The American astronaut and Russian cosmonaut about to embark on a one-year flight are similar in many ways: born in the 1960s, fathers of daughters, military backgrounds.
But there are differences, too. Scott Kelley, a divorced dad of two, still has a school-age daughter. Mikhail Kornienko is married to an OB-GYN, his daughter is grown, and he's a new grandfather.
Kelly and Kornienko leave the world behind this week for a year at the International Space Station. They've lived there before, although for only half that long and at separate times.
More on the crewmates:
This will be the fourth spaceflight for Kelly, 51, a former NASA shuttle commander and Navy test pilot whose identical twin brother, Mark, also was chosen as an astronaut in 1996. The two will conduct many of the same medical experiments over the coming year so scientists can compare the results.
Scott Kelly's first two flights were aboard shuttles. He spent more than five months on the space station in 2010-2011. It was during that mission that his sister-in-law, then Congresswoman Gabrielle Giffords, nearly died after being shot in the head in Tucson, Arizona.
Once he's back home in Houston, Kelly imagines it will be "hard to walk away" from spaceflight. He'd love to pilot one of the new U.S. spacecraft in development. But he figures if he cuts in front of other astronauts awaiting assignments, "someone will run me over with their car."
What will Kelly miss the most, besides his loved ones? The weather.
"It never changes on the space station," he said. "Even though it's a pretty nice environment, I guess it's like living in Southern California, people get sick of it ... after a while."
It will be the second space mission for Kornienko, 54, a former paratrooper whose helicopter-pilot father was part of the search and rescue team for the first Soviet cosmonauts back in the 1960s.
His father brought back souvenirs from the returning Soyuz capsules: uneaten food rations and pieces of the orange silky parachutes used for the final descent.
"Mom made gorgeous skirts out of them," he said. "I still have a small piece of one of those parachutes. I cherish it as if it were something sacred."
A religious man, Kornienko is taking into orbit a folding icon depicting the Madonna and Child.
His previous station stay was in 2010, 12 years after his selection as a cosmonaut. He figures he'll miss the same things he dreamed about last time he flew: water not in the form of blobs as in space, but water you can swim in, as well as grass, forests and fields.
Kornienko already says he'd take on another one-year mission—after a break, of course.
Explore further: Two astronauts will expand envelope with one-year spaceflight
More information: NASA: www.nasa.gov/content/one-year-crew/
Kelly on Twitter: twitter.com/StationCDRKelly/