South Pole Weekly Report, December 28, 2008

With one departure this week, the current IceCube population stands at 49. String numbers 6 and 12 were added to the IceCube array this week for a total of 9 deployed this season. Drilling of the tenth hole of the season is well underway and string 5 will be deployed in this hole before New Year’s.

Replacement Yale grip and back up installation.

Photo by M. Thoma

The drill crew took two days off over the Christmas holiday following the successful drilling of the eighth hole of the season. After the break, hole number nine was drilled and string six was deployed. Just prior to the break, the drill cable Yale grip was replaced and tested. An additional Yale grip was installed just above the new grip as an additional safety. The new grip was installed in a manner that allowed the drill pigtail connector to be mated with the main drill cable with enough slack that excess tension would not create problems in the pigtail during future use. The new Yale grip has a breaking strength of 30,000 lbs and a working load rating of 6000 lbs. The maximum load the cable will see is approximately 1700 lbs. Drilling of the eighth hole (string 12) commenced on December 21 at 8:30 am. Drill head communication was lost at 850 meters. The drill was then returned to the surface for inspection. Troubleshooting of the cable, pigtail, and extension indicated that the extension was defective. A second Yale grip was added to this cable above the factory installed Yale grip to allow slack between the pigtail and main drill cable. The load was carried by the new grip that was added above the factory-installed assembly. Drilling on this hole resumed without communication problems. The hole was completed around 3:30 am December 23. Drilling of the ninth hole (string 6) commenced at 3:30 am on December 26. Drill head communications continued to work well. A hose failure occurred on the pigtail section that is connected to the hard plumbing of the main hose reel. Both this section and the first full section were replaced at this time. Drilling resumed without incident and was completed around 2:30 pm, December 27. There have been occasional CRREL generator problems with the firn drill system. The RPSC generator engineer has diagnosed and repaired the problem. We have yet to find our way through the debris at location 37, but have new GPR data that indicates a possible location where there is minimal debris. Both TU 20s had minor hydraulic problems that have been repaired. The crews will have two days off over the new year after completing the tenth hole of the season.

This week featured no new incident reports and zero reportable injuries. This marks 56 plus days on the ice without a reportable injury. This week’s safety audit looked at drillers’ activities in the MHP and Shop buildings. The process audited looked at the repair of a heater fuel pump which involved two first shift drillers. In the shop, oil absorbent pads were used to contain the excess oil. Proper PPE (hard hats, eye protection) was also utilized. In the MHP, the work required a driller to get behind a heater so another driller was present to help and monitor the work. During the audit, the CO/smoke detector was also tested which sent a signal to the DCC. The DCC immediately checked on the drillers in the MHP via radio and the shift lead also verified the "all ok" response. No safety deviations were noted but drillers were reminded never to go behind a heater without someone else present in the MHP.

The day deployment crew on the String 12 installation.

Photo by T. Ham

Two string installations were completed this week and the final depth for both strings from the software was 2451 meters. String 12 was deployed on Tuesday, December 23rd while String 6 was placed in the ice on December 28th. The Paro Sensors have been performing well, however, the sensor’s breakout on String 6 created some concern when the connector for the device was found to be enclosed in a small icicle. A heat gun was used to remove what appeared to be frozen rain water and the sensor performed correctly.

This week in DOM testing Jens and Karen finished SPATs 14 and 15 without any failures. From SPAT 14 we provided 60 DOMs for String 6 leaving us with 4 spares. From SPAT 15 we saved back 6 spares and supplied 58 DOMs for String 11 (note that we provided a complete set of DOMs for String 11 last week: this is because the drilling order of the holes has changed). We reached the full complement of 60 DOMs for String 11 by including 2 DOMs from previous SPATs that had unclear results and were temporarily set aside—it was decided this week that they are good for deployment. Since we acquired 10 spares this week, we now have around 140 DOMs in the buffer.

Effort in this area focused on the ICL and included the installation of patch cables to DOM Hubs. Two strings were deployed this week, number 12 and number 6. All quads passed the Quad Connectivity Test (QCT).

All 38 tanks are in the freezing phase and the ice is growing. Our major project for the week was to visit every station and tidy up the tanks. Jens and Karen provided valuable assistance all week. Over the holidays, we experienced some blowing snow, and several of the tanks were heavily drifted and Junction Boxes were covered. We removed the snow from all tanks being careful to leave an inch or so when removing 4" or more. In addition to snow cleaning we also installed survey markers and recorded the heights, dressed the power and communication cables in coils around the markers, adjusted sunshades for minimum snow influx (especially around the FCU elbows, which required some excavation of the foam around the elbow), recorded the SJB numbers in pits that were not drifted over, and photographed the inside and outside of each tank. The IceTop water filter is being prepared for transport to New Zealand.

Helping at the tanks.

Photo by L. Shulman

OS and software upgrades have commenced on the SPS. It is estimated to continue through till January 5th. The database server had a hardware problem with one its disks resulting in a complete rebuild of the server. All other systems have been operating smoothly.

The second NARC Radio Cluster was deployed on string #6. This was a shallow deployment of "Neutrino Array Radio-frequency Calibration" instrumentation at 250m. The deployment took approximately four hours and was completed at 4:30am. The SPATS pinger will be deployed in the tenth hole of the season (string number 5) with the same settings and procedures as for strings 19 and 28. String 5 is approximately 1 km from string-D of the SPATS array and the data will provide the longest baseline for attenuation length analysis with SPATS.

Helping to land an LC 130.

Photo by M. Krasberg

The third and fourth strings have now been turned on. There were 4 "ultra-high current" frozen DOMs in the top half of string 36, and one "ultra-high current" frozen DOM near the top of string 28 (for a total of 5 DOMs with this symptom in the first four deployed strings of the season). In the first four years of deployment (40 strings), there have been a total of two DOMs which have shown identical symptoms. An investigation is ongoing. The drill team has been asked to help figure out what is going on.

An American named Todd Carmichael broke the unassisted solo world record for trekking to the South Pole from the 80th parallel (a distance of around 700 miles) by completing the trip in 39 days. Mark interviewed Todd for approximately two hours—he was a very interesting fellow. Todd broke his ski bindings during the first week and walked most of the way to the pole (pulling a 250 pound sled). This feat was confirmed when Mark later interviewed the third and fourth Fins to trek to the South Pole unassisted from the 80th parallel (they traveled along the same path and actually ran into Todd multiple times).

An excellent Holiday dinner was served on Christmas eve to everyone at the station.

An excellent Holiday dinner was served on Christmas eve to everyone at the station.