NASA astronaut Peggy Whitson, who spent a record-breaking 665 days in space, has retired from the space agency. Whitson, the 58-year-old NASA astronaut, holds the US record for most cumulative time in space.
She also claimed the title for most spacewalks by a woman -- 10 spacewalks totaling 60 hours and 21 minutes -- and set the record for most time spent in space by a US astronaut, placing eighth on the all-time space endurance list.
"It's been the greatest honour to live out my lifelong dream of being a NASA Astronaut," Whitson tweeted late on Friday.
Whitson also served as chief of the astronaut corps from 2009 to 2012, becoming both the first woman to hold the position and the first non-military astronaut corps chief.
As an astronaut, Whitson completed three long-duration missions to the International Space Station (ISS), setting records on each.
Traveling for the first time to the International Space Station (ISS) in 2002, Whitson took part in 21 science investigations and became NASA's first space station science officer.
In 2008, she returned to the ISS and became the first female commander of the space station.
During her most recent mission, from November 2016 to September 2017, Whitson became the first woman to command the space station twice.
"Thank to all who have supported me along the way. As I reminisce on my many treasured memories, it's safe to say my journey at NASA has been out of this world!" Whitson tweeted.