Monday, October 25, 2010

Out at the Shear Zone

Sorry for the long delay! We just got back from the shear zone, about 30 miles out from McMurdo. Seeing it for the first time really helped put in perspective what we've been working on for the last couple of years. The shear zone is the area where the Ross ice shelf meets the McMurdo ice shelf. The two shelves have different speeds, creating a particularly nasty area riddled with crevasses at the interface between the two. The traverse route crosses perpendicular to the shear zone, but still has to travel over 3.5 miles of heavily crevassed terrain. These cracks change season to season, and often times new ones open up each year. All of them are invisible from the surface, however, and many are hundreds of feet deep.

Jim and I drove a Case tractor to get to the South Pole Traverse camp on the near side of the shear zone. I found out while en route that our vehicle has an excellent fuel efficiency and burns 3 gallons of diesel per mile travelled. The route was covered in dense fog, which made it hard to see the flags marking the ice road. In those conditions out on the sea ice, it's a strangely surreal feeling to be surrounded by absolutely nothing but white, with no visible horizon or visible features of any kind. Luckily, we were able to navigate by GPS between flags, and reached the traverse camp on time.


Our Case, loaded up with Yeti and equipment in tow.


The SPoT camp, with living module (red) on the left, the H2 module (my living space) in blue, and several tractors.

We were initially supposed to have a week to test Yeti in the shear zone, but that got crunched down into 2.5 days. The first day, our goal was to collect radar data over a crevasse and setup the route that we would send it off on for an autonomous run the next day. Zoe and Allan headed out ahead of us in a Cat, and Jim and I followed in a tractor. We were looking for one specific crevasse that would give clean radar signatures so we could collect a data set that will later be used to autonomously detect crevasses. When Allan drove over the snow bridge in the cat, it opened up a small hole on the surface. Jim and I saw the hole just as we were about to drive over it, and weren't able to stop in time. We knew the crevasse was only a meter or two wide, but it was bizarre to look behind us and see the hold widened out to around 5 feet. We had to backup and drive back over the hole again, since the road was the only portion of the ice that had already been surveyed. The Case made an ominous sound clunking in and out of the hole, but we made it back across in one piece.

After successfully 'finding' a decent crevasse to survey with Yeti, we attempted to drive a rosette pattern to approach the crevasse from different angles with the robot. Our only goals were to keep Yeti driving straight and avoid the 5' hole we just made, and I found it absurdly difficult to keep Yeti safely away from the hole. At the time, I decided that this was target fixation, but we would soon find that Yeti has a magnetic affinity to holes in the ice and bamboo flag poles. While driving around autonomously, it seems to lock in with laser precision on the only one or two obstacles around for miles, which I'm sure is a corollary of Murphy's law.


It's almost 2am and I have to get up early for another long day of testing, but I'll write up the rest of the work at the shear zone tomorrow. Rest assured that Yeti did not fall in a hole, but did annihilate many bamboo poles.


Mt. Erebus, an active volcano, from a distance. It's not really nighttime, since the sun stopped setting last week, but it does go low and create very cool lighting conditions.

5 Comments:

At October 25, 2010 at 1:20 PM , Blogger Allie said...

My dad always said the brain can't process negatives. So if you told yourself NOT to do something you'd always do it because your brain would leave out the "not" and just hear "do". So instead you should tell yourself only what you SHOULD do. Sounds like you need to start playing Master of Psychology with Yeti. (If you want to know WHY I got that lesson at age 6, you'll have to email me privately.)

 
At October 27, 2010 at 9:04 AM , Anonymous Susan Koh said...

It's fascinating to read your blog. I sent the link to our FIRST Robotics team coordinators to pass on to their teams, to see the real-life applications of robots and be inspired!

 
At October 27, 2010 at 10:22 PM , Blogger Degenal Santos said...

Hi, My name is Degenal Santos, I am from Brazil. Roberta Palmiotto told me about your work and also about your interest in doing video conference. I really would love to set a video conference with you to learn more about your research and also about How global warming has affected this side of the planet.
My students have done a lot of work on that area since we have an environment program as part of our school curriculum.
My email is djsantos216@hotmail.com

May God bless you in this awesome work.
Sincerely
DJ Santos - teacher of ETEC HIGH SCHOOL IN BRAZIL.

 
At October 30, 2010 at 6:19 AM , Blogger Eric Trautmann said...

Allie - You're entirely right. I found that out the hard way learning to ski and trying to not hit trees. It's a lot easier if you look at the gaps and not at the trees.

Susan - Jim's been telling me about your work with micrometeorites which sounds incredibly cool (I'm making a guess that I have the right Susan, but let me know if I'm wrong :) Thanks for sending the link on, I met a few of the first team members two years ago and was humbled to realize they were probably a lot better at this stuff than I was...

Degenal - I'd love to speak with you and your students, I'll talk to you over email.

 
At October 30, 2010 at 10:45 PM , Blogger eikceb said...

Weeeee data, Eric you're awesome!

 

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