Astronaut Scott Kelly Returns to Earth After 340 Days in Space

Welcome back, Scott Kelly!

The 52-year-old astronaut returned back to Earth on Tuesday -- landing in Kazakhstan -- after spending 340 days in space aboard the International Space Station. While it didn't quite last a year, Kelly's trip marks the longest time an American astronaut has ever spent in space.

NEWS: Leonardo DiCaprio Auctions Off Space Voyage

Kelly joked about his return to his home planet on Tuesday.

"Thanks for following our #YearInSpace. The journey isn't over," Kelly tweeted. "Follow me as I rediscover #Earth! See you down below!"

NASA also tweeted video of Kelly's dramatic return on Tuesday, with Kelly happily pumping his fist to the crowd.

Kelly has been documenting his long journey in space on social media, often with a sense of humor. Watch this video he Instagrammed of himself floating in space in a gorilla costume.

And of course, there's the time he got to try the first lettuce grown and harvested in the space station.

But on an even more awesome note, check out the jaw-dropping views he was able to capture and share.

Kelly -- the twin brother of fellow astronaut Mark Kelly, who's married to former Congresswoman Gabrielle Giffords -- is scheduled to arrive in Houston, Texas on Wednesday. Kelly's twin brother -- as well as Vice President Joe Biden, Biden's wife, Jill Biden, and a few NASA officials -- are set to greet Kelly upon his highly awaited return, the New York Times reports.

NEWS: Justin Bieber Headed to Space

Meanwhile, check out ET's top five "lost in space" films ever made in the video below!