 Resupply for T-3 was hampered by a mix of varying obstacles.Due to the iceberg's constantly moving location, resupply had to be operated from two air bases Point Barrow, Alaska and Thule Air Base, Greenland.At that time, flights were conducted without navigational aids, and the aircraft landing on the constantly moving iceberg T-3 was performed solely by dead reckoning and celestial grid navigation, which was often hampered by long periods of twilight which prevented celestial observation.