The Institute - March 2022 - 62

cameras used thallium iodide lights
to illuminate the seafloor-which,
he says, emitted a green light rather
than white light. The former travels
through water better and allowed for
brighter photos.
Top: Scientists
use Alvin's
robotic arms to
collect samples
of sediment and
marine life.
Bottom: The
vessel in Eel
Pond in Woods
Hole, Mass.
Washington, D.C., the U.S. Office of
Naval Research made a presentation
about one of the submersibles: Trieste.
After the conference, the research
office sent a delegation, including
Vine, to Italy to see the 18-meter-long,
45-tonne vehicle.
The U.S. Navy purchased Trieste
in 1958 to conduct research. When
in 1960 it made an expedition to
Challenger Deep, the nethermost
point of the Mariana Trench, it was
the first time a manned or unmanned
vessel reached the deepest known
point of Earth's oceans. But Trieste
proved " too large and cumbersome
for routine operations throughout the
oceans, " according to a 2014 Eos article.
Vine and his research team, the
WHOI Deep Submergence Group, in
collaboration with the research office,
requested bids to build a smaller and
more maneuverable submersible.
General Mills, in Minneapolis, secured
the contract with a bid of US $498,500,
according to the Eos article.
Revolutionary engineering
Alvin, which was named after Vine, was
designed by General Mills engineer
Harold " Bud " Froelich. The vessel's
frame was built using syntactic foam,
which was buoyant and strong enough
to withstand extreme pressure. Alvin
MARCH 2022
weighed 15 tonnes and was about
7 meters long, according to WHOI. The
vessel was completed in 1964.
Propulsion equipment was housed
in the back of the vehicle along with
three lead-acid batteries and five
buoyancy spheres, which controlled
its vertical movement. Electrical and
fiber-optic connectors and cables were
encapsulated in oil-filled hoses and
boxes, making them waterproof. To
help Alvin withstand the high pressure,
the back was open so that seawater
could flow around the equipment.
The researchers and pilot sat in a
sphere at the front of the submersible.
The steel sphere, which was about
2 meters in diameter and had three
plexiglass windows, housed lifesupport
systems. In an emergency, the
sphere could detach and float to the
surface. Alvin also had landing skids so
that it could sit on the ocean floor.
Equipment in the sphere
controlled the submersible as well
as two robotic arms and cameras
that were mounted on the front. The
arms could be fitted with probes and
tools to take samples of sediment
and marine life. A specially designed
insulated box ensured that collected
samples weren't ruined by changes
in water temperature or pressure,
according to Foster. Alvin's still
Amazing achievements
Alvin's first major scientific discovery
happened by accident in 1968,
when the submersible sank about
1,500 meters to the bottom of the
ocean. A cable snapped while the
vehicle was being lifted out of the
surface ship that had carried it 217 km
off the Massachusetts coast to look for
whales. The crew escaped unharmed,
but the items they brought for lunch
sank with the ship.
When Alvin was recovered a year
later, the food-which included
soup, bologna sandwiches, and apple
slices-was " essentially intact, "
according to the Milestone's entry
on the Engineering and Technology
History Wiki. Researchers investigated
why the items didn't decay as
they would have on the surface.
They discovered that the pressure
suppressed the growth of the surface
bacteria that was in the food.
Another important discovery-
hydrothermal vents-was made on
a research trip led by oceanographer
Jack Corliss in the Galapagos Rift,
located in the South Pacific.
" Hydrothermal vents spew
poisonous superheated gas and metalladen
water, and yet scientists saw
creatures such as giant tube worms,
clams, and mussels thriving in the
environment, " says a 2020 Medium
article about Alvin.
Corliss saw that the ecosystem
was isolated from sunlight and soon
after, according to the 2020 article,
theorized that life might have first
emerged around such vents.
" Corliss believed that hydrothermal
vents contained all the conditions
necessary for the origin of life on
Earth, " the Medium article states.
During the past six decades, Alvin's
equipment has been upgraded many
times. It now includes an acoustic
navigation system, high-resolution
digital cameras, a video system, and
syntactic foam modules.
WOODS HOLE OCEANOGRAPHIC INSTITUTION,_1964-1965,_1964-1965,_1964-1965

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