News on the MARS node installation and HV connector failure
Diver in the MBARI test tank connects the MARS node to the Cable Termination Assembly in the blue frame.
Update: July 25, 2008
ODI installed the new generation of high voltage connectors to the MARS node MV housing and CTA this week at MBARI. Earlier these two connectors and their harnesses underwent thorough FAT testing at ODI, including high voltage testing under pressure for 18hrs at a time with intermediate connector mate/unmate cycles.
The entire MARS system from the Voltronics power supply through the cable simulator, Cable Termination Assembly, new MV connector harnesses to the MV power housing, with the sea water return, was then tested in the MBARI test tank over the following three days, with several mate/unmate cycles of the new connectors, and with periods left unmated under water for hours at a time. The entire system worked as expected. The next step will be installation by the CS Intrepid later this year in November.
Update: July 15, 2008
We now have a plan in place to get MARS operational before the end of this year. We have a repair vessel scheduled for later this year, and the new ODI connectors will be fitted to the node and spare Cable Termination Assembly (CTA) later this month to be ready for re-deployment.
MBARI has just signed a contract with IT International Telecom to undertake the MARS repair using their cable vessel IT Intrepid. The repair vessel will divert from its transit from Hawaii to the Panama Canal in November to undertake the MARS repair. Immediately after IT International Telecom installs the TRF/CTA and reburies the disturbed cable, MBARI will install the science node and verify the system performance. Providing all goes well, we anticipate being able to install science experiments shortly after the science node installation. The exact timing of the repair will depend on when IT Intrepid completes its installation work in Hawaii. We will continually update the information on this web page as we approach this time.
ODI will be here at MBARI the week of July 21-25 to install the new connectors on the MARS node and on our spare Cable Termination Assembly. In addition to many months of qualification testing, the new connector assemblies recently passed final acceptance tests at ODI’s facility that involved several mating and un-mating operations while under pressure (10,000 psi) with 10kV applied to the connector assemblies for durations of 18 hours at a time between the mating and un-mating operations.
Update: June 1, 2008
Right after the failure of the high-power connector in February, we contacted several telecommunications companies to investigate the availability of cable vessels to undertake the repair work. With several options that initially looked very promising we released a Request for Proposal (RFP) in mid-March for the Cable Termination Assembly (CTA) recovery and replacement. However, all three companies who initially showed an interest in submitting a bid, declined to turn in a proposal by the RFP deadline at the end of March. Apparently there is a major upturn in the telecoms market, placing high demand on cable ships needed to support cable installation contracts worldwide, making it difficult to find a cable installation vessel for our repair. We then investigated using a ship of opportunity, but after receiving a proposal a couple of weeks ago, this option proved to be too expensive to implement as proposed.
So the strategy we are adopting will be to:
- Replace the connectors on the spare CTA units that we have here on shore with the next generation of high voltage connectors. We will then re-test the spare CTA unit with the node that has been recovered, so that it will be ready for installation as soon as a suitable vessel becomes available at an affordable price. We have been working with ODI on the connector issue, and although it is still not clear why the power connector failed, we are planning on replacing the connectors with the next generation of ODI power connectors that have recently completed qualification testing for the NEPTUNE-Canada project. These connectors have higher design margins and will not have been sitting at the MARS node site for 12 months prior to being connected to the node, as was the case for the connectors that failed back in February. This work should be completed by the end of July 2008
- Re-install the repaired node any time after August 2008, once a suitable installation vessel becomes available at an affordable price.
This delay is most unfortunate and is a great hardship for all of the investigators planning to install instruments on MARS this year. We hope to get MARS back on line and operating as soon as we have an affordable repair solution.
Update: March 1, 2008
On Tuesday Feb 26th, the MARS node was installed into the Trawl Resistant Frame (TRF) out on Smooth Ridge 32 kilometers (20 miles) from Moss Landing in 900 meters water depth (the TRF is attached to the shore cable that was installed in March 2007.) The ROV pilots and ships crew did an outstanding job launching the node, flying the node down to the TRF, lowering the node into the TRF, and connecting the node to the TRF/cable with the fiber and power connectors. This part of the operation went flawlessly. The system was then powered up to 7.25kV and the node booted up as expected. Then, 20 minutes after powering up the system, we experienced a failure of the high voltage (HV) connector between the MARS Cable Termination Assembly (CTA) and the HV power housing in the node. The cause of the HV connector failure is unknown at this time, although it may well be associated with the connector being underwater at pressure since the cable was laid approximately 12 months ago.
Because of this problem, the node was recovered on Thursday Feb 28th and the failed connectors removed and returned to the supplier for inspection and failure mode evaluation.
This is a unfortunate and disappointing setback to the MARS project and, of course, to all of the scientists planning on using MARS this year.
At minimum, the repair will involve replacing the failed CTA with a new CTA fitted with connectors that will not exhibit the same failure mode. As for how long this will take, it will depend on both how long it will take the connector supplier to determine the cause of the connector failure and manufacture replacements connectors, and on the availability of a suitable repair vessel.
Providing electrical power and data connections for new research instruments in the deep-sea. That's the vision behind the Monterey Accelerated Research System (MARS). The system, currently under construction, consists of a 52-km (32-mile) undersea cable that carries data and power to a "science node" 891 meters (2,923 feet) below the surface of Monterey Bay. More than eight different science experiments can be attached to this main hub with eight nodes. Additional experiments can be daisy-chained to each node.
A new way of doing oceanography.
Most oceanographic instruments on the seafloor have no connections with the surface, so they have to run on batteries and store their own data. A cabled observatory like MARS removes those restrictions, allowing scientists to design new types of oceanographic equipment and study the ocean in new ways.
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| The MARS observatory will place advanced science instruments in deep water near the rim of the Monterey undersea canyon. Scientists on land will have constant access to their equipment through a seafloor cable (purple line) that carries both electrical power and data. |
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| The main "science node" of the MARS observatory (shown in orange) has eight "ports," each of which can supply data and power connections for a variety of scientific instruments. Five test experiments are presently planned. Scientists from around the world are encouraged to develop additional experiments for testing on MARS. |
A science and engineering testbed
The MARS undersea observatory testbed will allow scientists and engineers to:
Realizing a dream
The MARS project marks a major step toward realizing a long-held dream in ocean science. Because radio waves barely penetrate water, it is easier to get data from an interplanetary probe than from an instrument in the deep sea. Cabled undersea observatories are beginning to change this, linking seafloor instruments directly to scientists' desktops.
MBARI and its partners installed the MARS cable and main science node in early 2007. The first science instruments will be hooked up to the science node later. For more details on the MARS ocean observatory testbed, see the links at left.
An invitation to researchers
The MARS ocean observatory is intended as a testbed for the use of scientists and engineers who want to design and test instruments that will be used on other ocean observatories. We invite ocean scientists to consider deploying instruments on the MARS ocean observatory testbed. The MARS facilities will allow researchers to develop the tools and protocols necessary to take advantage of a seafloor power supply, real-time, high-bandwidth data transfer, and real-time control of experiments. The MARS system is designed so that tools and protocols developed here will be readily transferable to other cabled observatories as they come on line.
For additional information, contact MARS Operations and Management at marsoandm@mbari.org