I think one common misconception is that planetary protection only applies to one country or agency missions, but under the treaty, countries are responsible for the activities of their private companies too. How that works in practice is still unclear…

Operationally, the challenge is that not all missions will be science missions. Future missions might include construction, resource extraction, and many other activities with commercial purposes. Something astrobiologically interesting might be spotted (or missed) by a crew that isn’t there to look for life. If there’s no protocol for recognizing, documenting, and following up on that observation, we could lose valuable information. I must also say that science competes with other priorities for crew time and mission schedules, and a surprise discovery doesn’t wait for the next planning cycle.

You also suggested that human-led and robotic missions could complement each other. What might that look like in practical terms?

Well, robots have an extraordinary track record! The Phoenix lander found perchlorate on Mars, and Curiosity detected organic molecules, both major results for our field. So, I don’t think it’s a matter of robots vs. humans; it’s about what each can do best.

In practice, I envision it working as a division of labor across mission phases: before humans arrive, robots could scout and establish a baseline. They could characterize a site (especially sensitive ones like permanently shadowed craters or lava tubes) before any human activity has the chance to alter it. They could also go where it’s too risky or too contamination-sensitive to send people.

During human missions, the two could work together. Humans could make decisions on the spot, interpreting ambiguous observations in real time, changing sampling plans, and repairing or repurposing instruments when something unexpected shows up. Astronauts could also operate robots remotely from nearby, reaching hazardous areas without the long communication delays from Earth.

After missions, returned samples could be studied in labs on Earth with tools no spacecraft can carry, as we saw with the Apollo samples, which are still yielding results decades later.

Are there plans afoot yet to conduct astrobiology experiments on the Moon Base as part of the Artemis mission? If not, what type of experiments would you propose?

It looks like science is definitely starting to arrive. For example, just a few weeks ago, NASA selected new investigations for Moon Base that will look for lava tubes, study ice deposits, and monitor environmental hazards. There’s also interest in growing crops on the Moon and in seeing how microorganisms respond to lunar conditions.

What we haven’t seen yet is astrobiology built into the plan from the start, especially when it comes to contamination and protecting scientifically valuable places. And that worries some of us a bit, because some of the most interesting spots, like lava tubes and ice deposits, are also some of the first places human activity is likely going to change. Once we start building and mining, we can’t go back and see what was there before. So, we’d love to see astrobiology included now, while the work is still mostly robotic scouting.

If I could pick the experiments, I’d say we should first survey the chemistry of spots of interest before any construction or mining begins, so we have a clean baseline to compare against. Then I’d track our own microbes to learn how far they can spread from the base, how long they can survive, and whether they could ever be mistaken for something native. I think what we learn there could help us protect Mars too. I’d also run long-term experiments with microbes on the lunar surface to see how they adapt over many generations. And finally, I would probably study how molecules that could signal life break down under lunar radiation, which would help us make sense of whatever we find elsewhere.

Is there anything else you'd like to discuss that I haven't asked you about?

Sure. I’d like to speak to students directly. I want them to know that this transition is happening right now, and the frameworks for how astrobiology works on crewed missions are still being written. That means there’s room for early-career researchers to shape them. And something that might not be obvious is that the field needs people who can bridge disciplines; we need scientists who understand policy, engineers who understand biology, people from the social sciences and law, etc. 

Basically, if you’re interested in astrobiology but don’t see yourself in a traditional lab or mission role, there might still be a real place for you here! I’d also emphasize that this paper started as a community white paper for NASA’s Decadal Astrobiology Research and Exploration Strategy (DARES), and I believe getting involved in these community processes is one of the most direct ways to influence where the field goes.