Astronaut Scott Kelly's return to Earth on March 2, 2016, marked NASA's completion of its One-Year Mission. The study monitored Earth-bound and retired astronaut, Mark Kelly, as his identical twin brother, Scott, resided 249 miles above the ground in the International Space Station. Along with Russian cosmonaut Mikhail Kornienko, they orbited Earth for 340 days, 7 hours, and 44 minutes. The subsequent phase, the Twins Study, hopes to improve countermeasures that combat the mental and physical stresses of space travel, as well as study the unique genetic changes it causes. A comprehensive understanding of what the human body endures in space is crucial for NASA's next mission: sending humans to Mars!
As we approach the anniversary of Scott Kelly's touchdown, results from the Twins Study are being released. So what did we learn in the past three years from the One-Year Mission and the Twins Study?
5,440 Sunrises Later: The One-Year Mission
The One-Year Mission (1YM) acted as a “stepping stone to future missions to Mars and beyond.†Currently, NASA proposes that the round trip voyage to Mars would take 30 months. In order for humans to successfully travel to the red planet, scientists need to understand and attempt to offset the consequences spending years in microgravity will have on the body. To study these consequences, researchers on Earth developed experiments comparing Scott's and Mark's muscle strength, bone density, eyesight, microbiome, physical performance, metabolism and behavioral and mental health. And that's not even an exhaustive list! You can read more about the experiments here.
Data Analysis: The Twins Study
Since Scott's return, multiple institutions across America, along with one German university, are executing 10 studies under the overarching Twins Study. The data collected before, during, and after Scott's orbit will help scientists better understand the toll long-term spaceflight has on everything from metabolism to epigenetics, and even to the microbiota living inside the gut.
This study is monumental because it utilizes one of the best naturally occurring scientific experiments to distinguish between environmental and genetic influence: identical twins! Scott and Mark, who share nearly the same genetic material, were observed in two different environments: space and Earth, respectively. By comparing the biomedical data between the twins, scientists hope to uncover which changes are seen in both twins (indicating genetic influence) and which changes are unique to Scott (suggesting that the changes were due to Scott's environment in space). While deciphering the results will be difficult, proving that this type of analysis and genomics profiling is possible is a major advancement for both personal medicine on Earth and long-term human travel into the cosmos.
On my @NASA #retirement after a #YearInSpace: https://t.co/5InAr0R3se Thanks for following! The journey continues… pic.twitter.com/PIWpZlJ34K
— Scott Kelly (@StationCDRKelly) March 11, 2016
Reviewing The Year in Space (So Far)
Strangely Behaving DNA
Already, the 1YM and Twins Study are making waves in the medical field. One of the first reports released January 26 noted the strange alterations of Scott's telomeres while in space. Telomeres, located at the ends of chromosomes, act as caps that prevent chromosomes from sticking together. They also protect the genetic information in between from natural deterioration due to aging and stress. Scientists noticed that not only did Scott's telomeres lengthen during his time on the ISS, but they returned to their pre-flight size shortly after returning to Earth. For such a stressful event as space exploration, it's odd that DNA would respond in this manner. Keep your eyes and ears open for further results as scientists continue to analyze this remarkable study.
Eyes Can't See Clearly Now
Space does other bizarre things to the human body. While some of these effects are temporary, such as growing 2 inches taller due to lack of gravity, two-thirds of astronauts report impaired vision that does not correct itself once safely back on Earth. Scientists already knew that microgravity causes pressure to build up in the brain, which pushes on the backs of the eyes and causes vision problems. But what exactly was causing the pressure was not clear, until now.
#YearInSpace science continues. Dueling ultrasound scans 4 @ISS_Research fluid shifts study https://t.co/BM6Bt04Olu pic.twitter.com/7kXNovuCov
— Scott Kelly (@StationCDRKelly) March 15, 2016
Originally scientists thought vascular fluid (blood and lymph) was the culprit, but 1YM research from this past November suggests otherwise. Cranial MRI scans of astronauts from both short and long duration space flights revealed the offender: cerebrospinal fluid (CSF). The central nervous system, optic nerves included, is bathed by CSF. So when cranial pressure increases, the optic nerves become inflamed and the backs of the eyes flatten, causing folds in the retinas. These symptoms are now referred to as Vision Impairment and Intracranial Pressure. Understanding the physiological changes caused by shifting bodily fluids in microgravity is just one of many breakthroughs 1YM aims to uncover. With better understanding of phenomena like this comes improved remedial protocols, bringing safe long-term outer space missions closer to reality.
While humanity's knowledge of microgravity's effects on the body is growing, we still have much to learn. Before we send humans hurtling through the radiation-filled and lonely void that we call outer space, we must learn how to protect our bodies and our minds during the long journey. They don't call it the Final Frontier for nothing.
About the Author
 Leah Caplan is a graduate of the University of Georgia and a Research Associate at the Broad Institute of MIT and Harvard. Due to these advances in space exploration, she is reviving her dream of becoming the first woman on Mars – a dream realized at space camp circa 2003. While this southern belle is a bit far from home, she still takes pride in the Bulldawg Nation and remains steadfast in her liberal use of the word “y'all.†Check out some more blogs from Leah Caplan! |
