An airbag can include active vents to manage the pressure within the airbag when deployed. The active vent can be at least partially controlled by using a tether. A tether separator can be configured to separate the tether. The tether separator can include an explosive. The tether separator can be operatively positioned relative to the tether such that, when the tether separator is activated, the explosive produces shockwaves and/or heat energy. The shockwaves and/or the heat energy can cause the tether to be separated into two pieces. In some instances, a portion of the tether can be held in tension to facilitate the separation of the tether.