Scott Kelly: NASA Single Flight Record, Unique Study of Space Effects on Body

First Posted: Oct 30, 2015 10:49 AM EDT

U.S. International Space Station Commander Scott Kelly has officially spent more consecutive time in space than any other United States astronaut, surpassing the record early Thursday morning.

Kelly, who has been in orbit for 216 straight days, broke Michael López-Alegría's previous record of 215 days, set back in 2007. Kelly's mission began in March earlier this year, and is scheduled to end on March 2, 2016, on his 342nd straight day in orbit, according to NBC.

After the completion of the "Year in Space" mission, he will have logged 522 total days in space. He previously broke the U.S. record for total days logged in space on Oct. 16, his 383rd cumulative day, per NASA. He completed his first spacewalk, a seven hour repair mission, on Wednesday.

Kelly's time in space poses an even more interesting opportunity for NASA, however, which will commence once he has returned to Earth. The former U.S. Navy captain has an identical twin brother, Mark Kelly, who is a retired NASA astronaut. This unique opportunity will allow NASA to produce a deeper study of the effects long space stints have on the human body.

Before Kelly launched into orbit, he and his brother provided urine, blood, saliva, and fecal samples for baseline readings of their biological makeup. They are in the process of providing additional samples over the course of the mission, and for six months after it concludes, according to The Guardian. The twins share a genome, allowing NASA scientists to examine the effects space has on the human body and brain.

"We are looking at just about every level in the biological spectrum from the molecular level to the whole body integrated," said John Charles, a doctor on NASA's human research program. "This is possibly the most complex biomedical investigation ever done on the space station."

The different types of samples will be used for different examinations. The blood and saliva will allow for observation of the changes in the twins' genome, while the urine and fecal matter can show changes in metabolism and gut microbes.

Being in space causes immediate changes to the physiology of astronauts, affecting their bones and muscles, as well as bodily fluids. Due to the lack of gravity, the bones and muscles wear away, and fluids move up in the body to the chest and head, which is believed to put additional pressure on astronauts' brains.

"We hope to understand in incredible detail what happens as people are launched into space and live there," Mike Snyder, of Stanford University, who is leading one of 10 teams examining the twins' data, said. "What does it do to the human body? Humans in space experience dramatic differences, from high force during launch to loss of gravity and radiation exposure. We want to see how all these things affect the human body using modern tools."

While having such a limited group to examine for the study will have its shortcomings, NASA believes that the opportunity will still provide incredibly valuable information.

"There is not likely to be identical twin astronauts again, at least in my career, and probably in my lifetime. So this is really a once in a career, and perhaps a once in a lifetime opportunity," Charles said.

As of today, no American has spent more consecutive days off of our planet than my twin brother @StationCDRKelly. pic.twitter.com/Yr8hti3LEc

— Mark Kelly (@ShuttleCDRKelly) October 29, 2015