Scott Kelly

The photo used in the ad shows retired astronaut Scott Kelly, not Mark Kelly, the Democrat leading McSally in polls.

Seven percent of Scott Kelly's genes did not return to normal when he got home.

The changes happen as soon as an astronaut gets into space.

"The perspective of Earth from space is incredible," he writes. But the views from space "also show us changes; we need leadership to protect it."

Scott and Mark Kelly attended Pleasantdale Elementary School in their New Jersey hometown.

Just days after his return from the International Space Station, Scott Kelly sits down for a look back at his experience.

A look back at Kelly's nearly full year at the International Space Station.

The astronaut is about to come back to Earth after spending 340 consecutive days in space along with Russian cosmonaut Mikhail Kornienko.

The astronaut is scheduled to host a two-hour program Thursday at 5 p.m. ET.

NASA are again proving why being an astronaut is amazing

The successful blooming of the zinnia flower is a precursor to plant growth on Mars, according to NASA.

A new crew is en route to the ISS. NASA TV has coverage of the docking and hatch opening.

One crew returns from the ISS after 141 days in space as another prepares to launch on Tuesday.

Several ammonia leaks and minor system failures with the space station's cooling have occurred over the past five years.

The two astronauts exited the International Space Station for a six-and-a-half-hour spacewalk.

This feast is the first of its kind.

Videos, tweets and a Google doodle honor the historic moment in space exploration.

Scott Kelly's time on the ISS will prepare us for our deepest space explorations yet.