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Monday, August 20, 2007: Quality Assurance
Because supplies and time are very limited when working in the field somewhere as remote as Antarctica, quality assurance of every component becomes very important. Shown here is custom ethernet cable being checked under a microscope: mistakes unnoticeable to the human eye can cause subtle and hard to debug problems down the line.


Some of the most important pieces of SCINI to check every time we assemble are the pressure bottle O-rings. The rubber rings and the grooves they slide into were carefully designed and machined so that the rings aren't squeezed too tight, float loose, or get twisted around. Even a single hair or dust clump, let alone iron filings or clumps of dried sea salt, can get stuck around the ring and let water trickle through. In the lab we can check sealing surfaces under a microscope for foreign objects, but in the field we will rely on sharp eye sight and ceaseless vigilance. An additional worry in the field will be checking for fresh water that gets close to the rings: the Antarctic salt waters get colder than the freezing point of fresh water, and the formation of ice crystals can push aside the ring.

Another test is to stress out our power supplies with a high current load for an hour or so to see if they over heat. In the lab the power supplies for our thrusters are actually overheating, so we put them in a dish of alcohol to cool them down. When actually flying in the water in Antarctica, water temperatures will get down to -2 degrees Celsius (salt water freezes below the fresh water freezing point), which should help dissipate heat, but we still have to conduct that heat through our plastic bottle walls.

Monday, August 13, 2007: Cameras Update
We got a visit from the Elphel developers this past weekend and they dropped off new cameras (as well as helping us out with some integration engineering). We've got a new camera packed back into our waterproof bottle and should have some new video to share after our next submersion tests!

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This material is based on work supported by the National Science Foundation under Grant No. ANT-0619622 ( Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.