November 10, 2017, 8:35 AM|
Record-setting NASA astronaut Peggy Whitson returned from the International Space Station in September after a 288-day mission. She has spent more time in space than any other American. While in orbit, the 57-year-old biochemist started writing a letter to her 9-year-old self. She completed it with us back home in Houston at NASA’s Johnson Space Center.