Dec 3 – Last mission

We ran our last mission mission today. In addition, we also tested automated profiling, and ran automated profiling missions. Everything went smoothly and we are one step closer to running complete science missions (including profiling) autonomously in addition to bathymetry missions.

Kristof, Chris, Rachel and Vicky as the bot is pulled out for the last time.

We also managed to do a reasonable amount of robot disassembly and packing work today.

Peter and Bill loading up the syntactic foam into an ATV.

The syntactic foam is packed into yellow boxes that will be sling loaded by helicopters and flown to McMurdo tomorrow.

Rachel working on disassemblng some components.

The profiler in the process of being taken out of the bot.

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Preparing for below-halocline exploration of Taylor glacier

One of the science objectives of this year’s mission is to perform exploration of Taylor glacier, including sonar and visual imaging. This will require the robot to operate below the halocline. The halocline is at about 16 m depth and forms the dividing line between the freshwater lens at the top and the highly saline water at the bottom. The higher salinity of the water below the halocline means that the robot has to be ballasted with about 200 lbs of extra weight to be neutral in this layer. Since we do not want to unnecessarily disturb the halocline, the robot will start above the halocline from the bot-house. It will then drive to another melt-hole near the glacier another melt-hole close to the glacier, where we will lift it out partially with a gantry and ballast it.

Maciej, John and Peter have been working on getting this melt-hole ready for the past few days. They are almost done, and have the gantry installed today. The gantry will be used for partly lifting the bot out of the melt-hole.

Maciej and Jim working on the new melt-hole next to Taylor glacier. It has taken them about 5 days to get this far.

Maciej, Jim and Peter finished installing the gantry for lifting the bot today.

Maciej, Jim and Peter.

Vickie takes the plunge

We worked on a variety of issues today. Bart, Chris, Kristof and I worked on figuring out why we did not receive images form the sonde camera. Bill and Vickie tested the radio beacon. Maciej left for McMurdo and a replacement GA flew in.

But the highlight of the day was Vickie’s dive into the lake through the melt-hole. The main objective of her dive was to figure out whether the melt-hole diameter up-to its entire depth was large enough for the bot, and whether there were any jagged edges that could damage the bot or the fiber. We suspended an ice-axe for her which she used to chip away the rough surfaces. This makes her the first woman to dive in west lobe of Lake Bonney!

Bill helps Vickie into her dive gear. Several layers and a complete body suit has to be worn to dive in water this cold.

Vickie being lowered into the melt-hole.

I fed "the umbilical" cord to Vickie. This cord is fed as the diver requests or as the feeder senses the diver's movements. The idea is to not feed too much because the diver can get tangled but not pull too much to restrict the diver's motions. The umiblical a safety line to pull the diver up. Chris hung an ice-axe suspended from a chord down which helped us assess the melt-hole diameter.

Bart putting on the "syntactic foam" that adds buoyancy to the bot and allows it to hover.

We use bungee cords to tie some of of our stuff to the front of the ATVs. In our hurry to get to work, we used a 'normal' cord instead which got tangled in the wheel of an ATV. At the end of the day, Jim and Bill figure out how the problem and get the cord out.