Hello, and welcome back to The Friendly Neighborhood Shark Lady! I don’t know about you guys, but I grew up with a fascination with space. I wanted to go live on a spaceship and have cool science adventures like Zenon so badly. Maybe one day humans will be living in space or another planet, but our technology definitely isn’t quite there yet. NASA is currently doing a lot of interesting research on the effects of being in space for long periods of time on the human body in preparation for a mission to Mars. Today we are going to learn all about the challenges humans face in space.
In space, many of the challenges faced by humans are due to microgravity. For millions of years, humans have evolved to the gravitational pull felt on Earth. Everything about how our bodies work is adapted to Earth’s environment. This means that when our bodies are subjected to conditions outside of those regularly found on Earth, we can run into problems. Listed below are some of the top challenges that NASA is working on solutions for:
Loss of bone density:
In space, humans' bones excrete minerals at around 1% per month. In comparison, on earth, the elderly population loses these same minerals at a rate of around 1-1.5% per year. This loss of minerals, which in turn leads to a loss of bone density and strength, can lead to a greater risk of fractures in the future.
The increased excretion of calcium from bones, along with general dehydration, also leads to a higher risk of kidney stones.
Loss of muscle strength, endurance, and cardiovascular conditioning:
On Earth, your body is constantly fighting against the pull of gravity. Moving around, like walking, helps keep your muscles strong. When your body no longer has to counteract gravity to move, your muscles don’t have to work as hard. This decrease in work leads to a decrease in muscle tone, strength, and endurance.
Your heart is also a muscle. In space, it doesn’t have to work as hard to circulate blood throughout the body. Your muscles also require less blood when they aren’t working as hard, so your heart, again, doesn’t have to work as hard. This lack of work, like in your muscles, leads to lower cardiovascular conditioning.
The fluids in your body shift toward your head:
Due to the force of gravity always pulling down, our bodies are designed in a way to ensure that bodily fluids, like blood and spinal fluid, are pumped back up to the top of your body so that they don’t just pool in your lower body. Without gravity pulling it back down, the fluids tend to stay more toward the top of your body. The cerebrospinal fluid, which is the fluid surrounding your brain and spinal cord, also increases in volume.
This increase in fluid also causes an increase in pressure. This increased pressure on the eyes can cause permanent vision problems.
Studies have also shown that these fluids can cause the brain to swell. This can cause a multitude of neurological conditions, like chronic migraines. Research has shown that this swelling is still present up to a year after the astronaut has returned to Earth. They have not done any studies to see if it is still present after a year has passed.
Other challenges arise from the mental strain of being in space, isolated from everyone and everything on Earth, and only able to interact with a small group of people.
Stress hormones are elevated:
When your stress hormones are elevated your immune system can change. This can leave you more susceptible to allergies, illnesses, and diseases. You are also living in a closed system, so you would also be more likely to spread those illnesses to others.
Isolation and confinement:
Isolation from friends and family and confinement with a small group of individuals during long missions can lead to a decline in mood, cognitive abilities (like decision making), morale, and interpersonal interactions. This can lead to increased conflict between individuals, depression, boredom, and exhaustion.
The final big hurdle facing humans spending extended periods in space is radiation. Earth’s atmosphere filters out a lot of the radiation found in space. While in space, humans experience more than ten times the radiation we experience on Earth, which can cause a lot of problems.
Increased risk of cancer:
In general, cancer happens when the DNA of a cell mutates in a way that causes them to multiply quickly. Radiation can cause those types of mutations in DNA, so an increased exposure to radiation leads to an increased risk of developing cancer.
Radiation sickness:
Too much radiation exposure in a short amount of time can cause something called radiation sickness. Radiation sickness can cause nausea, vomiting, lack of appetite, and fatigue.
Damage to the central nervous system:
Exposure to large amounts of radiation can cause damage to the central nervous system. This can result in altered cognitive function, reduced motor function, and behavioral changes. This can be especially dangerous on a long term mission in space and could put the mission at risk. When in space, you need to be able to make critical decisions quickly and have superb hand-eye coordination in the case of emergencies and for tasks related to the mission itself.
Degenerative tissue diseases:
Increased radiation exposure can lead to different degenerative tissue diseases, like cataracts or cardiac/circulatory diseases.
While it may seem like there are a lot of things standing in our way when it comes to spending more time in space, NASA, as well as other space programs around the world, are working hard on finding feasible solutions to all of these problems and more! The future of space exploration is bright and I can’t wait to see all of the innovations that come along with it. What challenge surprised you the most? I know I had never even considered that the lack of gravity would mess with my bodily fluids and cause so much havoc. Thank you for learning with me today! I’ll see you all again Friday for another fabulous Finn Friday full of fun shark facts!
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