American astronaut Scott Kelly, 52, is safely back on Earth after spending 340 days in space—a record for an American spaceflight, reports Reuters. Kelly touched down in Kazakhstan at 4:26 a.m. GMT on Wednesday on a capsule carrying two other companions from the International Space Station: Russian cosmonaut Mikhail Kornienko, 55, who also spent 340 days in space, and Sergey Volkov, another Russian cosmonaut, 42, who has been in space for five and a half months.
During their 340 days in space, Kelly and Kornienko were the subjects of dozens of medical experiments and studies to see how human bodies cope with the long-term effects of weightlessness and exposure to the high-radiation environment of outer space. The results of these experiments will be used to help develop manned missions to Mars, which could see astronauts have journeys as long as two years.
Before Kelly and his crew took off from the ISS in the landing capsule that would bring them the three-and-a-half hour journey back to Earth, he snapped a picture and posted it on Twitter. “The journey isn’t over,” he wrote. “See you down below!”
That journey also involved more tests once Kelly is back. The American astronaut has an identical twin brother and NASA will study the two together to see if Kelly experienced any genetic changes during his 340 days in space.
If you’re wondering why Kelly is getting all the attention for spending 340 days in space and not his cosmonaut colleague Kornienko, it’s because 340 days is the record space flight for an American. Kornienko came almost 100 days short of the spaceflight record for a Russian. Between January 1994 to March 1995, Russian physician and cosmonaut Valeri Polyakov spent 438 days onboard the now-retired Mir space station. Polyakov’s record still holds for humanity’s longest spaceflight.