NASA Astronaut Becomes First Woman to Reach Challenger Deep

NASA astronaut Kathy Sullivan successfully reached the bottom of the Challenger Deep — considered the deepest underwater location on Earth —  roughly 11,000 meters (6.9 miles) beneath the surface of the Pacific Ocean, according to a blog post on EYOS Expeditions.

RELATED: THE 'FIVE DEEPS' EXPEDITION AND THE CHALLENGER DEEP

NASA astronaut reaches Challenger Deep

Considered the deepest-known place in Earth's oceans, Challenger Deep resides within the Mariana Trench — a sickle-shaped depression roughly 1,770 kilometers (1,100 miles) east of the Philippines. Beneath the weight of 11,000 meters of water, the water pressure at the bottom of the Challenger Deep is more than 1,000 times the pressure at sea level, reports CNET.

This isn't the first "historic first" for Sullivan. In the year 1983 — already a veteran of three space shuttle flights — she became the first American woman to walk in space. As the eighth human to reach the bottom of the precocious Challenger Deep (after Jacques Picard and Don Walsh in 1960), Sullivan has made a career of pushing the envelope in human exploration.

Sullivan was also the head of NOAA after her space career came to a close.

Sullivan's traveling companion to the Challenger Deep

The former NASA astronaut Sullivan (68 years old) was joined in her expedition by Victor Vescovo (54 years old) — entrepreneur and deep-sea explorer — and together they submerged in the deep-sea submersible called "Limiting Factor." The trip to the bottom lasted nearly four hours.

Vescovo was the fourth person in history to make their way to the bottom of the Challenger Deep as part of his "Five Deeps" expedition — a seven-day mission of making five dives into the Mariana Trench.

"As a hybrid oceanographer and astronaut this was a once in a lifetime day — seeing the moonscape of the Challenger Deep and then comparing notes with my colleagues on the ISS," said Sullivan to EYOS Expeditions.

Exploring the ultimate depths of the world's biggest ocean is incredible, but not always the easiest thing to visualize. This is why it's interesting to note that the Mariana Trench is roughly 1.6 kilometers (1 mile) deeper than Mount Everest is tall. While we probably won't see tourist packages to Challenger Deep soon, we should expect more of the world's adventurers to take the ultimate plunge to the darkest, most mystifying place on Earth.