Former NASA astronaut Kathryn D. Sullivan, the first American woman to walk in space, is now also the first woman to reach the deepest point in the ocean.

Sullivan, an oceanographer and veteran of three space shuttle flights, is the first person to achieve both feats. After returning from a nearly 7 mile dive to Challenger Deep in the Mariana Trench, Sullivan called her colleagues at the International Space Station, which is in orbit 254 miles above Earth.

“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," Sullivan said in a statement released Monday by EYOS Expeditions, the company coordinating the mission. 

Sullivan became the first American woman to walk in space in a 1984 mission on the space shuttle Challenger and later left NASA to become administrator at the National Oceanic and Atmospheric Administration, according to NASA.

She traveled to the deepest point in the ocean, located in the Western Pacific Ocean, on a submersible called the Limiting Factor piloted by Victor Vescovo of Caladan Oceanic before returning to its mothership the Pressure Drop. Vescovo, who has also piloted the Limiting Factor on a recent dive to the Titanic, became the fourth person to reach Challenger Deep last year.

Eight people have reached the bottom of Challenger Deep, including Vescovo, Sullivan and film maker James Cameron who reached the bottom in 2012, according to EYOS Expeditions.

Vescovo congratulated Sullivan on being "the first woman to the bottom of the ocean" on Twitter.

“We made some more history today," he said in a statement. "And then got to share the experience with kindred spirits in the ISS. It was a pleasure to have Kathy along both as an oceanographer during the dive, and then as an astronaut to talk to the ISS.”

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