Astronaut Scott Kelly is halfway to making history.
Along with Russian cosmonaut Mikhail Kornienko, Kelly is about six months into a year-long mission on board the International Space Station (ISS). If the men succeed, they'll be the first humans to ever spend a full year in zero gravity.
As a visual diary of his year in space, Kelly has posted a photo almost every day since arriving at the ISS in March 2015 - and the images have been incredible.
Scroll down to see some of his best work.