Kathy Sullivan, America's first woman spacewalker, reaches ocean's deepest point

On Sunday, June 7, Sullivan embarked on a dive to the Challenger Deep, a point nearly 36,000-feet below the surface of the Pacific Ocean within the Mariana Trench - about 320 kilometers southwest of Guam.

The location is believed to be the deepest known region in our oceans, the lowest of the many seabed recesses present around the globe.

According to EYOS Expeditions, the company coordinating the mission, Sullivan is the 8th person in the world to complete the daunting full ocean-depth dive.

The 68-year-old started the journey co-piloting a specially-designed submersible called the Limiting Factor with Victor Vescovo, a millionaire explorer funding the mission.

They both reached their destination, a muddy depression, without any hiccups, and spent an hour-and-a-half there capturing images.

After completing the dive, the duo began the ascent to reach the surface, which took 4 hours to complete.

Upon reaching their ship, Sullivan and Vescovo called astronauts aboard the International Space Station and shared their experience.

Vescovo said, "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."

Sullivan, now a former astronaut, had joined NASA in 1978 and became one of the first women to reach space as part of the agency's sixth Space Shuttle Challenger flight.

Then, on October 11, 1984, she ventured out in the darkness of space to carry out a nearly three-and-a-half-hour long spacewalk - the first ever to be executed out by an American woman.

Interestingly, the two environments explored by Sullivan operate at completely opposite extremes.

On one hand, space is a vacuum with no pressure at all, while on the other, the pressure at Challenger Deep is skull-crushing.

Sullivan said the pressure at the bottom is 1,000 times the pressure at sea level and equivalent to having 291 jumbo jets pressing down on Limiting Factor's hatch.