America's space champ ready to end yearlong flight, get home

And what about that private diary he assured to keep during his assignment - will all be shared by him?

And if that video is anything to go by, it certainly looks like he's had fun.

Now it's time to find out how he fared - and how he'll adapt to being back on Earth.

"You feel the physiological changes when you get to space, and you are beginning to feel that your body and brain think you don't need your legs anymore", he said.

"Sadly it will not last".

But did he really get taller than his brother? His identical twin brother Mark Kelly, a former NASA astronaut, is participating in a series of related studies looking for genetic changes caused by the high radiation and weightless environment of space.

"Humans use glasses to help them see better, but for robots, the fix is in their code", the space agency said on its website this week. "The hardest part is being isolated, in a physical sense, from the people on the ground that are important to you..." NASA spokeswoman Stephanie L. Schierholz told Space News that they had initially been limited to cargo deliveries for the ISS, but eventually included more specific terms such as the number of launchers involved. By the time Kelly checks out Tuesday and rides a Russian capsule to a landing in Kazakhstan, his mission will have lasted 340 days. Now the Human Research Program is building on that foundation by proposing more worldwide collaboration on future one-year space station missions.

Kornienko also will come back Tuesday and cosmonaut Sergey Volkov will be on the flight - though he did not spend a year on the space station. He will then be hustled home to Houston for more tests and weeks if not months of rehabilitation to recover from the punishing effects of an extended stay in zero gravity, including degraded vision and the loss of bone and muscle. The all-time record belongs to cosmonaut Valeri Polyakov, who spent 437 days on Mir from 1994-1995.

In contrast, the other company performing CRS missions, Orbital ATK of Dulles, Virginia, has been assigned just 10 flights and was not part of the end-year orders.

The growth of zinnias was a test-run before NASA plans to grow tomatoes on the ISS in 2017.