Autosub6000: results of its engineering trials and first science missions

In September 2007 on RRS Discovery, the Autosub6000 Autonomous Underwater Vehicle (AUV) completed its first deep water engineering trials, and less than a year later, fitted with a multibeam bathymetric mapping sonar, carried out its first science missions, as part of a geology and geophysics science cruise onboard the RRS James Cook to investigate potential geo-hazards (such as tsunami generating landslides) on the European and North African margin. In the spirit of true AUV autonomy, while the AUV was deployed, we used the ship for seabed coring operations, and once the AUV was recovered, the high resolution bathymetry which it had obtained guided the next coring operations. In this paper we will describe how we are tackling the issues that specifically affect a deep diving AUV capable of operating with true autonomy, and independently of the mother ship: How to carry enough energy for long endurance and range? How to operate safely and efficiently with varying buoyancy? How to maintain accurate navigation throughout missions lasting up to several days?