Abstract: The positions of balloons in a communication network of balloons, such as a mesh network of high-altitude balloons, may be adjusted relative to one another in order to try to maintain a desired network topology. In one approach, the position of each balloon may be adjusted relative to one or more neighbor balloons. For example, the locations of a target balloon and one or more neighbor balloons may be determined. A desired movement of the target balloon may then be determined based on the locations of the one or more neighbor balloons relative to the location of the target balloon. The target balloon may be controlled based on the desired movement. In some embodiments, the altitude of the target balloon may be controlled in order to expose the target balloon to ambient winds that are capable of producing the desired movement of the target balloon.

Abstract: Methods and systems are disclosed herein that may help to provide location-aware caching and/or location-specific service profiles in a balloon network. An exemplary method may be carried out by a balloon that is at a location associated with the first geographic area in a balloon network that includes a plurality of defined geographic areas, and may involve: (a) determining that a location-aware cache of a balloon should be updated with user-data associated with the first geographic area; and (b) in response to determining that the location-aware cache should be updated: (i) sending a location-aware cache-update request; (ii) receiving, as a response to the location-aware cache-update request, user-data that corresponds to the first geographic area; and (iii) storing the user-data that corresponds to the first geographic area in a location-aware cache of the balloon.

Abstract: Some embodiments provide a system that executes a native code module. During operation, the system obtains the native code module. Next, the system loads the native code module into a secure runtime environment. Finally, the system safely executes the native code module in the secure runtime environment by using a set of software fault isolation (SFI) mechanisms that use predicated store instructions and predicated control flow instructions, wherein each predicated instruction from the predicated store instructions and the predicated control flow instructions is executed if a mask condition associated with the predicated instruction is met.

Abstract: A balloon that includes an envelope with a gas contained within the envelope, as well as a payload connected to the envelope wherein the envelope has a first portion that has a first absorptive or reflective property with respect to allowing solar energy to be transferred to the gas within the envelope, and a second portion that has a second absorptive or reflective property with respect to allowing solar energy to be transferred to the gas within the envelope where the second absorptive or reflective property is different than the first absorptive or reflective property, and wherein the envelope is rotatable to allow a preferred ratio of the first and second portions of the envelope to be positioned facing the sun.

Abstract: Exemplary embodiments may involve hierarchical balloon networks that include both optical and radio frequency links between balloons. An exemplary network system may include: (a) a plurality of super-node balloons, where each super-node balloon comprises a free-space optical communication system for data communications with one or more other super-node balloons and (b) a plurality of sub-node balloons, where each of the sub-node balloons comprises a radio-frequency communication system that is operable for data communications. Further, at least one super-node balloon may further include an RF communication system that is operable to transmit data to at least one sub-node balloon, where the RF communication system of the at least one sub-node balloon is further operable to receive the data transmitted by the at least one super-node balloon and to transmit the received data to at least one ground-based station.

Abstract: Example embodiments may facilitate altitude control by a balloon in a balloon network. An example method involves: (a) causing a balloon to operate in a first mode, wherein the balloon comprises an envelope, a high-pressure storage chamber, and a solar power system, (b) while the balloon is operating in the first mode: (i) operating the solar power system to generate power for the balloon and (ii) using at least some of the power generated by the solar power system to move gas from the envelope to the high-pressure storage chamber such that the buoyancy of the balloon decreases; (c) causing the balloon to operate in a second mode; and while the balloon is operating in the second mode, moving gas from the high-pressure storage chamber to the envelope such that the buoyancy of the balloon increases.

Abstract: Disclosed embodiments relate to a combined shipping container and balloon deployment system for deploying balloons into a balloon network. Such a shipping container may allow one or more balloons to be transported to a desired launch location, and then launched directly from the shipping container.

Abstract: A balloon may include an optical-communication component, which may have a pointing axis. A pointing mechanism could be configured to adjust the pointing axis. The optical-communication component could be operable to communicate with a correspondent balloon via a free-space optical link. For example, the optical-communication component could include an optical receiver, transmitter, or transceiver. A controller could be configured to determine a predicted relative location of the correspondent balloon. The controller may control the pointing mechanism to adjust the pointing axis of the optical-communication component based on the predicted relative location so as to maintain the free-space optical link with the correspondent balloon.

Abstract: Methods and systems involving an incentivized recovery of balloon materials are disclosed herein. An example system may be configured to: (a) determine a landing location of a balloon, where the balloon has been configured to operate as a node in a balloon network; (b) detect a removal event corresponding to the balloon ceasing to operate as a node in the balloon network and descending to the landing location; and (c) in response to detecting the removal event, initiate a transmission of a recovery-assistance signal that is comprised of (i) location data corresponding to the landing location of the balloon and (ii) an indication of an incentive to recover the balloon.

Abstract: A balloon having an envelope and a payload positioned beneath the envelope. The envelope comprises a first portion and a second portion, wherein the first portion allows more solar energy to be transferred to gas within the envelope than the second portion. The balloon may operate in a first mode in which altitudinal movement of the balloon is caused, at least in part, by rotating the envelope to change an amount of the first portion that faces the sun and an amount of the second portion that faces the sun, and wherein the control system is further configured to cause the balloon to operate in a second mode in which altitudinal movement of the balloon is caused, at least in part, by moving a lifting gas or air into or out of the envelope.

Abstract: A balloon includes a cut-down device, a payload, and an envelope. A control system could be configured to determine a position of the balloon with respect to a predetermined zone. The cut-down device could be operable to cause at least the payload to land in response to determining that the position of the balloon is within the predetermined zone. The predetermined zone includes an exclusion zone and a shadow zone. The shadow zone could include locations from which the balloon would be likely to drift into the exclusion zone based on, e.g., historic weather patterns or expected environmental conditions. Boundaries of the shadow zone could be determined based on, for example, a probability of the balloon entering the exclusion zone.

Abstract: Some embodiments provide a system that executes a native code module. During operation, the system obtains the native code module. Next, the system loads the native code module into a secure runtime environment. Finally, the system safely executes the native code module in the secure runtime environment by using a set of software fault isolation (SFI) mechanisms that constrain store instructions in the native code module. The SFI mechanisms also maintain control flow integrity for the native code module by dividing a code region associated with the native code module into equally sized code blocks and data blocks and starting each of the data blocks with an illegal instruction.

Abstract: Disclosed embodiments may help a balloon network to provide substantially continuous service in a given geographic area. An example method may be carried out at a balloon that is at a location associated with the first geographic area in a balloon network that includes a plurality of geographic areas. The balloon may determine that it should update its balloon-state in accordance with a balloon-state profile for the first geographic area. Then, in response, the balloon may determine the balloon-state profile for the first geographic area, which may include one or more state parameters for balloons operating in the first geographic area. The balloon may then operate according to the balloon-state profile for the first geographic area.

Abstract: The positions of balloons in a communication network of balloons, such as a mesh network of high-altitude balloons, may be adjusted relative to one another in order to try to maintain a desired network topology. In one approach, the position of each balloon may be adjusted relative to one or more neighbor balloons. For example, the locations of a target balloon and one or more neighbor balloons may be determined. A desired movement of the target balloon may then be determined based on the locations of the one or more neighbor balloons relative to the location of the target balloon. The target balloon may be controlled based on the desired movement. In some embodiments, the altitude of the target balloon may be controlled in order to expose the target balloon to ambient winds that are capable of producing the desired movement of the target balloon.

Abstract: A balloon that includes an envelope with a gas contained within the envelope, as well as a payload connected to the envelope wherein the envelope has a first portion that has a first absorptive or reflective property with respect to allowing solar energy to be transferred to the gas within the envelope, and a second portion that has a second absorptive or reflective property with respect to allowing solar energy to be transferred to the gas within the envelope where the second absorptive or reflective property is different than the first absorptive or reflective property, and wherein the envelope is rotatable to allow a preferred ratio of the first and second portions of the envelope to be positioned facing the sun.

Abstract: A balloon may include an optical-communication component, which may have a pointing axis. A pointing mechanism could be configured to adjust the pointing axis. The optical-communication component could be operable to communicate with a correspondent balloon via a free-space optical link. For example, the optical-communication component could include an optical receiver, transmitter, or transceiver. A controller could be configured to determine a predicted relative location of the correspondent balloon. The controller may control the pointing mechanism to adjust the pointing axis of the optical-communication component based on the predicted relative location so as to maintain the free-space optical link with the correspondent balloon.

Abstract: A balloon may include an optical-communication component, which may have a pointing axis. A pointing mechanism could be configured to adjust the pointing axis. The optical-communication component could be operable to communicate with a correspondent balloon via a free-space optical link. For example, the optical-communication component could include an optical receiver, transmitter, or transceiver. A positioning system could be configured to acquire a first location, which could be based on the location of the balloon. A controller could be configured to acquire a second location, which could be based on a location of the correspondent balloon. The controller may determine an approximate target axis based on the first location and the second location. The controller may control the pointing axis of the optical-communication component within a scanning range based on the approximate target axis to establish the free-space optical link with the correspondent balloon.

Abstract: Exemplary embodiments may involve hierarchical balloon networks that include both optical and radio frequency links between balloons. An exemplary network system may include: (a) a plurality of super-node balloons, where each super-node balloon comprises a free-space optical communication system for data communications with one or more other super-node balloons and (b) a plurality of sub-node balloons, where each of the sub-node balloons comprises a radio-frequency communication system that is operable for data communications. Further, at least one super-node balloon may further include an RF communication system that is operable to transmit data to at least one sub-node balloon, where the RF communication system of the at least one sub-node balloon is further operable to receive the data transmitted by the at least one super-node balloon and to transmit the received data to at least one ground-based station.

Abstract: Some embodiments provide a system that executes a native code module. During operation, the system obtains the native code module. Next, the system loads the native code module into a secure runtime environment. Finally, the system safely executes the native code module in the secure runtime environment by using a set of software fault isolation (SFI) mechanisms that constrain store instructions in the native code module. The SFI mechanisms also maintain control flow integrity for the native code module by dividing a code region associated with the native code module into equally sized code blocks and data blocks and starting each of the data blocks with an illegal instruction.