When they were eight, three years after man landed on the moon, identical twins Scott and Mark Kelly told their grandmother, “Grandma, we’re going up in space someday,” their father Richard Kelly, a retired police captain who lives in Flagler Beach, Florida, recalled in a 2006 interview with Irish America. Their mother, Patricia, a retired police officer like her husband, said that she wasn’t surprised that her sons chose similar career paths. “I really do believe there is a genetic disposition for certain things,” she said. To keep the twins on equal footing, their parents refused to tell them which one was older until they were 16. Mark is older by six minutes. Both hold the rank of Captain in the U.S. Navy.

Scott recently returned from the space station after a little more than five months in space. Mark is currently captain of the six-man crew of the Endeavour, which embarked on its last flight into space on May 16th.

Scott was aboard the space station last January 8th, when Mark’s wife, Rep. Gabrielle Giffords, was critically wounded in a shooting rampage in Tucson, Arizona. He sent a heartfelt message from space, in which he made an emotional appeal calling for better citizenship. “We have a unique vantage point here aboard the International Space Station. As I look out the window I see a very beautiful planet that seems very inviting and peaceful. Unfortunately it is not. These days we are constantly reminded of the unspeakable acts of violence and damage we can inflict upon one another not just with our actions but also with our irresponsible words. We are better than this. We must do better.”

Rep. Giffords took a break from rehab to attend her husband’s launch of the shuttle flight Endeavour in Huston. Mark Kelly said that he felt his decision to go ahead with the flight was “right thing” thing for him to do. “I know her very well,” he said of Giffords, “and she would be very comfortable with the decision that I made.”