Explore the Deep Sea

Tools & Techniques


Jason is a two-part remotely operated submersible vehicle (ROV) system that can dive to 6500 m (4 miles) below the ocean surface.


Jason II/Medea being launched overboard. Image courtesy of B. Nichols.

Jason is used to collect photographs, seawater, living organisms and other samples from the seafloor. The seafloor is often more than 2.5km (1.5 miles) below the ship. So even descending at a rate of 30m per minute, it can take Jason more than an hour and a half to reach the bottom.

Maneuverable and versatile

Jason's two main parts, Jason II and Medea, are linked by a 35 m (120 ft) tether. From Medea, a cable runs all the way up to a winch on the ship, often many kilometers above. Thus, Jason II is only attached to the ship via Medea, and is not directly affected by the motion of the ship. It has six electric thrusters which can propel it up, down and sideways. This design means that Jason II is very maneuverable and stable.

Jason being launched. Image courtesy of L. Podowski

The Jason II / Medea system is controlled in real time by researchers in a control room on the ship's deck. In this dark space, lit by computer screens and video monitors, the pilot, navigator and engineer direct Jason II while researchers log data, capture interesting pictures and recommend what samples to collect. Instructions and power pass down the cable, and photographs and other data are sent back up it.


Jason II can take high-resolution photographs using seven high-quality cameras and associated lights. Cameras mounted on the bottom and front of Jason II can take a series of digital images that can be merged to form a large, composite, mosaic picture of the seafloor. Medea has a camera too, a black and white one, which is used to keep tabs on Jason.

Animals, microbes and seafloor

Biologist Stacy Kim opens a biobox that Jason has brought up from the seafloor. Image courtesy of B. Nichols

Jason's two collecting arms can grab or scoop up samples from the seafloor, and place them in collecting boxes and baskets. Jason usually carries at least four “bioboxes” (left) to carry rocks and larger animals to the surface — containers a bit like picnic coolers that Jason's arms can open and bungee shut.

Jason often uses a metallic-handled net to scoop up snails and other large, slow-moving animals, but some creatures are too small, too fast or too delicate to be easily captured with a net. Instead, Jason uses a “slurp pump”, to suck them into a water-filled container. The slurp pump can be used to suck up mud, sand and soft microbial mats, as well as fast-moving animals such as shrimp, crabs and squat lobsters.

Water samples

Closeup of one of Jason's multi-hinged arms. Image courtesy of B. Nichols

Jason can be equipped to take water samples and to measure the seawater's temperature, conductivity and depth.

Its arms (left) can grab a long, rugged thermometer and stick it into holes, against chimneys, in mussel beds and anywhere else the researchers want to know the temperature. The numbers are shown on a laptop computer in the control room, anywhere from 2 degrees Celsius (most of the deep ocean) to more than 350 (at active vents).

Water samples can be collected in a variety of ways:


Jason has a portable multibeam sonar system mounted on it (the SM2000). By flying 100m or so above the seafloor, it can create highly detailed relief maps. The closer to the bottom Jason flies, the more detailed the map.

Many hands make Jason work

Work goes on around the clock at sea, so Jason's shipboard team consists of three pilots, three navigators, three engineers and two data processors.

It's not unusual for Jason to be launched or recovered in the middle of the night, or in the early hours of the morning.

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