A deep sea drill
ing ship built in 1968 for ocean floor
studies by the Deep Sea Drilling Programme
. The Glomar Challenger was designed for computer controlled navigation
, using bow and stern thrusters and acoustic beacons on the sea floor. The propulsion
system enabled the ship to remain in a relatively stationary position over a drill site in water too deep to anchor
guidance systems allowed for the easy replacement of drill bit
s and exact reentry of bore holes in 6000 meters (20,000 ft) deep water.
Before its retirement in 1983, the Glomar Challenger had removed 96 kilometers (60 miles) of deep sea cores and the
studies of these cores alllowed for definite proof of seafloor spreading
and the discovery that no ocean crust
is older than approximately 180 million years.