Within the next decade one of humanity's remotest outposts, the British Antarctic Survey's (BAS) Halley 5 research station, will fall victim to the very thing it was built to investigate - global warming. Part of the 150m thick Brunt Ice Shelf to which the research station clings is set to break off, or calve.
The mass, measuring between 600km 2and 1,200km 2will then rapidly disintegrate into a treacherous sea of icebergs.
To get its 70-strong crew of scientists out of danger's way well before calving takes place, and to ensure that its internationally important meteorological and climatological research keeps going without interruption, BAS is accelerating plans to build a new Antarctic station, Halley 6. Last week three designs were selected from 86 entries submitted to a competition.
The three engineer-architect pairings - Expedition Engineering with Michael Hopkins, Buro Happold with Lifschutz Davidson and FaberMaunsell with Hugh Broughton - now have until next September to research the Antarctic environment and evolve their concepts. Construction of the chosen design is scheduled for two short Christmas to late February windows, in 2006-7 and 2007-8, when BAS can get its supply ship to the Brunt Ice Shelf. The £19M contract will be let on a design and build basis, with about £16M left for construction after transportation.
In organising a design competition, BAS has departed from tradition. 'We built Halley 1 in 1956 and have done another four since then. We've done a lot of the design work in house and gone to an architect only for detailed design, ' says BAS Halley 6 project manager and civil engineer Karl Tuplin.
Although BAS has enormous expertise in living in a -50infinity world of snow, ice and howling wind, its own designs tended toward 'extreme functionality', admits BAS head of physical sciences Mike Pinnock, a veteran of three seasons at Halley 3 during the 1970s. This time around, BAS wanted to see what private sector thinking would bring to the Brunt Ice Shelf.
The first four Halley stations were placed directly on the ice shelf 's surface and were quickly buried in Antarctica's 1.5m annual snowfall. 'If BAS had a motto it would be 'everybody digs', ' deadpans Pinnock. Halley 5 was equipped with jackable legs to keep it above ground level, although raising the structure is a full two day operation.
Pinnock estimates that the station's scientists spend about 40% of their time engaged in 'base duties' - anything from snow shovelling, through repair and maintenance of structures, equipment and infrastructure, receiving supply ships, to cooking and cleaning. The 60% of time spent setting up research equipment and running experiments is far from cushy.
But with Halley 6, BAS is setting out to reduce the time spent overcoming the 'challenge of survivability' by making the station building itself far more user friendly and comfortable, says Tuplin. 'Achieving that means we can allow more time for science, or alternatively we can reduce the numbers of people stationed there, ' says Pinnock.
'That reduces running costs and environmental impact.'
BAS has avoided detailed specifications for Halley 6, preferring to set a performance brief around particular challenges.
Tuplin has urged designers to look at new ways of using tried and tested technology, rather than bespoke solutions. 'If anything goes wrong, people out there are on their own, cut off from the rest of the world. They have to be able to fix things themselves.'
As well as being able to jack accommodation units up above each year's snowfall, BAS wants Halley 6 to be relocatable, as ice making up the Brunt Shelf flows 400m a year. Halley 5, completed in 1991, is founded on legs that, with the accumulation of snow, have effectively become deep friction piles, rooting it in the ice.
BAS will be looking to move Halley 6 up to 10km, two to three times over the course of its life. This has to be achievable using BAS standard 20t Caterpillar bulldozers.
All supplies, construction materials and equipment for the Halley research station are landed during the Antarctic summer on sea ice bounding the ice shelf proper. This has a nominal bearing capacity of 20t. Tractors used by BAS weigh in at 10t and sleds 3t, leaving only 7t for cargo.
Halley 6 will have to be built from small, lightweight components.
To keep Halley 6's environmental imprint as low as possible BAS has given designers a 125kV limit for energy generated from fossil fuels. Any additional power will have to be generated using renewable energy sources.
'But the biggest constraint is the programme. We have little more than four months construction time, spread over two years, ' says Tuplin.