NASA has unveiled incredible health findings after comparing an astronaut who spent 340 days in space to his twin brother on Earth.
Scott and Mark Kelly are twin brothers who have both had careers as astronauts with NASA.
While both spent time among the stars, Scott was selected for a historic mission in March 2015 - spending an incredible 340 days in orbit aboard the International Space Station (ISS) alongside Russian cosmonaut Mikhail Kornienko.
Over the course of nearly a year, Scott and the ISS crew conducted almost 400 experiments, helping scientists understand how space affects the human body, a critical step in planning for future deep-space missions, including trips to Mars.
While Scott spent nearly a year in orbit, his twin brother Mark Kelly, a former NASA shuttle commander, remained on Earth.
Their identical genetic makeup provided NASA with a perfect control subject, allowing scientists to compare the effects of space on the human body.
Both twins underwent extensive medical tests before, during, and after Scott’s mission. These included blood, urine, stool, and saliva tests, vision and cognitive assessments, and physical performance evaluations.
The results, published in "The Twin Study," revealed some surprising findings:
1. Scott’s body adapted well to spaceDespite spending nearly a year in microgravity, Scott did not develop any major long-term health issues linked to prolonged space travel. His immune system remained stable, and stress levels returned to normal shortly after landing.
2. Unexpected telomere changesOne of the biggest surprises involved telomeres - the protective caps at the ends of DNA strands that typically shorten with age.
However, in Scott’s case, his telomeres actually lengthened while in space. Since telomeres are linked to aging and diseases like cancer and heart conditions, this unexpected result left scientists stunned.
Steven Platts, deputy chief scientist with NASA’s Human Research Program, was impressed by the findings.
“The results we’ve seen… show the resilience and robustness of the human body,” Platts explained. “We’ve evolved here on Earth in a one-(gravity) environment, we grow up, we train, we do everything here, and yet, when we go into space… our bodies adapt and continue to function and, by and large, function extremely well.”
Most of Scott’s bodily changes returned to normal shortly after landing, except for a few markers that scientists had already expected to see in astronauts.
“This will guide future biomedical space research and allow us to have a safer journey to and from Mars,” Platts concluded.