Underground Texas Grotto meeting March 4, 2009 www.utgrotto.org The meeting is on Wednesday from 7:45 P.M. - 9:00 P.M. on the University of Texas Campus in 2.48 Painter Hall http://www.utexas.edu/maps/main/buildings/pai.html
The Presentation will be a subterranean journey by Victoria Siegel and Bill Stone www.stoneaerospace.com Sub-Ice Exploration of West Lake Bonney: ENDURANCE 2008 Mission Bill Stone Stone Aerospace, Austin, TX ENDURANCE (Environmentally Non-Disturbing Under-ice Robotic Antarctic Explorer) is a highly maneuverable, hovering autonomous underwater science platform descended from the DEPTHX vehicle, both of which were developed under NASA ASTEP funding. ENDURANCE had the specific mission of descending through a 3 to 5 meter deep melt hole in the ice cap of West Lake Bonney, Taylor Valley, Antarctica and conducting three autonomous science tasks: 1) measuring the 3D water chemistry of the lake; 2) mapping the underwater face of Taylor glacier where it enters the lake; and 3) charting the bathymetry of the lake bottom; and then 4) returning safely on its own to the melt hole – barely 0.25 m larger in diameter than the vehicle – from more than 700 m radial range and rising up the hole to be retrieved for data download and servicing for the next mission. Many features of ENDURANCE represented radical changes and improvements over its highly successful predecessor craft. Included among these was the development of an automated sub-sea servo winch and sonde payload with its nine water chemistry probes, high def imaging system, and bottom ranging altimeter. A specialized ice-picking behavior was developed to maximize cast initial proximity to the underside of the ice sheet and to reduce power consumption during casts. The navigation system was comprised of a three layer Kalman filter utilizing high grade dead reckoning, ultrashort baseline localization, and machine vision. Also new were web-based glacier imaging systems and a 120-degree swath high resolution multi-beam mapping sonar system – used for both lake bottom and glacier face mapping. All of these systems, following several days of initial shakedown in the – 4C water, worked flawlessly for the duration of the expedition, producing nearly 80 sonde casts spread over 80% of the lake area (2.5 km length x 1.25 km width x 40 m depth); greater than 100 million 3D sonar hits across the Taylor glacier; and more than 400 million bathymetric 3D hits on the lake bottom. The vehicle successfully demonstrated autonomous melt hole location, position lock and auto recovery on a routine, daily basis. A custom magnetic beacon tracking system was developed that allowed for real-time surface position fixes to be established on the vehicle – a powerful new feature that allowed us to precisely geo-reference all water chemistry samples. Many of the characteristics and capabilities of ENDURANCE – now successfully demonstrated for the first time in real under-ice complex settings beneath West Lake Bonney -- are the types of behaviors that will be needed for sub-ice autonomous probes to Europa, Enceladas, and other outer planet watery moons. Team ENDURANCE: UIC, Stone Aerospace, NASA, NSF OPP, University of Montana For information on Underground Texas Grotto activites, please see the website www.utgrotto.org All of our information is available through our link including officer contact info. Check it out and surf around for information on trips reports, new caver training, calendar, and link to get included on mass postings for either beginner trips or vertical rope training. We are busy with all kinds of activities that we discuss after each of our meetings as well. Come out and hang out with us for burgers, beer, and tall tales at the after meeting at Posse East. Posse East 2900 Duval Rd Austin Texas www.posseeast.com The UT Grotto is always looking for someone like you that has cool photos and a story to share about your caving adventures. Contact Gary to get your place in the spotlight. v...@utgrotto.org --------------------------------------------------------------------- Visit our website: http://texascavers.com To unsubscribe, e-mail: texascavers-unsubscr...@texascavers.com For additional commands, e-mail: texascavers-h...@texascavers.com
