NASA astronaut Peggy Whitson, who holds the U.S. record for most cumulative time in space, is retiring from the agency.
The news comes from a NASA release, which said Whitson's retirement was effective Friday.
NASA Administrator Jim Bridenstine called Whitson a testament to the American spirit, adding that her "determination, strength of mind, character, and dedication to science, exploration, and discovery are an inspiration to NASA and America."
Whitson, a native of Beaconsfield, Iowa, first came to NASA in 1986.
According to her NASA biography, she served in a number of scientific roles, including project scientist for the Shuttle-Mir Program and co-chair of the U.S.-Russian Mission Science Working Group, before her selection to the astronaut corps in 1996.
As an astronaut, NASA files show Whitson had a penchant for achievement, completing three long-duration missions to the International Space Station, setting records on each.
She made her first trip in 2002 as part of Expedition 5, during which she took part in 21 science investigations and became NASA's first space station science officer.
In 2008, Whitson returned on Expedition 16 and became the first female commander of the space station.
During her most recent mission, spanning Expeditions 50, 51 and 52 from November 2016 to September 2017, Whitson became the first woman to command the space station twice.
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 U.S. astronaut at 665 days.
Whitson’s time on the ground at NASA was no less groundbreaking.
She 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.
There is no immediate word on what the 58-year-old biochemist plans to do next, though it is not likely that she will choose a sedentary retirement.