January 9, 2008

Dear Cruise,

I think that making robots "talk" underwater must be a fascinating experience but also a challenging one. Isn't working on the boat hard? What is the hardest part of working on the boat and making the robots "talk"? Thanks for taking the time to answer my questions.

Leah M.
Lexington, MA

Dear Leah:

The most important part of working on a boat is to come prepared with everything that you might need. We cannot run down to the local hardware store if we have forgotten anything, so there is a lot of preparation before a cruise to make sure we are ready for anything that might happen. Of course, bad weather and waves that make the ship rock can also make it hard to work on a boat as everything slides around unless it is tied down – and that goes for computers and cameras, too! Fortunately, on this cruise, we are near the equator, so we have had good weather so far.

The hardest part of making the robots “talk” to the ship is that the ocean and the ship are noisy places (see the new Hot Topic on “The Scoop on Sound”) so we might not be able to hear the robots above the other noises. In addition, the speed of sound in seawater is much faster than in air, but the distances are large, so any communication with our robots is slow. Imagine the AUV is at a water depth of 4500 meters, and you send it a signal. With the speed of sound in water of 1500 meters/sec, it will take 3 seconds to get to the vehicle – and a reply will take the same amount of time.

Thanks for the question, Leah!

Susan Humphris

Dear Scientists,

My name is Connor Green and I am in Ms. Shield’s 7th grade class in Lexington, Massachusetts. I was wondering what kind of materials you used to build the inside of the Puma and Jaguar's brains and how you built the connection? Do the robots actually talk or send descriptions to the command center? To help pay for your expedition, do you have people that fund your research?

Thanks for taking the time to read these questions I have. Hope you find lots of new things.

Connor

Dear Connor:
Thank you for sending in some questions! The “brains” of Puma and Jaguar are embedded computers. You can think of them as being similar to a laptop computer but in a smaller package. 

How we build the connections is an interesting question. Graduate student Clay Kunz tells me that the most difficult ones are the connections that have to go through the waterproof housing from the computer “brains” to sensors on the AUVs that get wet. For this, engineers use “big, fat, rubber plugs” (in Clay’s words) that are designed to be watertight so that seawater cannot get into the electronics housing.

The robots don’t actually talk—they send data packages to the ship that are coded in such a way that we can understand what the message means.

In terms of how we pay for the expedition, a group of scientists and engineers wrote a proposal to the National Science Foundation to do this work, and we were lucky enough to get funded.

Hope you will continue to Dive and Discover!

Susan Humphris

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