Preliminary Polar Sea Trials of Nereid-UI: A Remotely Operated Underwater Vehicle for Oceanographic Access Under Ice

• Main Authors: Whitcomb, Louis L., Jakuba, Michael, German, Christopher R., Bowen, Andrew, Yoerger, Dana, Kinsey, James, Mayer, Larry A., McFarland, Christopher, Suman, Stefano, Bailey, John, Judge, Christopher, Elliott, Stephen, Gomez-Ibanez, Daniel, Taylor, Christopher L., Machado, Casey, Howland, J., Kaiser, Carl L., Heintz, Matthew, Pontbriand, C., O'Hara, L., McDonald, G., Boetius, Antje
• Format: Text
• Language: unknown
• Published: University of New Hampshire Scholars' Repository 2014
• Subjects: Arctic; Arctic Ocean; Gakkel Ridge; Greenland; Ice Shelf
• Online Access: https://scholars.unh.edu/ccom/61

We report the development and deployment of a remotely-controlled underwater robotic vehicle capable of being teleoperated under ice under real-time human supervision. The Nereid Under-Ice (Nereid-UI or NUI) vehicle enables exploration and detailed examination of biological and physical environments including the ice-ocean interface in marginal ice zones, in the water column of ice-covered seas, at glacial ice-tongues, and ice-shelf margins, delivering realtime high definition video in addition to survey data from on board acoustic, optical, chemical, and biological sensors. The vehicle employs a novel lightweight fiber-optic tether that will enable it to be deployed from a ship to attain standoff distances of up to 20 km from an ice-edge boundary. We conducted NUI’s first under-ice deployments during the July 2014 F/V Polarstern PS86 expedition at 86° N 6 W° in the Arctic Ocean - near the Aurora hydrothermal vent site on the Gakkel Ridge approximately 200 km NE of Greenland. We conducted 4 dives to evaluate and develop NUI’s overall functioning and its individual engineered subsystems. On each dive, dead-reckoning (Ice-locked Doppler sonar and north-seeking gyrocompass) complemented by acoustic ranging provided navigation, supporting closed-loop control of heading, depth, and XY position relative to the ice. Science operations included multibeam transects of under-ice topography, precision vertical profiles for the bio-sensor suite and IR/radiance sensor suite, IR/radiance/multibeam transects at constant depth interlaced with vertical profiles and upward-looking digital still-camera surveys of the ice, including areas rich with algal material. The fiber-optic tether remained intact throughout most of all 4 dives. Consistent with the NUI concept of operations, in 3 of 4 dives the fiber-optic tether eventually failed, and the vehicle was then commanded acoustically in a series of short-duration maneuvers to return to Polarstern for recovery. These preliminary dives ranging up to 800 m from Polarstern at a max. ...