Deep-ocean diving robot Nereus is gone and won't be replaced.
Last year, the Nereus, which is the only robot capable of diving into and exploring the deepest ocean trenches, was lost at sea while exploring the Kermadec Trench at 10,000 meters during a May 2014 research cruise. Now its creators from The Woods Hole Oceanographic Institution (WHOI) have announced that it will not be replaced. Instead of that, they will spread the insurance money for Nereus across multiple, lower-risk projects.
Nereus, a hybrid ROV operates in two complementary modes. It was unique because it could move and explore hadal zones freely. When Nereus locates something interesting, the vehicle's support team can bring the vehicle back on board the ship and transforms it into a remotely operated vehicle (ROV) tethered to the ship via a micro-thin, fiber-optic cable, while the other robots are designed to sink to the bottom to collect data until they're retrieved.
While we'll have to say goodbye to the Nereus, there are some other organizations currently developing vehicles that will be able bring us otherworldly footage straight from the deepest trenches of the ocean. One of them is The Schmidt Ocean Institute, which is planning to build a series of submarines that could lead to one capable of diving as deep as the Nereus could by 2019.