Nov 14 – Traveling east

November 22, 2009

We spent the morning looking at data from yesterday and trying to debug the communications failure problem. We had some ideas but we were not sure what the exact problem was. The mission for the day involved  traveling to the narrows – the part of lake that connects west lobe to the east lobe. The bot swam about 1.5 km to reach the far east – this is the farthest the bot had ever been. Much remains
unknown about this part of the lake and we were very excited to see the visualizations from the sonars on the bot. We might go there again later for getting more data.
While returning back, we had the same comms failure again. In a flash of inspiration, I was able to figure out what the problem was – a process that had memory leaks and was slowly eating up RAM till 100% was used.
Midway through the mission, it started to snow and Vickie and Bill had a tough time outdoors. It is fairly rare to snow in the dry valleys, so I was very excited. At the end of the day, Bill showed me how to track the robot using the radio beacon. Overall, this was a very good day for us and we have decided to take the day off tomorrow.

A map of lake Bonney showing the profiling points. The points that we have finished are shown in green. Today we went to the point farthest east (D21) on the grid. This point is at the far east of West lobe and at the start of "the narrows" - the narrow channel of water connecting the west lobe to the east lobe.

Bill and Vickie at the end of the day. They were out all day tracking the robot and marking the exact location at whihc it profiled. It snowed half the day making their task difficult.

The first snowfall I have ever seen.

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Nov13 – A successful mission and a blown tent in a very windy day

November 22, 2009

Vickie, Bill and Kristof went to the bot-house early to install the batteries (that Bart had fixed overnight) into the robot to give us an early start on the day’s mission. We started the profiling mission around 12:45 in the afternoon. The mission was largely uneventful and the robot went farther east than it had ever before. The batteries
worked very well, and we profiled at 20 points with a total mission length of about 3.2 km. We are optimistic that we can now profile at the far east end of the lake and come back without power running out – a total transit length of about 3 km. We still had a short partial comm loss at two grid points. We do not know the cause
yet and we plan to work on it tomorrow.

The day was very windy with Katabatics of more than 35 mph. Bill and Vickie had a rough time being outdoors for about 6 hrs tracking the bot. One of the propane heaters in the bot-house blew out, and we couldn’t get it to work. We were cold had to wear our big-reds all day. At the end of the day, my fingers and feet were really cold and I was happy to return to the warmth of the jamesway at Bonney camp.

The PI of our project, Peter Doran was scheduled to fly in to Bonney today from McMurdo. However, the bad weather prevented any flights from getting in. He will now come on Monday (hopefully).

After dinner, John mentioned that he had seen couple of tents turned upside down. We rushed out and found that my tent had almost blown away – it had just one guy- wire holding it. Some of my stuff had also blown away. Chris’s tent was almost uprooted . The entire team came out to help us fix our tents. My tent was torn and a new tent had to be setup for me. Now I have a new and more spacious tent. The tents had been setup for us when we came to Bonney camp and event though my tent
shook and creaked a lot in the wind, I had not bothered to fix it up. I should not have been negligent (and lazy)  and should have tied it and staked it up better. I am rather angry with myself for this. But we were lucky. John says that some people have had their tent with their stuff inside it fly down the valley!

Right now, at about 12:00 at night, the winds are still blowing and fog has rolled in over the hills. Thankfully, the temperature is not very low (only about -5 Celsius).

Some photos, thanks to Kristof, below.

Only one-guy wire prevented my tent, and all my stuff, from blowing down the valley.

Some of loose stuff blew away.

The entire team helped Chris and me set up our tents. Rachel, Bill, Vickie and myself.

The entire team helped Chris and me set up our
tents. Rachel, Bill, Vickie and myself.
Bill, Vickie and Bart.

A rough day

November 11, 2009

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.


First successful profiling mission

November 9, 2009

We just finished our first successful profiling mission today. We performed profiling at 19 points. The approximate length of the mission was 2.4 km. The mission was mostly uneventful. We saw some interesting microbial growth on lake bottom near the shore and also some iron leached out from sediments. John extracted some data from yesterday’s profile which shows some very interesting characteristics (I will post some of John’s plots and a map soon). We also ran down the batteries and now have a better characterization of the tripping behavior – this should help us plan future missions better. It’s been a very long day. We have worked non-stop for 14 hours. I am exhausted but elated. Below are some pictures.

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Chris setting up the charge cables for the bot.

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Mission control - Kristof, Shilpa and Chris.

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Biological matter at lake bottom in the shallow area near shore. This photo was taken by the camera of our main science package "profiler". The profiler spools down all the way to lake bottom and measure various chemical properties of lake water.

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Rust colored streaks at lake bottom. These are probably formed by iron leaching from the sediment. Almost looks like the surface of an alien planet.

H9-Sonde-2009-11-09--06-20-11-strange-stuff

Another picture of lake bottom. We don't know what we are seeing here.


Anything that can go wrong will go wrong

November 8, 2009

Yesterday

We had a very eventful day today. The day began well enough with us getting the bot in water before noon to perform our first profiling mission. Rachel was “tending” the fiber optic cable. This cable forms the communication link between mission control and the robot’s on-board computer. Tending the cable involves being aware of the robot’s current location with respect to the melt-hole and having an approximate estimate of the length of cable that must be spooled out, whether it should currently be spooled in (when the robot is moving towards the melt-hole) or spooled out (when the robot is moving away from the melt-hole) and the direction it should be pulled in/let out.

After the first few grid points, Rachel and Bart noticed that the fiber optic cable was caught somewhere because it wasn’t getting spooled in even when the bot was driving towards the melt-hole. We made the robot retrace its path in the hope of untangling the fiber. The fiber got unsnagged and we move on to further grid points. We had entanglement twice more and ended up driving about 500 m to just entangle the fiber.

Finally, after we had unsnagged the fiber, we decided to profile some more grid points. Just when the robot was about to approach a grid point, we lost communications. In a short time, we regained comunications. The main on-board computer had rebooted. However, the navigation instruments that provides estimates  of pose and orientation were not communicating.  We rebooted the on-board computer in the hope that ths will fix things, but after reboot none of the processes would run. We had no way of bringing the bot back without control of thrusters an knowing the position estimated.

The fiber optic cable can withstand a tensile force upto 300 lbs. The robot is positively bouyant and floats up to sit against the ice when its not being controlled. Ultimately, we ended up pulling the bot back with the fiber optic cable.  The day ended with several possible explanations, but no firm conclusion as to the cause of the various problems. We had a long day and decided to debug the problem the next day.

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Rachel tending the fiber-optic cable.

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John Priscu arrived a few days back. John and Chris discussing the profiling data.

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Bill and Bart pulled the bot about 150 m with the fiber-optic cable.

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The robot back in the melt-hole.


A dead penguin, a dead seal, and a calibration mission

November 6, 2009

We ran a mission today to get data that allows us to calibrate our  navigation instruments so we can quantify the error between the robot’s estimate of its pose and the ground truth (which we obtain by tracking the robot with a radio beacon and marking its GPS position). We also saw some obstacles in the limno-hut region where the fiber had gotten snagged  last year in our new visualizer.

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A dead penguin (between the two rocks). Emma had seen it some time back and told us about it. We stopped on our way to work today to see it.

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We also saw a seal skeleton. Myself and Chris.

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Chris, Rachel and Kristof.

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A thin layer of ice freezes over the melt-hole every night that needs to be cleared before we can run any missions. Emma helped us chip ice from the melt-hole today morning. Emma was clearly delighted to do this.

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Mission control. Myself, Kristof and Chris.


Expedition complete

January 6, 2009

Thank you all for your interest in this blog. Our 2008 expedition is complete and I take this opportunity to summarize the achievements for ENDURANCE. We will be writing papers on various aspects of the project and I will post the appropriate  links here.

The ENDURANCE project is funded by NASA’s ASTEP (Astrobiology Science and Technology for Exploring Planets) program. The objective of this program is to develop and utilize science and technology that will enable exploration and discovery of life forms on other planets and satellites. To develop and validate the technology, field testing is performed in extreme environments on the earth. Examples of such extreme environments on earth are the Antarctic Dry Valleys. Taylor Valley, where we performed our experiments is one of these dry valleys.

The achievements of this project for Nov-Dec 2008 can be divided into two categories.

1. Developed and demonstrated the technology for exploring under-ice lakes in Antarctica Dry Valleys for life forms

We demonstrated that current technology can be deployed to explore under-ice lakes on earth for life-forms. The under-water robot developed by Stone Aerospace measured the biogeochemical properties of water with an instrument package (profiler) all the way from the lake ice to the lake bottom. The profiler camera took pictures of the lake bottom that showed microbial mats, and hence confirmed the existence of life forms that have been found to exist through previous research.

Our vehicle was able to reach within 1 to 2 meters of a specified target and came back to within 2 to 3 meters of the melt-hole after travelling as much as 1700 meters. We developed a visual homing algorithm that consisted of (1) Finding a blinking light by moving in a spiral pattern and identifying it as a target to home to (2) A control algorithm to home to the identified target. This algorithm worked very well and allowed the robot to distinguish the target light source from other ambient light sources, to stay centered on the light source, and to rise through a melt-hole with tight clearances. We also demonstrated the ability to collect biogeochemical data along the entire depth of the lake and at any specified location in the lake.  We demonstrated the ability to profile the lake bottom and glacier face using the data collected by the on-board sonar sensors.

The navigation, homing and data-gathering capabilities make the vehicle a unique and useful tool for scientific exploration of under-ice lake environments.

2. Gathered data for characterizing the water properties and for producing a 3D map of the subsurface of West Lake Bonney

Using the profiler, we measured the biogeochemical properties at 70 grid points in West Lake Bonney. We also gathered sonar data for mapping Taylor Glacier face and the lake bottom. This data will be analyzed by Peter Doran and John Priscu to confirm their hypotheses about the physical and biogeochemical structure of  Lake Bonney and for building a 3D map of Taylor Glacier and subsurface of Lake Bonney. Andrew Johnson’s lab will be developing the visualizations for the data.