Launching ABE

ABE, the Autonomous Benthic Explorer, is an autonomous underwater vehicle that is used by scientists to survey the seafloor. ABE excels at tasks that require precise navigation, including bathymetric surveys, water column mapping, and photo mosiacking. Because it does not have a tether, ABE operates independently of the ship. ABE uses sonar transponders to navigate above the seafloor, much like the submersible Alvin and the remotely operated vehicle Jason.

Before ABE is deployed, a program of the assigned survey path is loaded into its memory. ABE collects data along the trackline or survey path, and these data are downloaded at the end of the mission after the vehicle is recovered. For this cruise, ABE will be collecting very accurate and precise bathymetric data to make high-resolution maps of the field and adjacent terrane. Because hydrothermal fluids emitted at vent sites like Lost City leave a chemical and thermal “signature” in the ocean, ABE will also collect information about the chemistries and temperatures of the fluids while surveying. These emitted fluids form plumes, or bodies of water with anomalous properties compared to those of the background ocean, and therefore they can serve as guides to finding to new fields. Think of cooling towers on energy plants that emit plumes of steam on a cool morning—the hydrothermal plumes are similar in nature. ABE is also equipped with two cameras that are capable of taking stereo images of the seafloor.

Mapping the Seafloor

ABE was developed by engineers at WHOI in 1993 and had its first successful dives in 1995 at the Juan de Fuca Ridge in the Pacific Ocean. Since then, it has been used in many different survey situations. ABE weighs about 1500 lbs and can operate at depths up to 6000 m. The vehicle’s average speed is around 65 cm/sec, and it can travel over 10 km at that speed. Because it has seven thrusters, ABE can move in any direction and also has the ability to hover in place. On this cruise, ABE will operate mostly during the night to complement the Alvin operations, which occur during the day. ABE also looks a lot like the Starship Enterprise, but this is supposedly just a coincidence.