People sometimes ask us to put something on the bottom of the sea, for example.
They have no idea how difficult this is. The practical difficulties apply mainly to activities we need to perform for scientists. Towing instruments, installing laboratory equipment onboard, access to buoys at sea with a small boat, placing and recovering moorings, taking whatever sample of bottom, water, fauna. You cannot just do those things; there are currents, animals, there is the buoyancy of the water that you have to fight.