The human body is a very flexible and an adaptable mass. It has inbuilt mechanisms that are able to change to suit different environments. Life in space and life on Earth are two separate conditions from the temperatures to the atmospheric pressure. Astronauts have to cope with these conditions to survive living in space, which may last up to months on end.
But we do not have to wonder any more after Scott Kelly become the first man to stay in space for 195 days. What made this experiment even more impressive is that Scott Kelly has a twin, Mark Kelly who stayed back on Earth. With their physiological and physical attributes almost identical, NASA could really examine living on Earth after going to space.
Preparations begin before leaving Earth, and they cover technical, personal and group pieces of training, including simulations that create a near space scenario to help them adapt to the different environment and any eventualities that may occur.
The Adaptation process of living in space
One thing that Scott Kelly and his colleagues unanimously agree on, is the food on Earth is much better. Food in space is carried in rations packed in plastic containers and even though it remains fresh for the duration there, it just doesn’t feel like food on Earth.
Showers and bathroom visits are easier on Earth thanks to gravity, according to Garret Reisman, who was a member of two Expedition crews and a total of 107 hours in space, and two spacewalks to his credit.
“First of all, the food is much better here on Earth,” said Garret. “And taking showers and going to the bathroom is much easier to do here too.”
On Earth, our heart has to fight gravity to keep our blood pumping to the upper parts of our body. Otherwise, due to gravity, all our body fluids would end up in our legs. In space, all body fluids are on an upward trend, and that gives the Astronaut what they call ‘puffy face’ and ‘bird legs.’ Canadian Astronaut Chris Hardfield says some crew members don’t recognize their colleagues at first due to the rounder and smoother faces. The change is immediate though when they land back on Earth, and their faces return to normal, as well as circulation.
Physiological functions change gradually
Some changes are not as quick, though, as Garret Reisman found out. The vestibular system which is responsible for motion, equilibrium and spatial orientation and has its headquarters in the ears, takes longer to adapt to Earth’s environment.
When in space, the brain shuts outs signals received by the ear as they are ‘garbage signal.’ The brain then enhances sight, to replace the loss of sound. Canadian Astronaut Roberta Bondar discovered that she did not need her glasses in space as her eyeballs had returned to a more rounded shape. Now the change- over the back to normal when an Astronaut lands on Earth, may take days.
A person who weighs 220 pounds on Earth weighs 84 pounds in space. That lack of weightlessness made Robert Garret Reisman feel like he was carrying the entire weight of the space shuttle immediately after he landed.
Sleeping is also interesting in space. While there are bunkers, an Astronaut can sleep anywhere as there is no up or down. As long as an Astronaut is strapped to something, so that they do not float around and bump into something.
Fighting that feeling of lack of weight when back on Earth, is another battle Astronauts have to engage.