After a year in space, NASA Scott Kelly is headed home Tuesday. With Russian cosmonaut Mikhail Kornienko, Kelly will board a Soyuz spacecraft to return to Earth. Coverage of Kelly's departure from the International Space Station begins at 4:15 p.m. EST with the hatch closure scheduled for 4:40 p.m. EST.

Kelly spent just over 340 days in space, a duration record for NASA astronauts. Through his previous missions to space, which included two space shuttle missions, Kelly will have spent 520 days off the planet after he returns to Earth Wednesday. Cosmonaut Sergey Volkov will join the one-year crew aboard the Soyuz spacecraft headed to Earth. Volkov completed a standard six-month mission after arriving at the space station Sept. 4.

After participating in over 400 investigations aboard the space station, the last duty Kelly performed in space was handing over command of the space station to NASA astronaut Tim Kopra Monday. Kopra will serve as Expedition 47 commander after the trio departs.

During the historic yearlong mission, Kelly helped with a number of expiriments that will lead to new insight on the effects of microgravity on the human body. Kelly is a twin, which gave NASA the opportunity to compare any changes that may have occurred during his mission to his twin brother, retired NASA astronaut Mark Kelly, who has remained on Earth.

The investigations will be pivotal in shaping the future manned mission to Mars. Unlike a six-month mission aboard the space station, an astronaut will have to spend years, including the return flight back, in space as part of any Mars mission.

After the hatch closure, the trio of astronauts will undock from the space station at 8:05 p.m. EST. The Soyuz space capsule is scheduled to land in Kazakhstan at 11:25 p.m. EST. Kelly will take part in a series of field tests prior to leaving Kazakhstan with an expected arrival in Houston Wednesday.

The NASA live stream of Kelly's last day in space can be viewed below.