By Girish Linganna
Mar 1: In the environment of the International Space Station (ISS) or any spacecraft that ventures into space, the gravitational force is significantly diminished compared to that experienced on Earth. Consequently, individuals often exhibit symptoms of "space sickness," including headaches, queasiness, and vomiting. On our home planet, we are greatly influenced by the force of gravity. To maintain our body's equilibrium, we rely on a minute organ known as the vestibular organ, which resides deep within our ears, specifically in the inner ear.
This organ in our inner ear, called the vestibular organ, takes the gravity and acceleration signals from our body and converts them into electrical signals. These signals are then sent to the brain. On Earth, the brain constantly receives gravity information from the vestibular organs and uses it to maintain our body's balance.
In the low gravity environment of space, the information received by the vestibular organs undergoes a change. This change is believed to cause confusion in the brain, resulting in space sickness. However, this condition is not persistent. If one spends a few days in space, the brain adapts its understanding of the vestibular information, leading to the resolution of space sickness.
Individuals respond differently to space sickness, with varying levels of severity, and some may not experience it at all. Upon returning to Earth, the re-exposure to Earth's gravitational pull can lead to "gravity sickness," which shares similar symptoms with space sickness.
The face often swells in space
When you're on Earth, gravity pulls blood and other fluids down to your lower body. In space, gravity is much weaker, so these fluids don't get pulled down and instead gather in your upper body. This is why astronauts' faces puff up in space. Their nose linings swell too, making their noses stuffy. If astronauts stay in space long enough, their body adjusts and the fluids spread out more evenly, reducing the puffiness in their faces after few weeks.
When astronauts come back to Earth, they often feel dizzy when they stand up, a condition called orthostatic hypotension. This happens because Earth's gravity is stronger than in space, making it harder for the heart to pump blood up to the brain. In space, the heart doesn't need to work as hard to move blood around, so the heart muscles can get a bit weaker. This weakness might also be why astronauts feel dizzy when they stand up after returning to Earth.
Bones and muscles weaken
If you spend a lot of time in space, your muscles and bones, especially in your legs and lower back, get weaker. On Earth, gravity affects you all the time, so you're always using your lower body muscles without even thinking about it. But in space, where there's hardly any gravity, you don't need to stand or use your legs to get around. Because of this, your muscles can weaken and your bones can lose mass if you're in space for too long.
Scientists are checking if medicines that stop bones from getting weaker work in space. Also, astronauts exercise for two hours a day on the International Space Station (ISS) to keep their muscles and bones strong.
Is radiation more intense in space?
In the vacuum of space, where there is no atmosphere, radiation levels are much higher and can have significant effects on human health.
The Earth is surrounded by an atmosphere that gives us the oxygen we breathe and shields living things from harmful UV rays and radiation. However, astronauts in space, where there's hardly any atmosphere, face much more intense radiation than we do on Earth.Being exposed to a high amount of intense radiation raises the chance of getting diseases like cancer.
Scientists and researchers are putting in a lot of effort to ensure that exposure to space radiation stays under a certain limit to protect astronauts from health issues.
Tight spaces can cause severe stress.
The International Space Station (ISS) offers more living space than earlier spacecraft, but activities are still far more restricted than on Earth. Astronauts often feel stress from living and working in close quarters with others for months, sometimes without even realizing it. The crew of the ISS, hailing from countries like Russia, America, Canada, Europe, and Japan, faces additional stress from language barriers and cultural differences. Efforts to lessen astronaut stress include creating ways for them to communicate with family and friends from space and improving the quality of space food.
(The author Girish Linganna of this article is a Defence, Aerospace & Political Analyst based in Bengaluru. He is also Director of ADD Engineering Components, India, Pvt. Ltd, a subsidiary of ADD Engineering GmbH, Germany. You can reach out to him at: girishlinganna@gmail.com)