SEATTLE -- What does spending a year in space do to the human body? We soon could find out.
Astronauts and identical twins Scott and Mark Kelly are busy undergoing medical tests with NASA. Scott is on a one-year mission in space while Mark is here on Earth.
Scientists want to know how space affects the aging process of the human body. Scott Kelly has been in space for eight months now. Thanks to video messaging, he is still in close contact with friends and family.
"It's a lot of time, but he's doing well," twin brother Mark said. "It's just my brother and a cosmonaut that are there for a full year."
Mark, the husband of former Congresswoman Gabby Giffords, is a crucial part of this mission. The latest tests were just last week.
"I had somebody from NASA travel to Tucson and take a lot of blood -- about 30 tubes of blood-- and other samples I had to deliver," said Mark.
NASA is conducting genetic and molecular research on both men to learn more about how people in space age just a bit more slowly than the rest of us.
"This is an ongoing thing where they're collecting data on me on the ground and collecting similar kind of data from my brother," said Mark. "Then when he gets back, they'll continue to follow us over a certain period of time."
Scott is due back in four months. In the meantime, he continues a daily routine of NASA work, exercise and occasional tweeting with fans on Earth, including President Obama.
Mark travels to Houston in September for a series of MRI and ultra sound tests.
