• Kathryn Sullivan was the first American woman to walk in space in October of 1984
  • This weekend, she made history again by becoming the first woman to reach the deepest known point in the ocean
  • Sullivan is the first human to have been to space and at full ocean depth

After making history as the first American woman to walk in space, former astronaut Kathryn Sullivan has made history again as the first woman to reach the deepest known spot under the ocean.

Sullivan first made history on Oct. 11, 1984, when she became the first woman to walk in space. She has now also conquered the deep after successfully descending to Challenger Deep, the lowest known point on Earth. This makes her the first woman and only the eighth person in history to reach Challenger Deep and the first human to have been to space and to the deepest point in the ocean.

"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 (International Space Station) about our remarkable reusable inner-space outer-spacecraft," Sullivan said in a statement from EYOS Expeditions, which collaborated with Caladan Oceanic to make the dive possible.

For the historic achievement, Sullivan and retired U.S. Navy officer Victor Vescovo descended to Challenger Deep aboard Limiting Factor, a two-person submersible, and safely returned to the surface. The first people to reach Challenger Deep were Swiss oceanographer Jacques Piccard and U.S. Navy Lieutenant Don Walsh in 1960.

Upon completing the dive, Sullivan and Vescovo celebrated by making a phone call to the International Space Station.

"It was amazing to set up a conversation between two 'spacecraft'; one operating as a platform for research in outer space, the other an exploration vehicle for 'inner space,'" EYOS Expeditions expedition leader Rob McCallum said. "Two groups of humans using cutting edge technology to explore the outer edges of our world. It highlighted the vast span of human endeavour while at the same time linking us close together as fellow explorers."

"Big congratulations to her!" Vescovo wrote on Twitter. Vescovo became the fourth person in history to reach Challenger Deep last year. The expedition with Sullivan was his third Challenger Deep dive.

Sullivan reportedly had a longstanding interest in the oceans, a fascination that she had before she became an astronaut. After three missions as an astronaut wherein she spent a total of 532 hours in space, Sullivan became the National Oceanic and Atmospheric Administration's (NOAA) chief scientist and later served as the agency's administrator.

Kathryn Sullivan
Kathryn Sullivan preparing for a potential third spacewalk. She was the first American woman to walk in space in October of 1984. NASA