US astronaut Peggy Whitson broke NASA's record on the weekend, clocking up a record length of time in space.
Historian Robert Pearlman says it's just the latest in a huge string of achievements Whitson has made in her career with NASA.
"Peggy - NASA refers to her as the 'space ninja' because she has quite a lot of records.
"She is now the most experienced American astronaut, having flown in space 665 days, 22 hours and 22 minutes, she is as well the most experienced woman to have ever flown in space.
"She set the record for the most space walks and the most time on space walks by a woman. She also was the first woman to command the Internation Space Station twice."
And at 57 years old, she's the oldest woman to have flown in space, he says.
Mr Pearlman says the importance of her achievements is the information it brings back to help further humanity's exploration of space.
