On March 1, after 342 days in orbit aboard the International Space Station, astronaut Scott Kelly will return to Earth with fellow year-in-space partner, cosmonaut Mikhail Kornienko.
Once they land, scientists will begin analyzing data from the men to study changes that occurred in their bodies over an extended stay in space. The things scientists learn about their health will help guide the planning process for a manned mission to Mars — it’ll take about a year to get there — in the not-so-distant future. In a first-of-its-kind study, Scott’s twin brother, former astronaut Mark Kelly, remained on Earth to serve as a human control for the experiment.
Scientists monitored changes to Kelly's vision, gut bacteria, bone density, metabolic activity, behavioral health and more. Back on Earth, his brother also underwent a series of physical and mental tests. It’ll be another six months to six years before we see published results from this unique experiment.
Throughout his stay, Scott Kelly invited the world to join him (virtually) on the ISS, and he provided us with an intimate glimpse of life in orbit and our planet. He became a household name with regular updates — from selfies to viral videos — from 249 miles above Earth. The photo to the left is a selfie Scott Kelly took six months into his mission on the ISS. Here’s a look back at the finest images from Scott Kelly’s historic year in space.
Scott Kelly waves goodbye alongside cosmonauts Mikhail Kornienko (top) and Gennady Padalka (bottom) as they board the Soyuz TMA-16M spacecraft ahead of their launch to the ISS on March 27, 2015.
Kelly, Kornienko and cosmonaut Sergei Volkov cram into the Soyuz capsule that will ferry them back to Earth. The seats have specialized liners that are customized to fit each person's body. Here, they perform a fit check Feb. 23 to ensure they'll be as comfortable as possible for the landing near Kazakhstan on Tuesday.
The module is just 23 feet long and 9 feet in diameter, and each passenger can carry about 3 pounds of items with them.
Astronauts and cosmonauts on the ISS see 15 to 16 sunrises and sunsets every 24 hours, and Kelly had an opportunity to witness roughly 5,000 spectacular sunrises during his stay in orbit. Even though Kelly saw plenty of sunrises from space, he didn't seem to grow tired of the view. Here's one of the last sunrises he enjoyed from the ISS on Feb. 29. He wrote the following message to go along with his tweet:
"Take a leap and explore new possibilities! #GoodMorning & Happy #LeapDay from @space_station! #YearInSpace"
The Soyuz spacecraft — carrying Kelly, Kornienko and Padalka — approaches the ISS on March 27, 2015.
Apart from spectacular sunrises, Kelly and the rest of the ISS crew was treated to spectacular aurora displays in the morning. As Kelly wrote, a sight like this made waking up easy:
"The daily morning dose of #aurora to help wake you up. #GoodMorning from @Space_Station! #YearInSpace"
Apart from sharing breathtaking photos and serving as a human guinea pig, Kelly had a hand in many of the 400 science studies that were taking place on the ISS. He cared for crops in the Veggie lab, tested out the SPHERES robotic satellites, took sound measurements, logged his sleep, measured radiation and more. In this image captured in April, Kelly performs routine eye exams with with astronaut Terry Virts.
Vision changes during extended stays in microgravity are critical health conditions that scientists are investigating.
If the auroras won't get you going in the morning, some ISS coffee should do the trick.
The ISS is equipped with one of the most complex water recycling systems ever designed, and it puts every drop of waste to good use. As Kelly explained in an April Twitter post:
"Recycle Good to the last drop! Making pee potable and turning it into coffee on @space station. #NoPlaceLikeHome"
One of Kelly's favorite places to view from space was the Bahamas — a nation comprised of some 700 islands and cays. On Sept. 18, 2015, Kelly shared this image of the coral-based archipelago.
Kelly tries on his spacesuit to ensure a proper fit inside an ISS airlock. On Oct. 28, the following day, Kelly would embark on the first spacewalk of his career. When he posted this photo, Kelly shared the following message with his Twitter followers:
"Day 212 Getting my game face on for #spacewalk Thanks for sticking w me #GoodNight from @space_station! #YearInSpace"
Hurricane Patricia became the strongest storm ever measured on the planet in October, generating winds over 200 mph. Atmospheric conditions and ocean temperatures combined in just the right way to rapidly intensify the storm. Fortunately, the storm weakened as it made landfall. Kelly snapped this photo of the powerful storm on Oct. 23.
The lights of Dubai in the United Arab Emirates, as seen by Kelly from the ISS.
On Dec. 1, 2015, Kelly posted this colorful image of Lake Mackay in Australia.
Christmas came early for the ISS crew in 2015. On Dec. 9, Kelly posted a picture of the Cygnus cargo ship preparing to dock with the space station. Cygnus was loaded with 7,700 pounds of food, hygiene articles, replacement parts, systems hardware and several dozen science experiments.
Scott Kelly poses for the camera during a spacewalk on Dec. 21, 2015. Kelly successfully moved the space station's mobile transporter rail car to make room for a Russian cargo supply spacecraft. Kelly was nine months into his mission when this photo was taken.
On Jan. 9, Kelly shared this image of a frozen Lake Rakshastal in Tibet.
In January, Scott Kelly showed off his green thumb and posted a picture of the first zinnia to bloom in space.
Zinnias were chosen as the next test of the ISS Veggie lab because their sensitivities to light and other environmental factors made them difficult to grow. They certainly posed a challenge for the crew. In December, the zinnias looked wilted and near death. But Kelly took over the horticultural duties on the ISS and helped lead a dramatic comeback. He cut away the dead foliage and sanitized the plants to control the mold.
In January, one of the zinnias bloomed and completed the comeback story.
A blizzard with hurricane-force winds crippled much of the East Coast on Jan. 23. Millions of people were forced to dig out in the days that followed.
Up in the ISS, Kelly snapped a photo of the storm as it barreled toward the coast. He caught this rare thundersnow event from his perch 249 miles above Earth.
Kelly captured this image of the Mediterranean Sea on day 304 of his mission. By that time, Kelly had completed 4,864 orbits around the planet.
Here's how Kelly celebrated Super Bowl Sunday. It was billed as a party, but no one on the space station showed up. Kelly is a fan of the Houston Texans, and he watched his team get knocked out of the playoffs 30-0 by the Kansas City Chiefs.