He gave us a glimpse inside his home near the Johnson Space Center and a peek at the life he will leave behind.
"I'll be 50 when I leave and when I come back I'll be 52," Kelly said.
The astronaut is flying to space to spend a year aboard the International Space Station, which is something no American astronaut has ever done before. He is set to break the record for the time in space by a U.S. astronaut.
Kelly is a veteran of three space flights, and recently spent six months aboard the ISS.
"Being twice as long, its going to make it a lot harder, and I like that aspect of it. Nothing's more exciting than flying into space," Kelly said. "I've got a couple of things going for me. One is that I've been to the space station before so I know what to expect, I know how I behave in that environment."
The other thing he mentions is the woman by his side, or more accurately, back here on Earth.
"Amiko works at NASA. She knows a lot about what I do," Kelly said. "She'll be in MI and at times talking about and watching what I'm doing. Between the two of us and NASA, giving us this support, and my previous experience, I think I'm pretty well situated to handle it. We'll find out!"
Kelly and his girlfriend Amiko Kauderer have been together more than five years.
"For me, it's like the most romantic long distance relationship ever," his girlfriend Amiko Kauderer said.
He's also leaving behind his daughters for a full year.
"When I told my kids about it, initially they thought it was awesome, but that was two years ago. As we get closer I think it's maybe starting to affect them a little more, they're nervous. But I think they know it's something I feel very strongly about," Kelly said.
Kelly and his crew will work six days a week on over 400 experiments during the year in space. On his day off, he says he will be most looking forward to catching up on sleep.
Only after Kelly was chosen for the mission did NASA realize it had a unique scientific opportunity. There is a chance to compare the effect of long-term exposure in space on Kelly to a near exact replica of his DNA here on Earth, his identical twin brother former astronaut Mark Kelly.
"Maybe there's something we can learn when I'm in space for a year compared to him," Kelly said.
They will both be human guinea pigs as NASA compares their bone loss, vision, immune system, and other traits.
"Even our cognitive ability. How does the brain function when in this extreme, isolated, microgravity environment for a long period of time?" Kelly said.
Upon his return, Kelly says he will look forward to a good shower. Without gravity, they can only give themselves sponge baths in space.
There are other common things he says he will miss.
"You miss weather, rain, variations in temperature, smell of a cool breeze," Kelly said.
One other thing he says he won't miss is the traffic.
"One of my great hopes is that I go to space for a year and that I-45 construction in Clear Lake is completely done!" Kelly said.
Kelly and his crew are scheduled to launch tomorrow at 2:42 p.m. Central time. Eyewitness News will stream it live on our website.
For more on Kelly's year in space, follow his Facebook and Twitter accounts, as well as NASA's website.