Half an hour into the operation, he stood and watched as a shell plummeted directly onto hard ground that was covered with a completely flattened net. The thing belly-flopped in a cloud of rocks and dust and tumbled end over end for something like a hundred meters before coming to rest in a big tangle of shroud lines and silky fabric. For the mechanisms that were supposed to disengage the shells from the parasails were sometimes failing and so the tumbling shell was getting wrapped in its shroud lines as it careered across the mesa.