The following information details work-in-progress and is specific to MARS.
The photographs A through D (see below) show all of the ODI connectors currently used as part of the MARS Primary Node and the present ODI-suggested Science Harness to connect instruments to the node. The connectors permanently affixed to the MARS Primary Node are called the MARS Node Science Port Connectors, which are shown in Photograph A. These Node Science Port Connectors are attached to the Communications Housing via a Penetrator.
It is tentatively planned for these same Science Port Connectors to be incorporated into
junction boxes or Secondary Nodes to maintain a consistent connector for science experiments. In this context these would also be referred to as
MARS Secondary Node Science Port Connectors, however they would have lower voltages available at the secondary nodes.
The same MARS Science Port connector could be reconfigured with an ROV handle at the far end of an extension cable to become a MARS Science Port connector with ROV stab. This could be used to connect to a single experiment with a dedicated extension cable.
The minimal equipment provided by ODI to connect an experiment to MARS is referred to as the MARS Science Harness. This consists of the
MARS ROV Flying Lead or Connector-Plug (see Photograph
B) connected to a MARS 12-way
Penetrator via 5–<100 m of cable. The ROV Connector-Plug connects to the Science Port Connector in all the configurations cited above.
Click on images below for larger view.
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| Photograph A | Photograph B | Photograph C | Photograph D |
Photograph C shows the complete ODI MARS Science Harness with the ROV Plug attached to the MARS Instrument Penetrator. To make the MARS Science Harness, the MARS Instrument Penetrator is rather large (3.5" flange) but has/will be qualified to pass Ethernet for >5–<100 m from the node. Costs for the entire MARS Science Harness are estimated at $9,000–$15,000, depending on the length of cable. Experiments that are targeted for NEPTUNE-Canada will need to be qualified for Ethernet at 3500 m operating depth.
Photograph D shows the MARS Penetrator Backshell with the 12 pins. The pin numbers and identification are provided in the Specification. This ODI MARS Penetrator has a 3.5" flange.
Several people have expressed a desire to use a smaller dry connector or penetrator to replace the large ODI 12-way penetrator. The large size of the MARS Penetrator provides space for the Ethernet pairs as well as the high voltage pins. This has been qualified in initial testing at WHOI. Reducing the size of the penetrator (and the space for the pins) would
require additional tests/qualifications. Alternatively, the penetrator could be affixed to the SIIM housing with small dry mate connectors for instruments. MARS Facility Staff can provide additional information about the status of this option. We recommend that they review interface hardware before purchasing.
MBARI DMO is concerned about the PBOF hose used by ODI due to its stiffness. This would be difficult to manipulate at short lengths and impossible to spool or coil for longer cables. The ODI-preferred
Mohawk cable could be extruded with PU with perhaps some fibers added to make a multipurpose cable. There are several vendors actively developing viable cable options. The MARS Facility Staff has this information.
The MARS Science Instrument Interface Modules are under development. Contact Gene Massion for more information about these interface solutions for Ethernet to serial and other voltage options.
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