Will It be Safe for Humans to Go to Mars? Maybe Not. | Almanac.com

Will It be Safe for Humans to Go to Mars? Maybe Not.

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Our limitation isn't technology, it's our own human physiology

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We’ve long had a fascination with going to Mars. The manned trip back to the Moon in late 2024 is the first step in getting humans to the Red Planet. But as planning for manned visits to Mars continues, researchers keep studying risk. Interestingly, it may not be technology that limits our exploration, but our own human physiology.

When Will Humans Go to Mars?

Since the 1960s, humans set out to discover what the Mars has to teach us. Now, NASA is hoping to land the first humans on Mars by the 2030s, though that’s probably ambitious and it’s too early to say. First, we must succeed in a manned Moon landing which will be the gateway to further space exploration.

How Long Does it Take to Get To Mars?

The trip to Mars depends on several factors such as the positions of Earth and Mars in their orbits as well as the speed of the spacecraft. But for perspective, the Mars Perseverance spacecraft took seven months to journey to Mars, landing on February 18, 2021. That’s only a one-way trip! Assuming a three-month stay, the round-trip journey would take at least 17 months.

However, we’re getting way ahead of ourselves with the travel plans.

Can Humans Survive a Trip to Mars?

As of now, researchers are looking at the risks to the human body and whether humans are even capable of surviving a trip to Mars.

Results from astronauts who’ve spent a long time on the International Space Station (ISS) show good reason for concern about space travel’s medical consequences. 

1. Bones and Musculoskeletal Effects

After extended time in weightless conditions, bone and muscle vanishes at 1% per month, and some of the loss is irreversible. During the Apollo missions, astronauts were so weak after eight days that they had to be pulled from their landing capsules. 

But even after the ISS astronauts started exercising during their six-month stays, many astronauts suffered back pain after returning to Earth because of the deconditioning of small muscles that supported their vertebrae. Bones aren’t just a framework; they are living matter that grows, repairs itself, and responds to gravity loads on Earth. 

Astronauts might look like they’re happily at the gym up there, on the treadmill in their underwear, but space is just not good for you. 

2. The Heart and Cardiovascular Effects

The low gravity and radiation in space also has caused circulatory problems for astronauts when they returned to Earth.

Hearts shrink in size, cardiac capacity goes steadily downhill, and there is an increased risk of heart attack later in life.

Lower gravity in space causes the arteries to become thinner, perhaps because the lower gravity needs less blood pressure for circulation. Astronauts returning to Earth do not get enough blood to their brain.

3. Immune System Affects

Things really get bad when you leave Earth orbit and pass outside our magnetosphere, which guards us from solar and cosmic radiation.

Apollo astronauts all saw flashes of light resembling shooting stars cross their visual fields about once a minute, as ions ripped through their eyeballs and brains.  Their radiation exposures were not trivial and, years later, Alan Shepard wondered whether his time in space gave him the leukemia that ultimately took his life in 1998. An intense solar mass ejection occurred just four months after the Apollo 16 astronauts returned to Earth. Had they still been off-planet, the 400 rem radiation dose could easily have killed them. 

Over half of the Apollo astronauts had some sort of immune problem. The immune system of an astronaut can resemble that of the elderly. In space, immune system changes happened after 30 minutes instead of 30 years.

However, recent studies of radiation hormesis surprisingly suggest that very low exposures may be harmless or even beneficial for health, and if verified could change the assessment about the long-term risk of hanging out on the Red Planet. 

Nonetheless, brain neurons would get destroyed by Martian surface radiation. One biologist estimates that during a two-year Mars mission an astronaut might lose between 13% and 40% of his brain cells, which greatly exceeds the 5% annual neuron necrosis suffered by some Alzheimer’s’ patients. 

Still Want to Travel to Mars?

People often talk of having colonies on Mars. But realists know that it’s a fairly high radiation place with no breathable air. Mar’s atmosphere is 100% carbon dioxide with a pressure just one percent of ours. 

My guess is that the “colonization” talk never stops because no other planet is even possible. Our other neighbor Venus is way too hot, as is Mercury, and the other planets are gaseous, with no surface to land on. So it’s Mars or nothing, so far as planets are concerned. The solution might be living underground there, as unpleasant as that sounds to this writer.

If you decide it’s more prudent to simply observe Mars from here on Earth, the next close Martian visit begins in December, next year. 

Learn more fascinating facts about Planet Mars.

About The Author

Bob Berman

Bob Berman, astronomer editor for The Old Farmer’s Almanac, covers everything under the Sun (and Moon)! Bob is the world’s most widely read astronomer and has written ten popular books. Read More from Bob Berman

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