McMurdo is 2385 miles from Christchurch NZ, where support flights originate[0]. Flying from the south coast of NZ at Invercargill saves 208 miles[1]. It's 3222 miles to the South Pole[2].

[0] http://www.gcmap.com/mapui?P=CHC-NZIR [1] http://www.gcmap.com/mapui?P=NZNV-NZIR [2] http://www.gcmap.com/mapui?P=CHC-NZSP