Flag Day in the USA. (06/14/2015) --- On the International Space Station June 14, 2015 the crew of Expedition 44 prepare to observe Flag Day in the USA in the Cupola, the 360 degree observation point.. Media Credits: NASA, Scott Kelly

Moonless with a chance of #Perseid meteors!. Astronaut Scott Kelly posted this photo of the Perseid meteor shower taken from the International Space Station on Instagram with the caption, 'Space weather forecast from @ISS: Moonless with a chance of #Perseid meteors!. Media Credits: NASA, Scott Kelly

#Goodnight #Earth! Make me proud. Astronaut Scott Kelly posted this photo taken from the International Space Station to Twitter on Sept. 5, 2015 with the caption, '#goodnight #Earth! Make me proud and I'll try and do the same. #YearInSpace'.. Media Credits: NASA, Scott Kelly

#Moon #Venus #Jupiter...#Earth Good night.. Astronaut Scott Kelly posted this photo taken from the International Space Station to Twitter on July 19, 2015 with the caption, 'Day 114. #Moon #Venus #Jupiter...#Earth Good night from @space_station! #YearInSpace'.. Media Credits: NASA, Scott Kelly

#Goodevening #Japan. Night Earth observation of Japan taken by Expedition 44 crew member Scott Kelly, with a Soyuz Spacecraft connected to the Mini Research Module 1 (MRM1), and a Progress Spacecraft visible.. Media Credits: NASA, Scott Kelly

#Athens, #Greece, #GoodMorning from @Space_Station.. Astronaut Scott Kelly posted this photo of Athens, Greece taken from the International Space Station to Twitter on July 12, 2015 with the caption, '#Athens, #Greece, #GoodMorning from @Space_Station. Wishing you the best. #YearInSpace'.. Media Credits: NASA, Scott Kelly

#Bahamas, the strokes of your watercolors are always a refreshing sight.. Astronaut Scott Kelly posted this picture of the Bahamas taken from the International Space Station on Twitter on July 19, 2015 with the caption, '#Bahamas, the strokes of your watercolors are always a refreshing sight. #YearInSpace.'. Media Credits: NASA, Scott Kelly

#GoodMorning to the Holy City of #Mecca #Makkah!. (06/19/2015) --- Astronaut Scott Kelly posted this photo taken from the International Space Station to Twitter on Sept. 23, 2015 with the caption, '#GoodMorning to the Holy City of #Mecca #Makkah! #YearInSpace'.. Media Credits: NASA, Scott Kelly

#Moonrise is upon us.. Astronaut Scott Kelly posted this photo of a moonrise from the International Space Station to Twitter on July 17, 2015 with the caption, 'Day 112. #Moonrise is upon us. Good night from @space_station! #YearInSpace'. Media Credits: NASA, Scott Kelly

#MilkyWay. You're old, dusty, gassy and warped.. Astronaut Scott Kelly posted this photo to Twitter on August 9, 2015 with the caption, 'Day 135. #MilkyWay. You're old, dusty, gassy and warped. But beautiful. Good night from @space_station! #YearInSpace'.. Media Credits: NASA, Scott Kelly

#GoodMorning #Aurora! Good to see you again.. Media Credits: NASA, Scott Kelly

Sunset returns! Perfect end.. Astronaut Scott Kelly posted this photo taken from the International Space Station to Twitter on August 1, 2015 with the caption, 'Day 127. Sunset returns! Perfect end. Thanks again for joining me today. Good night from @space_station! #YearInSpac. Media Credits: NASA, Scott Kelly

#Aurora is back in town.. Astronaut Scott Kelly posted this photo taken from the International Space Station to Twitter on June 27, 2015 with the caption, 'Day 92. #Aurora is back in town. Good night from @space_station! #YearInSpace'. Media Credits: NASA, Scott Kelly

#GoodMorning to those in the western #USA.. Astronaut Scott Kelly posted this photo taken from the International Space Station to Twitter on August 10, 2015 with the caption, '#GoodMorning to those in the western #USA. Looks like there's a lot going on down there. #YearInSpace'.

Moonlight over Italy. #BuonaNotte. Astronaut Scott Kelly took this photo of Italy from the International Space Station and posted it on Twitter saying, 'Day 180. Moonlight over Italy. #BuonaNotte Good night from @space_station! #YearInSpace'.. Media Credits: NASA, Scott Kelly

Just took this stunning picture of #SouthEastAsia.. Astronaut Scott Kelly posted this photo taken from the International Space Station to Twitter on Dec. 5, 2015 with the caption, 'Just took this stunning picture of #SouthEastAsia. #YearInSpace'. Media Credits: NASA, Scott Kelly

Hurricane #Patricia approaches #Mexico.. Astronaut Scott Kelly posted this photo of the Hurricane Patricia taken from the International Space Station to Twitter on Oct. 23, 2015 with the caption, 'Hurricane #Patricia approaches #Mexico. It's massive. Be careful! #YearInSpace!'. Media Credits: NASA, Scott Kelly

Enjoying the fruits of labor, literally.. Astronaut Scott Kelly posted this photo taken inside the International Space Station after a cargo delivery of fresh fruits and vegetables on Instagram with the caption, '#TuesdayTransformation Enjoying the fruits of labor, literally. #YearInSpace #zeroG #fresh #fruit #ISSCargo #HTV5 #spacefood #space. Media Credits: NASA, Scott Kelly

Color palette of the French coast. Astronaut Scott Kelly posted this photo of the Mediterranean coast of France taken from the International Space Station on Instagram.

#NYC last night.. Astronaut Scott Kelly posted this photo of New York City from the International Space Station on Twitter with the caption, 'My cosmonaut colleague Oleg Kononenko took this incredible picture of #NYC last night. Enjoy. #YearInSpace'. Media Credits: NASA, Oleg Kononenko

#Aurora's purple glow adds mystery to the nightscape. Astronaut Scott Kelly posted this photo of an aurora taken from the International Space Station to Instagram with the caption, 'Day 154. #Aurora's purple glow adds mystery to the nightscape. Good night from @ISS! #YearInSpace #space #iss #solarstorm #northernlights #goodnight.'. Media Credits: NASA, Scott Kelly

Moscow, Russia sparkles in the night. The International Space Station crew witness nightly scenes of our Earth's beauty after performing their duties. Here on Oct. 6, 2015, framed by the edge of a huge Station solar panel, the city of Moscow, Russia sparkles in the night with spoke streets streaming out across the land while an aurora of blue, white and purple contrast the star-filled sky.

The remnants of #Soyuz's fiery plunge. Astronaut Scott Kelly posted this photo taken from the International Space Station to Twitter on Dec. 11, 2015 with the caption, 'The remnants of #Soyuz's fiery plunge through the atmosphere. Congratulations on a successful landing #SoyuzTMA17M!'.

The remnants of #Soyuz's fiery plunge. Soyuz TMA-17M crew lands on Earth after 141 days on the space station. The vehicle landed northeast of the Kazakh town of Dzhezkazgan. Media Credits: NASA/GCTC/Andrey Shelepin

Another pass through #Aurora.. Astronaut Scott Kelly posted this photo of an aurora taken from the International Space Station to Twitter on August 15, 2015 with the caption, 'Another pass through #Aurora. The sun is very active today, apparently. #YearInSpace'. Media Credits: NASA, Scott Kelly

#GoodMorning #Egypt! Your colors never cease to amaze!. Earth observation taken during a day pass by the Expedition 46 crew aboard the International Space Station (ISS). Kelly posted this photo to Twitter on Dec. 24 2015 with the caption, '#GoodMorning #Egypt! Your colors never cease to amaze! #YearInSpace'. Media Credits: NASA, Scott Kelly

Houston and the Gulf Coast. Media Credits: NASA, Scott Kelly

Soyuz silhouette and #sunset colors of our magnificent #Earth.. Media Credits: NASA. Scott Kelly

A splash of #EarthArt over the #Bahamas!

SpaceFlower out in the sun for the first time!. Media Credits: NASA, Scott Kelly

Cool frozen lake in #Himalayas!. Earth observation taken during a day pass by the Expedition 46 crew aboard the International Space Station (ISS). Astronaut Scott Kelly posted this photo on Twitter with the caption, 'Cool frozen lake in #Himalayas! #YearInSpace'. Media Credits: NASA, Scott Kelly

Glass bottom spaceship over the #Bahamas!. -- Astronaut Scott Kelly posted this photo taken from the International Space Station to Twitter on Dec. 26, 2015 with the caption, 'Glass bottom spaceship over the #Bahamas! #GoodMorning from @Space_Station! #YearInSpace'.. Media Credits: NASA, Scott Kelly

Day 289. Out over the blue.. Earth observation taken during a day pass by the Expedition 46 crew aboard the International Space Station (ISS). Astronaut Scott Kelly posted this photo on Twitter with the caption, 'Day 289. Out over the blue. #GoodNight from @space_station! #YearInSpace'. Media Credits: NASA, Scott Kelly

The dance of #aurora. Media Credits: NASA astronaut Scott Kelly took this majestic image of the Earth at night highlighting the green and red hues of an Aurora. He tweeted this message along with the image: 'The dance of #aurora. #YearInSpace'

Over a #Shanghai night.. Earth observation taken during a night pass by the Expedition 46 crew aboard the International Space Station (ISS). Astronaut Scott Kelly posted this photo on Instagram with the caption, 'Day 318. Over a #Shanghai night. Wishes for a happy #ChineseNewYear! #GoodNight from @iss! #YearInSpace #LunarNewYear #YearoftheMonkey #China #earth #space #spacestation #iss'

Rare sunrise glow over #NewZealand on my 3rd #Christmas in space. Media Credits: NASA, Scott Kelly

#Italy and the #Alps last night were breathtaking!. Earth observation taken during a night pass by the Expedition 46 crew aboard the International Space Station (ISS). Astronaut Scott Kelly posted this photo on Twitter with the caption, '#Italy and the #Alps last night were breathtaking! #YearInSpace. Media Credits: NASA, Scott Kelly

Massive #snowstorm blanketing #EastCoast. (1/23/16) --- 'Massive #snowstorm blanketing #EastCoast clearly visible from @Space_Station! Stay safe! #blizzard2016 #YearInSpace' -- Scott Kelly

A thin blue line hints a new beginning with #sunrise.. Earth observation taken during a night pass by the Expedition 46 crew aboard the International Space Station (ISS). Astronaut Scott Kelly posted this photo on Twitter with the caption, 'Day 313. A thin blue line hints a new beginning with #sunrise. #GoodNight from @space_station! #YearInSpace'. Media Credits: NASA, Scott Kelly

Scott Kelly and Mikhail Kornienko marked 300 consecutive days in space. NASA astronaut Scott Kelly (left) and Russian cosmonaut Mikhail Kornienko (right) marked their 300th consecutive day aboard the International Space Station on Jan. 21, 2016. The pair will spend a total of 340 days in space on their one-year mission as researchers hope to better understand how the human body reacts and adapts to long-duration spaceflight. This knowledge is critical as NASA looks toward human journeys deeper into the solar system, including to and from Mars, which could last 500 days or longer.. Media Credits: NASA, Scott Kelly

That #polarvortex even looks cold from here!. Astronaut Scott Kelly posted this photo of the polar vortex taken from the International Space Station to Twitter on February 14, 2016 with the caption, 'That #polarvortex even looks cold from here! #Burr! #YearInSpace'.. Media Credits: NASA, Scott Kelly

Got to see the #SuperBowl in person after all!. Astronaut Scott Kelly posted this photo taken from the International Space Station to Twitter on Feb. 7, 2016 with the caption, 'Got to see the #SuperBowl in person after all! But at 17,500MPH, it didn't last long. #YearInSpace'.