Most people leave Antarctica in the winter. According to worldpopulationstatistics.com, the summer population of approximately 5000 drops to 1000 in the winter. In the interior the winter minimum temperature does drop into the -80C to -90C outside. In the coastal areas (where almost all the bases are located), the summer temperatures hit highs in the 5C to 15C range.
Given all that, I think it's safe to say that the station would be indoors at one of the established bases. Even in the interior in the winter, most of the equipment would not be exposed to temperatures outside their specs. That leaves only the antenna and feedline problems.
For feedline, Andrews or Heliax hardline is good for operations down to between -55C and -70C depending on the size/brand and can be idle at even lower temperatures. The research stations probably use something like this.
The good news for antennas is that Antarctica is mostly a desert with the average precipitation in the 4"-8" range. So, icing up might not be much of a problem. But is does get pretty windy. Most of Antarctic is at 3000-5000m altitude and the cold dense air runs "downhill" at the coast, especially in the presence of an approaching low preasure system, causing katabatic winds of as much as 220 km/hr.
So, depending on how long you want those dipoles to last, you could consider copper coated steel cables strung between a couple towers or posts.
There is a Yahoo! Group for Antarctic Hams which is open, poking around there might answer some additional questions. Since we are coming into the Southern Hemisphere summer, activity there is starting to pick up.