Identical Twins, One in Space, One on Earth
![](https://media.wnyc.org/i/800/0/c/85/1/markkellyscottkelly.jpg)
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 )
( NASA/Robert Markowitz / Wikimedia Commons )
Produced by Kristen Meinzer
Hosted by Todd Zwillich