just said you're not intimidate bid the depths. but then you said i think on other side of australia that they're working twice the depths of this one. >> sure. >> why aren't they doing that here? >> one is a scientific mission. it's called -- a brand new initiative called project hadal which means really the ocean. and we've got a new type of robot called nerius that can go down to the greatest ocean depths, even the same depths that james cameron dove to. but that's a scientific mission where everything has been planned out for years. this one on this side is much different. we're after a specific target, finding bits of an aircraft and retrieving two black boxes. so the only difference really in my mind is one side is driven by scientific question. this side driven by aircraft investigators. >> fabian, all four signals detected within 17 miles.