These samples must be taken on exactly the right position, so they must get to work when the ship has reached the correct position no matter what time of day it is. When a channel through the ice has to be found, this goes for the helicopter pilots as well.

Make this lower case
these samples must be taken on exactly the right position, so they must get to work when the ship has reached the correct position no matter what time of day it is. when a channel through the ice has to be found, this goes for the helicopter pilots as well.