Hot Water Drill
The primary scientific objective the WISSARD Project is to gain access to the subglacial environments beneath the West Antarctic Ice Sheet in the vicinity of the Whillans Ice Plain through the use of a hot water drill system (HWDS) and deploy scientific instruments through the borehole to explore these subglacial environments. The WISSARD Project requires a relatively mobile, modular HWDS and related components that can be relatively easily supported and maintained in the deep field by a well-defined logistical and operational model with suitable camp infrastructure. The University of Nebraska-Lincoln's involvement in the WISSARD Project has been to complete the design, testing and deployment of a traversable HWDS that is integrated with the over-ice traverse capability of the USAP (U.S. Antarctic Program), which can beused by the WISSARD Project. The WISSARD HWDS will provide access to sub-glacial and sub-ice shelf environments, through ice up to ~1,000 meters thick in Antarctica.The design of a successful deep field HWDS that can be efficiently used for exploratory work is based on careful planning, a focus on simple and practical design elements, the primary use of commercial off the shelf (COTS) components that can be replaced by a suitable inventory of spare parts, the thoughtful fabrication of customized fit-to-mission components to augment the COTS primary components, and peer-reviewed commissioning of the combined science and engineering modules in order to achieve asystems-wide integration that achieves logistical, operational and science objectives. UNL Hot Water Drill System (HWDS) Design and Operations Team. The UNL drill team on ice includes:
•Dr. Frank Rack, Executive Director, ANDRILL Science Management Office and Principal Investigator, WISSARD HWDS Project, University of Nebraska-Lincoln;
•Dennis Duling, Lead Driller, hired from the IceCube Project at the University of Wisconsin-Madison, is in charge of all operational aspects of the HWDS
•Daren Blythe, Dar Gibson, Graham Roberts, Chad Carpenter, Justin Burnett, Jeff Lemery and Robin Bolsey are all members of the UNL drill team.
Adam Melby is a controls engineer from EAD Controls of Omaha, NE, who is finalizing the command and control installation on the ice as part of the acceptance testing and commissioning of the WISSARD HWDS.
•Daren Blythe, Dar Gibson, and Chad Carpenter all had prior IceCube Project experience before joining the UNL team. Blythe, Gibson and Graham Roberts all deployed as part of the ANDRILL Coulman High Project (CHP) site surveys in 2010-2011 where they gained experience operating the ANDRILL hot water drill system.
•Robin Bolsey worked on the CalTech drill system as well as other systems with the Ice Coring and Drilling Services group at the University of Wisconsin-Madison.
•Justin Burnett and Jeff Lemery are mechanical engineers who are new to hot water drilling, and together with Adam Melby are experiencing their first trip to Antarctica.
• Dr. Steve Fischbein, Sr. Research Associate, ANDRILL Science Management Office, supports the drill team from off-ice in Nebraska and was involved in the entire design and fabrication process with the rest of the UNL drill team.
WISSARD Hot Water Drill System
The WISSARD HWDS includes the following primary modules:
- Melt Tank (MT) with a recirculating glycol loop carrying waste heat from the generators to melt snow;
- 3700 gallon capacity Water Supply Tank (WST) that connects to the Melt Tan and provides water to the rest of the system;
- Water decontamination and Filtration Unit (WFU) that purifies the water as it passes through the system;
- Two Heater-Pump Units (HPU-1, HPU-2) that heat the water to 90°C and pressurize the water to 1500 psi
- Hose Reel Unit (HRU) that is used to deploy the main and return drill hoses that go down into the ice; and,
- Command and Control Module (CCM) where the drillers monitor and control all aspects of the drill system operation.
There are also several auxiliary modules transferred from the ICECUBE Enhanced HWDS (EHWDS) that are being integrated into the final WISSARD system, such as:
- Two containerized 225 kV generators (GEN #1, GEN #2);
- Power Distribution Module (PDM); and,
- Day Fuel Tank (DFT) used for redistribution of fuel to the HPU modules.
Additional modules provided by either UNL or the USAP include:
- Storage Traverse Unit (STU),
- MECC Workshop Module (MWM); and,
- Several 3000-gallon capacity mobile steel fuel tanks (FT).
These are all shown schematically in the descriptive process flow and instrumentationdiagram (Figure 1), along with additional information about plumbing and sensorsinstalled between and among individual equipment within these containerized modules.