The first US woman to walk in space is now the first woman to reach the ocean's deepest point

Astronaut Dr. Kathy Sullivan, 68, is the first woman to reach the deepest point of the ocean, also known as the Challenger Deep, The New York Times reports. This point rests an estimated seven miles below the surface of the ocean. Dr. Sullivan is also the first woman from the United States to walk in space. Her recent achievement makes her the only person ever to have both walked in space as well as descended to the deepest point in the ocean. She completed the dive along with Victor L. Vescovo, the explorer who completely funded the mission.

Located in a muddy depression in the Mariana Trench, 200 miles southwest of Guam, the Challenger Deep is the lowest of several seabed recesses that can be found across the globe. Dr. Sullivan spent about an hour and a half with her diving partner exploring their destination from a specially designed deep-sea research submersible known as Limiting Factor. The pair captured images before beginning the roughly four-hour ascent back to the surface. According to EYOS Expeditions, the company organizing the logistics of the mission, Dr. Sullivan emerged from her 35,810-foot dive on Sunday.

Once she and Vescovo returned to their ship docked at the surface of the ocean, they celebrated by ringing up a group of astronauts aboard the International Space Station, which is found around 254 miles above the earth. In a statement released by Dr. Sullivan, she shared, "As a hybrid oceanographer and astronaut this was an extraordinary day, a once in a lifetime day, seeing the moonscape of the Challenger Deep and then comparing notes with my colleagues on the ISS about our remarkable reusable inner-space outer-spacecraft." Vescovo applauded her for being "the first woman to the bottom of the ocean." Taking to Twitter, he posted, "Big congratulations to her!"

Her diving partner was not the only who was full of praise for her. Tim Shank, a biologist at the Woods Hole Oceanographic Institution, called Dr. Sullivan "a consummate leader" in the study of the world’s oceans. "I’m thrilled to hear that she was in it," he stated of her dive in the Limiting Factor, the only submarine in the world that can reach the Challenger Deep. "Anytime we can reach such extreme places on Earth to learn about them, it’s a major event." The Challenger Deep was first discovered by the HMS Challenger, a British ship that sailed the globe from 1872 to 1876.

While many expeditions have been conducted to explore the region further, few can agree about the precise figures of the fissure's depth. Though many may still disagree about whether Dr. Sullivan truly did reach the deepest point of the ocean, there is no doubt that she has achieved a major feat. The astronaut first joined NASA in 1978 as part of the first group of US astronauts to include women and in 1984, became the first American woman to walk in space. After floating into the cargo bay of the shuttle Challenger, about 140 miles above Earth, she simply said, "That is really great."