The scientific drilling vessel Chikyu, which means "Earth" in
Japanese, was launched in 2005 with mantle drilling in mind. The
Chikyu holds the world records for scientific drilling of 7,740 meters
(25,393 feet) below the sea surface and 3,262 meters (10,702 feet)
into the ocean floor. Its large capacity for risers (vertical pipes)
uniquely provide a closed mud-circulation system for establishing a
deep borehole down to the upper mantle.
Because of numerous technological advances, for example in the
design and durability of drill bits, the estimated total cost has dropped
to well below 500M USD for 480-750 days of the mantle drilling
operations (Integrated Ocean Drilling Program-Management
International [IODP-MI], 2013).