On September 23, 2000 the Italian oceanographic ship URANIA deployed the station on the site 38° 32’ N – 12° 46’ E at 1900 m depth. Twelve hours later before leaving the area URANIA ship came back above the station to interrogate it acoustically and recover the first summaries of scientific data and system status parameters.

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bottom station deployment - september 2000

 
The communication system buoy deployment could only take place on December 18, 2000 during another URANIA cruise. Taking into account the buoy watch circle and the +/- 40 degree aperture angle of acoustic transducers, the buoy anchoring dead weight had to be placed between 500 and 1000 m from the station. The buoy deployment (previously simulated with Orcaflex software) was performed dead weight the last; that is the buoy is put at sea the first, then the mooring line is unreeled at the surface starting from a predetermined point so as to complete the operation by dropping the anchoring block at the due point. The mooring line then reaches progressively its final vertical configuration as the dead weight goes down. The dead weight reached the bottom after an hour at a distance of 600 m from the station.

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the communication system buoy - décembre 2000

 
From December 18 the station has been interrogated practically each day from Venice using as a rule the satellite link (the VHF radio link to Ustica Island being implemented in redundancy). The communications with the station was interrupted on February 26, 2001; the reason for it was identified later after the system recovery in April as a premature exhaustion of the primary batteries.

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PC interface for communicating with the station

 

The 1st expendable messenger surfaced on October 22, 2000; as it brought the first news of the station available since a month, it was recovered and its content immediately examined without waiting for the ARGOS transmission cycle: the scientific and ancillary equipment of the station were functioning normally.

The 2nd expendable messenger was released on December 20, 2000; it was left drifting and transmitted its data during 40 days till February 09, 2001 when it was in the south of Naples. It will not be recovered.

The 3rd one was released on February 16, 2000; it was left drifting about one week and then preventively recovered before the announced arrival of a bad weather period. The ARGOS transmission was pursued on land.

The 1st storing messenger was released by an acoustic order and recovered on December 07, 2000; the data records were satisfactory.

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storing messenger at sea surface - december 2000

 

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storing messenger recovery 

 
URANIA ship went back on the site from April 7 to 16, 2001 in order to recover the whole system. The buoy and its equipment were recovered on April 07; the equipment was found in very good state after almost 4 months at sea, except the exhaustion of the batteries which is hypothetically explained by the satellite antenna having stayed activated for abnormally long periods of time.

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the buoy after 4 months at sea - april 2001

 

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hauling the buoy aboard URANIA

 

Because of rough weather conditions the station could only be recovered on April 16; it was operating well; the 2nd storing messenger (and last one of the five), the recovery of which was made hazardous by sea conditions, was not released and recovered with the station.

At the end of the mission, the station was lowered for a short time in the deepest area around Ustica at 3400 m; it is the deepest stay ever performed in real conditions by the GEOSTAR-2 system, specified for a 4000 m service depth. The system generally sustained this test without problems.

For this first mission the scientific instrumentation of the station comprised:

  • 2 magnetometers, a scalar and a vectorial one
  • a gravimeter
  • a CTD probe and a transmissometer
  • a sequential water sampler with 48 bottles
  • an acoustic 300 kHz doppler current meter with a vertical range between 100 and 150 m.

The whole set of data sampled during seven months has been recorded on the hard drives of the station. The scientific teams participating in the project are now proceeding with the detailed analysis of this amount of data.