pings and confirm they're real, they're going to keep looking until they're confident things are stop being sent. we're well past the 30-day design limit of the pingers. we might expect to see an extra five, six days, but they are pretty much dead now. so it doesn't mean that if they rely on the ping data, we're not looking at 15,000 miles. we're probably looking at an area about the size of the city of washington. so it's come down a lot more. that becomes feasible. if you're sending one of these aevs down, they're moving very slowly, about 4 miles an hour. they're surveying a very small area. these only may be 50 meters, 100 meters. that will take a long time. so this is why they put so much effort on the pinger first. otherwise, it's just a random deployment. >> so mary, the follow-up to that statement i'm going to bring to you. if over the next 24 hour, 48