Fresh Breath

8 11 2009

Today, we all woke up to a rare phenomenon in the Dry Valleys. The quiet rustling on the fabric of my fly could only mean one thing: snow!

Snow From Tent Door

View from the door of my tent when I woke up this morning.

We took an easy morning, enjoying the calm, relatively warm weather. I made some pancakes. I ate some pancakes (and shared with everyone). Then we were ready to tackle solving the mystery problems of yesterday.

 

The team gathered for a brief meeting to decide on what the plan of action would be. We decided to look through as much of the data and logs we had to learn as much as we could before trying to open anything up.
As we looked through everything, a timeline for yesterday’s events began to emerge:
5:51 ENDURANCE begins slowing down to stop for waypoint F5
5:51 ENDURANCE central processor rebooted
5:55 We discover some of the serial ports aren’t working
6:01 We manually rebooted the central processor to fix the serial ports
6:02 The central processor comes up again, serial ports work
6:11 Many processes on ENDURANCE stop working
6:13 We rebooted the central processor again
6:15 The central processor comes up again, no processes work
6:29 We lose all communications with ENDURANCE
6:45 ENDURANCE is retrieved from the melthole

We went through all the evidence and figured out that the two events which had most confused us were pretty easily explained.ย  The 6:11 event was due to a hard drive filling up, the 6:29 event was due to the batteries running out. However, the original 5:51 event was never completely explained. It seems certain that the batteries restarted at that time, but we see no reason for that to have happened.

We ended the day with a good feeling, we’d figured out most of the most befuddling problems, and have a good idea of what to look for in the future, even if we don’t know the exact cause of the original failure. Tomorrow, we plan to do another science mission, fairly close to the melthole and in a safe area away from the glacier. To finish up the mission, we’ll do a few more tests to try to address some of the issues we think might have caused the original event, and end by running the batteries all the way down to get a better feeling for how they work when they’re almost empty.

Leaving the Bothouse

A happy crew leaving the 'bothouse tonight.

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4 responses

9 11 2009
Maria Richmond

Where did the snow from the morning go? There is none on the photo you took in the evening. That sounds like Boulder but not like Antarctica!
Also, tomorrow (our time) 11/9, it has been 20 years that the Berlin Wall fell!!!!
It has been 40 years that Sesame St. started!
Muttertier

10 11 2009
kristofrichmond

It’s very much like the Dry Valleys. It’s dry and cold enough that the snow here doesn’t melt, it sublimes directly from ice to vapor. In less than a day, as you can see.

9 11 2009
Sebastian Bleichert

I did not know that the Sesame St. has its 40th “anniversary”. You seem to be a great fan of it Maria ๐Ÿ™‚

Well that was really a critical situation. I can imagine that depending on the buoyancy and the structure of the ice above the bot there might be situations were the bot gets kind of stuck and cannot be pulled back easily. Is it really possible to have always the right ammount of ballast weight added to the bot so that it does neither sink nor rise up to the ice? I remember a blog entry from last year’s mission where it was described that microbubbles causes by natural gas in the lake’s water changed buoyancy tremendously.
Well at least I’m glad to hear that you were lucky and could bring the bot home.
Another point of interest to me is the harddrive fillup. Was it caused by mission /sensor data or due to log files which were created because of the system failure?
Take your time for answering the questions. There are probably more important things to do ๐Ÿ˜‰

10 11 2009
kristofrichmond

We are definitely concerned about getting the ‘bot stuck. For the most part, the underside of the ice is glass smooth with small undulations, so there’s not much to worry about there. When we get closer to the glacier, and go underneath it, we will certainly have to very careful and scan the ice ahead of us for any obstructions or unsafe areas.

The microbubbles do seem to affect the buoyancy, and temperature must also play a role. We currently check the buoyancy before the start of every mission and adjust it as close to just above neutral as possible, that seems to work well enough.

The hard drive fillup was caused by operator error trying to set up an automated script sorting through log files and creating a summary of the information in them. It ended up going into an infinite loop appending garbage to the summary file and filling up the filesystem. Basically poor communication between the team members in the heat of the moment trying to figure out the problem.

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