Seafloor Pressure Sensor Retrofit 2003
The Pacific Geoscience Centre (PGC) is researching seafloor crust pressure by monitoring pressure sensors deployind in sub-ocean drill holes. The installations are installed on the ocean bottom and are difficult and expensive to visit and service. When the sites were originally installed battery and power considerations limited the sites to about 1 sample an hour. Recent improvements in high density batteries allowed for the possibility of much higher sample rates. Unfortunately, the fixed storage capacity of the original instruments prevented higher sample rates because the logger would fill well before the scheduled 1-2 year return visit. Minerva Technology Inc. agreed to work with PGC to retrofit bulk storage onto the seabottom observatories allowing the use of high sample rates.
The retrofit kit needed to be simple and reliable to minimise the chance of problems during deployment by remote operated vehicle. A Minerva Technology MT01 logger was placed into the communication channel between the site and the ROV. The MT01 would provide bidirectional communication passthrough enabling the ROV to configure that site normally. The site was then placed in debug mode which generated human readable measurements once a second. The MT01 recorded this data and saved it to CompactFlash storage media. The increased capacity provided by the MT01 allowed substantially increased sample rates. The ROV detached leaving the MT01 and CORK on the seafloor. At the next site visit the MT01 would be retrieved and the data recovered.
The MT01 retrofit was deployed in 2003 and is expected to be retrieved in 2005. Due to the success of this retrofit process the MT01 was selected for further development and expanded deployment in 2004.
The following pictures show the MT01 retrofit kit being deployed in 2003.
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