Frustration and Elation

5 11 2009

This morning we all piled into our ATVs and headed of to the freshly melted ‘bot hole, ready to send ENDURANCE out on its first mission outside the melthole.

ATV on Moat

The Bonney morning commute. Chris driving half the crew on the ATV.

We wanted to do a basic set of tests of all the systems on ENDURANCE, in the actual Lake Bonney environment.
We got to the ‘bothouse and starting going through the launch checklist for ENDURANCE. Before every mission, we clean off sensitive sensors, intialize subsystems and verify that they are working correctly, make sure that everything is plugged in and sealed up, etc. We got to the step of running the test program on the thrusters, and noticed that half of them weren’t working. Hmm… Slightly frustrated, we started trying to figure out what was wrong. It finally turned out that the battery stack that powered those three thrusters had turned off overnight when it had gotten fully recharged. As you know from my previous post, these are new systems, and fairly complex. It turned out we had never really made a clear, easy-to-check indicator of whether the battery stack was on or not, so it took us a while to figure out.
That would all have been fine, but Murphy had some more tricks up his sleeve. In the process of trying to figure out the problem, we had tried to talk to some of the controller units that run the thruster motors. And accidentally set two of them to have the same address. That means, when commands were sent to one motor, both would respond. Not a good condition, since trying to change the address back would make both of them change. The only way we could figure out to reset them back to separate addresses was to unplug one of them. This unfortunately meant opening up the waterproof electronics can, a lengthy process involving the crane, cleaning, O-rings, and a 5-minute nitrogen purge to put everything back together.
Chris and MCU

Chris looking dejectedly at the motor controller electronics housing we had to open up this morning.

We got the thruster all fixed up and the battery turned on, and continued with the checklist, albeit with a few hours delay. I next went to clean of the front of the forward-looking camera on ENDURANCE…and noticed there was water inside the housing. This required another hour delay to disassemble, inspect and reassemble.
Inspecting Camera

Bart, Bill and Vickie inspecting the leaking camera housing.

Finally, with about 4 hours of delay, we got ENDURANCE in the water. And the results were very uplifting. All systems worked. There were a few little things to patch up here and there, but nothing that would throw a wrench in the works.
Best of all was the visualizer that shows what all of the sonar sensors on ENDURANCE “see”, a 3-D view of the underside of Lake Bonney. We were even able to see some objects that we lowered on ropes through the melt hole. This gives us confidence that we’ll be able to detect any forgotten science experiments that might be hanging from the ice roof. We were all very excited about being able to see ENDURANCE moving through it’s new environment on the computer visualization.
Excitement Over DeltaT

The team looking with excitement at the first views from the sonar data under Lake Bonney.




2 responses

5 11 2009

Great! Finally πŸ™‚

6 11 2009
Maria Richmond

I can never go to bed without first checking what ENDURANCE and the rest of you have been up to. So, wonderful to see and read tonight’s news. πŸ™‚

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