Which former astronaut became the first woman to reach Challenger Deep?

Former astronaut Kathryn Sullivan became the first woman to reach Challenger Deep on 7 June 2020.

Sullivan descended in the deep-submergence vehicle Limiting Factor with pilot Victor Vescovo during Caladan Oceanic’s Five Deeps expedition. The dive took her to the eastern basin of Challenger Deep, the deepest known point in the world’s oceans. She became the first woman to reach that seafloor and the first person to have both traveled into space and descended to Challenger Deep.

Sullivan was already a major figure in exploration. A geologist and oceanographer, she joined NASA’s first astronaut group to include women, flew on three Space Shuttle missions, and performed the first extravehicular activity by an American woman in 1984. She later served as administrator of NOAA.

A common mix-up is with Vanessa O’Brien, who also reached Challenger Deep in June 2020 and later became the first woman to reach both Earth’s highest and lowest points. Sally Ride, Mae Jemison, and Eileen Collins were astronauts, but none was first to Challenger Deep.