She's the 50th woman to go to space, and this latest voyage meant leaving her young son behind. In her first interview since returning to Earth, Nyberg discussed their reunion and life in orbit.
Astronaut by day, wife and mother 24/7 - that's how Nyberg describes herself. She told CBS News' Michelle Miller, "I honestly feel like I've accomplished the dream that I set out for."
She just returned to Earth after living and working on the International Space Station since May.
When she saw her son, Jack, for the first time upon her return, Nyberg said, "He started running with this big smile on his face, and it was very special, and then I just gave him a big hug, and he kind of stared at me for a while, you know, it's real mommy this time, it's not a video of mommy. ... That's the only way he'd seen me for five-and-a-half months."
Five-and-a-half months living like few others have, in the name of science and exploration. While her husband, a fellow astronaut, can probably relate, it's still a long time to be so far from home.
But Nyberg says it's really not lonely out in space. She said, "It's like being with your brothers. You get very comfortable with them. You know, it's like part of your- it has to be like a family."
Living life 250 miles above the Earth is no small feat.
Miller asked, "You just blasted off into space. What scares you?"
Nyberg replied, "I wouldn't call that scary. An interview would be more scary to me than sitting in a rocket."
But, in space, the stakes are much higher. Nyberg recalled, "Probably the thing that got my heart rate up the most during the whole mission was when I was operating the robotic arm to capture the HTV, the cargo vehicle, that came in during the middle of the mission. ... I'm at the controls, and if I don't capture this thing, all of this stuff that we're expecting to get on space station, that will be lost. ... That can get your heart rate going."
After all Nyberg has accomplished - including successfully completing that task - her modesty stands out.
Asked if she feels like a superhero, Nyberg said with a laugh, "No, not in the least. ... I'm just an average person, I think, you know, I had an average American upbringing. Somebody else in my situation might not think that they can do it; hopefully I can inspire them that yes they can."