Orbiting 250 miles above Earth, Virts - a life-long baseball fan, according to NASA  - 'has a very important goal for his time in space: photograph all 28 cities with a Major League Baseball (MLB) stadium.

Virts will post the photos to his Twitter and Instagram accounts. Using the hashtag #ISSPlayBall, you can join in the game and guess which the cities in the photos. "I grew up in Baltimore in the '70s and '80s as an Orioles fan and I started a lifelong love of baseball and the O's. It was my favorite sport that I played as a kid, and I played through high school," said Virts, according to NASA.

Virts and fellow crew members on his first spaceflight (Endeavour mission STS-130) constructed the space station's Cupola. The Cupola is a 31-inch window - the largest ever used in space - and is used for observation and photography.

"This is my favorite thing to do in orbit," Virts said, according to NASA. "I like to try to think of creative ways to take pictures, from a new perspective, or with new lighting. There is always something interesting looking out the window - if it's lightning, aurora, city lights at night, interesting geology on Earth, wide angle 'big picture' scenes of the Earth as a planet, the moon, planets or even stars - there is never a lack of good subject matter. You just have to be prepared and able to use the camera very quickly and proficiently. At the speed we travel a good picture is often fleeting and only available for a few seconds. It's also fun to take time lapse sequences that we can turn into movies that brings the view a little more to life. But as good as the camera is, it's just not even close to the same thing as being here in person."

One bit of baseball history that Virts has with him in space is a Jackie Robinson replica jersey. Robinson ended 80 years of segregation in baseball in 1947 and was inducted to the Baseball Hall of Fame in 1962. Robinson's number - 42 - has been retired from baseball, but as a member of Expedition 42, Virts keeps the number active in zero gravity each time he wears it.