Kelly performed a spacewalk outside the space station on November 6, 2015. Time – an important “link” When humans have the opportunity to explore Mars, the crew members will carry out the mission and travel to places millions of miles away from our planet. Scientists want to understand as much as possible about the potential effects of microgravity and radiation on the human body. A big step towards this goal is the One-Year Mission, when NASA astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko spent 340 days aboard the International Space Station from March 2015 to 2020. 2016. Space explorers have spent nearly a year living in zero gravity. The data collected before, during and after their flight made a big contribution. This will help researchers better understand what happens to the human body in space. One concern has arisen regarding astronauts, when their eyes change over long periods of time in space. This change is thought to occur when astronauts are in space for six months or more. Time spent in space also has potential impacts on their vision health. According to researchers, crew members typically spend four to six months on the space station. However, future planned missions lasting a year or longer should be considered. The effect on astronauts’ visual health as a result of long-term flight was previously known as visual impairment and intracranial pressure, or VIIP syndrome. The researchers are now referring to ophthalmic and neurological findings in astronauts after long-duration spaceflight, such as spaceflight-associated optic nerve syndrome, also known as SANS. A new study focusing on eye changes and problems astronauts Kelly and Kornienko experienced has been published in the journal JAMA Opthalmology. “About six months after astronauts began their space missions, we started to observe changes in the eyes of some people. Those changes didn’t show up during their roughly two-week mission aboard the space shuttle,” said study author Brandon R. Macias, director of the Cardiology and Vision Laboratory at NASA Johnson Space Center. in Houston said. According to Macias, the team’s preliminary findings suggest that the duration of the space mission could be responsible for changes in eye structure for the worse, such as swelling of nerve ending tissues. vision. This change has been noticed in some astronauts who have been on missions longer than a year in space. The premise for the future American astronaut Scott Kelly (left) and Russian cosmonaut Mikhail Kornienko (right) spent a year on the space station. The changes in astronauts Kelly and Kornienko were compared with crew members who spent about six months on the station. Both of these astronauts experienced many changes in eye structure. One of them developed mild optic disc edema. “Disc edema can occur when the nerve fibers at the back of the eye swell or when CSF (spinal fluid) builds up around the nerve fibers. If the swelling is severe and persists for a long time, visual function can be affected,” explains Macias. Meanwhile, the other astronaut suffered from optic disc edema and the growing growth of choroidal folds. Both of them used to not realize the changes they were going through. “The retina at the back of the eye is a smooth layer,” says Macias. Folds develop when this tissue becomes wrinkled and uneven. These folds can have different patterns depending on their location and severity. This condition has the potential to impair visual function.” Two astronauts recovered from optic disc edema after returning from space. However, the choroidal folds do not always fully recover. These structural changes did not result in any significant functional changes to the eye. “There is a concern, however, that longer space missions could contribute to more structural changes to the eye. The longer these structural changes take place, the more likely they are that they can cause damage to the retina,” warns Macias. The researchers believe the new findings are a reliable measurement for monitoring the crew members’ eye structures, as well as their long-term health upon their return to Earth. At the same time, the scientists also wanted to understand why some crew members had more eye changes than others. That information could help the team figure out how to prevent neuro-eye syndrome associated with space flight. The team will measure eye activity before, during and after the task by electromechanical methods. Simultaneously, the electrical response of the light-sensitive cones and rods of the eye is measured. Scientists will also look at changes in blood flow in the retina. This may provide more insight into why some crew members undergo more changes than others.

Mr. Scott Kelly while living on the ISS Station. Photo: NYT In a study published in the journal Circulation on March 29, scientists found that during 340 days in space, Mr. Kelly’s heart was reduced in size even though he still exercised hard for 6 days. week. Luckily, the smaller heart did not seem to have any effect on the health of Mr. Kelly when he returned to Earth in 2016. This finding has added to the list of the types of transformations the human body has to undergo in an unstable environment of gravity. Astronauts also tend to have head edema, eyeballs crushing, leg shrinkage, and bones become more brittle. According to the New York Times, Dr. Benjamin D. Levine, study author and professor of internal medicine at the Southwestern Medical Center at the University of Texas (USA), said: “Kelly’s heart has changed to adapts to reduced gravity conditions. It does not have any dysfunction. He is still healthy. Without gravity, the heart doesn’t need to pump blood fully, and like any other muscle, it is altered by decreasing the intensity of the activity. For Mr. Scott Kelly, the shrinking phenomenon still occurs regardless of the regular exercise 6 days / week on the ISS. This regimen has been shown to be effective in reducing brittle bones and reducing muscle mass. After 340 days in space, Mr. Kelly’s heart weight dropped by about 27%, from 190 grams to 140 grams. Mr. Kelly shared that his body also underwent some other changes, such as bone loss, and these phenomena have almost returned to normal. However, the miniature heart phenomenon could be a concern for future missions to Mars. Based on the experiences of Mr. Kelly and other astronauts on the ISS, Dr. Levine thinks that the upcoming visitors to Mars will remain in good health. However, problems can arise if an astronaut is injured, becomes ill and cannot exercise, or if the exercise equipment is damaged. With weaker hearts, they can be dizzy and faint as they step onto the red planet after months of weightless travel. Swimmer Benoit Lecomte. Photo: CNN In the study, Levine and his colleagues compared the heart of astronaut Scot Kelly to that of long-distance swimmer Benoit Lecomte, when he tried to swim across the Pacific in 2018. The buoyancy in the water has the same impact on the body as the weightless environment. Lecomte athletes spend most of the day in the horizontal position: 8 hours of swimming and 8 hours sleeping on a support boat. Scientists think that extended swimming hours will be strenuous enough to maintain Mr. Lecomte’s heart size. But instead, it shrinks at a rate nearly as fast as Mr. Kelly’s time in space. After more than 159 days, the Lecomte athlete abandoned the plan after swimming two thirds of the planned 5,650 miles because the boat was destroyed by a storm. Through ultrasound, it was found that his left ventricle was about 28 grams lighter. The left ventricle is the heart’s largest and most powerful chamber, pumping blood to the aorta and throughout the body. Dr. Levine expressed surprise when she learned the results. “I thought his heart would get bigger. That is a huge amount of training ”. In an interview, Benoit Lecomte estimated his heart rate could be below 100 while swimming, and described the intensity of long-distance swimming as walking briskly, or running very slowly. Now, the US Aerospace Agency (NASA) can design better training programs for astronauts. In space, Mr. Scott Kelly has been exercising 6 days a week, 30-40 minutes walking on the treadmill or cycling. In addition, he also uses a resistance machine to lift weights. “This practice regime is quite strenuous. I have to push weights quite hard. The weight is definitely heavier than I can lift at home, ”said Kelly, now retired at NASA, in an interview. Dr. Benjamin D. Levine said there is another study to track the hearts of 13 astronauts before and after 6 months on the space station. This unpublished study will provide a broader amount of data.