Scott Kelly Prepares for a Year in Space on ISS

Astronaut twins prep for pioneering space study.

— -- Scott Kelly is about to begin an expedition that’s out of this world – literally.

“There are risks and I am willing to accept that for what we are going to learn from it,” Kelly told ABC’s David Kerley.

Scott Kelly’s twin brother, Mark, who is also an astronaut, will be remain on Earth as an experimental control to help measure the changes to Scott’s body while in space.

“That's one of the things that makes it exciting and something I am really happy to be a part of,” he said.