Autonomous Research Bots Go for a Swim

Marine and ocean scientists put underwater machines to the test. Here's how two bots—one from NASA and one from NOAA—compare.




SOLO-TREC relies on an engine that uses phase-change materials, waxy substances that expand and contract when exposed to different temperatures. This expansion and contraction pressurizes oil stored inside the engine, which in turn generates electricity to recharge the batteries on-board.

Despite this advantage, SOLO-TREC's low overall charge limits its range of motion and its capacity to power a wider variety of research tools. SOLO-TREC is currently only used for passive chemical and temperature testing. Other AUVs, such as Fetch1, developed by marine scientist Mark Patterson at the Virginia Institute of Marine Science, can power propellers and more advanced sensors, such as advanced imaging and video devices.

With their various research capabilities, AUVs have grown in popularity among scientists. "They can be programmed to do dull, dirty and dangerous [work]—anything humans don't want to do themselves," says Patterson, who recently led Fetch1 on an expedition for the National Oceanic and Atmospheric Administration to investigate sediment build-up off the shore of the Caribbean island of Bonaire.

Depending on the tools aboard the vessel, AUVs seem to have the three Ds covered. The bots can take readings of ocean temperature and chemistry, monitor behavioral patterns of marine life and make seismic readings to locate oil and gas deposits; they are also used by the Navy for surveillance and intelligence-gathering to improve homeland security.

As scientists develop new technologies, their AUVs can specialize in different tasks. Here are the specs on two well-known AUV models.


Length: 6.5 feet

Weight: 183 pounds

Maximum depth: 1640 feet

Power source: Rechargeable batteries, charged inside the vessel via thermal recharging engine

Battery life: 8 hours per charge

Range of motion: Moves vertically in the water; no propeller for horizontal movement

Features: GPS, satellite 2-way communication, CTD (Conductivity, Temperature, Depth) sensor

Applications: measures water quality (pH, dissolved oxygen, chlorophyll) and temperature


Length: 6.5 feet

Weight: 220 pounds

Maximum diving depth: 500 feet

Power source: Rechargeable batteries, charged on boat or docking station

Battery life: 18 hours per charge (at 3 knots)

Range of motion: Can move vertically; propeller enables forward motion

Features: GPS, Wi-Fi, microwave RF modem, CTD sensor, altimeter, side scan sonar, video camera

Applications: Capture video of ocean floor, 2D imaging of animals and plants, measures water quality and temperature

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