On April 24, astronaut Peggy Whitson broke the record for most days in space by a US astronaut. Jeff Williams, the previous record holder, had a total of 534 days in space. By the end of her current mission, Whitson will have spent more than 650 days in space. Whitson became an astronaut in 1996. She first went into space in 2002. Since then, she has set other records, including the most spacewalks by a female astronaut. In 2007, she became the first woman to command the International Space Station.