Hadal landers: the DEEPSEA CHALLENGE ocean trench free vehicles

Unmanned free vehicles, using kerosene-filled envelopes for lift, have been used since the late 1930's to deliver scientific instruments and samplers to the seafloor. Recent advances in glass spherical housings have provided a cost-effective option for operations into ocean trenches. During his 2012 DEEPSEA CHALLENGER Expedition, Explorer James Cameron pushed the design limits with both manned submersible and unmanned lander designs. This paper describes the unmanned lander design and operational experiences during that successful expedition.