Nereus, a robotic submarine, has started exploring the deepest-known part of the world's oceans called the Challenger Deep, located in the Marianas Trench near the CNMI and Guam.
On Sunday, the hybrid remotely operated vehicle Nereus passed the 10,000-meter mark.
Challenger Deep is reported to be 11,000 meters deep, more than 1.2 miles deeper than Mount Everest is high.
At that depth, pressure reaches 1,100 times the pressure at the surface.
After a six-hour journey to the bottom on Sunday, Nereus reached 10,600 meters deep, according to the Woods Hole Oceanographic Institution, which is conducting the May 23 to June 6, 2009 expedition.
WHOI (www.whoi.edu), the world's largest private, nonprofit ocean research, engineering and education organization, is using the free social networking and micro-blogging service Twitter to help document the progress of the Nereus exploration of Challenger Deep.
For the latest update on the WHOI exploration, go to http://twitter.com/WHOIExpeditions.
The WHOI-led team aboard the research vessel Kilo Moana is conducting a series of sea trials with Nereus, taking the vehicle to ever-greater depths from 1,000 meters to 4,000 meters, then 8,000 meters and ultimately, 11,000 meters.
WHOI's goal is to take Nereus to the deepest abyss on Earth, the Challenger Deep.
At 4am on Monday, Nereus was recovered and brought back to the surface before launching dive No. 12 yesterday morning.
Early yesterday afternoon or at about 1pm, Nereus was again nearing the 10,000-meter mark after over six hours, and was still descending, according to WHOI's latest entry on Twitter.
The Nereus project is led by Andy Bowen and Dana Yoerger of WHOI and Louis Whitcomb of Johns Hopkins University.
The science team includes Patty Fryer, a geologist at the University of Hawaii, and WHOI biologist Tim Shank, Biologist.
Nereus is the first unmanned vehicle to explore the Marianas Trench since 1995, when the Japan Agency for Marine-Earth Science and Technology brought its ROV Kaiko there. Kaiko was lost in 2003 after the cable it was suspended from snapped.
The first and only manned expedition to the Mariana Trench occurred in 1960, when Jacques Piccard and Don Walsh traveled there in the U.S. Navy-owned bathyscaphe Trieste.