Sea Gliders for Other Worlds

An anonymous submitter writes: "NASA has, for the moment, killed funding for research leading to an underwater probe for Europa's suspected saltwater ocean. But it's possible that this is a good thing. SPACE.com proposes that U.S. Navy-funded research into underwater gliders could offer a superior means of probing Europa, exploring Venus, and even diving into the methane/ethane seas of Titan. NASA wanted a big battery and propeller machine under the ice of Europa, but that might break down, stir up water that should left undisturbed, and leak lubricants into a pristine research environment. The navy wants gliders with internal actuators because they have no flaps or propellers, no lubricant, and one already exists that could "fly" under the Pacific from Seattle to Tokyo on a penlight battery! Another model uses no batteries for locomotion at all, but instead taps heat gradients."

Comments

Re:Problems with a reverse heat gradient

[wyrmis]

Not only are you correct about the heat flow changing the way we think about water (we could feasibly due tests near to "lava" rifts in our own ocean floor to make sure it works)...there is a lot of speculation as to its center. If it gets there, and the heat gradient has been misjudged...then the balance will be off. If it gets there, and it turns out that the heat gradient is extremely variable from one point to another...then the balance will be off.

Also, if it gets there...and it turns out the liquid is too thick or (due to extra-fluid movement) too thin...then...yep, the balance will be off. The fact is that, while I am almost in love with the tech-idea, I don't want to wait for six or seven years just to say "Oops...let's try again, adjust up point 03 on the reaction slope" and then wait another how many years to here "Oops...ok, we are going to need..."

Dang it! It would break my Heart!

Gliding torpedo

[John Jorsett]

I knew a Navy engineer who wanted to make a gliding torpedo. It would be slow, but so quiet that it would be undetectable. He also thought that it could be programmed to hold a ship 'hostage', poised just beneath it and set to detonate if the ship changed position. Don't know if anything ever became of his ideas, but they were interesting.

Locomotion from Buoyancy?

[jcr]

A glider in water has an option that a glider in the air doesn't: it can alternate between being heavier and lighter than the fluid around it.

Suppose this glider had a buoyancy tank which could be expanded or contracted like a fish's swim bladder. Whether rising or falling, it can trade altitude for horizontal motion.

It wouldn't be fast, but it probably doesn't need to be.

-jcr