Nature:
In 1964 the US Navy commissioned the
DSV
Alvin, a small, manned research submarine. Since its
launch,
Alvin has been responsible for several major
discoveries such as ecosystems powered by hydrothermal vents
instead of sunlight. In 2011, after making observations of the
Deepwater
Horizon oil spill, the vessel began a $41 million retrofit
that has just been completed. On 25 May,
Alvin will leave
Woods Hole Oceanographic
Institution in Massachusetts for a series of certification
cruises off the coast of Oregon. Its upgrades include a larger
sphere with extra windows and cameras for human occupants,
longer manipulator arms, and a larger sample collection
container. The new titanium sphere is capable of reaching
depths of 6500 m, but the craft will still be limited to its
previous maximum depth of 4500 m because its lead-acid
batteries are not suitable for the lower mark. Susan Humphries,
who was in charge of the retrofit, hopes that lithium-ion
batteries will soon be safe enough to be added during regular
maintenance in the next 5 years.
