NASA has aims to have humans on Mars by the 2030s—but long-distance space travel comes with a unique set of health problems.
How will those who make the trip cope with the mental and physical rigors of the journey? What role will isolation and stress play? And what are the health dangers?
“I’d be very surprised if we didn’t see a Mars mission in our lifetime,” says Marc Jurblum, a training psychiatrist at the University of Melbourne and a member of the Australasian Society of Aerospace Medicine’s Space Life Sciences Committee.
“We have the basic capabilities. It’s physically possible. We have the understanding and the technology to do most of it.”
Jurblum talks about some of the key health issues facing prospective space travelers:
1. Space sickness
On Earth, tiny gyroscopes in your brain give you spatial awareness—they tell you when you tilt your head, accelerate, or change position. But it’s different in space.
“In Zero G, those don’t work as well and, as a result, astronauts suffer a lot of nausea. A lot of them spend days feeling incredibly unwell. It’s like being seasick.”
And there are many examples. In 1968, NASA launched Apollo 8. Astronaut Frank Borman suffered such a bad bout of space sickness on the way to the moon that Mission Control considered shortening the mission.
Fortunately, just like people going to sea eventually get their sea legs, astronauts develop space legs within about two weeks. But once they return to Earth, the opposite is true—many of them have to work hard to get their ‘Earth legs’ back.
2. Anger and other emotions
Space travel is still inherently dangerous. Essentially you are floating through an airless vacuum in a sealed-up container, only staying alive because of the machinery recycling your air and water. There is little room to move and you’re in constant danger from radiation and micro-meteorites.
“Any person can break given enough stress. We’re looking at how to prevent this.”
“We don’t know what months and months of living in an unchanging capsule habitat with only blackness outside the little window will do to people’s minds.”
Jurblum, who has a graduate certificate in space studies from the International Space University, has been involved with research groups looking at how to maintain mental health in extreme environments, including using interventions such as meditation and the positive impact pictures of nature can have on space travelers.
“You don’t need to do anything. Just having those pictures in your environment has a positive psychological effect on concentration, emotional resilience and cognitive performance,” he says.
“We don’t know what months and months of living in an unchanging capsule habitat with only blackness outside the little window will do to people’s minds,” he says. “Even if you turn the ship around, Earth will be a distant speck of light. There’s little more than hydrogen atoms for hundreds of thousands of kilometers around you.”
Virtual Reality may also help by giving the astronauts a rest from the monotony.
Then there’s the issue of emotions. On Earth, if people get upset with their boss or workmate they might take out their frustrations at home or the gym. In space, astronauts can’t afford to get angry with each other—as they must be able to react really quickly, communicate, and work as a team.
Astronauts often divert that anger onto Mission Control. One crew aboard the Skylab space station got so angry at mission control that the astronauts shut down communications for 24 hours.
In contrast, a positive psychological phenomenon of space travel is the “overview effect.”
“Most astronauts who have gone into space have come back with a change of perspective. They become more environmentalist, spiritual, or religious.”
NASA astronaut Ron Garan described it as “the realization that we are all traveling together on the planet and that if we all looked at the world from that perspective we would see that nothing is impossible.”
3. Growing weaker
There is no gravity on the International Space Station, and Mars only has about a third of Earth’s gravity. This instantly plays havoc with the human body.
Astronaut’s faces grow puffy and round, and they constantly feel like they have the flu with blocked sinuses.
“Your body has developed to push fluid up to your brain against gravity. In space, too much fluid gets pushed up to the top half of your body so it then tries to get rid of fluid by making you urinate more, and you end up dehydrated,” Jurblum says, adding our muscles are so used to fighting gravity on Earth that its absence means they weaken and waste.
“…if you sneeze in space, all the droplets come straight out and keep going. If someone has a flu, everyone is going to get it.”
“Astronauts must do two to three hours of exercise every day just to maintain muscle mass and cardiovascular fitness. The heart loses muscle which would be extremely dangerous if they didn’t maintain it through exercise.”
Tight, elastic body suits or “penguin suits,” developed by the Soviet space program, attempt to mimic the effects of gravity on muscles by providing a deep compression force on the skin, muscle, and bone—meaning they have to work harder to perform normal movements. But they’re far from perfect, Jurblum says.
4. Eye problems
A common hazard on the International Space Station is the fine specks that float around the cabin, often lodging in the eyes of astronauts and causing abrasions. But the lack of gravity and the movement of fluids are what can cause the most serious issues.
Most astronauts end up wearing glasses in space and when they come back, some even have permanent changes to their vision,” Jurblum says.
The deterioration results from the fluid shift to the head building up in the skull where it bulges into the back of the eyeball and changes the shape of the lens. “This bulging seems to cause the irreversible vision problems we’re trying to understand and manage.”
5. Coughs and colds
If you catch a cold on Earth, you stay home and it’s no big deal. Space is another story. You’re living a densely packed, confined space—breathing recirculated air, touching common surfaces over and over again, with a lot less opportunity to wash.
The human immune system doesn’t work as well in space, so mission members are isolated for a few weeks before lift-off to guard against illness.
“We’re not sure why, but it seems that bacteria are more dangerous in space. On top of that, if you sneeze in space, all the droplets come straight out and keep going. If someone has a flu, everyone is going to get it and there are limited medical facilities and a very long way to the nearest hospital.”
6. Medical emergencies
Luckily, there have not yet been any major medical emergencies in space, but astronauts have training to deal with them, Jurblum says.
For instance, ISS astronauts have developed a way to perform CPR in zero gravity by bracing their legs on the ceiling while pushing down on the patient on the floor below.
While a rescue from the ISS can be performed within a day, the people who go to Mars will be an eight-month journey away, and they need to be prepared to manage on their own, Jurblum says.
And that requires practice. Here on Earth, Mars Analogs simulate some of the conditions human beings could experience during a future mission to Mars, allowing researchers to work on solutions to situations like what to do if a team member breaks their leg while outside the base.
“How do you lift them on a stretcher, get them into an airlock, out of their suit, and onto a surgical table with a doctor, a botanist, and a couple of scientists to help do surgery? You may have an orthopedic surgeon on Earth sending you information on how to do it, but there is a 20-minute time delay,” Jurblum says.
Despite these health hurdles, Jurblum says humans venturing to Mars isn’t a matter of if, but when. And one of the keys to this is keeping those space pioneers healthy, 54.6 million kilometers away from Earth.
“In the next 30 years we’ll see all this happening, and it will be an international effort.”