Research Vehicle Reaches the Bottom of the Ocean 165
timothy found BBC coverage of the voyage of the Nereus, which on May 31 dove to the bottom of the Challenger Deep in the Marianas Trench. Only two vehicles have accomplished this feat before, the last 11 years ago. "The unmanned vehicle is remotely operated by pilots aboard a surface ship via a lightweight tether. Its thin, fibre-optic tether to the research vessel Kilo Moana allows the submersible to make deep dives and be highly manoeuvrable. Nereus can also be switched into a free-swimming, autonomous vehicle. ... The Challenger Deep... is the deepest abyss on Earth at 11,000m-deep, more than 2km (1.2 miles) deeper than Mount Everest is high. At that depth, pressures reach 1,100 times those at the surface."
Nice, but what does it do? (Score:3, Insightful)
It may give us access to 100% of the sea floor, but given the expense of sea exploration, how much will we actually explore? Setting records is nice and all, but it takes time, effort, and money to map the deep sea floor in any kind of detail.
It should be able to take samples and such, but what about repeat dives? The artile was a bit lacking, but hopefully google will turn up the juicy details on this particular little bot....
Twists in the fiber optic cable (Score:5, Insightful)
I worked on an ROV simulation back in the 90's and we needed to keep track of how many times the ROV turned around because twists accumulate in the cable. At some point you may have to sit in place and spin for a bit to undo the twists. Terrible things happen when the tether gets too twisted.
Re:Twists in the fiber optic cable (Score:3, Insightful)
My uneducated guess is that the cable is so long that you'd wind up with (for example) a CW twist near the top of the cable and a CCW twist near the bottom of the cable - twists at the top wouldn't propagate all the way down.