Before revision: Drillings at the landing site at 90°N showed an average ice thickness of 2.5 metres on April 16, 1990 275px|This pressure ridge at the North Pole is about 1 km (0.62 mi.)
After revision: (8.2 feet)Drillings at the landing site at 90°N showed an average ice thickness of 2.5 metres on April 16, 1990 275px|This pressure ridge at the North Pole is about 1 km (0.62 mi.)