An airborne payload control system comprising: an unmanned aircraft; a payload line comprising a first end and a second end, the second end of the payload line configured to couple to a payload; a sensor configured to sense information about the payload line including position, velocity, and altitude of the second end of the payload line; a winch system on the unmanned aircraft operable to spool the payload line, the winch system comprising a main reel, a first and a second pinch roller (230a, 230b), and a first motor, wherein: the first end of the payload line is wound around the main reel; the payload line is threaded between the first pinch roller and the second pinch roller; the first motor is configured to turn the main reel; and one or more controllers operable to: receive, from the sensor, the information about the payload line; and based on the received information, provide instructions to the unmanned aircraft and the winch system in order to control a position of the second end of the payload line, including reeling the payload line in or out and controlling, based on the received information, one or more of the flight path, speed, orbit, and altitude of the unmanned aircraft, characterised by the winch system comprising a second motor configured to turn the first and second pinch rollers (230a, 230b), wherein, in response to reeling the payload line in or out, the one or more controllers are operable to: instruct the first motor to turn the main reel and instruct the second motor to apply a braking function; or instruct the second motor to turn the first and second pinch rollers (230a, 230b) and instruct the first motor to apply a braking function, either instruction permitting tension to be maintained in the payload line between the main reel and the first and second pinch rollers (230a, 230b). an unmanned aircraft; a payload line comprising a first end and a second end, the second end of the payload line configured to couple to a payload; a sensor configured to sense information about the payload line including position, velocity, and altitude of the second end of the payload line; a winch system on the unmanned aircraft operable to spool the payload line, the winch system comprising a main reel, a first and a second pinch roller (230a, 230b), and a first motor, wherein: the first end of the payload line is wound around the main reel; the payload line is threaded between the first pinch roller and the second pinch roller; the first motor is configured to turn the main reel; and one or more controllers operable to: receive, from the sensor, the information about the payload line; and based on the received information, provide instructions to the unmanned aircraft and the winch system in order to control a position of the second end of the payload line, including reeling the payload line in or out and controlling, based on the received information, one or more of the flight path, speed, orbit, and altitude of the unmanned aircraft, receive, from the sensor, the information about the payload line; and based on the received information, provide instructions to the unmanned aircraft and the winch system in order to control a position of the second end of the payload line, including reeling the payload line in or out and controlling, based on the received information, one or more of the flight path, speed, orbit, and altitude of the unmanned aircraft, characterised by the winch system comprising a second motor configured to turn the first and second pinch rollers (230a, 230b), wherein, in response to reeling the payload line in or out, the one or more controllers are operable to: instruct the first motor to turn the main reel and instruct the second motor to apply a braking function; or instruct the second motor to turn the first and second pinch rollers (230a, 230b) and instruct the first motor to apply a braking function, instruct the first motor to turn the main reel and instruct the second motor to apply a braking function; or instruct the second motor to turn the first and second pinch rollers (230a, 230b) and instruct the first motor to apply a braking function, either instruction permitting tension to be maintained in the payload line between the main reel and the first and second pinch rollers (230a, 230b).