Previous bases at Halley
While there are many strong scientific reasons for Halley’s location on the Brunt Ice Shelf, supporting a station on a floating ice shelf creates a number of unique challenges. The region receives around a metre of snow accumulation every year so any object left out on the surface is quickly buried. The original Halley station, a simple collection of wooden huts, was quickly overcome by the rising snow. Although new buildings were added over the following years these too were buried, forming a multi-level complex far below the surface. By the time Halley I was abandoned it was 14 metres deep, and the temperature of the living and sleeping facilities had dropped to -18C.
|Original Hut after the first winter.||Several years later the base had been expanded and occupies several levels.|
In 1967 a new station was built to replace the original complex. Halley II was also made up of a series of wooden huts, but the roofs were reinforced with steel supports to help support the weight of the snow. Unfortunately this proved no more successful than the original design and the station had to be abandoned after just seven years.
|Halley 2 after its first winter.|
Halley III was the first station specifically designed to be able to cope with being buried by the ice. The buildings were prefabricated huts surrounded by corrugated steel conduits, which helped prevent the movement of the ice from crushing the structures inside. Halley III lasted for 12 years before it was abandoned in 1983. By this stage it was becoming too deep to access safely. Also, heat escaping from the buildings increased the movement of the surrounding the ice, which crushed the steel tubing and distorted the structure of the base.
|The Halley III entrance shaft.|
|Construction of Halley III.||Halley III reemerging from the ice shelf many years later.|
For Halley IV, two storey huts were housed inside conduits made from interlocking plywood panels. The panels contained specially constructed air gaps which were designed to prevent the heat from the station from escaping into the ice. It was hoped that this would reduce the distortions and prevent the buildings from being crushed as quickly as Halley III. Unfortunately windtails that formed while the base was being buried warped the cylindrical shape of the external structure, reducing its strength and allowing heat to escape. With the wooden tube no longer supporting the weight of the accumulating snow, it became an ongoing task to periodically excavate the ice above the buildings to keep it from crushing the wooden structures below. By 1985, just a couple of years after Halley IV was occupied, it became clear that another new station would be required.
|Halley IV after its first year of scientific operation.|
|Construction of Halley IV.||Clearing snow from the roof of Halley IV to prevent the buildings being crushed.|
After seven years of planning, design and construction Halley V was completed in February 1992. The new station had a revolutionary design which departed significantly from the approach of the previous four stations. Instead of attempting to strengthen against the pressure from the ice, Halley V consisted of three wooden structures built on jackable steel legs to keep them above the snow surface. In subsequent years additional buildings mounted on skis were added. These could be moved annually by bulldozers to keep them from being buried. Maintaining the buildings above ground level allowed Halley V to outlast any of the previous stations while providing greatly improved conditions for those living on site.
|The Laws Platform was the main accommodation platform at Halley V.||The Laws, with the Simpson Platform and melt tank in the background.|