US astronaut Scott Kelly has broken American record for days in outer space on Friday.

Orbiting above the Himalayas, Kelly tweeted "records are meant to be broken." NASA said it was Kelly's 383rd day living in space during four missions.

Kelly is currently on more than halfway through a nearly year-long mission aboard the International Space Station. The mission is aimed at helping the scientists to study how the human body responds to long-duration space flights. NASA says on Earth, scientists are involved in same kind of studies on Kelly's identical twin brother, retired astronaut Mark Kelly.

Kelly broke the record set by astronaut Mike Fincke, according to NASA. "Breaking such a record for time in space is important because every additional day helps us better understand how long-duration spaceflight affects bodies and minds, which is critical to advancing NASA's journey to Mars," NASA said in a press release on Friday.

Kelly will return to Earth on March after spending 522 days in space. He launched on March 27 from Kazakhstan aboard a Russian Soyuz rocket along with two cosmonauts. One of the cosmonauts, Mikhail Kornienko, will also stay at the ISS for the one-year mission.

Russian cosmonaut, Gennady Padalka, owns the world record for most days spent in orbit. He returned on September 12 after remaining in outer space of 878 days, said Russia's Federal Space Agency.

Aboard the ISS at a speed of about 15,500 miles per hour, Kelly is soon approaching another record -- the single-longest space flight by an American. He is scheduled to hit that mark on October 29.