How space flight impacts the body: What NASA learnt from the twins study

On April 12, the National Aeronautics and Space Administration (NASA) in the US released the findings of a landmark study on the impact of spaceflight on human bodies. With the help of a set of twins, NASA was able to study how the human body adapts and changes in extreme conditions like space.

For the ‘Twins Study’, NASA worked with 10 research teams between 2015 and 2016 to provide a biomolecular understanding into how the human body responds during these space flights that include weightlessness and radiation. A total of 84 scientists in eight different states in the US collaborated on this project.

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The study “serves as a genomic stepping stone to better understand how to maintain crew health during human expeditions to the Moon and Mars”, says NASA.

The ‘Twins Study’ helped further the understanding of telomeres, human immunity systems, and gene expression.

How was the study conducted?

NASA’s Human Research Program enlisted two now-retired astronauts—Scott and Mark Kelly—who are also twin brothers.

Scott has logged more than 520 days in space, spread across four flights and holds the record for the most time in orbit by an American astronaut. In March 2015, he launched, with cosmonaut Mikhail Kornienko, for a year-long mission at the International Space Station (ISS).

It was during this mission to the ISS that Scott began his participation in the study. He stayed in space for 340 days and conducted close to 400 experiments to collect data on how his body changed.

Interestingly, during the study, Scott also completed 5,440 orbits around the Earth and did three spacewalks.

Mark has also had an illustrious career as a NASA astronaut. He has clocked 5.28 million miles in travelling in space and has orbited the Earth 202 times in 12 days and 18 hours. He provided a “baseline” for observation on Earth, while Scott was the test case.

Key findings in the NASA ‘Twins study’

NASA Chief Health and Medical Officer, J.D. Polk, said that a major finding of this study is the need for personalised medicine in keeping astronauts healthy.

The study also found instances of chromosomal inversions, changes in cognitive function, and broken chromosomes re-attaching themselves, and changes in gene expression changes and immune system.

NASA says there were notable changes in telomeres—protein structures at either end of a chromosome, whose length shorten with age.

During the study, Scott’s telomeres were longer in space and returned back to baseline length within hours of his return to earth, while Mark’s telomeres remained stable throughout. Scott’s healthy diet and regular exercise could have contributed to this telomere length.

NASA added that studying telomeres, biomarkers of aging, is important and future year-long studies are being planned around it.

By taking a flu vaccine in space, Scott was able to prove that his immunity system behaved normally even in space.

“A fully functioning immune system during long-duration space missions is critical to protecting astronaut health from opportunistic microbes in the spacecraft environment”, says NASA.

Another vital finding relates to gene expression—the manner in which a body responds to the environment. Although Scott’s genes changed while in space, most of them returned to normal in six months when he returned to Earth.

Why is the NASA Twins Study important?

These findings could be vital research for the Indian Space Research Organisation (ISRO) that is planning missions with humans on board.

The first manned space flight by ISRO, called Gaganyaan, will send three humans into space for about a week. This mission will be in a low orbit, about 400 kilometres from the Earth’s surface, and the crew will conduct experiments on microgravity

“The Twins Study gave us the first integrated molecular view into genetic changes, and demonstrate how a human body adapts and remains robust and resilient even after spending nearly a year aboard the International Space Station”, says Chief Scientist of NASA’s Human Research Program Jennifer Fogarty.

This study will be explored for years to come as it has become the base for biomedical and genomics research. It also provides insight into what astronauts might endure if they travel to the Moon or longer distances to nearby planets like Mars.

The project will also help develop therapies and vaccines that will help address health problems and conditions for astronauts in space.

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Rhea Arora is a Staff Writer at Qrius