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Waiting on Pins and Needles
January 14, 2008 (posted January 15, 2008)
Written by Susan Humphris, edited by Kristen Kusek

As we enter the final days of the cruise, we are in a race against time. When we left Natal, Brazil on the last day of 2007, we had bold plans and knew that challenges lay ahead of us.

And for the last 9 days at our work site on the southern Mid-Atlantic Ridge, everyone has worked incredibly hard, and made considerable progress. A crowning moment was Puma’s dive yesterday, when we saw some whopping signals on its sensors indicating that it was very close to zeroing in on the seafloor source of a big hydrothermal plume.

Late last night, we selected an area of seafloor about 300 meters by 250 meters (about 1,000 feet by 820 feet) that Jaguar, Puma’s tag-team partner, would survey. Its mission was to “mow the lawn” in a pattern with about 10 meters (33 feet) between each of the lines, and collect digital imagery of the seafloor in search of hydrothermal vents.

Just after midnight, we rolled Jaguar out on to the fantail (stern of the ship), ready to launch it on its mission. But once we began the pre-dive checks, Jaguar’s “brain” failed to turn “on.” Something was wrong with the power supply, and the batteries were not providing the electricity Jaguar needs to run.

We had to abort the launch—and the fantail suddenly looked like a pit stop in a car race.

A group of engineers rapidly removed the battery housing from Jaguar and hauled it into the main lab, where engineer John Bailey disassembled it. He found a problem serious enough that it could not be fixed quickly, so another group went into action to pull the battery housing from Puma. Its battery supply was taken apart, and John took the parts out of Puma that he needed to fix Jaguar.

Six hours later, with some of Puma’s “guts” in it, Jaguar was on its way to the bottom
while a tired “pit crew” went to get some rest.

What we didn’t know at the time was that there were even more difficulties ahead.

About a quarter of the way into its survey, the engineering team started receiving information packets from Jaguar reporting that it couldn’t figure out its altitude (height) off the bottom, it was not moving, and its sensors were seeing rapid changes in Eh (the chemical reactivity of the fluid, an indicator of hydrothermal activity).

Had it bumped into a hydrothermal vent chimney? Was it trying to drive into the seafloor?

After what seemed a long wait, Jaguar was on the move again, but its altimeter (which indicates its height off the bottom) was not working. Everyone feared it would continue to keep trying to drive into the seafloor in search of the bottom.

“In this situation, the safety of the vehicle must come first,” said Chief Scientist Hanu Singh as he asked MIT-WHOI graduate student Clay Kunz to send the “abort” command.

But Jaguar did not obey.

Even though we keep sending “abort” commands, at the time of this writing Jaguar is still moving along the bottom. Unless a command gets through, we will have to wait until the battery power drains and it floats slowly to the surface.

There has been a lot of guessing as to what is causing Jaguar’s strange behavior, but we still do not know for sure. So, here we all wait on pins and needles. Many of us are hopeful that despite the odd behavior, Jaguar may come back with pictures of the seafloor and hydrothermal vents.

Read the new interview

Dan Conrad

Dan Conrad: Dan Conrad, who has taught physics for more than 20 years at Baltimore Polytechnic Institute, has a lifelong passion for both science and art. Read the interview »

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