VOA科学技术2024--Research Explores How Space Travel Affects Human Body

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Childhood cancer survivor¹ Hayley Arceneaux and three other American civilians² went to space in 2021. They travelled in a mission called Inspiration4 for the private company SpaceX.

The four-member crew made history as the first all-civilian team to orbit Earth. But they also provided the most detailed³ data ever on the effects of space travel on the human body.

New research based on this data details changes in the brain, heart, muscles, kidneys, skin, immune system and stress levels. The research also provides information on the activity of cell structures called mitochondria in zero-gravity, increased radiation, and other changes experienced in space travel.

More than 95 percent of the health changes, or biomarkers, returned to normal levels in the months after the crew returned to Earth. But some abnormalities, including in the mitochondria continued, the researchers said. But the data suggested that spaceflights - at least short-term trips - are not big health risks.

"We did not see anything that was worrisome, thankfully," said Chris Mason. He is a professor of physiology⁴ and biophysics at Weill Cornell Medicine in New York who helped lead the research. The studies were published Tuesday in Nature and other journals.

Mason added that there was evidence of brain stress during the mission, which has also been found in previous studies.

Mason said this might be explained by findings in experimental mice flown to space. The mice experienced disruptions in the blood-brain barrier, a layer of cells protecting the brain.

Brain function was not affected⁵, Mason noted⁶.

Arceneaux is a doctor's assistant at St. Jude Children's Research Hospital in Memphis, Tennessee, and the mission's medical officer. Her three crewmates, two men and one woman, were monitored before, during and after the flight. They went through extensive testing and provided blood, saliva⁷ and other bodily materials.

The research also included information from 64 astronauts who had longer stays on the International Space Station (ISS) and other missions. Inspiration4 flew at about 590 kilometers above Earth, higher than the ISS. That means the crew faced higher radiation levels.

The beginning of a "second Space Age" led by private space travel companies has increased the demand to understand health risks, says Afshin Beheshti. He is with the Blue Marble Space Institute of Science in Seattle, Washington, and helped lead the research.

Researchers consider the amount of time in space to be an important factor in the health effects.

The longer the time in space, "the greater the increase in health risks observed," Beheshti said.

Beheshti added the data detailed the major effect of spaceflight on mitochondrial and immune function.

The "new findings indicate that microgravity and space radiation systematically⁸ affect the body, leading to dysfunction at the cellular⁹ level that impacts multiple organs, including muscles, kidneys, heart, skin, and (central nervous system) tissues," Beheshti said.

He added that spaceflight is known to quicken aging and many diseases. But, he said, the research is identifying major health risks that can be targeted for preventative treatment.

The scientists are looking forward in their work.

"If humans are going to be living and working in space, or living on the moon and Mars," scientists need a basic understanding of how the body responds to space, Mason said.

Words in This Story

immune system - n. the system that protects your body from diseases and infections

stress - n. a state of mental tension and worry caused by problems in your life, work, etc.

gravity - n. the natural force that tends to cause physical things to move towards each other

function - n. the special purpose or activity for which a thing exists or is used

saliva - n. the liquid produced in your mouth that keeps your mouth moist and makes it easier to swallow food