White Paper Title: 
The Next-Generation of Mid-Ocean Ridge Technology: Developing Vehicles, Sensors, and Autonomy for Advancing Scientific Surveying, Sampling, and Observation

Deep submergence vehicles remain workhorses of mid-ocean ridge research and are the primary means for scientists to access the MOR and obtain data, samples, and observations. The duration of the Ridge 2000 (R2K) program has seen the transition to next-generation ROVs and the Alvin HOV will soon undergo significant upgrades. These platforms will continue to provide valuable access, especially for sampling and observation. However their limitations in mobility, endurance, and cost (amplified by the decreasing number of UNOLS vessels and increasingly competitive research funding) prevent them from transforming ocean science and motivates exploring new vehicle technologies.

Last year marked the 10th anniversary of ABE's bathymetric survey of the EPR and the 15th anniversary of ABE's magnetic survey of the Juan de Fuca – two pioneering surveys of MORs and oceanography in general. These surveys demonstrated to the community the potential of AUVs to transform deep ocean science, and, over the last decade, AUVs have evolved from a nascent technology to mature tools for ocean exploration and research. Their survey capabilities include bathymetry, magentics, optical imaging, and exploring and localizing new hydrothermal vents (AUVs have contributed to the discovery of numerous new vent sites over the last decade. In addition, AUVs are used in coordination with HOVs and ROVs to enhance investigations with these vehicles (with data obtained with an AUV often informing HOV or ROV operations within a few hours) and increase the overall cruise productivity. These successes demonstrate the capabilities of AUVs however we have yet to fully exploit the potential of these vehicles to transform MOR investigations and oceanography in general.

Until now, the challenges facing the ocean robotics community have been developing and operating vehicles in the extreme ocean environment. Having met these challenges, we can focus our research on enabling ocean robots to undertake missions previously considered impossible or difficult. Examples include achieving a 1000-km mission (essential for surveying large portions of the MORs and observing possible water-column interactions between vent sites); undertaking an extended multi-month (or year) temporal survey of a site (ABE's originally defined mission); further developing the capabilities of these vehicles to operate in extreme regions including the high-latitudes (e.g., Gakkel Ridge) and using AUVs to autonomously respond to events (a compelling link to OOI). Achieving any one of these goals would radically alter how we research the MORs and provide the entire community with a valuable new capability. The technology used by the MOR community has broad impacts throughout the oceanographic community and society in general – for example, pressure tight samplers (developed for hydrothermal vent sampling) and the Sentry AUV were both used this past June to help research the impact of the Deepwater Horizon Oil Spill.

To achieve this next generation of vehicles requires continued exploitation and development of a number of technologies including:

1. Navigation in the Mid-Water Column - Doppler sonars and landmark navigation have significantly improved near-bottom navigation, however, few sensors provide horizontal state measurement in the mid-water column, thereby vitiating our ability to precisely navigate in this region of the ocean. The limited amount of sensors measurements available at these depths implies that model-based state estimators and multiple vehicle navigation will be essential to implementing navigation in this area. Present techniques are sufficient for oceanographic research, however the continually increasing interest in biological and physical oceanography in the mid- water column motivates developing improved navigation systems.

2. AUV Compatible Sensors – Developing sensors to better measure and observe MOR processes has been a key element of the R2K program, however more effort needs to be made to develop sensors possessing the power and size characteristics necessary for deployment on an AUV. This task is essential as any advances in vehicle engineering or autonomy will be fruitless without sensors. Crucial to this objective is the MOR community identifying and prioritizing sensors that have the potential to transform investigations.

3. Optimal Surveying, Advanced Autonomy, and Autonomous Data Processing and Classification – Traditionally, the oceanographic engineering community has relied upon trajectories defined a-priori. The time and power necessary to achieve tasks can be optimized by selecting trajectories based on data obtained in-situ. Combining these measurements with models of vehicle dynamics and scientific processes can provide simultaneous estimates of the vehicle and environmental state, thus allowing for optimal completion of objectives. As AUVs conduct longer duration missions, the need for these vehicles to independently process and classify data will become increasingly important. This capability would allow AUVs to react to events autonomously – altering trajectories or (in the future) obtaining samples. In addition, crucial data could be transmitted acoustically to other AUVs or surface vessels. This capability is also crucial in traditional HOV and ROV operations, where the increasing amount of data obtained essentially saturates scientists at-sea and reduces their to interpret and act on data while still on-station. On-shore data management and archiving is important but data analyzed post-cruise is effectively “too late” with follow-up data and sample collection postponed (often years) until future cruises.

4. Multiple Vehicles – The deployment of multiple vehicles to sites of scientific interest coupled with improved environmental and navigation estimation algorithms increases our ability to effectively search, locate, and study scientific processes. The ability of vehicles to operate in the same region and share information will allow for reductions in the resources (e.g., LBL transponders, high-resolution sensors) necessary for ocean exploration. These advances will significantly alter our abilities to use underwater vehicles in oceanography, and potentially alter ocean exploration strategies.

Achieving all of the above goals is beyond the scope of R2K or any successor program, however, given R2K's history of using new ocean technology to advance it's scientific objectives, technology should be a key component of any future program. The objective should not be limited to technology made available by other programs but to actively fund and foster new technology development crucial to MOR science. The MOR community should rise to the challenge of identifying crucial missing data sets for MOR science and the technology necessary to obtain these measurements. Based on this consensus, the community should advocate and support a long-term effort, both technical and scientific, to develop the necessary technology and implement it in MOR investigations. A crucial criteria in selecting this “Apollo Program of MOR science” must be its application to other fields of science. For example, advancing our ability to measure fluxes would not only benefit MOR science but the developed technologies and methodologies could be applied to enhancing investigations of the role of the ocean in climate change or improving assessment of marine pollution. A program of this size and scope could potentially resonate with NSF programs traditionally not pursued by the MOR community, including cross-cutting programs at NSF. We should aim high – the sea surface (and beyond) is the limit - and develop the technology necessary to understand the MORs and it's interactions with the ocean and Earth as a whole.