Friday, February 01, 2008

Miracles Can Happen

It seems that our day finally came, and that we only needed one! I was surprised that we went out, considering that the sky was very grey. During the flight there was a white out. I could not discern ice from sky. There was no horizon. Was that ice or ground fog below me? Fortunately our pilots (after a little searching) were able to find the instrument and land. (More on these spectacular couple of pilots later.) The weather continued to be poor. In fact, during recovery it started to snow a couple times, although it never amounted to much. It just covered the tools a bit and made small things hard to find. The temperature was -13C (9F), and a slight wind was blowing that carried enough wind chill to make cheeks really burn.

We worked in pairs. Terri and Yoann tackled the palette boxes on the priority list. Larry and I began the process of disassembly with the goal of reaching the SCD. This worked very well, and four people was the right number for an instrument like CREAM, which needed a lot of unscrewing and had numerous parts, many of them quite heavy. We looked for visual evidence of the S3/CVD failure but did not find anything.

There were some interesting moments during recovery. Once the TCD paddles were removed, Larry and I were faced with the wall of the TCD support structure. After removing the outrigger supports and numerous bolts, the thing would not budge. Tolerances were so tight that we could not slide it out. After nearly half an hour of beating on the thing, we got out the saws-all and cut a mounting bracket. From then on things went much better for a while. The CherCam was a challenge because of its weight and tight fit, but its removal went very smoothly once we realized the support brackets were easily dismountable from the frame. Once it was out, uprighting the palette was trivial. We then proceeded to remove the framing so that we could easily remove the SCD and everything below it. The cross members on top were cut, but nothing else (except the afore-mentioned bracket).

The new method of calorimeter removal with the trays was challenging but very effective. There were a few design issues that made for trouble. The very small flathead screws were apparently RTVed in and a couple heads were stripped during removal, so the cover had to pried off around them. The 3.5 inch long screws did not stand up enough to remove them after unscrewing them and could not be pulled out of the insets because the tolerance was very tight around the screwhead. But these were minor issues. It took just over an hour to prepare to remove the first layer (eg pulling off tape, which is very difficult with gloves and when the tape is cold, separating cookies, some of which had screws whose heads got stripped as well). However, once we got going, loading the trays took less than an hour. Overall I would give this new process a B+. A few minor design changes or perhaps even more details in the instructions would make it get an A+, if such is possible for moving 1000 lbs.


Meanwhile, the area around the detector looked like a tornado had blown through. Note the lack of a horizon in the photo above. We wrapped electronics boxes in ESD bags, and set the detectors out on blue foam or in the snow. Around 5PM Terri and Yoann worked with the pilots to load the plane. Terri identified the priority items so that they would go out that first day, and packed the electronics more carefully with bubble wrap. Did you know that tape does not stick at those low temperatures? It made for some challenging moments.

But in the end we were able to load about 80% of CREAM onto the plane. The pilots, Jim and Louis (who was French Canadian and spoke with Yoann in French, much to his delight) were absolutely fantastic. They were committed to getting as much back as they possibly could, and got out in the snow with us to help carry these behemoths over to the plane. They stayed an hour or two later than they probably were supposed to in order to get as much as possible. The pilot was a true professional when it came to tight loading. I put myself through college working in a moving company, where it was important to stack stuff from floor to ceiling tightly to get as much as possible in and to keep the load from shifting. Jim rivaled the best packers I worked with in those days.

All that is left for pickup today by planes on their way to or from other sites is two calorimeter trays, two bags of cables, the palette, the TCD support structure, the frame pieces, and a few odds and ends. The pile in the picture is all that is left.

Recovery is very hard on an instrument. While CREAM landed easily, and it appeared there was no damage to the science instruments, the subsequent handling takes a toll. I think you could count on one hand the number of cables that did not get cut. Consider that all the TCD paddles were removed with only one joint breaking. In the subsequent handling of about a dozen times every joint ended up broken. After removal from the instrument they sat in the snow. They were then handed into the plane, loaded, flown about, removed to the ground at Willie Field, loaded in our truck, hauled to LDB, and finally removed into the hanger. All the instruments were handled that many times. The heavier they are the harder it is to handle them. Only two people, maybe three, can really be in the Twin Otter loading. It is a very small cargo hold. Devices with brackets still on offer a hold for carriers. Imagine wrapping your feet in sopping wet towels, wrapping a quilt around your body, and wearing the biggest winter gloves you have owned, then walking through sand dunes carrying 300 pound delicate instruments. Not an easy task.

We will go through everything we brought back over the next couple of days. We'll examine the S3 and CVD parts more closely to see if we can find any reason for the failure. Everything will get packed up into the sea crate. After that, the instrument will arrive in Palestine around mid-March, and someone has to go down to pick up the pieces.


Meanwhile, life in McMurdo continues. The fuel ship has finished unloading and is preparing to leave. The Palmer is gone. Yesterday's off-continent flight practically emptied out my dorm, leaving it blissfully quiet. I was able to luxuriate in a hot shower this morning, instead of the usual tepid poor excuse for one I usually get. I had to turn in my skis, since for some reason the gear issue season is finished. I am not sure what I will do to entertain myself until my plane leaves once I am finished packing the sea crate. But I'll manage, because I can sleep in and can put my field gear away. I'll get to see the cargo ship arrival and unloading, which I understand is a really crazy time here, when looking both ways before you cross the street is essential in order not to get run over by forklifts shuttling goods and crates.

2 comments:

Anonymous said...

Hi & Happy Groundhog Day!

Totally fascinated with those pictures & wonderful descriptions. You deserve that shower! Rest up--your Dad will be in Rambo gear when he gets there. He waited until last possible to change the ticket - darn!
Big Cyber-hug,
Marilyn

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