NASA recently released initial results from its Human Research Project (HRP)

NASA: Retired NASA Astronaut Mark Kelly, left, fist pumps his identical twin brother, NASA Astronaut Scott Kelly through glass as Scott Kelly and fellow crew mates, Russian cosmonauts Gennady Padalka, and Mikhail Kornienko of the Russian Federal Space Agency (Roscosmos) participate in a press conference while in quarantine Thursday, March 26, 2015, at the Cosmonaut Hotel in Baikonur, Kazakhstan. Mark Kelly, who flew four space shuttle missions and commanded the final flight of space shuttle Endeavour, will participate in biomedical studies on the ground while his twin is on board the orbiting laboratory. Scott Kelly, Kornienko, and Padalka launched to the International Space Station in the Soyuz TMA-16M spacecraft from the Baikonur Cosmodrome in Kazakhstan March 28, Kazakh time (March 27 Eastern time.) As the one-year crew, Kelly and Kornienko will return to Earth on Soyuz TMA-18M in March 2016. Photo Credit (NASA/Bill Ingalls)

While Scott spent the year in space Mark was on the ground. This wasn't simply a coincidence, NASA created the Human Research Project (HRP) to study the effects of space travel on the human body. Mark was the control subject, and now that Scott is back on Earth, his genes are continuing to be studied to see the effects, if any.

And there definitely are. NASA described the gene expression changes as "fireworks in space." 

Twins Study Principal Investigator Chris Mason, Ph.D., of Weill Cornell Medicine said these "fireworks" occur when the human body is in space and temporarily lasts after the genes return to Earth. 

“This study represents one of the most comprehensive views of human biology. It really sets the bedrock for understanding molecular risks for space travel as well as ways to potentially protect and fix those genetic changes," Mason said.

So what changes are happening exactly? Well, Mason says thousands of gene changes. NASA has created pages and pages of resources on their updated findings within their HRP webpage. Over 200 researchers nationwide are studying how spaceflight affects four major areas: human physiology, behavioral health, microbiology/microbiome and molecular/omics. 

The full research project is set to be completed and released by early 2018.

Scott Kelly, NASA astronaut, spent almost an entire year in space aboard the International Space Station. You might have seen his space photography, widely shared and retweeted on social media.

Did you know Scott has an identical twin brother, Mark?