The conditions in Antarctica make it nearly impossible to fly in and out of outside of the summer months of November to January, making evacuation efforts extremely rare.
Among the risks of flying in to the south pole in the middle of winter are violent winter storms, limited fuel freezing into an unusable jelly, and being the only plane flying on an entire continent requiring one to be completely self-sufficient.
In the 60 years the research station has been operating for, this is the third rescue mission to have been carried out.
In the past, the austral winter prevented people with serious health conditions from getting out. In 1999, one woman found a lump in her breast and completed her own biopsy, and then administered her own chemotherapy. She waited six months for the winter to thaw for it to be safe enough for a rescue plane to land.