ISS commander Scott Kelly has entered the record books by spending the most cumulative days in space for any US astronaut.

The Nasa astronaut has been in space for 383 days and counting, beating Mike Fincke, a two-time space station resident, who was the previous record holder at 382 days. Breaking such a record for time in space is vital for Nasa’s research into finding out how a trip to Mars impacts the human mind and body.

‘Records are meant to be broken. Look fwd to one of my colleagues surpassing my end 500+ days on our #JourneyToMars,’ Kelly tweeted today.  

Kelly is set to break another record October 29 on his 216th consecutive day in space, when he will beat astronaut Michael Lopez-Alegria’s record for the single-longest spaceflight by an American. Lopez-Alegria spent 215 days in space as commander of the Expedition 14 crew in 2006. The 51-year-old launched on a Russian Soyuz spacecraft from Baikonur Cosmodrome in Kazakhstan on March 27 and is scheduled to return to Earth on March 2, 2016, for a total of 522 days in space. Waiting for him is his girlfriend of seven years, Amiko Kauderer, who is in Texas, working as a public relations officer at Nasa. Scott Kelly’s trip is designed to test how the human body copes with prolonged space travel.

Nasa is planning to compare Kelly’s health to that of his identical twin brother, retired astronaut Mark Kelly, who has remained on Earth. Called the ‘Nasa Twin Study’, the Kellys will be subjected to 10 experiments in four areas: human physiology, behavioural health, microbiology and molecular.

Mark who is married to former Congresswoman Gabrielle Giffords, says he has no intentions of consuming bland space-type food or working out and running two hours a day on a treadmill, as his brother is doing in space. ‘This is a chance in a lifetime,’ said Dr Craig Kundrot, the deputy chief scientist of Nasa’s Human Research Program.

‘In this case we’ve got two genetically identical individuals and we can monitor what kind of changes occur in Mark in an ordinary lifestyle and compare those to the changes that we see in Scott.’ By staying on the station for 12 months, the astronauts will also provide key information on how an eventual Mars mission - estimated to last three years there and back - might play out.

A mission to the red planet will require long periods of time in reduced-gravity environments, both in space and on the surface of the red planet. But, until now, crew members have only spent about six months on the Space Station at a time.

Kelly is not the only human breaking records for time in space. Expedition 44 commander Gennady Padalka broke the 10-year-old record for the number of cumulative days in space June 28, as he reached 804 days in space. When he returned to Earth September 11, Padalka had spent 879 days living and working in space. 

As well as carrying out numerous scientific experiments on the ISS, Kelly has been a prolific photographer. Earlier this week, he captured a series of ethereal images of Australia from his lofty perch on the ISS. The photographs make the country appear to be covered in sapphire coloured rivers, red veined mountain ridges and yellow lakes.

With a likeness to cells under a microscope the breath-taking photographs give an almost eerie representation of Australia. This week, he also demonstrated what water looks like in space by popping an Alka-Seltzer tablet into a dyed globule of water. Scientists at the International Space Station carried out the experiment to test their brand new camera.