Balloon launch tower

Aspects of the disclosure relate to launching high-altitude balloons. For example, a launching system may include a tower having a tubular portion and a top portion. The tubular portion may include an interior space for launching the balloon and the top portion may be configured to allow the balloon to pass into to a space outside of the tower. The tubular portion may also include a plurality of openings configured to redirect air from outside of the tower and into the interior space in order to cause a cyclone of air from the opening towards the top portion. A covering device may be positioned within the tower in order to control airflow from the outside of the tower through the plurality of openings and to cause the cyclone of air.

BACKGROUND

Computing devices such as personal computers, laptop computers, tablet computers, cellular phones, and countless types of Internet-capable devices are increasingly prevalent in numerous aspects of modern life. As such, the demand for data connectivity via the Internet, cellular data networks, and other such networks, is growing. However, there are many areas of the world where data connectivity is still unavailable, or if available, is unreliable and/or costly. Accordingly, additional network infrastructure is desirable.

Some systems may provide network access via a balloon network operating in the stratosphere. These networks may include a large number of high-altitude balloons inflated with lighter than air lift gas and deployed from the ground.

Deploying such balloons under other than ideal weather condition can become very difficult. For example, launching such balloons in a windy environment can be potentially hazardous to bystanders, and in some cases, windy conditions can cause damage to the balloons before they are fully inflated and deployed. Solutions such as using a wind shield to block wind from one direction are less useful when wind changes direction and may have to be constantly adjusted. Tubular towers which protect balloons during inflation may work well until a balloon is actually launched and moves out of the exit at the top of the tower. A strong cross wind can cause the balloon to hit the exit of the tower potentially damaging the balloon. Similarly, launching a balloon from a structure such as a warehouse or hangar may work well until the balloon leaves the protection of the structure and into windy conditions.

BRIEF SUMMARY

Aspects of the disclosure provide a system for launching balloons. The system includes a tower having a tubular portion and a top portion. The tubular portion includes an interior space configured for launching a balloon. The top portion is configured to allow the balloon to pass into to a space outside of the tower. The system also includes a plurality of openings. Each opening of the plurality of openings is configured to redirect air from outside of the tower and into the interior space in order to cause a cyclone of air from the opening towards the top portion. The system also includes a covering device positioned within the tower. The covering device is configured to move between a first position and a second position. The second position allows for reduced airflow from the outside of the tower through the plurality of openings, and the first position allows for airflow from the outside of the tower through the plurality of openings to cause the cyclone of air.

In one example, the top portion includes an outer flange configured to reduce a likelihood of the balloon contacting the top portion when the balloon passes into the space outside of the tower. In another example, each opening of the plurality of openings includes an angled portion located within an outer wall of the tower configured to cause order to cause the cyclone of air. In another example, each opening of the plurality of openings is configured to cause the cyclone of air to direct the balloon through the tower to reduce a likelihood of the balloon contacting an interior surface of the tubular portion. In another example, each opening of the plurality of openings is configured to cause the cyclone of air to direct the balloon through the tower and towards the top portion. In another example, the covering device is configured to be rotated within the tower in order to move between the first position and the second position. In another example, the covering device includes a shape that is complementary to an inner surface of the tower. In another example, the system also includes the balloon. In another example, the covering device is configured to be rotated between the first position and the second position.

In another example, the covering device includes a plurality of holes extending through the covering device configured to allow air from the plurality of openings to flow into the interior space. Each hole of the plurality of holes corresponds to at least one opening of the plurality of openings. In addition, when the covering device is in the second position the plurality of holes are configured to be misaligned with corresponding ones of the plurality of holes. Further, when the covering device is in the first position, the plurality of holes are configured to at least partially align with corresponding ones of the plurality of openings in order to allow for airflow from the outside of the tower through the plurality of openings and to cause the cyclone of air.

DETAILED DESCRIPTION

The technology relates to launching high altitude balloons, and in particular, in windy environments. Because of the size and expense of such balloons it can be difficult to safely launch such balloons in high wind environments. In the past, launches have been aided by using peanuts (specialized clamps for launching high-altitude balloons), wind shields, tubular towers with top openings, or from generally enclosed structures such as a warehouse or hangar. Each of these may have significant draw backs based upon their configurations which can cause balloon launches to be slow, unpredictable, and potentially damaging to the balloons. To address these drawbacks, a specialized launch tower may be used.

As an example, a launch tower may be shaped generally as a tube. The tower may have a top portion that flares out into a bell-like shape. This shape may allow for a balloon that is exiting the tower not to hit the sides of the tower. The tube may include an interior space extending through the tower from the top portion within which allows for the balloon to be placed into the tube and inflated before launch. Thus, the width of the interior space may be at least some minimum distance greater than the maximum width of the balloon, again in order to avoid the balloon hitting the sides of the tube.

The sides of the tower may include a plurality of openings that extend from the outside of the tower to the interior space in the tube. These openings may be shaped in order to redirect air from outside of the tower into the tube in an upward spiral flow. This spiral flow may create an internal cyclone effect pulling the air through the opening and out of the tower at the top portion.

The openings may include various shapes such as slots, circles, ovals, etc. In one example, each opening may include a flange or lip portion on the inside of the opening that redirects the air into an upward direction. This flange may be angular, beveled, or curved in order to direct the air into a particular orientation, such as 45 degrees or more or less relative to the opening. Alternatively or in addition to the flange, the opening itself within an outer wall of the tower may be shaped to redirect the airflow into an upward direction.

In order to allow for placement of the balloon within the tower without the spiral airflow, the plurality of openings may include covers. As an example, these covers may include external louvers that can be opened or closed via a mechanical actuating system to increase or decrease the airflow from outside of the tower, through the openings, and into the interior space of the tube. In this regard, when the louvers are opened whatever wind that passes through the openings may be redirected into the cyclone of air. When the louvers are closed, airflow from outside of the tower and through the openings may be restricted or completely stopped.

In another example, these covers may include an internal cover device that can be changed between positions where the plurality of openings are covered to where the plurality of openings are uncovered via a mechanical actuating system. As an example, the internal cover device may also include a plurality of holes that when aligned with the plurality of openings the plurality of openings are uncovered. The internal cover device may also be configured to be rotated, for example, using bearings or some other mechanical actuating device such that the plurality of holes are eventually no longer aligned with the plurality of openings thereby covering the plurality of openings. To allow the internal cover device to rotate more easily within the tower, the internal cover device may have a shape that is complementary to the interior wall of the tower. In this regard, both the interior wall of the tower and the internal cover device may include a rounded or circular shape.

Again, by changing the position of the internal cover device, this may increase or decrease the airflow from outside of the tower, through the openings, and into the interior space of the tube. In this regard, when the plurality of openings are uncovered whatever wind that passes through the openings may be redirected into the cyclone of air. When the plurality of openings are covered, airflow from outside of the tower and through the openings may be restricted or completely stopped. In some instances, the plurality of openings may also be partially uncovered.

The features described herein allow for a controlling the launch of expensive, high-altitude balloons in environments with relatively high wind speeds. The faster the wind speeds against the tower when the louvers are opened, the faster the internal cyclone effect will be inside the tube. This in turn, may more quickly move the balloon up through the tube and out of the top portion, while at the same time reducing the likelihood of the balloon hitting the inside of the tube.

FIG. 1depicts an example system100in which a high altitude balloons as described above may be used. This example should not be considered as limiting the scope of the disclosure or usefulness of the features described herein. System100may be considered a “balloon network.” In this example, balloon network100includes a plurality of devices, such as of high altitude balloons102A-F as well as ground base stations106and112. Balloon network100may also include a plurality of additional devices, such as various computing devices (not shown) as discussed in more detail below.

As shown, the devices of system100are configured to communicate with one another. As an example, the balloons may include free-space optical links104and/or radiofrequency (RF) links114in order to facilitate intra-balloon communications. In this way, balloons102A-F may collectively function as a mesh network for packet data communications. Further, at least some of balloons102A-B may be configured for RF communications with ground-based stations106and112via respective RF links108. Some balloons, such as balloon102F, could be configured to communicate via optical link110with ground-based station112.

As noted above, to transmit data to another balloon, a given balloon102may be configured to transmit an optical signal via an optical link104. In addition, the given balloon102may use one or more high-power light-emitting diodes (LEDs) to transmit an optical signal. Alternatively, some or all of the balloons may include laser systems for free-space optical communications over the optical links104. Other types of free-space optical communication are possible. Further, in order to receive an optical signal from another balloon via an optical link104, a given balloon may include one or more optical receivers.

The balloons102A-F may collectively function as a mesh network. More specifically, since balloons102A-F may communicate with one another using free-space optical links, the balloons may collectively function as a free-space optical mesh network where each balloon may function as a node of the mesh network. As noted above, the balloons of balloon network100may be high-altitude balloons, which are deployed in the stratosphere. As an example, the balloons may generally be configured to operate at altitudes between 18 km and 25 km above the Earth's surface in order to limit the balloon's exposure to high winds and interference with commercial airline flights. Additional aspects of the balloons are discussed in greater detail below, with reference toFIG. 2.

FIG. 2is an example high-altitude balloon200, which may represent any of the balloons of balloon network100. As shown, the balloon200includes an envelope210, a payload220and a plurality of tendons230-250attached to the envelope210.

The high-altitude balloon envelope210may take various forms. In one instance, the balloon envelope210may be constructed from materials such as polyethylene that do not hold much load while the balloon200is floating in the air during flight. Additionally, or alternatively, some or all of envelope210may be constructed from a highly flexible latex material or rubber material such as chloroprene. Other materials or combinations thereof may also be employed. Further, the shape and size of the envelope210may vary depending upon the particular implementation. Additionally, the envelope210may be a chamber filled with various gases or mixtures thereof, such as helium, hydrogen or any other lighter-than-air gas, hereafter, lift gas. The envelope210is thus arranged to have an associated upward buoyancy force during deployment of the payload220.

The payload220of balloon200is affixed to the envelope by a connection260such as a cable. The payload220may include a computer system (not shown), having one or more processors and on-board data storage. The payload220may also include various other types of equipment and systems (not shown) to provide a number of different functions. For example, the payload220may include an optical communication system, a navigation system, a positioning system, a lighting system, an altitude control system and a power supply to supply power to various components of balloon200.

In view of the goal of making the balloon envelope210as lightweight as possible, it may be comprised of a plurality of envelope lobes or gores that have a thin film, such as polyethylene or polyethylene terephthalate, which is lightweight, yet has suitable strength properties for use as a balloon envelope deployable in the stratosphere. In this example, balloon envelope210is comprised of envelope gores210A-210D.

The individual envelope gores210A-210D may be shaped so that the length of the edge seam connecting adjacent envelope gores is greater than the length of a centerline of the envelope gores. Thus, the envelope gores210A-210D may be shaped to better optimize the strain rate experienced by the balloon envelope210. The pressurized lifting gas within the balloon envelope210may cause a force or load to be applied to the balloon200.

The tendons230-250provide strength to the balloon200to carrier the load created by the pressurized gas within the balloon envelope210. In some examples, a cage of tendons (not shown) may be created using multiple tendons that are attached vertically and horizontally. Each tendon may be formed as a fiber load tape that is adhered to a respective envelope gore. Alternately, a tubular sleeve may be adhered to the respective envelopes with the tendon positioned within the tubular sleeve.

Top ends of the tendons230,240and250may be coupled together using an apparatus, such as top cap201positioned at the apex of balloon envelope210. Bottom ends of the tendons230,240and250may also be connected to one another. For example, a corresponding apparatus, e.g., bottom cap202, is disposed at a base or bottom of the balloon envelope210. The top cap201at the apex may be the same size and shape as and bottom cap202at the bottom. Both caps include corresponding components for attaching the tendons230,240and250, and may be formed from stainless steel or aluminum.

The balloons described above may be inflated with lighter than air lift gas and launched from a launch tower.FIG. 3Ais an example cross-sectional side view of a launch tower300shown over ground302. The launch tower300includes a top portion304that flares out into a bell-like shape306. As noted above, this shape may prevent or reduce the likelihood of a balloon exiting the tower hitting the sides of the tower thereby reducing the likelihood of damage to the balloon where there is a cross wind at the top portion306of the tower.

Below top portion304is a tube308. The tube includes interior space310extending through the tower308from the top portion304. The interior space310may allow for a balloon to be positioned within the tube308of the tower300, inflated with lift gas, and deployed upwards through the top portion304of the tower300. Thus, the width of the interior space310may be at least some minimum distance greater than the maximum width of the balloon, again in order to avoid the balloon hitting the sides of the tube.

The walls308A and308B of the tube308include a plurality of openings312. Each opening of the plurality of openings312extends from an area314outside of the tower300to the interior space310of the tube308. Thus, each opening of the plurality of openings312may allow air to flow from area314through that opening and into the interior space310.

The openings of the plurality of openings312may include various shapes such as slots, circles, ovals, etc. In one example, each opening may include a flange314or lip portion on the inside of the opening. This flange314may be angular, beveled, or curved in order to direct the air into a particular orientation, such as 45 degrees or more or less relative to the opening. Alternatively or in addition to the flange, the opening itself within walls308A and308B of the tube308may be shaped in order to direct airflow from the area314outside of the tower into the interior space310in a particular direction.

The shape of the plurality of openings312and/or flanges316may actually allow the openings and/or flanges redirect air from area314and into the interior space310in an upward spiral flow. This spiral flow may create an internal cyclone effect pulling air through the plurality of openings312and out of the tower300at the top portion304. For example, as shown inFIG. 4, wind or airflow (represented by dashed lines402) may enter the openings312which, in combination with the flanges316, redirect the airflow402in the direction of arrows404. This may cause an internal cyclone of air (a portion of a cyclone represented by dashed line406) to move around balloon200within the interior space310. The cyclone of air moves from the tube308towards the top portion304until it exits the tower300.

In order to allow for placement of the balloon200within the tower300and to control airflow as well as the cyclone of air, the plurality of openings312may include covers. As an example, these covers may include external louvers408that can be opened or closed via a mechanical actuating system (not shown) to increase or decrease the airflow from the area314outside of the tower, through the plurality of openings312, and into the interior space310.FIG. 5is an example depicting a first set of louvers502(corresponding to a portion of louvers408) in an open configuration and a second set of louvers504(also corresponding to a portion of louvers408) in a closed configuration. In this example, louvers are shown in different configurations at the same time, but in other examples, the louvers may all be in the open or may all be in the closed configuration at the same time. When the louvers are in an open configuration, as shown by louvers504, whatever airflow from area314that passes through the plurality of openings506(corresponding to a portion of the plurality of openings312) may be redirected into the cyclone of air. When the louvers are in a closed configuration, as shown by louvers502, airflow from the area314and through the plurality of openings508(corresponding to a portion of the plurality of openings312) may be restricted or completely stopped.

By way of further example,FIG. 6includes three detail views600,620, and640of two of the plurality of openings312, here openings602and604, with corresponding louvers606and608(corresponding to two of louvers408) and flanges610and612(corresponding to two of flanges316). In view600, louvers606and608are depicted in the closed configuration allowing airflow from area314to be redirected into the cyclone, while in views620and640, louvers606and608are depicted in the open configuration restricting or completely stopping airflow through the openings602and604. View620also demonstrates the angle θ of flange612which redirects airflow in the direction of arrow614(corresponding to one of arrows404).

FIG. 7is another example cross-sectional side view of a launch tower700shown over ground702. Tower700may include many of the features of tower300. For example, tower700includes a top portion704that flares out into a bell-like shape706. As noted above, this shape may prevent or reduce the likelihood of a balloon exiting the tower hitting the sides of the tower thereby reducing the likelihood of damage to the balloon where there is a cross wind at the top portion706of the tower.

Below top portion704is a tube708. The tube includes interior space710extending through the tower708from the top portion704. The interior space710may allow for a balloon to be positioned within the tube708of the tower700, inflated with lift gas, and deployed upwards through the top portion704of the tower700. Thus, the width of the interior space710may be at least some minimum distance greater than the maximum width of the balloon, again in order to avoid the balloon hitting the sides of the tube.

The walls708A and708B of the tube708include a plurality of openings712. Each opening of the plurality of openings712extends from an area714outside of the tower700to the interior space710of the tube708. Thus, each opening of the plurality of openings712may allow air to flow from area714through that opening and into the interior space710.

The openings of the plurality of openings312may include various shapes such as slots, circles, ovals, etc. In one example, each opening may extend through a respective portion316of walls708A or708B with an angular, beveled, or curved shape in order to direct the air into a particular orientation, such as 45 degrees or more or less relative to the opening.

The shape of the portions716of the plurality of openings712may actually allow the openings to redirect air from area718and into the interior space710in an upward spiral flow. This spiral flow may create an internal cyclone effect pulling air through the plurality of openings712and out of the tower700at the top portion708. For example, as shown inFIG. 8, wind or airflow (represented by dashed lines802) may enter the openings712which, in combination with the flanges716, redirect the airflow802in the direction of arrows808. This may cause an internal cyclone of air (a portion of a cyclone represented by dashed line806) to move around balloon200within the interior space710. The cyclone of air moves from the tube708towards the top portion708until it exits the tower700.

In order to allow for placement of the balloon200within the tower700and to control airflow as well as the cyclone of air, as with tower300and plurality of openings312, the plurality of openings712may include an internal cover device. For example, returning toFIG. 7, tower300includes an internal cover device718. The internal cover device318can be changed between configurations where the plurality of openings712are covered as shown inFIGS. 7 and 8, to configurations where the plurality of openings712are uncovered, as shown inFIG. 9, via a mechanical actuating system (not shown).

As an example, the internal cover device718may also include a plurality of holes720that when aligned with the plurality of openings712as shown inFIGS. 7 and 8, allow airflow from area714through the plurality of openings712and the plurality of holes720. The internal cover device718may also be configured to be rotated, for example, using bearings or some other mechanical actuating device such that the plurality of holes are eventually no longer aligned with the plurality of openings thereby covering the plurality of openings as shown inFIG. 9.

To allow the internal cover device718to rotate more easily within the tower, the internal cover device718may have a shape that is complementary to an interior wall of the tower. In this regard, both the interior wall of the tower700(for example an interior surface of walls708A and/or708B) and the internal cover device718may include a rounded or circular shape.

FIG. 10is an example of 5 top-down cross-sectional views1000,1010,1020,1030, and1040of a portion of wall708A or708B of tower700. In each of the views, an interior surface of a portion1002of wall708A (or708B) is generally curved and complementary to the shape of a portion1006of internal cover device718. In addition, portion1002of wall708A (or708B) includes opening1004(corresponding to one of the plurality of holes712), and portion1006of internal cover device718includes hole1008(corresponding to one of the plurality of holes720).

Again, by changing the position of the internal cover device718, this may increase or decrease the airflow from area714, through the plurality of openings712, and into the interior space710. In view1000, the hole1008is shown as aligned with opening1004. In this configuration, which may be considered a fully open configuration, whatever airflow from area714that passes through the opening1004may be redirected into the cyclone of air. The internal cover device718may then be rotated, for example in the direction of arrow1012in view1010. In view1010, the hole1008is shown as slightly misaligned with opening1004. In this configuration, which may be considered a partially open configuration, airflow from area714that passes through the opening1004may be reduced from that of view1000. The cover device720may then be further rotated, for example in the direction of arrow1022in view1020. In view1020, the hole1008is shown as completely misaligned with opening1004. In this configuration, which may be considered a closed configuration, airflow from area714that passes through the opening1004may be restricted or completely stopped from entering the interior space710.

The internal cover device718may also be rotated from the closed configuration back towards the open configuration. For example, the internal cover device718may be rotated in the direction of arrow1032in view1030. In view1030, and similar to view1010, the hole1008is shown as slightly misaligned with opening1004. Once again, the internal cover device718is in the partially open configuration where airflow from area714that passes through the opening1004may be reduced from that of view1000but increased from that of view1040. The cover device720may then be further rotated, for example in the direction of arrow1042in view1040. In view1040, the hole1008is shown as aligned with opening1004. Once again, the internal cover device718is in the open configuration where airflow from area714that passes through the opening1004may be redirected into the cyclone of air.

Alternatively, rather than rotating in two different directions relative to the portion1002of wall708A (or708B) in order to change between the open and the closed configurations, the internal cover device718may be rotated in one or two directions over a larger angle. For example, the internal cover device718may be configured to rotate for 360 degrees or less in order to align or misalign the openings and holes. In this regard, a single hole may be configured to be aligned with a plurality of different openings as the internal cover device718is rotated.