NASA astronaut Scott Kelly, who returned Wednesday from a record-setting 340-straight days on the International Space Station, said looking down on planet Earth for so long made him a far more committed environmentalist.

"The Earth is a beautiful planet. It's practically everything to us. It's very important to our survival, and the Space Station is a great vantage point to observe it, and to share our planet in pictures," Kelly said during a press conference in Houston on Friday.

His photos earned him a wide social media following as he gazed down on everything from smog-choked cities to spiraling hurricanes and typhoons.

"You also notice how the atmosphere looks and how fragile it looks."





"You also notice how the atmosphere looks and how fragile it looks," Kelly said. "It makes you more of an environmentalist after spending so much time looking down at our planet."

Kelly, who now holds the NASA record for the most days in space as an American astronaut, is currently undergoing a battery of medical tests along with his twin brother, former astronaut Mark Kelly, in order to help NASA learn more about how the human body changes throughout long-duration stays in space.

Such knowledge is vital to pulling off a longer space exploration mission, such as a trip to Mars, which would likely take nearly three years to make a round trip, while exploring part of the red planet.

For now, though, Kelly has come back to his home planet with a keener eye for humanity's collective impact on the land, sea and air.

"We’ve got to take care of the environment," he said. "I do believe we have an impact on that [the health of the environment], and we do have the ability to change it if we make the decision to.”