Three ISS astronauts return to earth with key research

Armed with key human research experiments, three crew members from the International Space Station (ISS) landed safely on Earth early Saturday.

The experiments include blood samples for NASA's "Twins Study", a unique research demonstration to understand the effects of long-duration spaceflight on astronauts and further NASA's use of personalised medicine in space.

Additional samples for the salivary markers and microbiome studies also returned to Earth.

The landing in Kazakhstan wrapped up a 168-day mission for one cosmonaut and a brief 10-day visit for two, the US space agency said in a statement.

Expedition 44 commander Gennady Padalka of the Russian Federal Space Agency (Roscosmos) and visiting crew members Andreas Mogensen of ESA (European Space Agency) and Aidyn Aimbetov of the Kazakh Space Agency touched down at Dzhezkazgan in Kazakhstan at 6.21 a.m. on Saturday.

During their short time in orbit, they participated in a number of experiments on behalf of their respective space agencies, focusing on the areas of human research, Earth observation and technology development.

One item, the Skinsuit, was tested in orbit by ESA astronaut Andreas Mogensen.

Some astronauts' spines have been shown to lengthen as much as seven cm in weightlessness which can cause pain.

The Skinsuit was demonstrated in microgravity to see if it may help astronauts counteract potential back problems in microgravity.

The specially designed overalls simulate gravitational forces from Earth by constricting the body from shoulders to feet.

"Testing this clothing item in space may help astronauts with any back pain they experience on long-duration missions," NASA stated.

Samples from one rodent research study also returned as well.

These types of experiments examine how microgravity affects animals, providing information relevant to human spaceflight, discoveries in basic biology and knowledge that will have direct impact toward human health on Earth.