Nadia: Navette de diagraphie-etat de developpement present et evolution ulterieure

In July 1988, the first re-access to a deep sea borehole was performed using the logging shuttle NADIA 1 and the manned submersible NAUTILE during the cruise FARE. This operation was conducted on the site DSDP 396 B, drilled by the Glomar Challenger within the framework of the Deep Sea Drilling Project in 1976, close to the axis of the mid Atlantic Ridge at 23 degree N. A temperature logging hole and a fluid sampler was introduced in that hole and lowered to -300 m below the sea floor. It was the first time such an operation was done without a drill string and a drilling ship equipped with a dynamic positioning system. From this experience, a new logging shuttle, NADIA 2, was developed. NADIA 1 was designed with the objective of demonstrating the feasibility of the reoccupation of a deep sea borehole. NADIA 2 is a real logging unit, able to operate most of the logging tools used in the Ocean Drilling Programme. NADIA 2 can also be used as an ocean bottom observatory with an autonomy of weeks to a few months on the sea floor.