American astronaut Jeff Williams has set a new record for most cumulative time in space for a U.S. astronaut. On Wednesday, Williams surpassed 520 days living in space, breaking Scott Kelly’s record set during his nearly year-long mission aboard the International Space Station. Williams will be heading back to Earth on September 6, which will extend his record to 534 days. The first 10 days of Williams’ time in space date back to 2000, when he was a flight engineer aboard Space Shuttle Atlantis during STS-101 as the shuttle was involved in helping put the finishing touches on the space station. According to NASA, Williams returned to space in 2006 for a six-month flight aboard the ISS. He returned to space three years later, again at the ISS. That brought his total to 362 days in space. His current mission began March 18. While the American record is impressive, it is only enough for Williams to rank 14th on the list of astronauts and cosmonauts with the most time spent off the planet Earth. At the top of the list is Gennady Padalka, who has spent 879 days in space over five missions. Williams’ record is not expected to last long as astronaut Peggy Whitson is scheduled to surpass him in 2017 as part of a mission that will begin this November. Whitson has the most time in space for a female.