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The Deep Submergence Alvin An Advanced Platform for Direct Deep Observation and Research by W. Bruce Strickrott

WHOI

34 The Journal of , Vol. 12, No. 1, 2017 Copyright Journal of Ocean Technology 2017 Copyright Journal of Ocean Technology 2017 The Journal of Ocean Technology, Vol. 12, No. 1, 2017 35 Human occupied vehicle (HOV) Alvin enables this challenge, a team of WHOI engineers in-situ data collection and observation. collaborated with the US to develop the deep submergence vehicle Alvin and in June The question “what is the most extreme of 1964 Alvin officially entered service. Since creature you encounter during a deep dive its commissioning, Alvin has made thousands in Alvin?” is often asked during our public of dives and has played a critical role in outreach events with schools and museums. the continuing advances in oceanographic There are many answers and all are worthy science (Figure 1). Alvin’s entry into service of the title as most extreme – the giant Rifita as a scientific research tool represented a Pachyptila tube-worms that live and feed at significant change to the methods used to hydrothermal vent environments; Alvinella study the deep ocean. Pompejana worms that live directly in the high temperature vent fluids; the unique Thousands of scientific observers have used vent shrimp, Rimicarus Exoculata, that use Alvin to make the amazing journey to the specialized cells on their carapace to sense seafloor. Their experiences have led to many hydrothermal vents in the infrared spectrum. significant discoveries and helped uncovered All thrive in extreme environments. However, the secrets of Earth’s deep water environments. the most appropriate answer to the question Today, a newly rebuilt Alvin remains in service is that human beings are the most extreme and continues operations as a valuable asset for species in the deep ocean. deep sea research and understanding.

Humans are not physically capable of surviving Alvin is Never Finished – An Evolving Design in the high pressure, often toxic, environment Periodically, Alvin’s systems are replaced and of the deep ocean. However, we are capable of upgraded with more advanced components and safely visiting harsh environments on Earth and the newest . Through the years, in our solar system. To do so, humans have had the vehicle’s capabilities have continually to utilize our amazing intellect to overcome the evolved to meet the changing demands of the challenges to a physical presence in extreme scientific users and to enable new methods for environments. Through the application of our oceanographic research. understanding of the natural world and our knowledge of physical laws, humans have In 2013, the Alvin team completed the most developed advanced technologies to enable extensive upgrade to the vehicle’s systems successful human visitations to the harshest since its original inception. Completion and locations on Earth. certification of the new vehicle represented the culmination of years of design studies, For over 51 years, the Woods Hole project planning and new system development. Oceanographic Institution (WHOI) has The major overhaul and upgrade period was a exhibited this unique human trait through significant technological endeavour intended the operation of one of the world’s premier to greatly improve Alvin’s capabilities and to extreme , the manned, deep ensure that the vehicle is an advanced, 21st submergence vehicle Alvin. century deep sea research tool.

Beginning of a Legacy Bigger is Better – Alvin’s New Sphere In the early 1960s, Allyn Vine, a WHOI A principal part of the upgrade was the oceanographer, identified the need for a new installation of a new personnel class of . At that time sphere. The new sphere is the third in Alvin’s there was no effective means for scientists history, replacing a smaller sphere installed to perform direct research, exploration and in 1973. WHOI engineers, in collaboration experimentation in the deep sea. To tackle with the Southwest Research Institute and the

36 The Journal of Ocean Technology, Vol. 12, No. 1, 2017 Copyright Journal of Ocean Technology 2017 Figure 1: Alvin dive WHOI statistics. scientific user community, optimized the new The replacement sphere represents a significant sphere configuration and in- environment. improvement over the older system, which was Sphere size, maximum depth rating, total smaller, had only three small viewports, no viewport compliment, size and placement overlapping observation areas and was limited were important variables considered during to a depth of 4,500 metres. the design phase. Staying Afloat – Complex Ultimately, the new personnel sphere was 20% larger, capable of diving to 6,500 metres and Primary buoyancy for deep water vehicles includes a suite of five strategically placed is provided by externally mounted syntactic viewports. Three large (18 cm) forward facing foam material. As a part of the upgrade, Alvin viewports and two smaller (13 cm) side received new lighter foam rated for 6,500 viewports provide excellent overlapping fields of metres. Every block was extensively tested for view extending from the front of the submersible manufacturing quality and pressure tolerance to the extreme port and starboard sides. to ensure the material was adequately safe for

Copyright Journal of Ocean Technology 2017 The Journal of Ocean Technology, Vol. 12, No. 1, 2017 37 manned use. Advanced machining technologies component of the data system. Equipment allowed implementation of complex shapes interfaces used analogue circuitry with no that give the new vehicle a modern, more additional digital command and control streamlined appearance. capability. Science data needs utilized serial data methods (RS232) to transfer information Ergonomically Speaking – Alvin’s New to dedicated in-hull notebook Interior (typically user supplied). The system was The larger sphere and new systems required limited in bandwidth and had no significant a redesign of the in-hull environment. WHOI means for real-time vehicle system and science engineers solicited input from scientific users, data integration and processing. All data students from the Rhode Island School of travelled over hard-wired circuits with the Design, experienced spacecraft engineers associated limit to data transfer rates. and senior Alvin pilots to develop the new interior. The final design balances personnel The new submersible includes a modern, comfort, equipment placement and access vehicle-wide data network that links with a configuration that naturally promotes primary vehicle systems and sensors with use of the five viewports (Figure 2). New a suite of in-hull computers and externally seating arrangements, ergonomically placed distributed microprocessors and controllers. piloting controls, HD touch screen interfaces Intelligent science interfaces and dedicated and video monitors transform Alvin’s interior. microprocessor controlled power supplies Observers entering the vehicle for the first time are linked throughout the data system via a routinely use the word “wow” to describe their redundant fibre optic data loop. Video and impression of the new design. imaging systems are integrated into the wider data system for access and control. Science Light Speed – Fibre Optic Penetrators supplied sampling devices and sensors utilize Principal to Alvin’s mission is the ability to the network to collect and process large collect large quantities of dive data. External quantities of environmental data. Advanced, sensors and components continually send user supplied sampling tools, notebook information to the in-hull network for display computers, tablets and any other network and processing. To enable high speed data capable equipment can easily integrate into the transmission, WHOI engineers worked with new data system. Lancer Systems to develop a high-pressure fibre optic penetrator for Alvin. Through-hull Alvin’s data system is designed specifically penetrators are populated with a total of 24 to enable users to integrate novel high-tech optical fibres that provide a superb means sampling devices and sensors for enhanced to transmit large quantities of data and high data collection. definition video information. High-speed transmission of vehicle commands and system Taking Command – The New Command status are effectively distributed through the and Control System vehicle’s new data network. Historically, Alvin has relied on analogue circuitry to provide pilot and observer interface Network of the Deep – Alvin’s New Data with submersible systems and manoeuvring System controls. Although effective, the method Prior to 2012, Alvin’s data system was limited supplied little informational feedback to the in the ability to process large quantities of pilot for system status and fault evaluation. data. While there was a serial data network The new Alvin includes a fully redesigned for a small number of in-hull science data command and control (C&C) system that computers, the system did not utilize a greatly enhances the pilot’s ability to manage dedicated in-hull network as a primary the submersible’s systems.

38 The Journal of Ocean Technology, Vol. 12, No. 1, 2017 Copyright Journal of Ocean Technology 2017 Utilizing a hybrid digital/analogue command Alvin retains a redundant analogue control architecture, the C&C balances an integrated system for use in the event of a full digital microprocessor interface with robust hard- system failure. The backup system uses the wired circuits. System commands are same piloting devices (joysticks, potentiometers, initiated via a modern touch screen graphical switches) for three-axis manoeuvring. user interface (GUI). Dedicated GUI pages provide automated and manual control Alvin’s new position control system represents of ballasting, sensors, external lighting, a significant improvement to the vehicle’s cameras, and numerous other submersible ability to support scientific operations. Alvin components and systems. Primary battery is now capable of performing very accurate and bus-power information and individual mapping and photo-mosaic missions, component status is reported real-time for precision transects over long distances and display. Any identified faults are visually stable position holding near bottom sampling flagged to notify the pilot of potential sites (Figure 3). problems or reduced performance. All data is recorded and available post-dive for Are We There Yet? – New Navigation System performance evaluation. In the early days, Alvin used very primitive systems for navigation during a dive. Simple The new C&C system is highly adaptable acoustic methods provided ranges between and configurable to meet the needs of the and sub. Visual cues and natural an individual dive series and provides landmarks, dead-reckoning and hand- a significant improvement to Alvin’s drawn maps were often used to create an operational capabilities. understanding of a particular dive location. Correlating sample information with accurate Xs, Ys and Zs – Precision Manoeuvring in positional information was difficult. Three Axes Prior to the upgrade, Alvin used six thrusters Eventually, acoustic methods were developed to provide motion in three axes (3-fore/aft, to provide more accurate means to track the 2-vertical, 1-rotational). The single horizontal submersible. Acoustic beacons and ranging thruster, mounted near the stern of the methods (long baseline navigation) improved vehicle, provided limited capability for Alvin the ability to track vehicle position during dives. to rotate in-place and direct lateral motion was not possible. The new vehicle includes Presently, Alvin uses a modern navigation an additional forward-mounted, horizontal system that provides very accurate positional thruster that enables full rotational and lateral information. The shipboard system uses a motion capabilities. resident ultra-short baseline acoustic navigation set to determine the vehicle’s position Proportional manoeuvring commands are relative to the ship. Accurate shipboard GPS initiated via two joysticks. A primary joystick information is used to determine Alvin’s controls fore/aft, rotational and lateral motion position on Earth. with a secondary joystick controlling vertical motion. Digital manoeuvring modes include On board the submersible, Doppler velocity auto-heading, auto-altitude, auto-depth, auto- sensors, a fibre optic gyro, magnetic compass X/Y and stick-lock. Additional manoeuvring and attitude sensor provide vehicle specific command inputs are possible through fore/aft/ information to the Alvin data and navigation vertical potentiometers and lateral/rotational computers. WHOI engineers developed an control switches. Incremental positional control advanced navigation “engine” to calculate in three axes is available via a dedicated GUI and display vehicle position on the in-hull page on the C&C touch screen. navigation touch screen display. Dive specific

Copyright Journal of Ocean Technology 2017 The Journal of Ocean Technology, Vol. 12, No. 1, 2017 39 WHOI

40 The Journal of Ocean Technology, Vol. 12, No. 1, 2017 Copyright Journal of Ocean Technology 2017 Figure 2: Alvin’s new interior balances personnel comfort, equipment placement and access with a configuration that naturally promotes the use of the five viewports with new seating arrangements, ergonomically placed piloting controls, HD touch screen interfaces and video monitors.

Copyright Journal of Ocean Technology 2017 The Journal of Ocean Technology, Vol. 12, No. 1, 2017 41 target locations, navigational waypoints and file. Dive specific navigational and meta-data high definition bathymetric map underlays are embedded in the frame-grabber file and (obtained from WHOI’s Sentry AUV) are extremely useful for post-dive review and are available for use during the dive. All mission planning. Frame-grabber files are navigation data is recorded and available offloaded post-dive and are now available post-dive for future mission planning and online for public access on the WHOI web site. science data correlation. Degrees of Freedom – Enhanced Dedicated shipboard navigation stations provide Manipulation and New Workspace parallel navigation processing and display to Alvin is a workhorse for science and routinely topside watch-standers and scientific observers. carries a large array of scientific sampling tooling, collection devices and deployable Lights, Cameras, Action – High Definition sensors. The science work space is located Imaging and Lighting at the front end of the submersible and Initially, the sub carried only a small number of includes the sample platform (basket) and stand-alone external film and video cameras. two hydraulic, seven-function manipulators Observers utilized in-hull handheld 35 mm (Figure 4). Before 2012, the science payload cameras as a principal source of dive images. was limited to approximately 90 kg and two Image quality, post-dive availability and long manipulators were mounted at fixed locations term stability were limited. with limited total effective range of motion.

Since then, Alvin’s complement and The new sub includes a redesigned work space type of camera equipment has evolved in with a modular fully configurable science tandem with advancements in photographic basket. Useful payload is doubled to 180 kg technologies. Imaging data (still and video) and manipulators are mounted on extended, is now a significantly important component rotational swing-arms that provide an of Alvin’s data product. The new vehicle additional degree of freedom. Manipulators can incorporates a professional grade in-hull now rotate 135° from the front of the vehicle to video system with a number of integrated the port and starboard sides of the . high quality external video and digital still cameras. It is fully configurable and Dedicated power channels (electric/ adaptable, and able to readily incorporate the hydraulic) and high speed data system newest camera technologies (4 K). interfaces (wired and fibre optic) are resident on the basket for use by science supplied The system uses six high definition video sampling equipment and cameras. cameras, two mounted on digitally controlled pan and tilt units, two with integrated pan In Case of Emergency – Thruster Releases and tilt mechanisms, one super wide-angle Alvin is designed to ensure that the pilot has fixed focus and one HD still/video camera. appropriate responses to the many potential Digital video and still images are recorded emergency situations. Redundant systems and on high density digital disk media. Multiple emergency procedures ensure the vehicle safely pilot and observer HD video monitors and returns to the surface. The original design camera controllers provide the ability to included a sphere-release mechanism to enable view and manage the external cameras and an emergency return to the surface, but during collected images. the upgrade WHOI engineers determined that installation of the new personnel sphere A specialized frame-grabber system collects required removal of the sphere release incremental snapshots of user selected video capability. To ensure the new vehicle retained sources to create a time-based sequential image an appropriate emergency response, WHOI

42 The Journal of Ocean Technology, Vol. 12, No. 1, 2017 Copyright Journal of Ocean Technology 2017 Figure 3: Alvin’s new position control system represents a significant improvement to the vehicle’s ability to support scientific operations. Alvin is now capable of performing very accurate sonar mapping and photo- mosaic missions, precision transects over long distances and stable position holding near bottom WHOI sampling sites.

Figure 4: Alvin is a workhorse for science and routinely carries a large array of scientific sampling tooling, collection devices and deployable sensors. The science work space is located at the front end of the submersible and includes the sample platform (basket) and two hydraulic, 7-function manipulators. Manipulators are mounted on extended, rotational swing-arms that provide an additional degree of freedom, and can now rotate 135° from the front of the vehicle to the WHOI port and starboard sides of the submarine. engineers designed specialized component system provides the capability to share dive data release mechanisms. Manipulators, science and digital still images with the surface observers. basket, main batteries and thrusters use an A dedicated science observation station on the electrical/mechanical release system that support ship displays vehicle navigational enables jettisoning of an assembly in the event information, still images and mission data and of an emergency. A releasable “rescue-” an acoustic SMS messaging channel allows with an ultra-high strength synthetic line text between the topside enables additional emergency support from and subsurface scientists. With proper cruise the surface ship. Multiple circuit redundancies planning, dive data transferred to the surface ensure emergency systems function in the ship can be made available for transfer to shore- event of a loss of vehicle power. side participants via telepresence.

The Sound of Data – Wireless Data Transmission The Future is Now – Taking the Sub to 6,500 Alvin engineers are currently implementing an Metres acoustic data transmission system to enable At present the WHOI team is finalizing design wireless data transfer to the surface ship. The work to complete certification for operations

Copyright Journal of Ocean Technology 2017 The Journal of Ocean Technology, Vol. 12, No. 1, 2017 43 to 6,500 metres. Final system integration and Observers return from a dive with a wealth of certification is scheduled for completion in human experience, enhanced by the high quality 2020. Operations to 6,500 metres will provide vehicle images and data. This combination is scientists with the opportunity to conduct unmatched by any unmanned system. research from shallow ocean depths into the and will greatly increase Alvin’s For over 51 years the manned deep access to Earth’s . submergence vehicle Alvin has ensured scientists have access to the deep sea. The A Continuing Legacy new enhanced Alvin will continue enabling Early deep ocean research utilized relatively important discoveries well into the future, primitive methods to collect data and proving that through the combination of the specimens with sampling performed by application of our intellect with advances in scientists on the surface ship. Trawl nets, technology, humans will remain as the most Nansen water samplers, dragged dredges extreme creatures on the seafloor. u and other crude mechanisms provided very limited capabilities to directly understand Bruce Strickrott is the Group seafloor environments. In time, Manager and senior pilot of the technological advances improved the ability to manned deep submergence vehicle Alvin, operated as a better survey the oceans. , magnetometers part of the US National Deep and other techniques allowed seafloor mapping Submergence Facility at the and helped to identify areas for focused Woods Hole Oceanographic research. But none of these advances enabled Institution. He has worked as a member of the Alvin Group human visitation of deep water environments. since 1996 and has over 330 dives as Pilot in Command. Alvin’s arrival in the 1960s forever changed He obtained an ocean engineering degree from Florida the nature of deep sea investigation. Atlantic University. While at college he worked as a scuba dive master aboard the University’s research the R/V Today, deep ocean research requires Oceaneer IV, working to support engineering diving projects. Mr. Strickrott spent six years in the US Navy working the use of innovative tools for effective on surface combatant as a electronics experimentation. Advances in unmanned technician including deployments during Operation Desert systems (ROVs, AUVs, gliders) provide a Shield/Desert Storm. When not working with Alvin, he lives new suite of capabilities for research, but on Cape Cod with his family and enjoys promoting exciting nothing will supplant the value of an actual careers in science, math and engineering to college and physical presence at a sampling site. Although high school students. advanced imaging technologies have greatly improved the value of remote viewing, these new technologies cannot equal the capability of human eyesight when employed for direct observation of the seafloor.

Presently, the use of new technologies and enhanced sensor and sampling capabilities ensures that Alvin remains an important tool for scientific research. Alvin’s inherent ability to collect large quantities of scientific data significantly adds to the overall value of a trip to the seafloor.

44 The Journal of Ocean Technology, Vol. 12, No. 1, 2017 Copyright Journal of Ocean Technology 2017