Aspects of the disclosure relate to terminating flight of a balloon that may include separating a connection between a balloon envelope and a payload of the balloon. In one example, a payload separation apparatus includes a first shaft configured to attach to the envelope, a second shaft configured to attach to the payload, a pair of arms, and a bracket arranged to secure the pair of arms to the first shaft. In another example, a system includes a flight termination assembly having a cutting edge configured to cut an opening in the envelope and a payload separation apparatus. The apparatus includes a first shaft configured to attach to the envelope, a second shaft configured to attach to the payload, a pair of arms, and a bracket configured to secure the pair of arms to the first shaft. The system also includes a controller configured to activate the cutting edge.

Aspects of the disclosure relate to terminating flight of a balloon that may include separating a connection between a balloon envelope and a payload of the balloon. In one example, a payload separation apparatus includes a first shaft configured to attach to the envelope, a second shaft configured to attach to the payload, a pair of arms, and a bracket arranged to secure the pair of arms to the first shaft. In another example, a system includes a flight termination assembly having a cutting edge configured to cut an opening in the envelope and a payload separation apparatus. The apparatus includes a first shaft configured to attach to the envelope, a second shaft configured to attach to the payload, a pair of arms, and a bracket configured to secure the pair of arms to the first shaft. The system also includes a controller configured to activate the cutting edge.

Aspects of the disclosure relate to terminating flight of a balloon that may include separating a connection between a balloon envelope and a payload of the balloon. In one example, a payload separation apparatus includes a first shaft configured to attach to the envelope, a second shaft configured to attach to the payload, a pair of arms, and a bracket arranged to secure the pair of arms to the first shaft. In another example, a system includes a flight termination assembly having a cutting edge configured to cut an opening in the envelope and a payload separation apparatus. The apparatus includes a first shaft configured to attach to the envelope, a second shaft configured to attach to the payload, a pair of arms, and a bracket configured to secure the pair of arms to the first shaft. The system also includes a controller configured to activate the cutting edge.

A method of fabricating a high-altitude balloon. The method includes coextruding at least two adjacent continuous layers of extrudate, extrusion-bonding the layers of extrudate to one another along an edge of the sheets of extrudate to form a seam, and cooling the extrudate.

A method of fabricating a high-altitude balloon. The method includes coextruding at least two adjacent continuous layers of extrudate, extrusion-bonding the layers of extrudate to one another along an edge of the sheets of extrudate to form a seam, and cooling the extrudate.

A high altitude balloon including a payload, a balloon film with lifting gas disposed within the balloon film, a sealing ring operably coupled to the balloon film, a retention element configured to retain the payload in contact with the sealing ring, and a release element configured to cause the retention element to release the payload.

Aspects of the disclosure relate to flight termination systems for tethered aerial vehicles. For instance, a flight termination system for a tethered aerial vehicle including an envelope may include a tool and a tether. The tool may include a first piece configured for attachment to an interior surface of the envelope and including a cutting blade. The tool may also include a second piece configured for attachment to an exterior surface of the envelope. The tether may be attached to the first piece such that when in use, a force on the tether causes the tool to cut an opening into the envelope.

Aspects of the disclosure relate to flight termination systems for tethered aerial vehicles. For instance, a flight termination system for a tethered aerial vehicle including an envelope may include a tool and a tether. The tool may include a first piece configured for attachment to an interior surface of the envelope and including a cutting blade. The tool may also include a second piece configured for attachment to an exterior surface of the envelope. The tether may be attached to the first piece such that when in use, a force on the tether causes the tool to cut an opening into the envelope.

Innovative new systems and method of operating the systems, wherein the system comprises an airborne platform comprising an unmanned balloon; a payload that is separate from the unmanned balloon; a transceiver; a flight termination device; at least two separate power sources; a sensor; a processor; a pump; a valve; and an object that when broken separates the unmanned balloon and the payload, are disclosed herein.

Innovative new systems and method of operating the systems, wherein the system comprises an airborne platform comprising an unmanned balloon; a payload that is separate from the unmanned balloon; a transceiver; a flight termination device; at least two separate power sources; a sensor; a processor; a pump; a valve; and an object that when broken separates the unmanned balloon and the payload, are disclosed herein.