A rough day

Today was another one of those days when everything goes wrong. We wanted to run a mission towards the east side of West Lake Bonney. We switched to a new 2 km long fiber-optic cable to enable communications for this long mission. Vickie and Bill spent most of the morning spooling out the cable from into a box, and building a strain relief to connect the new cable to the bot. The strain relief reduces the tensile stress on the connector of the fiber-optic cable. I spent the morning organizing data from previous missions and writing scripts to copy, organize and backup data in the future.

We started our mission around 2:00 in the afternoon. After a very efficient profile at the first grid point, we were starting to fell pretty optimistic about the mission. However, in the middle of profiling at the second grid point, about 420 m from the melt-hole, we suddenly lost communications with the bot. The science instrument package (profiler) was spooled down and was hanging about 25 m below the bot. As of this morning, the recovery script to bring the bot home in case of communication failure was still incomplete and we did not have that running.

Fortunately, the bot was resting on the under-surface of the ice and was not executing any motion commands. The only option for recovering the bot was to slowly pull on  the cable. The depth of the lake along the straight line from the bot’s location to the melt-hole was high enough to allow us to pull it back without running the profiler into the ground.  It took us about 3.5 hours to pull the bot back.

The first thing that came to our mind was that the problem had something to do with the new fiber-optic cable. After pulling the bot back, we found that the cable was working fine. Chris found out that he could not ping the router that talks to the main on-board computer. He thinks that the power supply in the main computer pod is flaky and caused the router to shut down. We will debug this problem further tomorrow.

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Chris tugs on the fibre-optic cable to pull the bot in as I measure the length of the cable pulled in.

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After pulling for about 3.5 hours, we recovered the bot and pulled it out of the melt-hole. The profiler is hanging by the green cable about 25 m below the bot.

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We opened up the main computer pod to inspect the router and power supply. Chris and Bart inspecting the pod. The pod-cover is seen hanging from the gantry.

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