First American woman to walk in space becomes first woman to dive to deepest spot on Earth

Kathy Sullivan, a former NASA Space Shuttle astronaut and the frst American woman to walk in space back in 1984, just added another record to her illustrious career by becoming the first woman to visit Challenger Deep — the bottom of the Mariana Trench — during a daring expedition last weekend. She's now also the only human to have ever been up in orbital space and down below at maximum ocean depth.

Thirty-six years after blasting off in the Space Shuttle Challenger, Sullivan was aboard Caladan Oceanic's flagship support vessel the DSSV Pressure Drop en route to the famous dive spot off the coast of Guam. Once at the targeted destination on June 6, she and Caladan Oceanic's CEO, undersea explorer Victor Vescovo, boarded the "Limiting Factor" submersible (see it in action in the video below) and dropped to the deepest point on the planet at 35,810 feet in a history-making adventure.

After returning seven miles back up to the surface, Sullivan had the rare opportunity to make a phone call to astronauts aboard the International Space Station to share her achievement.

"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," wrote Sullivan in a statement.

Sullivan and Vescovo's advanced subsea craft was the first commercially-certified full-ocean-depth DSV (deep submergence vehicle). Vescovo financed the design and supervised the construction of the multi-million dollar deep-diving vessel himself and acted as Sullivan's pilot for the record-breaking voyage. This was his third descent to Challenger Deep.

Caladan Oceanic's team planned a series of eight dives during its stay over the Mariana Trench, observing volcanic vents, searching for new species of deep sea marine life, and mapping pools for the U.S. Exclusive Economic Zone for the National Oceanographic and Atmospheric Administration (NOAA).

Sullivan started her career as one of the first women inducted into NASA's astronaut corps in 1978, and became the first American female astronaut to walk in space in 1984. During her 15-year NASA run, she flew on three Space Shuttle missions, including the flight that deployed the Hubble Space Telescope in 1990.