As part of NASA’s Twins Study, astronaut Scott Kelly has been sent to the International Space Station for a year, while his twin brother Mark has remained on Earth, with the aim of comparing two genetically identical people to get a better idea of how space affects the human body. Technically, upon his return, Scott should actually be ‘younger’ than his twin. The reality is sure to be vastly different.
As Tech Insider noted, the fact Scott will be travelling at much faster speeds than his brother who is subject to Earth’s gravity, the Theory of Relativity tells us that at the end of his one-year mission, Scott will “technically be 0.01 second younger than his twin brother Mark”.
What the Einstein’s theory does not take into account (and we’ll give Albert a break on this one – he came up with the theory around the same time the Wright Brothers were getting their flying machine off the ground) is how taxing spaceflight is on the human body.
We’ve given a detailed breakdown of the massive issues associated with space travel before on Techly, so here’s a summary from NASA:
That’s a lot of health issues to deal with, and those are based on NASA’s observations of relatively short missions – Scott’s 250-plus days to date make his the longest ever mission by a US astronaut, and there are months left before his return.
Long-term there’s no real evidence to suggest this is a Jack-style ageing issue – you don’t return from space 10 years older, destined to die at a relatively young age. While the average age of astronauts is much lower than the average person, it’s an extremely dangerous job, and the average age is brought down due to incidents such as the Challenger, Columbia and Apollo 1 disasters.
But Neil Armstrong lived to the ripe old age of 82, while Buzz Aldrin and Jim Lovell are still going strong at the age of 85 and 87 respectively.
But these ageing issues are a concern, because if we want to send people to Mars, what state are their bodies going to be in upon arrival?
They will be entering the most alien environment humankind have ever experienced, so being in top shape is going to be of the utmost importance, but after six months taking the pounding the body does from space’s heightened radiation levels and zero gravity, how many health issues are the first Mars explorers going to face?
“We know people’s vision gets worse after six months in space. What if around nine months it gets really bad?” Mark Kelly asked US News. “Imagine you are trying to send a crew to work on Mars, but by the time they get there they could be nearly blind.”
Then there’s simply standing up. As NASA note:
The longer an astronaut spends in space, the more difficult it is for their brain to readapt to gravity. Astronauts returning to Earth after living aboard the International Space Station for that amount of time have exhibited balance control problems, muscle weakness and cardiovascular deconditioning.
Imagine if the first people to land on a neighbouring planet landed, then didn’t the physical capabilities to simply stand up and explore. Worse, think of the magnitude of the tragedy if their bodies were so depleted they couldn’t take care of themselves without serious medical attention, the best of which will be hundreds of millions of kilometres away.
These are the kind of logistical issues NASA are grappling with in their pursuit of putting people on Mars – and why their estimates are so much more conservative than the likes of SpaceX and MarsOne. They aren’t just worried about being able to bring astronauts home from the Red Planet, they want them to thrive during their two-year mission up there.