February 21, 1964

Twin astronauts and U.S. Navy captains Mark and Scott Kelly were born on this day in 1964 to Richard and Patricia Kelly, Irish-American police officers in Orange, New Jersey. 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. Scott has spent 180 days, 1 hour and 51 minutes in outer space, clocking in significant time from his term as a long-duration crew member aboard the International Space Station, while his brother has spent 54 days, 2 hours and 4 minutes. They are the first twins to have both been in outer space, though they were never in orbit at the same time. Mark is married to former Arizona Senator Gabrielle Giffords.