NASA makes us proud to be Americans. And even more so, the agency is an engine of discovery and innovation that benefits all ...

Mark and Scott Kelly, twin brothers and former NASA astronauts, spoke to "CBS Mornings" about how the agency is set to lose ...

Kelly laments the death of astronaut Jim Lovell and a U.S. disinvestment from science while sidestepping White House talk.

Mark Kelly wrote that his parents also taught him and demonstrated for him the importance of a strong work ethic. His father told the boys they could join the welders' union, he had a contact there.

Identical twins Mark Kelly, left, and brother Scott, right, are veterans of multiple spaceflights. Scott Kelly lived aboard the International Space Station for 340 days in 2015-16. NASA ...

June 21, 2011 -- Mark Kelly, the astronaut husband of Rep. Gabrielle Giffords, announced today he is retiring from NASA to spend time with his wife and write a memoir with her.

Kelly has an identical twin, Scott Kelly, who was also a NASA astronaut. From 2015 to 2016, Scott spent nearly a year aboard the International Space Station, while Mark stayed on the ground.

Former NASA astronaut Mark Kelly is running for a Senate seat in Arizona. He is married to former Arizona Rep. Gabby Giffords, who was shot in the head at a "Congress on your corner" event in 2011.

Kelly says his twin brother, Scott Kelly, who just returned to Earth after 340 days in space, was temporarily 2 inches taller. NASA is studying the pair to explore what spaceflight does to the body.

But Kelly won’t be alone. He’ll be joined by his identical twin, retired NASA astronaut Mark Kelly. The pair have been participating in what might be the most far-out twin study ever conducted.

Mark and Scott Kelly are the only twins that have ever traveled to space — and their experience will be invaluable if we want to get to Mars one day. The brothers are taking part in what NASA ...