Peggy Whitson returned to earth over the weekend, completing a record-breaking trip to the International Space Station.
She and two other crewmates made a parachute touchdown in Kazakhstan at around 2.30 UK time on Sunday.
During this latest mission, Ms Whitson travelled 122.2 million miles and 4,623 orbits of the Earth.
Over the course of three trips into space, Whitson a total of 665 days in orbit, including 288 days on the current mission, a total which exceeds any other American or woman worldwide.
Only seven Russian men have logged more space time, including Gennady Padalka, who currently holds the world record with 878 days in orbit.
Whitson also broke the record for the world’s oldest female astronaut, at age 57, the most experienced female spacewalker and the first woman to command the International Space Station twice.
The space scientist spent much of her time in orbit on experiments, including studies of cancerous lung tissue.
She also studied the physical changes in an astronaut’s eyes caused by extended stays in a microgravity environment. Additional research included a new lung study tissue, which could pave the way forward for stem cell research in space.
Speaking to reports on Monday, Whitson said the experience was ‘one of the most gratifying jobs I’ve ever had’.
She said: “I am working on paying forward some of the advice and mentoring that I received on my journey in hopes that one day those young people will do the same and look back on a life in which they leapt at the opportunities and broke their own records.”
Expedition 53 will continue with Randy Bresnik, the new commander of the International Space Station. He spoke with admiration for Whitson, calling her an “American space ninja”.
Ms Whitson said she was looking forward to seeing family and friends and had especially missed a flushing toilet and eating pizza.