Identical Twins, One in Space, One on Earth

NASA Expedition 45/46 Commander, Astronaut Scott Kelly along with his brother, former Astronaut Mark Kelly at the Johnson Space Center, Houston Texas speak to news media outlets on Jan.19, 2015.
( NASA/Robert Markowitz / Wikimedia Commons )

Produced by Kristen Meinzer

Hosted by Todd Zwillich

Produced by PRI and WNYC