US Navy finally starts replacing killer dolphins with mine-hunting Knifefish drones

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http://www.extremetech.com/extreme/140679-us-navy-finally-starts-replacing-killer-dolphins-with-mine-hunting-knifefish-drones




US Navy finally starts replacing killer dolphins with mine-hunting Knifefish drones
By John Hewitt on November 21, 2012 at 12:58 pm

The military use of sea mammals reached its height during the Cold War. It is a story filled with fascination and intrigue, including trained killer dolphins — and even counter-killer-dolphin dolphins. Our enlightened times now herald greater thoughtfulness towards our fellow sapients. New undersea robots like the US Navy’s Knifefish, together with a heavy dose of fiscal reality, have begun to close this chapter of military history.

Roughly 17 million barrels of oil pass through the Straight of Hormuz between Oman and Iran each day. When Iran threatened to close it down earlier this year, Pentagon officials determined that the estimated arsenal of 2,000 undersea mines could be cleared in about a week. In this case, a German-made drone known as the Seafox would be tasked for the job. The 4-foot (1.2m), 100-pound (45kg) Seafox is semiautonomous but relies upon a fiber optic tether for communications. It “diffuses” mines after identifying them by triggering an explosive self-destruct sequence that effectively ends its own tour of duty. At $100,000 a pop, other solutions to keep the routes of commerce safe and open are needed.

The Navy has now set its sights on the Knifefish, named for the freshwater fish that images objects using electric fields. At 19 feet (5.8m) and 1700 pounds (770kg), the torpedo-shaped drone is much larger than the Seafox and will greatly extend its capabilities. It is powered by lithium-ion batteries and can remain active for up to 16 hours, giving it a much longer range. It also uses a low-frequency synthetic aperture sonar that can penetrate beneath a soft sea floor. The Knifefish will be able to tell actual mines from other submerged debris with better accuracy. Mines will be able to be fingerprinted in real time by using resonance patterns obtained during imaging and comparing them to known signatures. Eight units will be jointly built by General Dynamics and Bluefin Robotics, at a total cost of $20 million. Naval divers will still carry out many mine clearing operations themselves, but drones will reduce dive frequency and associated risk.

The deployment of Knifefish, and their larger intended successors, raises a few strategical issues and hints to the need for greater cooperative efforts between nations. Not yet able to destroy mines directly, the Knifefish will initially map and image mines, and send the data elsewhere. Tankers or cruise ships that can afford extra assurance, or insurance as the case may be, might use a Knifefish-like shepherd when navigating critical waterways. At some point however, with many vessels sweeping and reporting the same threat concerns, someone has to take responsibility to go and eliminate them. The question of whose job this becomes is reflective of a similar drama soon to be played out in space with the looming problem of orbital debris.