The Balloon Guidance System (BGS for short) consists of several elements which work together to alter the trajectory (flight path) of the balloon system. We use the term BGS to refer to the entire system including hardware and software, equipment that flies with the balloon, equipment that remains on the ground (computers for example), and the personnel required to operate the equipment.

The flight segment of the Balloon Guidance System (BGS) is all the hardware and software that flies with the balloon. The flight segment consists of a BGS wing assembly a tether, and a gondola interface package (TIP), as well as software that is loaded on computers.

The gondola interface package (GIP) remains physically attached to the gondola (equipment package) of the balloon. A winch system reels out a very long tether that supports the wing assembly. Initially, the wing assembly is stowed compactly with the gondola at launch and the tether is held on a very large spool. The GIP also includes interface hardware and software to accept commands from and relay data to the balloon payload.

The wing assembly is the portion of the BGS flight segment that is lowered on the end of the tether. The largest element of the wing assembly is a wing on end. The wing is the element that generates the aerodynamic forces which alter the balloon's flight path. The wing assembly includes a rudder to control the direction of the wing's pull. An electronics module in the wing assembly uses solar power and batteries to control the rudder, process data from various sensors, and communicate by radio with the GIP.