ROPOS may look like an upended refrigerator, but what it lacks in form it
more than makes up for in function. The Remotely Operated Platform for
Ocean Science has more gadgets than you can shake a five-function arm at
(which is one of those gadgets, by the way). Take a closer look at this
deep-sea robot, one of only four in the world that can dive to depths of
more than 10,000 feet. (Just don't get too close to that five-function
arm. According to a ROPOS technician, "its jaw could take your arm off.")
ROPOS is powered by pressurized hydraulic fluid. Two vertical hydraulic
thrusters lie in here. There are also two lateral and two fore-aft
thrusters. All told, ROPOS has 30 horses under the hood when in deep mode,
which currently allows dives to about 10,000 feet but that will soon
increase to almost 17,000 feet. (In shallow-water, "liveboat" mode—that
is, in less than 1,200 feet of water and tethered directly to the ship—ROPOS is a 40-horsepower machine.)
The foam filling this pack aids buoyancy and is so dense that it cannot be
made any denser by the enormous pressure at 10,000 feet. It might be foam,
but it ain't light: when in "liveboat" mode, ROPOS tips the scales at 3,600
pounds, while in deep mode (shown here), which features nothing more than a
fatter foam pack, it weighs in at a full 6,000 pounds. (back to diagram)
Unlike most equipment on ROPOS, which adjusts to the pressure at depth,
this titanium cylinder maintains one atmosphere of pressure—the same as
at the surface. It houses the delicate telemetry system, which guides the
robot based on instructions coming down through the tether from the
joystick-wielding pilot high above. On the other side of ROPOS is a
separate science telemetry system.
The 1,000-foot-long tether connects ROPOS to the cage, which has its own
11,800-foot electrical-optical cable to the surface. All data, from
directional commands sent down from the pilot sitting in the mother ship to
live imagery beamed up from ROPOS, travel through this thin umbilical.
This flow-injection device samples hydrothermal vent water and analyzes it
for dissolved minerals such as sulfur, lead, gold, and silver. (back to diagram)
Whenever a piece of equipment is added to or removed from ROPOS, these lead
weights are removed or added to compensate. Fine-tuning the vehicle's trim,
which is kept slightly positive, is vital to ensuring the highest
The five functions are shoulder up/down, elbow, yaw, wrist rotate, and jaw
open/close. There is also a seven-function arm (not visible in this
picture), with, in addition to those above, wrist up/down and wrist yaw.
Both arms can lift 600 pounds at full extension.
Beneath the five-function arm is a hydraulically activated "biobox."
Measuring roughly 30 inches long by a foot wide and high, it can be thrust
out, its lid open and shut, and then pulled back in. (back to diagram)
Resembling the video-game snapper, this is the jaw that could bite your arm
off (see above). It's used to collect samples of known volume from the
seabed. Not visible in this photo, ROPOS also has a rotating sample tray
with four sub-dividable compartments, and a variable-speed, reversible
suction sampler that can pump a respectable 78 gallons a minute.
This cylindrical trap, known to many a fisherman, is simply set down on the
bottom and picked up later. ("We've caught octopus, crab, seems like
everything but fish," a ROPOS technician admitted.)
This is ROPOS' main camera. It's a Sony DXC-950 broadcast-quality color
NTSC camera with 16x zoom. Out of sight in this photograph is the SIT, a
very-wide-angle, very-low-light camera. ROPOS' cage also has its own
camera. (back to diagram)
These are 250-watt arc lights, which are brighter and closer to daylight
than the 250-watt incandescent light (seen just in front of the arc light
that is to the right in the picture). Together, the lights illuminate the
ocean floor out to between 50 and 75 feet ahead.
This is the strobe light for the main camera.
This scanning, color-imaging sonar, modified with a lower frequency and
narrow-beam head for enhanced long-range response, allows ROPOS to "see"
perhaps 350 feet ahead. Such long-range vision is invaluable in navigating
through the highly variable terrain of a spreading center, where the black
smoker chimneys may be found.
This relay transponder "pings" continuously. Its signals are bounced off an
acoustic net of transponders placed nearby on the seafloor. The time lag of
each return determines where on the bottom ROPOS is at any given time. The
tracking is integrated with differential GPS, the ship's heading, and wind
speed and direction. All told, this navigation system enables ROPOS pilots
to know where their charge is to within 20 feet. (back to diagram)