Blog

How bad is space travel for your health? The answer to that question will be crucial not only for astronauts who aspire to go to Mars, but also for the burgeoning space tourism industry, which plans to send anyone who can afford it into orbit.

In what has been billed as the most comprehensive look yet at the health effects of space, dozens of papers were published Tuesday using new data from four SpaceX tourists aboard the first all-civilian orbital flight in 2021.

Researchers from more than 100 institutions around the world sifted through the data to show that human bodies change in a variety of ways after reaching space, but most return to normal within months of returning to Earth.

Our bodies are subjected to enormous stress while in space, from exposure to radiation to the disorienting effect of weightlessness.

By studying astronauts, researchers have known for decades that spaceflight can cause health problems such as bone loss, as well as heart, vision and kidney problems.

Fewer than 700 people have ever traveled in space, which means the sample size is small — and governments can be reticent when it comes to sharing all their discoveries.

However, the four American tourists who spent three days in space on the Inspiration4 mission were happy to see their data made public.

The first results, which were compared with 64 other astronauts, were published in Nature magazines on Tuesday.

When people are in space, they experience changes in their blood, heart, skin, proteins, kidneys, genes, mitochondria, telomeres, cytokines and other health indicators, the researchers found.

But about 95 percent of their health indicators returned to their previous level within three months.

“I love my space scar”

The “big take-home message” is that people mostly recover quickly after spaceflight, said one of the study’s lead authors, Christopher Mason of Weill Cornell Medicine.

Mason told reporters that he hopes the “most thorough crewed study we’ve ever had” will help scientists understand what drugs or measures will be needed in the future to help protect people going into space.

The Inspiration4 mission, funded by its billionaire captain Jared Isaacman, had the stated goal of demonstrating that space is accessible to people who haven’t spent years training for the feat.

To do this, the four civilian astronauts underwent a huge number of medical tests.

“I love my space scar,” nurse Haley Arsenault said of the residual scar from a skin biopsy. She was only 29 when she went into space.

One study found that the telomeres—the shoelace-like caps that protect the ends of chromosomes from fraying—in all four subjects dramatically lengthened when they arrived in space.

But all of their telomeres shrank back to nearly their original length within months of their return to Earth.

Because telomeres also lengthen as people age, finding a way to deal with this problem could help “us mere mortals” in the never-ending fight against aging, said Susan Bailey of Colorado State University.

It could even lead to anti-aging products like “telomerase face cream,” the study’s author speculated.

A safe mission to Mars?

Looking at the data so far, “there’s no reason we can’t safely get to Mars and back,” Mason said.

“You probably wouldn’t take multiple trips because there’s a lot of radiation,” he added.

One of the studies found that mice exposed to radiation equivalent to 2.5 years in space suffered permanent kidney damage.

“If we don’t develop new ways to protect the kidney, I would say that by the time an astronaut can get to Mars, they may need dialysis on the way back,” lead study author Keith Sue of the London Tubular Center said in a statement.

But Mason stressed that the research is “really mostly good news.”

“I think it’s good for people who think: maybe I’ll be in space in six months,” he said.

Although there isn’t enough data to say anything definitively, female astronauts appear to be more tolerant of the stress of spaceflight, he added.

“This could just be because women have to bear children,” meaning their bodies are more used to big changes, Mason said.