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Fall 2021

So Far Yet So Close

Northwestern faculty and alumni are providing their expertise to get humans safely to Mars. By Emily Ayshford

Image: Photograph courtesy of NASA

For the first settlers, the sunrise on the first morning would look unusually faint — a distant sun peeking over a dusty horizon. Breakfast would consist of shelf-stable foods, perhaps some freeze-dried fruit, and a fresh plant or two, grown throughout the long journey. Walking around the habitat, the travelers would feel out of sorts, their bodies buoyant, unmoored in this slighter gravity, and fatigued from the long journey that would have already exposed them to numerous risks: loss of muscle mass and performance, high levels of radiation and the psychological pitfalls of a lengthy, confined expedition.

Yet with great risk comes great reward. When they pull on their spacesuits, unlock the hatch and step outside, they would be greeted by a terrain no human has walked upon before: the cold, dusty, rocky landscape of the red planet.

It’s not an exaggeration to say that sending humans to Mars would be one of the greatest feats of human ingenuity ever. It is perhaps even the inevitable next step in our desire to explore. For decades, scientists and engineers have been preparing for the journey. Now human missions finally seem on the horizon: NASA hopes to send astronauts to Mars in the 2030s, and SpaceX hopes to go even sooner, by 2026. 

Ensuring humans can survive together on a small spacecraft and then thrive on an unforgiving planet still requires much more work. NASA has outlined several specific hazards that astronauts will face, including microgravity, social isolation and confinement, and hostile or closed environments, which include small spacecraft and habitats that must keep astronauts safe and healthy. Each inspires its own set of threats. 

Yet outer space has a way of inspiring good work. Northwestern researchers, students and alumni are part of a global undertaking aimed at both understanding and mitigating such hazards. Though they will likely never visit the red planet, they are helping to pave the way for those who will.

“There’s a lot of interest in large-scale 3D printing of concrete. It opens the doors to new kinds of concrete structures.” — Matthew Troemner

HAZARD: Gravity (or lack thereof)

It begins with a rumbling, as the engine systems start up. Soon, the rumbling turns into a shaking, and before long you feel the spacecraft begin to rise into the air, away from Earth. It accelerates rapidly, the gravitational force pushing you back against your seat. Your body shakes and rattles as the rocket speeds up, rising into the stratosphere. You hear several loud bangs as the boosters and other pieces of the spacecraft detach, falling back to Earth.

And then, just a few minutes after launch, Earth’s gravitational force drops, and the feeling hits you: microgravity.

“Microgravity gives you a psychological high of realizing that you’re no longer confined to Earth,” says neurobiology professor Fred Turek, who has flown many times on NASA’s “Vomit Comet,” an airplane that gives passengers the free-floating feeling of microgravity by climbing to 35,000 feet, then nosediving. The effect induces nausea for some, euphoria in others. “You can do somersaults in the air, over and over. It’s a feeling of, ‘Wow, this is fantastic!’ ”

But microgravity can wreak havoc on our made-for-Earth bodies. It causes our muscles to lose mass, our bones to lose density and the fluids in our bodies to shift up into our heads, causing vision problems. A trip to Mars would expose astronauts to several shifts in gravity, including weightlessness on the six-plus–month voyage, then Martian gravity, which is just 38% the strength of Earth’s gravity.

To better understand how this could affect astronauts’ bodies, NASA has been studying the effects of microgravity, most famously on astronaut Scott Kelly, who was aboard the International Space Station for 340 days in 2015–16, the longest single mission for a NASA astronaut.

Turek, the Charles and Emma Morrison Professor of Neurobiology, and research professor Martha Vitaterna ’92 PhD, both from the Weinberg College of Arts and Sciences, were part of a team of scientists who studied the effects of space travel on Kelly’s body. They had a built-in control with Scott’s twin brother, Mark, an astronaut who remained back on Earth.

They found that Scott’s microbiome — the trillions of bacteria and organisms that line our gut, help us digest food and send molecules throughout our bodies — shifted during his time in space. More than 90% of gut bacteria belongs to two categories: Firmicutes and Bacteroidetes, both of which contain a mix of good and bad bacteria. Scott’s ratio of these two groups shifted while in space: The number of Firmicutes increased, while the number of Bacteroidetes decreased.

Though Scott and his brother ate different foods, the shift couldn’t be attributed to diet alone: Researchers also saw the same shift in a group of mice who spent time aboard the ISS, and not in their control counterparts who ate the same food on Earth.

The change could be due to microgravity, but the results need further study. The answer could have profound implications for long-term space travel, since the microbiome has been implicated in many immune diseases and even mental health issues such as anxiety and depression. The ultimate goal is to understand what interventions would be needed to maintain microbiome health throughout the journey.

“If you’re sending an astronaut to Mars, you’re sending them with millions of their little bacterial friends,” Vitaterna says. “It’s an important part of the body, and you want to use anything you can to safeguard the health and well-being of that body.”

To continue this research, Vitaterna is participating in an experiment with the Japan Aerospace Exploration Agency to put mice in artificial gravity — including at levels that approximate the gravity of Mars — to further study the effect on their microbiomes.

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Sand dunes in a crater in the northern plains of Mars. Image: NASA/JPL-CalTech/University of Arizona

HAZARD: Isolation and confinement

“All the conditions necessary for murder are met if you shut two [people] in a cabin measuring 18 feet by 20 and leave them together for two months,” former Soviet cosmonaut Valery Ryumin wrote in his diary in 1980.

Astronauts traveling to Mars are the ultimate isolated team. Not only must they work long hours and live with their co-workers in a confined environment, they must do it without much additional support: As they travel farther from Earth, messages from Mission Control could take up to 20 minutes to reach them.

If those conditions are indeed ripe for murder, behavioral science researchers Noshir Contractor and Leslie DeChurch are prescient detectives, working to suss out a crime before it happens. Both are experts on team performance, as well as space travel buffs: As a child, DeChurch watched from a Florida beach as the space shuttle Challenger exploded in 1986, and Contractor interned for the India Space Research Organization in college.

Contractor, the Jane S. and William J. White Professor of Behavioral Sciences at Weinberg, the McCormick School of Engineering and Applied Science, and the Kellogg School of Management, studies teams as networks — how relationships among members affect overall team performance — while DeChurch, professor of communication studies and chair of the department in the School of Communication, studies the psychology of teamwork and leadership. Though the two researchers study team dynamics from different angles, they have been building a model to determine how to build astronaut teams that can work together in isolated environments and how to repair teams that aren’t working well together.

Participants live in a space-like habitat at NASA’s Human Exploration Resource Analog. Credit: HERA Photos: Bill Stafford/NASA/JSC

To do so, the researchers and their teams have interviewed astronauts who formerly lived on the ISS and have studied teams within 17 different space mission analogs — where regular people live in an isolated, space-like environment for weeks or months on end. Much of their data has come from the Human Exploration Research Analog at NASA’s Johnson Space Center in Houston.

Some insights seem self-evident: the importance of team members simply saying “please” and “thank you” to each other, and the value of meticulous scheduling that creates a familiar rhythm to the day. Other insights could have the potential to change the outcome of a mission entirely. For example, when an astronaut has to perform a stressful task, like a spacewalk, it can consume their mind for the entire day, meaning tasks they perform beforehand might not receive as much thought and care.

Importantly, researchers also found that creative thinking and decision making decline after the midpoint of the mission — an especially consequential insight, considering the duration of a Mars mission. Part of that is due to the decreased stimuli in the environment: eating the same foods, talking with the same people, looking at the same dark view, hour after hour. The insight also reflects what is called the “third-quarter phenomenon.” During this time, the excitement of the beginning has waned, but the end of the long trip is not quite in sight. Motivation is down; tensions are up. 

“This shows that teams really do need care along the way to ensure they continue performing at high levels,” DeChurch says.

Using this data, the duo is creating a model that NASA could incorporate into a mission dashboard for its upcoming Artemis missions to the moon — a precursor to Mars missions. The model can predict with 80% accuracy how teams will work together. It can then use that information to “re-pair” teams throughout the mission. That is, if two team members aren’t getting along, they can be paired with other team members for certain tasks.

“We want to not just predict what will happen within teams,” Contractor says. “We want to be able to change it and optimize it. Perhaps two people will need a cooling-off period or will need to get reassigned to tasks that they really enjoy doing. We want them to continue to find success together and build better bonds.”

“All the conditions necessary for murder are met if you shut two [people] in a cabin measuring 18 feet by 20 and leave them together for two months.” — Valery Ryumin, cosmonaut

HAZARD: Hostile or closed environments, including small spacecraft and habitats

Keeping the crew alive and thriving during the flight is only the first part of the challenge. When humans land on Mars, they will disembark to find a cold, rocky landscape rife with dust storms and radiation from outer space, knowing that this is the place they will call home for months or even years to come.

Such isolation and self-reliance have been common challenges in voyages throughout most of human history. Explorer Ernest Shackleton wrote that his ill-fated trip across Antarctica that began in 1914 was full of “high adventure, strenuous days, lonely nights, unique experiences and, above all, records of unflinching determination, supreme loyalty and generous self-sacrifice.”

But in our hyperconnected, constructed world, it can be difficult to imagine such a dangerous, remote existence, or how such a landscape would affect the very team meant to study it. 

3D printer Mars habitat

A depiction of the envisioned 3D-printing process to form the habitat’s protective shell. Credit: Martian 3Design by Northwestern Team

That’s what Mars analog missions are for. Brian Shiro ’00, an aspiring astronaut, has been a pseudo-Martian several times, including at the Flashline Mars Arctic Research Station on Canada’s Devon Island, the Mars Desert Research Station in Utah and the NASA-funded Hawaii Space Exploration Analog and Simulation (HI-SEAS).

At these analog sites, the crew lives and works under constraints similar to those they would face on Mars. Days are filled with performing extravehicular activities, running research projects, writing research reports to mission support, and doing chores such as habitat maintenance and cooking meals. The rules are strict: No going outside without wearing a spacesuit, no real-time communication with Earth, no browsing the internet, no more than five minutes of shower time per week. And anything that breaks must be fixed with available tools and materials.

Shiro, a geologist who studied volcanoes in Hawaii for his doctorate, was co-investigator from 2013 to 2018 at the HI-SEAS site, where he trained crews to navigate rocky landscapes in their spacesuits and collect geological data. He also studied the effects of isolation on teamwork and crew performance in harsh environments.

Shiro applied to be an astronaut multiple times and was among a group of highly qualified top applicants. Though he was not selected, he still holds out hope for private space travel.

Living on Mars, he says, “the goal would be to keep everyone alive and working well together, to make sure crews stay sane, happy and healthy.” 

But to create a livable community on Mars, astronauts would need shelter — ideally one that was ready for them when they landed. NASA has said that it could send 3D-printing robots to Mars to build shelters in advance of human arrival, but what materials they would use remains an open question. 

“You cannot ship cement bags from Home Depot to Mars,” says Gianluca Cusatis, professor of civil and environmental engineering at McCormick.

Several years ago, Cusatis and his graduate student Matthew Troemner developed an answer to the Mars construction problem: Marscrete, a concrete made from a Martian soil simulant and sulfur, which is abundant on the planet. 

Marscrete was a success: It is two to three times stronger than Earth-based sulfur concrete, and it reacts with the metals in the Martian soil, making the material as strong as the concrete used to build skyscrapers on Earth (typically made of gravel, cement and water). That’s important, because the planet faces several meteorological and astronomical hazards, from dust storms to radiation to meteor strikes.

A Northwestern team’s Martian habitat design for NASA’s 3D-Printed Habitat Challenge. Credit: Martian 3Design by Northwestern Team

In 2018, Troemner, Cusatis and other team members put Marscrete to the test when they designed a Martian habitat as an entry into NASA’s 3D-Printed Habitat Challenge. The igloo-like structure includes a lab, kitchen, bathroom and private bedrooms and takes into account Martian gravity and the planet’s shifting sand dunes.

They knew they had a strong enough design to withstand the climate, but to make the design human-friendly, they consulted with professors from across the University. Turek, an expert on circadian rhythms, suggested a design that would help maintain astronauts’ sleep-wake cycles during a Martian solar day, which is 24 hours and 39 minutes. That led the team to include hue-changing lights that shine cooler colors during the day and more reddish tones in the evening. They also included monitors that showed a video feed of the area outside — a pseudo-window to the Martian day.

The design won fifth place in the Level 1 Virtual Design Challenge. The next step was to build the shelter. To do so, they designed a 3D printer and created a specialized 3D-printing facility on campus capable of printing Marscrete. 

Though they did not advance in the NASA challenge, the team plans to use the facility for concrete research, both with sulfur and other earthly materials. “There’s a lot of interest in large-scale 3D printing of concrete,” Troemner says. “It opens the door to new kinds of concrete structures.”

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Participants live in a space-like habitat at NASA’s Human Exploration Resource Analog. Image: HERA Photos: Bill Stafford/NASA/JSC

Return to Earth

When the first astronauts on Mars ultimately return to Earth, they face months or even a year of readjusting to a life of Earth-level gravity, an assortment of tastes, smells and sounds, and a new daily routine of endless choices. 

And for the rest of the earthbound world, the research that helped get astronauts to Mars and back will lead to a better understanding of our bodies and our relationships.

Knowing that astronauts can be stressed out before they take a spacewalk can give us insights into our own workflows. If you have a difficult task coming up, DeChurch says, don’t schedule important work beforehand. And also recognize the importance of a daily rhythm and flow, Contractor says.

“The people who report having good mental health, especially in a crisis, create structure that they adhere to that makes it possible to add meaning to their lives,” he says.

Cusatis and Troemner are using what they’ve learned to partner with companies to develop sulfur-based concrete as a more environmentally friendly alternative to regular concrete. Oil companies, for example, have an abundance of sulfur left over from the refining process. Finding a way to integrate that into 3D-printed concrete could be a way to use the material in new situations, such as military deployments or disaster relief.

“Students get excited about working on projects related to Mars,” Cusatis says. “But it’s not just about designing for NASA challenges. Our work in 3D printing and using new materials for structures can really be applied to making construction better here on Earth. That will have real consequences for our own planet.”

Emily Ayshford ’12 MFA is a freelance writer in Chicago.

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Reader Responses

  • This is an impressive and informative article that addresses some of the challenges of a manned mission to Mars. However, it leaves unanswered the question about this endeavor that I have come regard as the quintessential understanding about this project — why? Why would we want to spend a trillion dollars and very possibly $2 trillion to visit a planet that is deadly in so many ways and has nothing of value on it? It is an irradiated planet with practically no atmosphere but yet just enough to cause deadly storms that appear in an instant.

    Is the answer as to "why" to be found in the contracts that would need to be created with private industry to build the hardware to sustain life in space and on Mars? I read an article a number of years ago that suggested the name of the first space ship to Mars with people should be the "USS Pointless". There is no reason to expend resources to take people to Mars. Our destiny is on this planet with one atmosphere and 1G (gravity) where we evolved. We should take better care of our only home.

    Robert Jacobsen ’77 Los Angeles, via Northwestern Magazine

  • Absolutely a superb article. Have they considered the possibility of using A.I. robots programmed for the initial set ups and possible other duties on Mars as said? Just curious.

    Robert Hellen Sr. ’68 Carson City, Nev.

  • Thanks for this informative article about the physical and psychological challenges of long-distance space travel. As an informal educator at a science museum where we engage guests to discuss the challenges of living on another planet, I found this article especially helpful!

    Chris Rademacher ’96 MBA, Chicago

  • Very fascinating article. Learned a lot. I had never heard of 3-D printing of concrete before.

    Janet Schoendorf ’69 Nosara, Costa Rica, via Northwestern Magazine

  • Very interesting and informative. I definitely found this to be an article I wanted to read in its entirety.

    Jim Keiser ’66 Oak Ridge, Tenn., via Northwestern Magazine

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