Credit: NASA

Station Commander Jeff Williams passed astronaut Scott Kelly, also a former station commander, for most cumulative days living and working in space by a NASA astronaut (520 days and counting). Williams is scheduled to land on Sept. 6, for a record total of 534 days in space.

The Expedition 47/48 mission is Williams' fourth spaceflight and third long-duration stay on the space station, a first for an American. Williams served as the flight engineer and lead spacewalker for space shuttle Atlantis' STS-101 mission in 2000. He was a flight engineer for the 's Expedition 13 in 2006, when the station had only two modules and three crew members. In 2009 and 2010, he served as a on Expedition 21 and commanded Expedition 22, when the Tranquility module and cupola were added to the station. During that mission, he also became the first astronaut to interact live with NASA's social media fans and followers. His Aug. 19 spacewalk was the fourth in Williams' career; Williams and fellow NASA astronaut Kate Rubins will embark on another spacewalk Sept. 1.

In this photograph taken on June 30, 2016, Williams monitors bowling ball-sized internal satellites known as SPHERES (Synchronized Position Hold, Engage, Reorient, Experimental Satellites) during a maintenance run in the International Space Station's Japanese Kibo Laboratory Module.

Provided by NASA