Whitson's first spaceflight started with the launch of STS-111 to ISS as a flight engineer on June 5, 2002.
On June 5, 2002, Peggy Whitson embarked on her first spaceflight aboard the Space Shuttle Endeavour on mission STS-111. Serving as a flight engineer for Expedition 5, she began her first long-duration mission on the International Space Station (ISS). This mission marked a crucial step in her career, setting the stage for her future leadership roles aboard the ISS. Whitson's work as a flight engineer contributed significantly to scientific research and international collaboration in space exploration.