A tether management system is disclosed. The tether management system includes a spool, a tension sensor, a controller and a moveable pulley. The spool is rotatable to reel in and reel out a tether. The tension sensor measures a tension of the tether. The controller receives a desired tension of the tether and controls the rotation of the spool to reel in and reel out the tether based on a difference between a measured tension from the tension sensor and the desired tension of the tether. The moveable pulley is disposed to engage tether between the spool and the tension sensor. The moveable pulley being able to be biased and moveable along a linear path to adjust a tension of the tether when the tension of the tether deviates from the desired tension. A method for managing tether is also disclosed.