A deep ocean data recovery module

Developments in undersea acoustic telemetry make it feasible to read low to moderate amounts of data from subsea instruments from shipboard. When it is necessary to recover gigabytes of data, however, the time and energy required by an acoustic telemetry link can become prohibitive, particularly for battery powered instrumentation. A pop-up module has been developed to allow the recovery of 2-4 Gbytes of data from both moored and bottom-mounted subsea systems, without the need for recovery of the primary oceanographic instrumentation. The pop-up module is based on a recoverable acoustic transponder, to which are added a 3.5-inch, 2.1-Gigabyte, SCSI hard disk drive and a 80386SL-based controller. The pop-up controller is connected to the subsea system using pressure-balanced, oil-filled, underwater mateable connectors that separate when the pop-up is released. Two channels of data can be transferred from the subsea system to the pop-up at 125 kbps each. The initial application of the pop-up module is to recover data from autonomous vertical hydrophone arrays developed for the Acoustic Thermometry of Ocean Climate (ATOC) program. Four pop-up modules mounted on the subsurface float supporting the array allow the recovery of data at approximately quarterly intervals during a year-long deployment.