MOOS Design Requirements Recommendations

From the November 2000 MOOS Meeting

1. General:

a) We should reorganize the Design Requirements Document to consolidate information so that information on each topic is found in only one place.

2. Availabilty/ Reliability:

a) We shoulds define the maximum amount of continuous time that the system would be not in communication with shore. In determining this number it should be assumed that event response is covered by on-board detection with subsequent automatic event response initialization (eg seimometer detects activity, on board processor increases instrument sampling rates or launches an AUV)

b) Communication latency should be changed to 1hr (currently 1hr - 4 hr)

c) Reliability requirements of the entire system should be defined in addition to the number provided for the availability of the buoy/shore communication link.

3. Minimum Depth

a) We should define the minimum deployment depth of mooring system. In deriving this figure we should take into account the option of deploying the mooring in deeper water and running fiber to a shallow water node,

4. Survival Conditions

a) We need to investigate further the applicable criteria for storm survival (10yr, 25yr etc). In selecting this figure we need to consider the fact that critical wear components will be replaced at regular intervals.

Although DEOS are designing to the 50 yr storm criteria, their buoys are left for periods of 10yrs on stations in unhospitable environments, eg southern ocean etc. In addition DEOS are designing buoys for site specific conditions so a 50yr storm criteria in one location provides a different design criteria to a 50yr storm in another location. In addition we are not designing the MBARI moorings to the same design criteria as the DEOS moorings.

b) The mooring design should include the possibility of including a weak link so that if storms are experience that exceed the design criteria, the surface expression may be lost, but other system components may be saved (ie AUV docking stations, AUV's, riser cable, benthic expressions etc.

5. Deployment

a) We should investigate whether the constraint of needing the MOOS mooring to be able to be deployed from the Point Sur is consistent with other design requirements. This will become apparent as the designs are developed for the Concept Review. If this becomes an unreasonable constaint on the design, we should consider relaxing this constraint

b) We should consider transportation regulations in the design so that we can haul the buoy by road to another dock for loading on a ship for deployment.

6. Oceanographic process time constants

a) For multi process oceanographic processes we should take into consideration the time constant for the process being measured to ensure that AUV synoptic missions are completed in an acceptable time (water mass moves from Davenport to M1 in about 1-2days, upwelling area needs to be surveyed in 1 day)

7. Canyon Processes/ Carbon Cycling/ Active Ridge Processes

a) Instrumentation requirements (power, bandwidth, instrumentation) for carbon cycling should be considered to be the same as the instrumentation requirements of the Canyon Processes Use Scenario.

b) We should consider accommodating multiple mooring configurations where appropriate (eg U type). This was also relevant to measuring mass and heat loss on active mid ocean ridges where subsurface buoys may be needed 100m from ocean bottom.

c) There is no science need to have a Vertical Profiler on the mooring in the same configuration as benthic nodes and instuments.

8. Instrument Communication

a) The instrument SW interface needs to accommodate powerup/power down commands.

b) What snap shop data needs to be sent to shore?

9. Power

a) What power is needed for the node to node link for 10baseT and 100baseT. Does communication system need sleep mode for the 100baseT option?

10. Vandalism

a) We should carefully consider the deployment locations, and where appropriate, take account of the potential impact of vandalism. Systems that attract vandalism include solar panels, wind generators, anemometers.

11. Geographical Locations for Deployment

a) We should not design the MOOS mooring for the conditions in the Western Pacific. MBARI will not be sending a ship there on a yearly basis for maintenance of buoys

b) The MOOS mooring should be designed for applications that need the unique capabilities that are being incorporated into the mooring design (event response, AUV docking, comm link between the surface expression and benthic instruments). If applications do not need these unique capabilities, but are identified as being design drivers, we should consider removing these requirements. Examples include:

• If the 5kt current at Eqpac turns out to be a serious design driver we should consider removing this location from the design requirements. MOOS subsystems could still be used at these locations, but not the entire mooring. For instance the controller could be used on mooring designs that already operating at this location and are know to survive these conditions.
• We need to investigate and quantify the effect of the Juan de Fuca/Gorda Ridge/ environmental conditions on the design and cost of the MOOS mooring. If the design impact is minimal, this should be our limiting design criteria. If the impact is significant, we should review the cost benefit in light of the possibility (funding dependant) of using NEPTUNE or DEOS moorings (ie the additional mooring cost compared to the science benefit of deploying a mooring in advance of the installation of NEPTUNE)