The technology relates to techniques for lighter than air vehicle redundant pressure sensor calibration. A lighter than air (LTA) vehicle can include a redundant pressure sensor calibration system, including a high precision pressure sensor onboard the LTA vehicle and two or more additional pressure sensors onboard the LTA vehicle, where the two or more additional pressure sensors are each redundant with the high precision pressure sensor. The two or more additional pressure sensors can be calibrated based on pressure measurements from the high precision pressure sensor and the two or more additional pressure sensors at two or more altitudes, wherein the high precision pressure sensor is calibrated before a flight of the LTA vehicle.

The technology relates to techniques for lighter than air vehicle redundant pressure sensor calibration. A lighter than air (LTA) vehicle can include a redundant pressure sensor calibration system, including a high precision pressure sensor onboard the LTA vehicle and two or more additional pressure sensors onboard the LTA vehicle, where the two or more additional pressure sensors are each redundant with the high precision pressure sensor. The two or more additional pressure sensors can be calibrated based on pressure measurements from the high precision pressure sensor and the two or more additional pressure sensors at two or more altitudes, wherein the high precision pressure sensor is calibrated before a flight of the LTA vehicle.

Rigid structural-frame dirigible comprising an internal framework divided in internal zones fixedly clearly separated and sealingly isolated therebetween through rigid partition means in fixed union with the internal frame itself, and suitable for being evacuated to a vacuum regime, respectively forming as many vacuum zones (3A; 3B; 3C).

Rigid structural-frame dirigible comprising an internal framework divided in internal zones fixedly clearly separated and sealingly isolated therebetween through rigid partition means in fixed union with the internal frame itself, and suitable for being evacuated to a vacuum regime, respectively forming as many vacuum zones (3A; 3B; 3C).

The technology relates to techniques for a dynamic threshold for a pressure or altitude trigger for a lighter than air vehicle. A method of operating a system of an LTA vehicle can include setting a dynamic threshold of a system to a first value based on one or both of a first measured pressure altitude and a first measured absolute pressure, receiving an indication that the LTA vehicle has increased its altitude, and setting the dynamic threshold of the system to a second value based on one or both of a second measured pressure altitude and a second measured absolute pressure. A flight termination system for an LTA vehicle can include mechanical actuation systems configured to be triggered based on dynamic thresholds. A method of terminating the flight of an LTA vehicle can include triggering the mechanical actuation systems based on dynamic thresholds.

The technology relates to techniques for a dynamic threshold for a pressure or altitude trigger for a lighter than air vehicle. A method of operating a system of an LTA vehicle can include setting a dynamic threshold of a system to a first value based on one or both of a first measured pressure altitude and a first measured absolute pressure, receiving an indication that the LTA vehicle has increased its altitude, and setting the dynamic threshold of the system to a second value based on one or both of a second measured pressure altitude and a second measured absolute pressure. A flight termination system for an LTA vehicle can include mechanical actuation systems configured to be triggered based on dynamic thresholds. A method of terminating the flight of an LTA vehicle can include triggering the mechanical actuation systems based on dynamic thresholds.

The technology provides a launch rig structure capable of filling a very large balloon envelope while the balloon is arranged vertically. The filled balloon is capable of staying aloft in the stratosphere with its payload for months or longer. The launch rig structure is configured to rotate up to 360° in response to current wind conditions. It includes an integrated lifting boom and gas handling system to fill the envelope. A payload release assembly is configured to couple with a rigid connection member of the balloon, enabling the envelope to be filled while in a vertical orientation. The payload release assembly is part of a launch cart that is positioned within the interior space of the launch rig. A gripper assembly engages with the rigid connection member. Once the envelope is filled, the gripper assembly disengages from the connection member so that the balloon floats away from the launch rig.

The technology provides a launch rig structure capable of filling a very large balloon envelope while the balloon is arranged vertically. The filled balloon is capable of staying aloft in the stratosphere with its payload for months or longer. The launch rig structure is configured to rotate up to 360° in response to current wind conditions. It includes an integrated lifting boom and gas handling system to fill the envelope. A payload release assembly is configured to couple with a rigid connection member of the balloon, enabling the envelope to be filled while in a vertical orientation. The payload release assembly is part of a launch cart that is positioned within the interior space of the launch rig. A gripper assembly engages with the rigid connection member. Once the envelope is filled, the gripper assembly disengages from the connection member so that the balloon floats away from the launch rig.

The technology described here relates to LTA vehicle launch configuration and in-flight optimization. A method for automated ballast dropping by an LTA vehicle in flight may include receiving, by an in-flight ballast model, an initial lift gas fill amount and an initial ballast amount, generating altitude ranges based on a remaining lift gas amount and a current system mass of the LTA vehicle to determine whether the remaining lift gas amount is within a ballast drop lift gas range, determining whether a convergence criterion for the remaining lift gas amount is met, the convergence criterion indicating a convergence between a remaining lift gas estimate and a remaining lift gas model, determining that dropping a ballast increment will not decrease an overall ballast amount below a target ballast amount corresponding to the remaining lift gas amount, and causing the LTA vehicle to drop the ballast increment.

The technology described here relates to LTA vehicle launch configuration and in-flight optimization. A method for automated ballast dropping by an LTA vehicle in flight may include receiving, by an in-flight ballast model, an initial lift gas fill amount and an initial ballast amount, generating altitude ranges based on a remaining lift gas amount and a current system mass of the LTA vehicle to determine whether the remaining lift gas amount is within a ballast drop lift gas range, determining whether a convergence criterion for the remaining lift gas amount is met, the convergence criterion indicating a convergence between a remaining lift gas estimate and a remaining lift gas model, determining that dropping a ballast increment will not decrease an overall ballast amount below a target ballast amount corresponding to the remaining lift gas amount, and causing the LTA vehicle to drop the ballast increment.