Analysis of Alternatives for USAP Resupply
CURRENT LOGISTICS SUPPORT IN ANTARCTICA
The key logistics element of the present United States Antarctic Program (USAP) resupply system is the annual shipborne resupply of fuel and cargo to McMurdo Station during late January and early February. During this single logistic event, nearly all fuel and cargo needed by USAP stations is transported to McMurdo Station. Throughout the austral summer season, supplies and materials are distributed from McMurdo Station, usually by air, to local science camps, South Pole Station, and remote field camps. Small amounts of materials continue to be delivered to McMurdo by air from Christchurch, New Zealand, and by direct sea deliveries to Palmer Station (amounting to approximately 5 percent and 1 percent of total USAP annual fuel and cargo, respectively, in the case of Palmer Station) during the research season.
The amount of fuel and cargo delivered annually to McMurdo Station is so large (e.g., in 2004-2005, 8,400,000 gallons of fuel [58,600,000 pounds] and 14,200,000 pounds of cargo) that the only cost-effective methodology with acceptable risk has been to utilize a fuel tanker and a cargo ship. Presently these are non-icebreaking, but ice-strengthened, ships operated by the Military Sealift Command (MSC). These require support from large icebreakers—two working together in some years—to open a shipping channel through the ice to McMurdo Station, which is then used by the resupply ships. Ice conditions on the final 20 km of the sea approach are nearly always heavy and have been increasingly very heavy in the past six years. The sea approach to McMurdo Station has also in recent years involved a much longer ice transit than the norm experienced by USAP in earlier decades (recently up to 135+ km). These factors, plus the aging condition of the only two U.S. icebreakers designed to be powerful enough for the McMurdo icebreaking mission, have made future annual break-ins unduly vulnerable to failure. It is therefore important to understand alternatives for the USAP resupply.
Recognizing this situation, the National Science Foundation (NSF) Office of Polar Programs (OPP) initiated an internal study in 2004 of several USAP resupply alternatives. The OPP director subsequently asked the external OPP Advisory Committee (OAC) to form a resupply subcommittee to oversee and guide this analysis of alternatives and to develop its own recommendations concerning resupply options, both to ensure continuity of operations and national policy of the USAP and to help ensure that the most cost-effective and reliable approaches are implemented. The following discussion is a synthesis of the NSF subcommittee’s report.1
ALTERNATIVES FOR ANTARCTIC RESUPPLY
A review of the current USAP logistics plan highlighted that a single point of potential failure within the resupply system exists because of dependence on the annual, shipborne delivery of fuel and cargo to the hub at McMurdo Station. Simply stated, under the system prevailing through 2005, if the ships miss one delivery of fuel and/or cargo to McMurdo Station, the logistics chain is broken. This dependence places the whole USAP at risk due to the role of McMurdo Station as the sole redistribution point for USAP fuel and cargo and the lack of on-continent reserves. Therefore, it is prudent to amend this single point of potential failure and also provide means to continue science support at and from McMurdo and South Pole Stations in the event of a temporary disruption in delivery. In fact, recent iceberg calving and drift in McMurdo Sound created difficult icebreaking conditions that could easily have made the present mode of resupply inoperable, even for 100 percent fit icebreakers.
For details see the full report at http://www.nsf.gov/od/opp/opp_advisory/final_report/oac_resupply_report_081205.pdf
This highlighted that a backup, alternative, or redundant supply system is necessary for the USAP. The appropriate choices can both result in efficiencies in the present system and enable new major science by virtue of the developed logistics plus net USAP energy savings that can then be applied to science.
First, it is widely recognized that although the approach is not new, the most cost-effective manner to transport the large amount of fuel and cargo required for the USAP, with acceptable risk, is through shipborne delivery to the principal point of use and redistribution (i.e., McMurdo Station). The tonnage that USAP requires to be delivered to McMurdo Station makes annual air delivery of the total both impractical on several grounds and unrealistically expensive. Hence, it can be assumed that barring an as-yet-unprecedented crisis, fuel and at least a major share of cargo will be delivered there by sea. Also, there is no alternative deep-water harbor within hundreds of miles. Thus, if a ship with fuel or cargo destined for McMurdo Station cannot reach the pier, the USAP must contend with unloading the fuel or cargo onto shelf (glacial) ice or onto sea ice. Consequently, the preferred mode for shipborne logistics support remains to provide tankers and cargo ships, escorted to the pier by an icebreaker capable of opening the supply channel through the ice.
This mode of resupply, however, contains the single point of potential failure in the present system. If alternatives could be developed to accommodate an occasional year in which very heavy ice conditions preclude fuel delivery, the vulnerability of the resupply system would be lessened. It should be noted, however, that the heaviest ice years near McMurdo Station have recently occurred consecutively, not randomly. The presence of large icebergs kept sea ice in the McMurdo region, allowing it to grow very thick and hard in places beginning in 2000. Yet there remains the possibility that in any year the icebreaker(s) used to support the McMurdo break-in could be unavailable (e.g., damaged), the entry to the channel to McMurdo Station could be blocked by an iceberg, or other circumstances could prevent a complete seaborne resupply.
If one annual fuel delivery is missed, or deliberately skipped, the fuel storage capacity at McMurdo Station must be sufficient to supply the USAP for at least a second year; thus, a scheme to supply more fuel than at present is required to create the reserve. This is not yet possible, but there are feasible fuel management scenarios that may provide a fuel reserve. For example, an NSF internal study indicates that if total fuel storage at McMurdo Station is increased from the present 9.5 million gallons to 16 million gallons (neither unreasonable nor unduly expensive), and a tanker is used with 20 percent greater capacity than the one used at present, and if fuel reserves were employed on a one-time basis, the USAP could endure one missed annual delivery of fuel only three years after completion of the larger tank farm.
Another step in reducing the risk to the USAP from the dependence on annual delivery to McMurdo Station is through investing in resources to produce a paradigm shift in the South Pole Station supply chain logistics and methodology, with a goal to significantly reduce, if not eliminate, the single point of potential failure related to operating all South Pole Station logistics through McMurdo Station. At present, NSF is investigating the construction of a hard surface processed snow runway at South Pole Station capable of receiving heavy-lift wheeled aircraft—for example, directly from New Zealand or South America. This option appears to be relatively inexpensive and may take only a few years to construct. It also appears feasible to develop a safe, efficient ground-based traverse capability between various key points (e.g., McMurdo Station, South Pole Station, and an ice shelf or sea-ice edge) for support of both science and logistics missions of the USAP. The NSF reported that the proof-of-concept ground traverse between McMurdo Station and South Pole Station has now been completed.
These logistical changes would also allow existing resources to be used to support new expeditionary science and other program priorities. For example, a large number of valuable LC-130 aircraft flight hours—currently expended on fuel, cargo, and personnel transport flights between McMurdo and South Pole Stations—could be used to access parts of Antarctica that are now difficult or impossible for USAP to support by air from McMurdo Station.
In addition, other options may help reduce the portion of fuel and cargo required to be delivered directly to McMurdo Station. If the icebreaker(s) used to break in to McMurdo did not require refueling from the fuel delivered to McMurdo, the same fuel tanker used today could supply sufficient extra fuel to rapidly build a reserve, as long as the fuel storage capacity at McMurdo is increased. The present Polar class icebreakers require refueling in the Antarctic to maintain icebreaking capability because they do not have sufficient seawater ballast capacity to keep the hull at the depth needed to break heavy ice unless they are nearly fully fueled. NSF reports that it is examining the feasibility of these and similar measures, related to the systems under its purview.
Logically, it may appear that the present dependence on Polar class icebreakers would be eliminated by moving all USAP logistics to a base that did not require breaking heavy ice. An Antarctic coastal base must, however, offer more than simply a location accessible by sea. Major additional considerations include depth of the harbor, weather at key times of the year, suitability of local terrain for locating buildings and storage facilities, support for aircraft, relation to USAP science support and other missions, and so forth. While it is true that McMurdo Station and Scott Base (New Zealand station) are the only present-day Antarctic stations that require Polar class icebreakers for austral summer access, it should be recognized that these are the only Antarctic bases in the Ross Sea sector and also that their location is well chosen. For example, their location within the southwestern Ross Sea is particularly important because this area
typically experiences wind-driven clearing of the sea ice, which greatly aids navigation and access. These conditions make McMurdo Station the southernmost station with marine access, and no other Antarctic coastal station offers 1,000 km air access to the South Pole.2
At least three independent government studies have examined the issue of alternate locations to carry out the functions now based at the USAP McMurdo Station.3 Collectively, these studies stressed that McMurdo Station (1) is the most valuable high-latitude location for operations and science; (2) is suitable for airlift capability, which enables exploration of the continent for scientific study; and (3) should be maintained at its location with permanent facilities. The NSF subcommittee study also concluded that NSF should investigate ways to reduce and restructure the size and impact of its McMurdo area operations. For example, that study noted that it may be possible to (1) move some support services to New Zealand, (2) use support groups whose operational mode requires minimum on-continent personnel and limited during-season rotations, (3) limit on-continent days per science team member to those required for the immediate mission, and (4) provide economic incentives to contractors for saving energy and reducing impact on-continent.
In summary, 50 years of U.S. Antarctic experience, in addition to recent rethinking, have not yet provided the USAP with a compelling alternative to a major base at McMurdo Sound. Some alternative base locations may provide improved support for certain aircraft or reduction in required icebreaking, but not both. These do not address other vital U.S. criteria, such as support for South Pole Station or specific science activities.
One remaining aspect must be addressed: What are the alternatives in the McMurdo region for landing seaborne materials? Because no alternative harbor exists, the only potentially viable choices are landing fuel and cargo onto a glacial ice edge or onto sea ice in the vicinity of McMurdo Station and traversing them to McMurdo Station.
Antarctic ice shelves occur where glacial ice rides out over the ocean. Some ice shelf areas are relatively stable, though break-off of icebergs can and do occur. NSF internal studies show that ice shelves in the McMurdo Station region rise tens of meters above sea level, well above the reach of any ship’s crane. Thus, to unload cargo onto a suitably stable, but high, ice shelf, a notch must first be cut into the ice shelf down to at least the height reachable by the ship’s crane. Those experienced with this procedure, however, indicate that it is not fully satisfactory. Furthermore, it is not yet clear if any area of the Ross Ice Shelf within acceptable ground traverse range of McMurdo Station has the characteristics required to support a stable ice ramp. It might be possible, however, to locate a region of the ice shelf suitable to pump fuel up onto the shelf into a holding facility, with subsequent traverse to McMurdo Station. The NSF reports that it may further investigate this possibility, which might provide some partial, emergency backup fuel delivery capability. If an ice shelf ramp were to be constructed on the Ross Ice Shelf to support alternative remote resupply of McMurdo Station, entry-point storage and traverse infrastructure sufficient to handle the materials delivered onto the ice shelf must be developed, and appropriate personnel hired and trained.
Another technique used to deliver fuel and cargo to some nations’ Antarctic stations is to discharge the materials directly onto sea ice and transport them to a base via traverse. Operators must contend with the inherent instability of sea ice and the quickly manifested effects of transient winds, but under some circumstances it can be done successfully. The USAP has on at least one recent occasion (2003) found it necessary to lay several miles of hose from the closest location its resupply tanker could reach relative to the McMurdo tank farm. The complete fuel operation took a total of 17 days (6 days setting up, 4.5 days pumping, and 6 days breaking down) and was successful. However, considering the large amount of cargo and fuel required annually, plus the many risks and uncertainties, the OAC rejected reliance on this method except as a contingency backup because the methodology carries risk presently judged unacceptable for routine use with the large amount of material landed annually for the USAP.
Hence, despite the potential logistics alternatives, shipborne delivery of fuel and cargo to McMurdo Station will continue to play a key role in current and future USAP logistics. Although steps may be employed to reduce the strict requirement for annual resupply by sea, for the foreseeable future the United States will still need to see that a sea-ice channel is broken and that cargo and fuel ships are escorted through that channel to the vicinity of McMurdo Station where supplies can be offloaded. This will require the assistance of an icebreaker capable of breaking the sea ice in the southern Ross Sea (i.e., a Polar class icebreaker).