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Del Rio, TX, United States

Sahl J.W.,Colorado School of Mines | Fairfield N.,Carnegie Mellon University | Harris J.K.,University of Colorado at Denver | Wettergreen D.,Carnegie Mellon University | And 2 more authors.

The deep phreatic thermal explorer (DEPTHX) is an autonomous underwater vehicle designed to navigate an unexplored environment, generate high-resolution three-dimensional (3-D) maps, collect biological samples based on an autonomous sampling decision, and return to its origin. In the spring of 2007, DEPTHX was deployed in Zacatón, a deep (∼318 m), limestone, phreatic sinkhole (cenote) in northeastern Mexico. As DEPTHX descended, it generated a 3-D map based on the processing of range data from 54 onboard sonars. The vehicle collected water column samples and wall biomat samples throughout the depth profile of the cenote. Post-expedition sample analysis via comparative analysis of 16S rRNA gene sequences revealed a wealth of microbial diversity. Traditional Sanger gene sequencing combined with a barcoded-amplicon pyrosequencing approach revealed novel, phylum-level lineages from the domains Bacteria and Archaea; in addition, several novel subphylum lineages were also identified. Overall, DEPTHX successfully navigated and mapped Zacatón, and collected biological samples based on an autonomous decision, which revealed novel microbial diversity in a previously unexplored environment. © Mary Ann Liebert, Inc. 2010. Source

Gulati S.,Stone Aerospace | Gulati S.,University of Texas at Austin | Richmond K.,Stone Aerospace | Flesher C.,Stone Aerospace | And 6 more authors.
Proceedings - IEEE International Conference on Robotics and Automation

Chemical properties of lake water can provide valuable insight into its ecology. Lakes that are permanently frozen over with ice are generally inaccessible to comprehensive exploration by humans. This paper describes the integration of several novel and existing technologies into an autonomous underwater robot, ENDURANCE, that was successfully used for gathering scientific data in West Lake Bonney in Taylor Valley, Antarctica, in December 2008. This paper focuses on three novel technological and algorithmic solutions. First, a robust position estimation system that uses an acoustic beacon to complement traditional dead-reckoning is described. Second, a novel vision-based docking algorithm for locating and ascending a vertical shaft by tracking a blinking light source is presented. Third, a novel profiling system for measuring water properties while causing minimal water disturbance is described. Finally, experimental results from the scientific missions in 2008 in West Lake Bonney are presented. ©2010 IEEE. Source

Febretti A.,University of Illinois at Chicago | Richmond K.,Stone Aerospace | Gulati S.,Stone Aerospace | Flesher C.,Stone Aerospace | And 5 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

We evaluate the use of Poisson reconstruction to generate a 3D bathymetric model of West Lake Bonney, Antarctica. The source sonar dataset has been collected by the ENDURANCE autonomous vehicle in the course of two Antarctic summer missions. The reconstruction workflow involved processing 200 million datapoints to generate a high resolution model of the lake bottom, Narrows region and underwater glacier face. A novel and flexible toolset has been developed to automate the processing of the Bonney data. © 2012 Springer-Verlag. Source

Stone W.,Stone Aerospace | Hogan B.,Stone Aerospace | Flesher C.,Stone Aerospace | Gulati S.,Stone Aerospace | And 8 more authors.
Proceedings of the Institution of Mechanical Engineers Part M: Journal of Engineering for the Maritime Environment

This paper describes the 2008 and 2009 Antarctic deployments of the National Aeronautics and Space Administration ENDURANCE autonomous underwater vehicle (AUV). The goal of this project was to conduct three autonomous tasks beneath the ice cap 4m thick of West Lake Bonney: first, to measure the three-dimensional (3D) water chemistry of the lake at prespecified coordinates; second, to map the underwater face of the Taylor Glacier; third, to chart the bathymetry of the lake bottom. At the end of each mission the AUV had to locate and return through a hole in the ice slightly larger than the outer diameter of the vehicle. During two 10-week deployments to Antarctica, in the austral summers of 2008 and 2009, ENDURANCE logged 243h of sub-ice operational time, conducted 275 aqueous chemistry sonde casts, completed a 3D bathymetry survey over an area of 1.06 km2 at a resolution of 22cm, and traversed 74 km beneath the ice cap of West Lake Bonney. Many of the characteristics and capabilities of ENDURANCE are similar to the behaviours that will be needed for sub-ice autonomous probes to Europa, Enceladus, and other outer-planet icy moons. These characteristics are also of great utility for terrestrial operations in which there is a need for an underwater vehicle to manoeuvre precisely to desired positions in 3D space or to manoeuvre and explore complicated 3D environments. © Authors 2010. Source

Stone W.C.,Stone Aerospace | Hogan B.,Stone Aerospace | Siegel V.,Stone Aerospace | Lelievre S.,Stone Aerospace | Flesher C.,Stone Aerospace
Annals of Glaciology

VALKYRIE (Very-deep Autonomous Laser-powered Kilowatt-class Yo-yoing Robotic Ice Explorer) is a NASA-funded project to develop key technologies for an autonomous ice penetrator, or cryobot, capable of delivering science payloads through outer planet ice caps and terrestrial glaciers. This 4 year effort will produce a cylindrical cryobot prototype 280cm in length and 25cm in diameter. One novel element of VALKYRIE's design is the use of a high-energy laser as the primary power source. 1070nm laser light is transmitted at 5kW from a surface-based laser and injected into a customdesigned optical waveguide that is spooled out from the descending cryobot. Light exits the downstream end of the fiber, travels through diverging optics, and strikes an anodized aluminum beam dump, which channels thermal power to hot-water jets that melt the descent hole. Some beam energy is converted to electricity via photovoltaic cells, for running on-board electronics and jet pumps. Since the vehicle can be sterilized prior to deployment, and forward contamination is minimized as the melt path refreezes behind the cryobot, expansions on VALKYRIE concepts may enable cleaner access to deep subglacial lakes. This paper focuses on laser delivery and beam dump thermal design. Source

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