Kazakhstan – Astronaut Scott Kelly and cosmonaut Mikhail Kornienko are set to come home Tuesday night after 340 days on the International Space Station (ISS). They marked the longest mission in the 16 years since humans began occupying the orbiting science laboratory. Launched on March 27, 2015, Kelly and Kornienko will return to Earth on Russia’s Soyuz TMA-18M spacecraft and land on Kazakhstan.

Their year-long mission focused on gathering medical data to support longer missions in the future out into the solar system, especially sending humans to Mars.

“I am hopeful, and I think we will learn a lot about longer-duration spaceflight and how that will take us to Mars someday”, Kelly said in a recent in-flight press release.

Astronaut Scott Kelly (left) and cosmonaut Mikhail Kornienko (right) are set to come home Tuesday night after 340 days on the International Space Station. Photo credit: NASA
Astronaut Scott Kelly (left) and cosmonaut Mikhail Kornienko (right) are set to come home Tuesday night after 340 days on the International Space Station. Photo credit: NASA

But Kelly and Kornienko’s record-setting mission on the ISS is not the longest spaceflight of all time. They come behind four cosmonauts who have previously been part of missions to the former Russian space station Mir. Those spaceflights each lasted more than a full year.

Medical tests will be performed to examine Kelly’s health after 340 days in zero gravity

After landing in Kazakhstan, Kelly will fly back to the Johnson Space Center in Houston. He will go through extensive medical testing to evaluate the effects of nearly a year in zero gravity and help him readapt to terrestrial life, according to a report by CBS News.

Derrick Pitts, chief astronomer and planetarium director for the Franklin Institute of Philadelphia, told reporters that doctors will first examine the astronaut’s cardiovascular functioning.

Pitts told CBS News that Kelly’s heart has not been working hard because it spent nearly a year without the influence of gravity and that tests will determine the current strength of his heart muscle. Doctors will also look at the resilience of his blood vessels.

In addition, doctors will evaluate Kelly’s musculature and bone density. Pitts explained that there is a pause in bone cells production when the human’s body spends a long time without the force of gravity. He clarified that the astronaut is not in any danger due to these changes but medical tests will show the exact degree of the alterations in his inner bone structure.

A very important test to evaluate Kelly’s body will be performed on his eyes since under zero-G conditions the eye structure suffers some deformation that has caused concern among doctors who have examined astronauts who come back from space missions, Pitts said.

As for Kelly’s legs, it will take him some time to get used to them on Earth. Pitts said he will not walk around so much until he gets his terrestrial legs back and added that doctors will also examine the psychological effects of spending 340 days on the ISS.

Source: CBS News