Patent Description:
Antennas, such as ultrahigh frequency ("UHF") antennas, may require a large size in order to provide efficient radiofrequency performance for the application (e.g. for space applications). For example, antennas used in space applications, such as traditional UHF antennas may be too large to be easily accommodated on the earth deck of a satellite and need to be stowed to fit inside the launcher fairing. Further, due to the large size, difficulty may arise when servicing of space-based antennas in outer space is required as the large size of the antenna can inhibit transport of replacement antennas.

More generally, extendable structures, one example of which is a deployable antenna, are desired that have a stowed (non-deployed) configuration and a deployed configuration. Such an extendable structure can act as a support for a mass, such as a radiating element of an antenna, attached directly or indirectly to the extendable structure, such that the mass is extended or translated with the deployment of the extendable structure. Preferably, the ratio of the extendable structure in the stowed configuration to the deployed configuration is relatively low, to limit the space occupied by the extendable structure in the stowed configuration while still being capable of extending to an appropriate length for the application in the deployed configuration. <CIT> & <CIT>) teach of a deployable helical antenna connected to a support structure formed of rings and longerons. <CIT>), dating from <NUM> discloses a deployable helical antenna connected to a boom formed of annular segments and bands. <CIT>) discloses a deployable helical antenna forming a cylindrical structure formed of toroidal members connected by bands.

Accordingly, there is a need for an improved deployable antenna assembly and improved systems and methods for deploying an extendable structure that overcome at least some of the disadvantages of existing systems and methods.

The present invention provides a system for a deployable antenna assembly in accordance with claim <NUM>. The deployable antenna assembly is provided with an extendable pillar configured to extend in an axial direction along a deployment axis of the deployable antenna assembly to deploy an antenna. The extendable pillar includes at least one extendable element configured to convert between a stowed configuration and a deployed configuration, wherein the extendable element in a deployed configuration is longer in the axial direction than the extendable element in a stowed configuration; and a launcher configured to initiate conversion of the plurality of extendable elements from the stowed configuration to the deployed configuration, thereby extending the extendable pillar and deploying the antenna.

The deployable antenna assembly may further include a helical radiating element configured to connect to the extendable pillar such that an extendable section of the helical radiating element is translated in the axial direction along the deployment axis upon the extension of the extendable pillar in the axial direction, the helical radiating element configured to transmit or receive a radio frequency (RF) signal. The deployable antenna assembly may further include a fixed base support connected to the helical radiating element, wherein the fixed base support stabilizes the helical radiating element when the helical radiating element extends concurrently in the axial direction with the extendable pillar. The launcher includes a retaining device configured to retain each extendable element in the stowed configuration in which extension of the respective extendable element is constrained and the extendable element stores potential energy that is releasable to extend the extendable element along the deployment axis.

The retaining device includes ball bearings positioned to contact each extendable element, and movement of the ball bearings initiates conversion of each extendable element from the stowed configuration to the deployed configuration. The retaining device may include a retaining wire, the retaining wire under tension when the extendable element is in the stowed configuration, and wherein the launcher is configured to release the tension from the retaining wire to initiate conversion of the extendable element from the stowed configuration to the deployed configuration.

The extendable pillar may include a plurality of extendable elements. The launcher may initiate conversion of each of the extendable elements sequentially. The launcher may initiate conversion of each of the extendable elements simultaneously. Each of the extendable elements may include at least one spring tape extendable structure, the at least one spring tape extendable structure folded when the extendable element is in the stowed configuration and unfolded when the extendable element is in the deployed configuration. The at least one spring tape extendable structure is constrained in the stowed configuration and stores potential energy releasable to extend the respective extendable element in the axial direction.

The helical radiating element may operate at an ultrahigh radiofrequency wavelength.

The axial and bending stiffness for the at least one extendable element may be greater in the deployed configuration than in the stowed configuration. The axial and bending stiffness may be at least <NUM> orders of magnitude greater in the deployed configuration than in the stowed configuration.

The launcher may guide the at least one extendable element along the axial direction during conversion from the stowed configuration to the deployed configuration.

The system includes a plurality of extendable elements, wherein each extendable element is configured to: connect with another extendable element to form an extendable pillar, wherein the extendable pillar is configured to extend in an axial direction along a deployment axis; and convert between a stowed configuration and a deployed configuration, wherein each of the extendable elements in a deployed configuration is longer in the axial direction than an extendable element in a stowed configuration; a launcher configured to: connect with the extendable pillar; and initiate conversion of the plurality of extendable elements from the stowed configuration to the deployed configuration; and a helical radiating element configured to: connect, directly or indirectly, to the extendable pillar; extend an extendable section of the helical radiating element, wherein the extendable section is translated in the axial direction along the deployment axis upon the extension of the extendable pillar in the axial direction; and transmit or receive a radio frequency (RF) signal.

The system may include a fixed base configured to connect with the helical radiating element, wherein the fixed base stabilizes the helical radiating element when the helical radiating element extends concurrently in the axial direction with the extendable pillar.

The launcher may be configured to initiate conversion of each of the extendable elements sequentially. The launcher may be configured to initiate conversion of each of the extendable elements simultaneously.

The extendable elements may include a plurality of spring tape extendable structures, wherein each of the plurality of spring tape extendable structures is folded when the extendable element is in the stowed configuration and unfolded when the extendable element is in the deployed configuration. Each spring tape extendable structure is constrained in the stowed configuration and stores potential energy releasable to extend the respective extendable element in the axial direction.

The axial and bending stiffness for the at least one extendable element may be greater in the deployed configuration than in the stowed configuration. The axial and bending stiffness may be at least <NUM> orders of magnitude greater in the deployed configuration than in the stowed configuration. The launcher may guide the at least one extendable element along the axial direction during conversion from the stowed configuration to the deployed configuration.

Provided in another aspect of the invention is a method of deploying an antenna, in accordance with claim <NUM>.

The extendable pillar may include a plurality of extendable elements.

The extendable elements may be converted from the stowed configuration and the deployed configuration sequentially.

The extendable elements may be converted from the stowed configuration and the deployed configuration simultaneously.

The extendable elements may include a plurality of spring tape extendable structures, wherein each of the plurality of spring tape extendable structures is folded when the extendable element is in the stowed configuration and unfolded when the extendable element is in the deployed configuration.

Converting the extendable element between the stowed configuration and the deployed configuration may include converting one or more spring tape extendable structures from a folded configuration to an extended configuration, thereby releasing potential energy stored by the one or more spring tape extendable structures in the folded configuration.

The method may include inputting a command on a user terminal to convert each of the extendable elements from a stowed configuration to a deployed configuration; transmitting the command from a base station to a communications satellite, the extendable pillar disposed on the communications satellite; and performing the method described above in response to receiving the command. The may include transmitting or receiving an RF signal at an ultrahigh radiofrequency wavelength via the extended helical radiating element. The axial and bending stiffness for each extendable element may be greater in the deployed configuration than in the stowed configuration. The axial and bending stiffness may be at least <NUM> orders of magnitude greater in the deployed configuration than in the stowed configuration. The method may further include guiding, via a launcher, each extendable element along the axial direction during conversion from the stowed configuration to the deployed configuration.

Provided is a method of sequentially deploying an extendable structure comprising a plurality of extendable elements. The method includes retaining, via a retaining device, each of the plurality of extendable elements in a stowed configuration, wherein each respective one of the plurality of extendable elements includes a at least one spring tape extendable structure, and wherein the at least one spring tape extendable structure is constrained in the stowed configuration and store potential energy releasable to extend the respective one of the plurality of extendable elements along a deployment axis of the extendable structure; sequentially deploying each of the plurality of extendable elements from the stowed configuration to a deployed configuration, the sequentially deploying for a respective one of the plurality of extendable elements including: actuating the retaining device to release the respective one of the plurality of extendable elements; and passively deploying the released respective one of the plurality of extendable elements along the deployment axis via release of the potential energy stored in the at least one spring tape extendable structure of the released respective one of the plurality of extendable elements.

Each respective one of the plurality of extendable elements may include an interface ring attached to the plurality of spring tape extendable structures, wherein the retaining includes retaining the interface ring in a stowed position via the retaining device, wherein the actuating includes actuating the retaining device to release the interface ring, and wherein the passively deploying includes deploying the interface ring along the deployment axis via extension of the plurality of spring tape extendable structures via release of the stored potential energy.

The retaining device may include a plurality of ball bearings including at least one ball bearing per interface ring, wherein the at least one ball bearing contacts the interface ring to retain the interface ring in the stowed position and prevent the interface ring from deploying along the deployment axis, and wherein the actuating the retaining device includes displacing the at least one ball bearing such that the at least one ball bearing does not contact the interface ring, thereby releasing the interface ring.

The axial and bending stiffness for each extendable element may be greater in the deployed configuration than in the stowed configuration.

The axial and bending stiffness may be at least <NUM> orders of magnitude greater in the deployed configuration than in the stowed configuration.

The launcher may guide each extendable element along the axial direction during conversion from the stowed configuration to the deployed configuration.

Provided is a system for sequentially deploying an extendable structure. The system includes the extendable structure comprising a plurality of extendable elements extendable from a stowed configuration to a deployed configuration along a deployment axis of the extendable structure, each respective one of the plurality of extendable elements including a at least one spring tape extendable structure; a retaining device for retaining each respective one of the plurality of extendable elements in the stowed configuration in which the at least one spring tape extendable structure of the respective one of the plurality of extendable elements are constrained and store potential energy that is releasable to extend the respective one of the plurality of extendable elements along the deployment axis; an actuator for sequentially deploying each of the plurality of extendable elements from the stowed configuration to the deployed configuration by: actuating the retaining device to sequentially release each respective one of the plurality of extendable elements; and passively deploying the respective ones of the plurality of extendable elements via release of the potential energy stored in the at least one spring tape extendable structure of the respective ones of the plurality of extendable elements.

Other aspects and features will become apparent, to those ordinarily skilled in the art, upon review of the following description of some exemplary embodiments.

The drawings included herewith are for illustrating various examples of articles, methods, and apparatuses of the present specification. In the drawings:.

Various apparatuses or processes will be described below to provide an example of each claimed embodiment. No embodiment described below limits any claimed embodiment and any claimed embodiment may cover processes or apparatuses that differ from those described below. The claimed embodiments are not limited to apparatuses or processes having all of the features of any one apparatus or process described below or to features common to multiple or all of the apparatuses described below. A description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary, a variety of optional components are described to illustrate the wide variety of possible embodiments of the present invention.

Further, although process steps, method steps, algorithms or the like may be described (in the disclosure and / or in the claims) in a sequential order, such processes, methods and algorithms may be configured to work in alternate orders. In other words, any sequence or order of steps that may be described does not necessarily indicate a requirement that the steps be performed in that order. The steps of processes described herein may be performed in any order that is practical. Further, some steps may be performed simultaneously. When a single device or article is described herein, it will be readily apparent that more than one device / article (whether or not they cooperate) may be used in place of a single device / article. Similarly, where more than one device or article is described herein (whether or not they cooperate), it will be readily apparent that a single device / article may be used in place of the more than one device or article.

The following relates generally to deployable antenna assemblies, and more particularly to a deployable antenna assembly having an extendable structure. The deployable antenna assembly includes an extendable pillar configured to extend along a deployment axis of the deployable antenna assembly. The extendable pillar includes a plurality of extendable elements. Each extendable element is configured to convert from a stowed configuration to a deployed configuration, the conversion extending the extendable element in an axial direction along the deployment axis. The deployable antenna assembly provides that an extendable element in the deployed configuration is longer in the axial direction than the extendable element in the stowed configuration. The extendable pillar also includes a launcher configured to initiate conversion of the plurality of extendable elements from the stowed configuration to the deployed configuration. The deployable antenna assembly also includes a helical radiating element. The helical radiating element is connected to the extendable pillar such that an extendable portion of the helical radiating element extends concurrently in the axial direction with the extendable pillar.

The deployable antenna assemblies, systems, and methods provided herein may provide various advantages over conventional assemblies, systems, and methods such as improved transmittance and reception of radiofrequency signals. Accordingly, the high volume ratio between deployed and stowed configurations may provide for the use of larger antenna assemblies, which inherently provide better RF performance. When the deployable antenna assembly is in a stowed configuration, the deployable antenna assembly possesses a low stowed to deployed ratio, for example in the order of between <NUM> and <NUM>. The low ratio may provide for improved storage and transport capabilities for the antenna assembly over traditional assemblies. The low ratio also allows for transport of larger antennas that traditionally may not have been transported or may have been costly to do so. Improved storage and transport also provides additional advantages when the deployable antenna assembly is incorporated into a applications such as spacecrafts or satellites where storage capacity is minimal. The low stowed-to-deployed ratio of the deployable antenna assembly may enable transport of more deployable antenna assemblies on a single spacecraft.

Additionally, the method of deploying the antenna assembly may also provide for the advantage of low-shock deployment of the antenna. Low-shock deployment allows for minimal impact of mechanical forces on the antenna assembly during deployment. Such low-shock deployment may be particularly advantageous in some applications, such as space-based applications, where shock forces should be controlled to limit impact on surrounding structures such as spacecraft and components onboard. The assemblies, systems, and methods provided herein also provide for the advantages of low cost and low mass antenna assemblies. The present disclosure also relates generally to extendable structures, and more particularly to systems and methods for deploying an extendable structure. The systems and methods for deploying the extendable structure may advantageously provide a relatively low-shock deployment of the extendable structure. In particular, the present disclosure provides systems and methods for sequential deployment of an extendable structure.

Referring now to <FIG>, shown therein is a system <NUM> for satellite-based communication using a deployable antenna assembly, according to an embodiment. The system <NUM> includes a ground segment <NUM> and a space segment <NUM>. The space segment <NUM> of system <NUM> includes communications satellites 110a, 110b, and 110c. Communications satellites 110a, 110b, 110c are referred to herein collectively as communication satellites <NUM> and generically as communication satellite <NUM>. It is to be understood that the system <NUM> may include any number of communication satellites <NUM> (i.e. one or more). In a particular embodiment, the satellite <NUM>, without limitation, is a low-earth orbit (LEO) satellite. The satellite may be also be used in other orbits other than a LEO. In embodiments of the system <NUM> including a plurality of satellites <NUM>, the satellites <NUM> may be referred to collectively as a satellite constellation or satellite network.

The communications satellites 110a, 110b, 110c each include a deployable antenna subsystem (antenna subsystems 112a, 112b, 112c, respectively). Deployable antenna subsystems 112a, 112b, 112c are referred to herein collectively as deployable antenna subsystems <NUM> and generically as deployable antenna subsystem <NUM>. The deployable antenna subsystem <NUM> may be configured to perform RF transmission or RF reception in a predetermined signal frequency band. In an embodiment, the predetermined signal frequency band is an ultrahigh frequency (UHF) band. In another embodiment, the predetermined signal frequency band may be L-band, S-band, or VHF. Communications satellites 110a, 110b, and 110c communicate with one another via inter-satellite communication links <NUM>.

The ground segment <NUM> includes a gateway earth station ("GES") <NUM> (or gateway station <NUM>). The system <NUM> may include a plurality of gateway stations <NUM>, which may be positioned at different locations. The gateway station <NUM> may be located on the surface of the Earth, in the atmosphere, or in space. The gateway station <NUM> may be fixed or mobile. The gateway station <NUM>, which may be surface-based or atmosphere-based, includes one or more devices configured to provide real-time communication with satellites <NUM>. The communications satellites <NUM> communicate with the gateway station <NUM> via communication downlink <NUM> and communication uplink <NUM>. In <FIG>, only communications satellite 110a is shown with communication links <NUM>, <NUM>, but it is to be understood that communications satellites 110b, 110c form similar communication links with the gateway station <NUM>.

The gateway station <NUM> is configured to establish a telecommunications link <NUM>, <NUM> with a satellite <NUM> when the satellite <NUM> is in "view" of the gateway station <NUM>. The gateway station <NUM> transmits and/or receives radio ("RF") waves to and/or from the satellite <NUM>. The gateway station <NUM> may include a parabolic antenna for transmitting and receiving the RF signals. The gateway station <NUM> may have a fixed or itinerant position. The gateway station <NUM> sends radio signals to the satellite <NUM> (uplink) via communication link <NUM> and receives data transmissions from the satellite (downlink) via the communication link <NUM>. The gateway station <NUM> may serve as a command and control center for a satellite network (or "satellite constellation"). The gateway station <NUM> may analyze data received from the satellites <NUM> and/or may relay the received data to another location (i.e. another computer system, such as another gateway station <NUM>) for analysis. In some cases, the gateway station <NUM> may receive data from the satellite <NUM> and transmit the received data to a computing device specially configured to perform processing and analysis on the received satellite data.

The gateway station <NUM> may further be configured to receive data from the satellite <NUM> and monitor navigation or positioning of the satellite <NUM> (e.g. altitude, movement) or monitor functioning of the satellite's critical systems (e.g. by analyzing data from the critical system being monitored). The gateway station <NUM> may include any one or more of the following elements: a system clock, antenna system, transmitting and receiving RF equipment, telemetry, tracking and command (TT&C) equipment, data-user interface, mission data recovery, and station control center.

The ground segment <NUM> of system <NUM> also includes a user terminal <NUM>. The user terminal <NUM> may be a fixed or mobile terminal. The user terminal <NUM> may be any device capable of transmitting and/or receiving RF communication signals. The user terminal <NUM> includes an RF communication module for transmitting and/or receiving the RF signals. The user terminal <NUM> may be, for example, a computing device, such as a laptop or desktop, or a mobile device (e.g. smartphone). The communications satellite 110c communicates with the user terminal <NUM> via communications link <NUM>. Communications performed by satellite 110c via communications link <NUM> may include transmission and reception. While <FIG> shows communication link <NUM> established between the satellite 110c and the user terminal <NUM>, it is to be understood that the user terminal <NUM> may establish a similar communication link with satellite 110a or 110b. Similarly, the communications satellite 110c may establish similar communication links with other user terminals.

Referring now to <FIG>, shown therein is a communications satellite <NUM> of <FIG>, according to an embodiment. The communications satellite <NUM> includes a satellite bus <NUM>. The satellite bus <NUM> provides the body of the satellite <NUM>. The satellite bus <NUM> provides structural support and an infrastructure of the satellite <NUM> as well as locations for a payload (e.g. various subsystems, such as the deployable antenna subsystem <NUM>). Components of the communications satellite <NUM> may be housed within an interior of the satellite bus <NUM> or may be connected to an external surface of the satellite bus <NUM> (directly or indirectly through another component).

The communications satellite <NUM> includes a propulsion subsystem <NUM> for driving the communications satellite <NUM>. The propulsion subsystem <NUM> adjusts the orbit of the satellite <NUM>. The propulsion subsystem <NUM> includes one or more actuators, such as reaction wheels or thrusters. The propulsion subsystem <NUM> may include one or more engines to produce thrust. The communications satellite <NUM> includes a positioning subsystem <NUM>. The positioning subsystem <NUM> uses specialized sensors to acquire sensor data (e.g. measuring orientation) which can be used by a processing unit of the positioning subsystem <NUM> to determine a position of the satellite <NUM>. The positioning subsystem <NUM> controls attitude and orbit of the satellite <NUM>. The positioning subsystem <NUM> communicates with the propulsion subsystem <NUM>. Together, the positioning subsystem <NUM> and the propulsion subsystem <NUM> determine and apply the torques and forces needed to re-orient the satellite <NUM> to a desired attitude, keep the satellite <NUM> in the correct orbital position, and keep antennas (e.g. the radiating array <NUM>) pointed in the correct direction.

The communications satellite <NUM> includes an electrical power subsystem <NUM>. The electrical power subsystem <NUM> provides power for the radiating array subsystem <NUM>, as well as for other components. The power may be provided through the use of solar panels on the satellite bus <NUM> that convert solar radiation into electrical current. The power subsystem <NUM> may also include batteries for storing energy to be used when the satellite <NUM> is in Earth's shadow. The communications satellite <NUM> includes a command and control subsystem <NUM>. The command and control subsystem <NUM> includes electronics for controlling how data is communicated between components of the communications satellite <NUM>. The propulsion subsystem <NUM>, the positioning subsystem <NUM>, and the power subsystem <NUM> may each be communicatively connected to the command and control subsystem <NUM> for transmitting data to and receiving data from the command and control subsystem <NUM>.

The communications satellite <NUM> also includes a thermal control subsystem (or thermal management subsystem) <NUM>. The thermal control subsystem <NUM> controls, manages, and regulates the temperature of one or more components of the communications satellite 110within acceptable temperature ranges, which may include maintaining similar components at a generally uniform temperature. Generally, the thermal control subsystem <NUM> protects electronic equipment of the radiating array subsystem <NUM> from extreme temperatures due to self-heating of the radiating array subsystem <NUM> (i.e. by operation of the signal amplification components of the radiating array subsystem). The thermal control subsystem <NUM> may include active components or passive components.

The communications satellite <NUM> may also include other payload subsystems <NUM>. The other payload subsystems <NUM> may include any one or more of optical intersatellite terminals, gateway antennas, filters, cables, waveguides, etc. The communications satellite <NUM> includes a deployable antenna subsystem <NUM>. The deployable antenna subsystem <NUM> includes a deployable antenna assembly <NUM> and an onboard processor ("OBP") <NUM>. The deployable antenna assembly <NUM> is communicatively connected to the OBP <NUM>. The OBP <NUM> may be part of the satellite's payload.

Referring now to <FIG>, illustrated therein is a block diagram of a deployable antenna assembly <NUM>, in accordance with an embodiment. The deployable antenna assembly <NUM> may be the deployable antenna subsystem <NUM> of <FIG> or the deployable antenna assembly <NUM> of <FIG>. The deployable antenna assembly <NUM> includes an extendable pillar <NUM>. The extendable pillar <NUM> is configured to extend in an axial direction of the deployable antenna assembly <NUM>. The extendable pillar <NUM> includes at least one extendable element <NUM>. Each extendable element <NUM> is configured to convert between a stowed configuration and a deployed configuration. The deployable antenna assembly <NUM> provides that an extendable element <NUM> in a deployed configuration is longer in the axial direction than the extendable element <NUM> in a stowed configuration. In some embodiments, the extendable pillar may optionally include a plurality of extendable elements 310a, 310b, 310c. Each of the plurality of extendable elements 310a, 310b, 310c may convert from the stowed configuration to the deployed configuration sequentially or simultaneously.

The extendable pillar <NUM> also includes a launcher <NUM>. The launcher <NUM> may be a sequential launcher. The launcher <NUM> is configured to initiate conversion of the plurality of extendable elements <NUM> from the stowed configuration to the deployed configuration. The deployable antenna assembly <NUM> also includes a helical radiating element <NUM>. The helical radiating element <NUM> is connected to the extendable pillar <NUM> such that an extendable section <NUM> of the helical radiating element <NUM> extends passively and concurrently in the axial direction with the extension of the extendable pillar <NUM>. The helical radiating element <NUM> may optionally have a fixed section <NUM>. The fixed section <NUM> may be configured to provide rigid support for the extendable section of the helical radiating element.

Referring now to <FIG>, illustrated therein is a method <NUM> of deploying an antenna, in accordance with an embodiment. The method <NUM> includes, extending an extendable pillar along an axial direction, at <NUM>. The method <NUM> provides that the extendable pillar includes a plurality of extendable elements. The method <NUM> also includes converting each of the plurality of extendable elements between a stowed configuration and a deployed configuration, at <NUM>. The method <NUM> provides that each of the extendable elements in the deployed configuration are longer in the axial direction than an extendable element in the stowed configuration. The method <NUM> also includes extending a helical radiating element concurrently with the extendable pillar in the axial direction, at <NUM>.

Optionally prior to <NUM>, the method <NUM> also includes inputting a command on a user terminal to convert the antenna from the stowed configuration to the deployed configuration at <NUM>. Conversion includes converting each of the extendable elements from a stowed configuration to a deployed configuration, at <NUM>. In other cases, the antenna may be deployed automatically without user input. Optionally, the method <NUM> also includes transmitting the command inputted at <NUM> from a base station to a communications satellite on which the deployable antenna is disposed, at <NUM>. Optionally, at <NUM>, the method <NUM> includes stabilizing the helical radiating element with a fixed support when the helical radiating element extends concurrently in the axial direction with the extendable pillar. In some embodiments, the fixed support is a fixed base.

Referring now to <FIG>, shown therein is a system <NUM> for deploying an extendable structure, according to an embodiment. Various interactions, interfacing, connections, or attachments between components of the system <NUM> are represented in <FIG> by arrowed lines. The system <NUM> includes a deployable boom <NUM>. The deployable boom <NUM> has a stowed (or non-deployed) configuration and a deployed configuration. The volume occupied by the deployable boom <NUM> in the stowed configuration is smaller than the volume occupied by the deployable boom <NUM> in the deployed configuration. The deployable boom <NUM> defines a deployment or boom axis. The deployable boom <NUM> is configured to deploy (i.e. extend) axially along the deployment axis. By deploying, the length of the deployable boom <NUM> is increased.

The system <NUM> also includes a deployable mass <NUM>. Generally, the system <NUM> uses the deployable boom <NUM> to deploy or translate the deployable mass <NUM> along the deployment axis. The deployment of the deployable mass <NUM> may be considered passive in the sense that deployment of the deployable mass <NUM> is caused by the deployment of the deployable boom <NUM>. Passive deployment of the deployable mass <NUM> may be achieved via directly or indirectly connecting or attaching the deployable mass <NUM> to the deployable boom <NUM>. The deployable mass <NUM> may be any mass or structure for which there is a desire or need to translate the mass or structure along the deployment axis of the deployable boom <NUM>. In an embodiment, the deployable mass <NUM> is an antenna radiating element. The antenna radiating element may be a helical radiating element. In another embodiment, the deployable mass <NUM> may be a sensor device or a camera or vision system.

The deployable mass <NUM> may be an extendable mass. Such an extendable mass may have a stowed configuration and deployed configuration where the extendable mass has a smaller volume in the stowed configuration than in the deployed configuration. For example, the deployable mass <NUM> may have a fixed attachment point and an axially translated attachment point. Deployment of the deployable boom <NUM> may translate the axially translated attachment point of the extendable mass along the deployment axis while the fixed attachment point remains fixed, thereby extending the extendable mass. The extendable mass may have additional attachment points between the fixed attachment point and the axially translated attachment point. In an embodiment, the extendable mass may be an extendable helical radiating element of an antenna. The deployable boom <NUM> includes an extendable structure <NUM> and a launcher <NUM> for deploying or extending the extendable structure <NUM>.

The extendable structure <NUM> includes a plurality of extendable elements <NUM>. The extendable elements <NUM> are connected to form a continuous structure along the deployment axis. For example, each extendable element <NUM> may be connected to at least one other extendable element <NUM>. Each extendable element <NUM> has a stowed configuration and a deployed configuration. The extendable element <NUM> has a smaller volume in the stowed configuration than in the deployed or extended configuration. The extendable element <NUM> stores potential energy in the stowed configuration that is releasable to cause conversion of the extendable element <NUM> from the stowed configuration to deployed configuration (i.e. extension of the extendable element). The deployment of each extendable element <NUM> causes the extendable structure <NUM> to extend in length.

An extendable element <NUM> includes a deployable interface ring <NUM> and a at least one spring tape extendable structure <NUM> (or "spring tape <NUM>" or "spring blade <NUM>") fixed to the deployable interface ring <NUM>. For example, the spring tapes <NUM> may be fixed or otherwise attached to the deployable interface ring <NUM> at the outer periphery of the deployable interface ring <NUM>. The number of spring tapes <NUM> may be at least four. In an embodiment, the number of spring tapes <NUM> may be eight. In some embodiments, the extendable element <NUM> may be a single part. For example, the extendable element <NUM> may include a spring tape <NUM> made in one unified component. For example, the extendable element <NUM> may include a spring tape blade post and blade made of carbon fiber reinforced polymer on a mandrel. The spring tapes <NUM> are used to generate a translational force along the deployment axis and to provide a stiffness once in the deployed configuration. In some embodiments, the spring tapes <NUM> may be, without limitation, a spring steel, beryllium copper, or any composite material thereof.

The spring tapes <NUM> include a stowed configuration and a deployed configuration. In the stowed configuration, the spring tapes <NUM> store potential energy for deployment purposes. For example, the spring tapes <NUM> may be compressed, such as by bending or folding, to achieve the stowed configuration. Once deployed (i.e. the potential energy is released and the spring tape extends), the spring tapes <NUM> provide stiffness and strength to the extendable structure <NUM>. The spring tapes <NUM> may be axisymmetrically around the deployment or boom axis. This may produce a translational deployment load along the axial direction of freedom of the deployable boom <NUM>. The spring tapes <NUM> may provide an efficient extendable structure <NUM> as the spring tapes <NUM> perform multiple functions including energy storage in the stowed configuration and assembly stiffness when in the deployed configuration. The potential energy stored in the spring tapes <NUM> may be sufficient to ensure deployment under scenarios including friction and parasitic loads (e.g. worst case scenarios).

Generally, the spring tapes <NUM> of an extendable element <NUM> are fixed to and disposed between the deployable interface ring <NUM> and an adjacent ring. A first end of the spring tapes <NUM> is attached to the deployable interface ring <NUM> and a second end of the spring tapes <NUM> is attached to the adjacent ring. The deployable interface ring <NUM> is a structural component of the extendable structure <NUM> (e.g. ring) that gets deployed in the direction of extension along the deployment axis under the force of the spring tapes <NUM> connected thereto. The adjacent ring may be a deployable interface ring <NUM> of another extendable element <NUM> (e.g. a lower ring in the extendable structure <NUM>) or may be a fixed structure (e.g. ring) that does not deploy (e.g. at a fixed end of the extendable structure <NUM>). Where the extendable element <NUM> is the furthermost extendable element <NUM> in the direction of deployment (e.g. at the top of the extendable structure <NUM>), the deployable interface ring <NUM> may be a structural support component or other structural element (e.g. a halo, as described herein) which is translated along the deployment axis upon deployment. In the stowed configuration, the spring tapes <NUM> are constrained between the deployable interface ring <NUM> and the adjacent interface ring by a retaining device (retaining device <NUM>, described below) until release (freeing the deployable interface ring <NUM>).

The launcher <NUM> is configured to deploy the extendable structure <NUM>. The launcher <NUM> may be a sequential launcher for sequentially deploying the extendable elements <NUM> of the extendable structure <NUM>. The launcher <NUM> may be a simultaneous launcher for simultaneously deploying the extendable elements <NUM> of the extendable structure <NUM>. The launcher <NUM> uses a release mechanism <NUM> to effect conversion of the extendable elements from the stowed configuration to the deployed configuration. Thus, the release mechanism <NUM> is configured to hold the extendable elements <NUM> in the stowed configuration and release the extendable elements, the release causing the conversion of the extendable elements <NUM> from the stowed configuration to the deployed configuration. The release mechanism <NUM> includes an actuator <NUM> and a retaining device <NUM>.

The retaining device <NUM> is configured to retain the extendable elements <NUM> in the stowed configuration. In particular, the retaining device <NUM> retains the deployable interface rings <NUM> in their respective stowed positions such that potential energy is stored in the spring tapes <NUM>. The retaining device <NUM> may include a hold down and release mechanism. The retaining device <NUM> may retain the interface rings <NUM> in the stowed position directly, through direct contact with each interface ring <NUM>, or indirectly (such as by retaining a halo component at the top or end of the extending end of the extendable structure <NUM>).

The actuator <NUM> is operatively connected to the retaining device <NUM> for actuating the retaining device <NUM>. The actuator <NUM> actuates the retaining device <NUM> (or some component thereof) to release the retaining device <NUM> and free the extendable elements <NUM>. Once freed, the spring tapes <NUM> of a respective extendable element <NUM> release the stored potential energy, causing extension of the spring tapes <NUM>, and the extendable element <NUM>, from the stowed configuration to the deployed configuration. The actuator <NUM> may be a linear actuator. In an embodiment, the actuator includes a pin puller. It will be readily apparent that any type of actuator <NUM> may be used. Accordingly, the control scheme of the actuator may differ depending on the type of actuator <NUM>. For example, the actuator may be, without limitation, a linear actuator, a rotary actuator, a spring/damper actuator, a high output paraffin pin puller actuator, or any combination thereof.

The actuator <NUM> may be configured to actuate a component of the retaining device <NUM> axially along the deployment axis in the direction opposite the direction of deployment or extension. Such actuation of the retaining device <NUM> may cause release or disengagement of some component of the retaining device <NUM> (e.g. ball bearings, frangibolt ® or sepnut) previously retaining an extendable element <NUM> in the stowed configuration. The release or disengagement promotes the release of the stored potential energy in the spring tapes <NUM> and the extension of the extendable element <NUM>.

In an embodiment, the retaining device <NUM> includes a camshaft and ball bearings (see for example <FIG>). The retaining device <NUM> may enable a sequential deployment of extendable elements <NUM>. Each deployable interface ring <NUM> is retained by one or more ball bearings. In the stowed configuration, the ball bearings are captured between the camshaft, a launch tube of the deployable boom <NUM> (e.g. guiding post <NUM> or a portion thereof), and the deployable ring <NUM>. The actuator <NUM> actuates the camshaft (e.g. via a pin puller pulling a pin connected to the camshaft) along the deployment axis in the direction opposite the direction of deployment to free the ball bearings retaining a first deployable interface ring <NUM>. Once all bearings are freed from the first deployable interface ring <NUM>, the first deployable interface ring <NUM> initiates its deployment under the force of the spring tapes <NUM>. The actuator <NUM> provides the force to exert the relative movement between the camshaft and the launch tube to achieve the controlled deployment of the deployable interface ring <NUM>. The process of deploying the first deployable interface ring <NUM> can then be repeated in sequence for each additional deployable interface ring <NUM> in the extendable structure <NUM>. The order of ring <NUM> deployment allows all the rings <NUM> to deploy in a controlled fashion, including the last deployed ring <NUM>. Spring tapes <NUM> between the freed ring <NUM> and the adjacent ring are constrained by the ball bearings until release.

In another embodiment, the retaining device <NUM> includes a retaining wire and a frangibolt ®, sepnut, or similar component (see for example <FIG>). The retaining device <NUM> may enable a simultaneous deployment of extendable elements <NUM> and the release mechanism <NUM> may be a single release mechanism. The retaining wire includes a first end connected to a deploying end of the extendable structure <NUM> (e.g. attached to the deployable interface ring or other structural component furthermost at the deploying end) and a second end connected to a fixed end of the extendable structure <NUM> (e.g. a base ring or base support). The second end is connected to the frangibolt® or sepnut. The actuator <NUM> actuates a component of the retaining device to disengage the connection between the frangibolt ® or sepnut and the retaining wire, causing the release of the retaining wire. Release of the retaining wire frees the extendable elements <NUM> to deploy along the deployment axis under the force of the spring tapes <NUM>.

The system <NUM> also includes a support structure <NUM>. The support structure <NUM>, or components thereof, may be extendable. The extendable support structure <NUM> includes a stowed configuration and a deployed configuration. The extendable support structure <NUM> may be connected or attached to the extendable structure <NUM> such that the extendable support structure <NUM> extends (i.e. is deployed) passively as the extendable structure <NUM> is deployed. The support structure <NUM> may constrain the deployable mass <NUM> (e.g. helical radiating element) along the axial and/or radial axes when the deployable mass <NUM> is deployed by the extendable structure <NUM>. The support structure <NUM> may constrain the deployable mass <NUM> to ensure its out-of-axis positioning.

In an embodiment, the support structure <NUM> includes a skirt and a halo. The skirt may provide a support to the deployable mass <NUM> (e.g. helix) in the radial direction once deployed. The flexibility of the skirt may be minimized in the axial direction in the stowed state to minimize potential energy required for deployment. The deployable mass <NUM> may be connected to the extendable structure <NUM> directly (represented by line <NUM>) or may be connected to the extendable structure <NUM> indirectly through attachment to the support structure <NUM> (which is attached to the extendable structure <NUM>).

The deployable boom <NUM> also includes a guiding post <NUM>. In some embodiments, the guiding post may not be present. The guiding post <NUM> may be a launch tube. The guiding post <NUM> may be a telescopic post. The guiding post <NUM> may ensure that the deployment of the extendable structure <NUM> occurs along a single degree of freedom to ensure a reproducible behavior of the deployment dynamics. In a sequential deployment, the guiding post <NUM> may ensure that each stage of deployment (i.e. deployment of an extendable element <NUM>) is guided by along the axial direction. In a simultaneous deployment, the guiding post <NUM> may be a telescopic post that guides the extendable structure <NUM> along the axial direction. The telescopic post may deploy with the same stored energy as the deployable boom <NUM>. The telescopic post may function to guide the rings <NUM> along the radial direction.

The deployable boom <NUM> may be considered a passive deployable boom. The system <NUM> manages the release of the stored potential energy in the spring tapes <NUM> from the stowed to the deployed configuration. The deployable boom <NUM> promotes a controlled deployment by releasing the potential energy stored in the stowed system in the spring tapes <NUM> to the deployed configuration along the boom axial degree of freedom. The deployable boom <NUM> may implement a sequential deployment to limit the maximal shock generated at the end of each stage of deployment (i.e. deployment of each extendable element <NUM>).

The system <NUM> may provide deployment simplicity by using potential energy stored in the stowed system. In contrast, existing deployment systems (e.g. deployable antennas) require a motor to provide the energy to the system. The actuator <NUM> may be of minimal mass as the power that needs to be delivered to the system <NUM> is reduced compared to existing designs (e.g. using motors to provide energy). In a sequential deployment implementation, the actuator power required to release each stage of the extendable structure <NUM> sequentially is relatively low as actuation friction loads are minimized. The sequential deployment implementation of system <NUM> may provide relatively low shocks compared to a non-sequential deployment system. In a simultaneous deployment implementation, the deployment may be performed with the actuation of a single release mechanism. The simultaneous deployment implementation may produce shocks that are significant but repeatable, thus allowing the adjacent structure to be designed and qualified to the shock levels. The deployment system <NUM> may provide controlled deployment of the release dynamic along the axial boom direction (deployment axis). This may promote or ensure repeatable deployment dynamics and on-earth testing.

For a long deployment boom <NUM> (e.g. equal to or longer than about <NUM>), the stored energy may be released sequentially to ensure that each stage is guided by the guiding post <NUM> along the axial direction and that the shock generated by the energy release at the end of each deployment stage is limited. For short deployable booms (less than about <NUM>), the stored energy may be released simultaneously while the extendable structure <NUM> is guided along the axial direction with a telescopic post (post <NUM>) that deploys with the same stored energy as the deployable boom <NUM>.

Referring now to <FIG>, shown therein is a method of deploying a deployable antenna assembly, according to an embodiment. The method <NUM> may be implemented using the system <NUM> of <FIG>. At <NUM>, an antenna radiating element (e.g. deployable mass <NUM>) is attached to an extendable structure (e.g. extendable structure <NUM>) such that the antenna radiating element is axially translated upon extension of the extendable structure. At <NUM>, a retaining device (e.g. retaining device <NUM>) is used to retain a plurality of extendable elements (e.g. extendable elements <NUM>) of the extendable structure in a stowed configuration. In the stowed configuration, a plurality of spring tapes (e.g. spring tapes <NUM>) of the extendable elements store potential energy.

At <NUM>, the extendable structure is extended (or deployed) by disengaging the retaining device using an actuator (e.g. actuator <NUM>). The actuator causes the retaining device to disengage, which causes the release of the potential energy stored in the spring tapes. At <NUM>, mass dampers are used to dissipate kinetic energy released while the extension (or deployment) of the extendable structure. The mass dampers may absorb vibrations and shock released by each of the extendable elements when each extendable element converts from the stowed configuration to the deployed configuration. At <NUM>, the antenna radiating element is axially translated along a deployment axis of the extendable structure via extension of the extendable structure. The axial translation of the antenna radiating element may thus be concurrent with the deployment of the extendable structure. As previously noted, the antenna radiating element may be connected directly to the extendable structure or indirectly through an extendable support structure (e.g. support structure <NUM>) that is connected to the extendable structure. In this sense, the axial translation of the antenna radiating element can be considered passive as it is achieved through extension of the extendable structure. In cases where the antenna radiating element is an extendable radiating element (e.g. extendable helical radiating element), the axial translation includes extending the extendable radiating element.

Referring now to <FIG>, shown therein is a method <NUM> of deploying an antenna assembly having a helical radiating element and a support structure, according to an embodiment. The method <NUM> may be performed by the deployment system <NUM> of <FIG>. The helical radiating element may be the deployable mass <NUM> of <FIG> and the support structure may be the support structure <NUM> of <FIG>. At <NUM>, a first end ("fixed end") of an extendable helical radiating element ("helix") is attached to a fixed support structure of the deployable antenna assembly and a second end ("axially translatable end") of the extendable helix is attached to an extendable support structure of the deployable antenna assembly. The extendable helix may be attached to the extendable support structure at additional attachment points in between the first end and second end. At <NUM>, the extendable support structure is connected to a deployable boom (e.g. deployable boom <NUM>). The extendable support structure is connected to the deployable boom such that the extendable support structure extends along the deployment axis of the deployable boom when the deployable boom is deployed. As such, the extension of the extendable support structure can be considered passive as it is achieved through deployment of the deployable boom.

At <NUM>, each of a plurality of extendable elements (e.g. extendable elements <NUM>) of the deployable boom are retained in a stowed configuration. The extendable elements are each retained by an interface ring that is in a stowed position. In the stowed position, the interface ring constrains spring tapes connected to the interface ring (and an adjacent ring or structure) in a bent configuration. The spring tapes in the bent configuration store potential energy that can be released to deploy the deployable boom. At <NUM>, the interface rings are released via an actuator. The actuator may release the interface rings by releasing a retaining device. The interface rings may be release sequentially or simultaneously. In an embodiment, the actuator may actuate a camshaft, causing the displacement of ball bearings which, prior to displacement, retained the interface ring in the stowed position. In another embodiment, the actuator may cause a hold down and release mechanism to release, causing a single release of all the interface rings. At <NUM>, extendable elements that were constrained in the stowed configuration by the retained interface rings are passively deployed to a deployed configuration. The passive deployment is achieved by releasing the potential energy stored in the spring tapes.

At <NUM>, the extendable support structure is extended through deployment of the extendable elements at <NUM>. The extension of the extendable support structure is passive as it is a result of the connection of the extendable support structure to the deployable boom and deployment of the deployable boom. The extension or deployment of the extendable support structure may thus be concurrent with the deployment of the deployable boom (i.e. with <NUM>). At <NUM>, the second end of the extendable helix is axially translated along the deployment axis via extension of the extendable support structure. The axial translation is achieved, in part, through the attachment at <NUM>. Axial translation of the second end of the extendable helix causes extension of the extendable helix between the first and second end along the deployment axis.

Referring now to <FIG>, shown therein is a method <NUM> of deploying an extendable structure using a sequential deployment technique, according to an embodiment. The method <NUM> may be performed using the system <NUM> of <FIG>. At <NUM>, a deployable boom is provided (e.g. deployable boom <NUM>). The deployable boom includes a plurality of extendable elements. Each extendable element includes a deployable interface ring and a plurality of spring tapes attached to the deployable interface ring. The spring tapes are also attached to a second structural component, which may be the deployable interface ring of another extendable element, a fixed base ring or other base structure (e.g. at the bottom of the extendable structure). At <NUM>, each of the deployable interface rings is retained in a stowed position via a retaining device (e.g. retaining device <NUM>). In the stowed position, the deployable interface ring biases the spring tapes fixed to the deployable interface ring into a bent or folded configuration that stores potential energy in the spring tape.

At <NUM>, the retaining device is actuated to release a first deployable interface ring of a first extendable element. This may include, for example, actuating a camshaft to displace one or more ball bearing retaining the first deployable interface such that the first deployable interface ring is no longer retained (e.g. no longer constrained by or in contact with the ball bearings). At <NUM>, the first extendable element is passively deployed by the release of the potential energy stored in the spring tapes attached to the first deployable interface ring. The first deployable interface ring initiates its deployment under the force of the spring tapes. The spring tapes generate a translational force along the deployment axis. At <NUM>, steps <NUM> and <NUM> are repeated, sequentially, for each additional extendable element in the deployable boom. For example, the retaining device is further actuated to release a second deployable interface ring, and the second extendable element is passively deployed via the spring tapes.

Referring now to <FIG> and <FIG>, shown therein is a deployable antenna assembly <NUM>, according to an embodiment. In an embodiment, the deployable antenna assembly <NUM> may be a deployable UHF antenna assembly. Various features, components, and functionality of the deployable antenna assembly <NUM> will now be described.

Referring now to <FIG> and <FIG>, shown therein is the deployable antenna assembly <NUM> in a stowed (non-deployed) configuration <NUM> (<FIG>) and a deployed configuration <NUM> (<FIG>). The stowed configuration <NUM> is a fully stowed configuration (i.e. all extendable elements are in a stowed configuration) and the deployed configuration is a fully deployed configuration (i.e. all extendable elements are in a deployed configuration). The assembly <NUM> includes a fixed section <NUM> and an extendable section <NUM>. Upon deployment, the extendable section <NUM> extends along a deployment axis <NUM> (defined by a deployable boom, described below) in a deployment direction <NUM>. The deployment direction <NUM> of the extendable section <NUM> is away from the fixed section <NUM>. The fixed section <NUM> of the assembly <NUM> is shown in isolation in <FIG>. The extendable section <NUM> of the assembly <NUM> is shown in isolation in <FIG>.

The assembly <NUM> includes a helical radiating element ("helix"). The helical radiating element <NUM> includes an extendable helix <NUM> connected to a fixed helix <NUM>. The helix <NUM>, <NUM> is configured to transmit or receive RF signals. The RF signals may be of a predetermined signal frequency band. The signal frequency band may be a UHF signal frequency band. The fixed section <NUM> includes a base cup <NUM>. The base cup <NUM> includes a first surface <NUM> and a second surface <NUM> opposing the first surface <NUM>. The fixed section <NUM> includes a transmission line housing <NUM> which houses a transmission line carrying the RF signal to and from the helical radiating element <NUM>. The fixed section <NUM> includes a rigid helix support <NUM>. The rigid helix support <NUM> is cylindrical in shape. The rigid helix support <NUM> supports an extendable helix <NUM> and a fixed helix <NUM>.

The rigid helix support <NUM> includes a first surface <NUM>, a second surface opposing the first surface <NUM> (not visible), and an exterior surface <NUM>. The rigid helix support <NUM> includes an inner cavity <NUM>. The inner cavity <NUM> receives a portion of the extendable section <NUM> of the assembly <NUM>. The inner cavity <NUM> may extend the length of the rigid helix support <NUM> from the first surface <NUM> to the second surface (not shown). The second surface of the rigid helix support <NUM> is mounted to the first surface <NUM> of the base cup <NUM>. The first surface <NUM> of the rigid helix support <NUM> provides an attachment surface for an extendable helix and for a skirt (support structure). The rigid helix support <NUM> includes skirt connectors <NUM> disposed on the first surface <NUM> for connecting the skirt elements to the rigid helix support <NUM> (and thus to the fixed section <NUM>). Includes extendable helix connectors for connecting the extendable helix to the top surface of the fixed section. Includes an extendable helix termination point.

The fixed section includes the fixed helix <NUM>. The fixed helix <NUM> is disposed on the exterior surface <NUM> of the rigid helix support <NUM>. The fixed helix <NUM> includes a first end <NUM> and a second end <NUM>. The fixed helix <NUM> extends from the first end <NUM> to the second end <NUM>. The first end <NUM> of the fixed helix <NUM> connects to a fixed helix-extendable helix connection point <NUM>. The connection point <NUM> facilitates signal transmission from the extendable helix <NUM> to the fixed helix <NUM> or vice versa. The second end <NUM> of the fixed helix <NUM> connects to a fixed helix-transmission line connection (not visible) for signal transmission from the fixed helix <NUM> to the transmission line or vice versa. The fixed helix-transmission line connection point traverses a helix-transmission line connection area <NUM> of the base cup <NUM>. The connection area <NUM> enables the connection to traverse the base cup <NUM> (between first <NUM> and second surfaces <NUM>) to the transmission housing <NUM>.

Referring now to the extendable section <NUM> (shown in isolation in <FIG>), the extendable section <NUM> includes a first end <NUM> and a second end <NUM>. The extendable section <NUM> includes a deployable boom (or extendable pillar) <NUM>, a support structure including a skirt <NUM> and a halo <NUM>, and the extendable helix <NUM>. The second end <NUM> of the deployable boom <NUM> is disposed in the interior cavity <NUM> of the rigid helix support <NUM>. The deployable boom <NUM> includes a base ring <NUM> at the second end <NUM>, which is mounted or otherwise attached to the first surface <NUM> of the base cup <NUM>. The base ring <NUM> thus attaches the deployable boom <NUM> to the fixed section <NUM> of the assembly <NUM>. The halo <NUM> is attached to the deployable boom <NUM> near the first end <NUM> of the extendable section <NUM>. The halo <NUM> provides support for the extendable helix <NUM> by providing a rigid attachment point for the skirt <NUM>. The skirt <NUM> includes a plurality of skirt elements <NUM>. The skirt elements <NUM> attach to the halo <NUM> at the first end <NUM> of the extendable section <NUM> and extend towards the second end <NUM> of the extendable section <NUM>, where the skirt elements <NUM> attach to the first surface <NUM> of the rigid helix support <NUM>, thus connecting the skirt <NUM> to the fixed section <NUM>. The skirt elements <NUM> are extendable in the deployment direction <NUM> and have a stowed configuration and a deployed configuration. In some embodiments, flex blades may positioned between the halo <NUM> and the skirt <NUM> to precharge the skirt <NUM> and reduce lateral deviations of the extendable helix <NUM> in orbit.

The extendable helix <NUM> includes a first end <NUM> proximal the base ring <NUM> and a second end <NUM> proximal the halo <NUM>. The first end <NUM> of the extendable helix <NUM> is connected to the first end <NUM> of the fixed helix <NUM> at the fixed helix-extendable helix connection point <NUM>. The second end <NUM> of the extendable helix <NUM> is connected to the skirt <NUM> at the first surface <NUM> of the fixed section <NUM>. Generally, the first end <NUM> of the extendable helix <NUM> is fixed and the second end <NUM> of the extendable helix <NUM> is axially translatable in the deployment direction <NUM> along the deployment axis upon deployment of the deployable boom <NUM>. The extendable helix <NUM> is also attached to the skirt elements <NUM> at additional attachment points along the length of the extendable helix <NUM>.

Generally, the deployable boom <NUM> is configured to extend in the deployment direction <NUM> along the deployment axis <NUM> when converting from the stowed configuration <NUM> to the deployed configuration <NUM>. Extension of the deployable boom <NUM> drives the halo <NUM> in the deployment direction <NUM>. The skirt elements <NUM>, which are connected at one end to the halo <NUM>, are extended as the halo <NUM> moves in the deployment direction <NUM>. The extendable helix <NUM>, which is connected to the skirt elements <NUM>, extends in the deployment direction <NUM> as the skirt elements <NUM> extend.

Referring now to <FIG>, a cross-sectional view of the antenna assembly <NUM> in the stowed configuration <NUM> is shown. The deployable boom <NUM> is shown disposed in the interior cavity <NUM> of the rigid helix support <NUM>. The deployable boom <NUM> is attached to the first surface <NUM> of the base cup <NUM> via the base ring <NUM>. The base ring <NUM> is mounted to the base cup <NUM> at an aperture <NUM> in the base cup <NUM>. The deployable boom <NUM> includes a launch tube <NUM>. The launch tube <NUM> is attached to the base ring <NUM>, which attaches the launch tube <NUM> to the base cup <NUM> (and fixed section <NUM>). The launch tube <NUM> includes an interior cavity <NUM>. The deployable boom <NUM> includes a launcher <NUM>. The launcher <NUM> is disposed in the interior <NUM> of the launch tube <NUM>. The launcher <NUM> initiates conversion of the extendable elements from a stowed configuration to a deployed configuration (which correspond with the stowed configuration <NUM> and the deployed configuration <NUM> of the assembly <NUM>). The deployable boom <NUM> further includes a plurality of extendable elements <NUM>. Each extendable element <NUM> includes an interface ring <NUM> and a plurality of spring tape extendable structures <NUM> fixed to the interface ring <NUM>.

The interface rings 964a, 964b, 964c, 964d, 964e, 964f, <NUM> are disposed around the launch tube <NUM>. The interface rings 964a, 964b, 964c, 964d, 964e, 964f, <NUM> have a stowed position (shown in <FIG>) and a deployed position (which is assumed in the deployed configuration <NUM>).

The number of spring tapes attached to the interface rings in <FIG> is eight. In other embodiments, the number of spring tapes attached to the interface rings may vary. For example, the number of spring tapes <NUM> may be at least four. The spring tapes 962a, 962b, 962c, 962d, 962e, 962f, <NUM>, <NUM>, 962i are arranged axisymmetrically around the deployment axis (deployable boom). Generally, the spring tapes <NUM> attach to the interface ring <NUM> which is part of the same extendable element at one end and an adjacent ring (which is considered the interface ring of the extendable element below) at the other end. In the case of the spring tapes proximal to the base cup <NUM>, the spring tapes may attach to an interface ring <NUM> at one end and the base ring <NUM> at the opposing end.

Generally, in the stowed configuration <NUM>, the interface rings <NUM> are retained by a retaining device (not shown) in the stowed position, which constrains the spring tapes <NUM> between the retained interface ring and the adjacent ring into a folded or bent configuration. The spring tapes <NUM> in the stowed configuration store potential energy that can be released to cause extension of the deployable boom <NUM>.

To initiate deployment of the deployable boom <NUM>, and conversion of the assembly <NUM> from the stowed configuration <NUM> to the extended configuration <NUM>, the launcher is actuated opposite the direction of deployment <NUM>. Actuation of the launcher <NUM> causes the retaining device to disengage, which releases the interface rings <NUM>. The free interface rings <NUM> are deployed in the deployment direction <NUM> via release of the potential energy stored in the spring tapes <NUM>. Deployment of the interface rings <NUM>, and extension of the spring tapes <NUM>, deploy the deployable boom <NUM> along the deployment axis <NUM>. Extension of the deployable boom <NUM> causes deployment of the skirt <NUM> and the extendable helix <NUM>. The launcher <NUM> initiates extension of each of the spring tapes 962a, 962b, 962c, 962d, 962e, 962f, <NUM>, <NUM>, 962i to transition from a folded shape (as shown) to a fully extended shape that is parallel to the deployment axis <NUM>, thereby extending the respective extendable element as the extendable element converts from a stowed configuration to a deployed configuration. The extension translation/displacement of the interface ring of the extendable element causes release of potential energy that is stored in the spring tapes <NUM> of the extendable element <NUM> when in the folded (stowed) shape. Accordingly, release of a plurality of spring tapes <NUM> in a sequential manner provides improved stability during deployment and release of the stored potential energy.

In some embodiments, the launcher <NUM> sequentially initiates the conversion of each of the extendable elements 966a, 966b, 966c, 966d, 966e, 966f, <NUM>, <NUM>. The sequential extension of spring tapes <NUM> enables the deployment of the extendable helix <NUM> to be a low-shock deployment, which may reduce the risk of damage or other unwanted or adverse effect caused by an excessively forceful deployment. When all of the extendable elements <NUM> are in the deployed configuration, the extendable helical radiating element <NUM> is fully deployed (deployed configuration <NUM>). In some embodiments, release of the extendable elements <NUM> may be sequential. In other embodiments, the release of the extendable elements <NUM> may be simultaneous. In some embodiments, the antenna <NUM> may be a long deployable antenna (longer than about <NUM> in the axial direction when in the deployed configuration, e.g. <NUM>-<NUM>). Long deployable antenna assemblies, such as a deployable antenna assembly that is longer than <NUM> in the axial direction <NUM>, may be released sequentially. Sequential release of the long deployable antenna assembly may ensure that each stage is guided by a post (e.g. launch tube <NUM>) along the axial direction and that the shock generated by the energy release resulting from the deployment of the extendable element <NUM> is limited.

In some embodiments, the antenna <NUM> may be a short deployable antenna (shorter than about <NUM> in the axial direction when in the deployed configuration). In some cases, a short deployable antenna may be configured to implement a simultaneous deployment in which all extendable elements <NUM> in the deployable boom deploy simultaneously upon initiation by the launcher <NUM>. In some embodiments, the release of each of the spring tapes 962a, 962b, 962c, 962d, 962e, 962f, <NUM>, <NUM>, 962i is simultaneous. Accordingly, the launcher <NUM> may simultaneously initiate the conversion of each of the extendable elements 966a, 966b, 966c, 966d, 966e, 966f, <NUM>, <NUM> from the stowed configuration <NUM> to the deployed configuration <NUM>. Short deployable antenna assemblies, such as a deployable antenna assembly that is shorter than <NUM> in the axial direction, may be released simultaneously while the deployable antenna assembly is guided along the axial direction with a telescopic post that deploys with the same stored energy as the deployable antenna assembly.

The deployable boom <NUM> uses spring tapes <NUM> to generate a translational force along the deployment axis <NUM> and to provide stiffness once the extendable elements <NUM> are in the deployed configuration. The spring tape may be fixed to interface rings <NUM> at approximately every <NUM> inches along the deployable boom <NUM>. In the stowed configuration, the spring tapes <NUM> of the expandable elements <NUM> store potential energy for the purpose of deployment. Once deployed, the spring tapes <NUM> provide stiffness and strength to the deployable antenna assembly. The axial stiffness may be increased by at least <NUM> orders of magnitude when the spring tapes <NUM> are in the deployed configuration compared to the stowed configuration. The deployed stiffness may be linear over a large range of axial or bending loads applied on the spring tapes <NUM>. While the spring tapes <NUM> may be used to provide loads around a rotational degree of freedom, the axisymmetric assembly of the spring tapes <NUM> around the deployment axis <NUM> produces a translational deployment load along the axial direction <NUM> of the deployable boom <NUM>.

Referring now to <FIG>, shown therein is a plurality of extendable elements <NUM> of an extendable section (e.g. extendable section <NUM>) of a deployable antenna assembly (e.g. assembly <NUM>) in isolation, according to an embodiment. In particular, the extendable elements <NUM> form part of a deployable boom (or extendable pillar). The extendable elements <NUM> are illustrated in a stowed configuration. In the stowed configuration as part of a deployable boom, the extendable elements are retained in the stowed configuration by a retaining device (not shown in <FIG>). The extendable elements <NUM> in <FIG> represent a variant of the extendable elements shown in <FIG>. In particular, extendable elements <NUM> vary in the number of spring tape extendable structures per interface ring (four in <FIG> versus eight in <FIG>).

The extendable elements <NUM> include interface rings 1402a, 1402b, and 1402c. Interface rings 1402a, 1402b, 1402c are referred to collectively as interface rings <NUM> and generically as interface ring <NUM>. Each interface ring <NUM> includes an aperture <NUM> through which a launch tube (e.g. launch tube <NUM> of <FIG>) is disposed. Each interface ring <NUM> includes a plurality of spring tape attachment points <NUM> for attaching spring tape extendable structures to the interface ring <NUM>.

The extendable elements <NUM> include spring tape extendable structures (or spring tapes) 1408a, 1408b, 1408c, 1408d, 1408e, 1408f, <NUM>, <NUM> referred to collectively as spring tapes <NUM> and generically as spring tape <NUM>. The spring tapes <NUM> are in a stowed configuration in which the spring tapes <NUM> are folded or bent. In the stowed configuration, the spring tapes <NUM> store potential energy that can be released to extend the extendable elements <NUM> in deployment direction <NUM>. The spring tapes 1408a-1408d are attached to interface ring 1402a at a first end and to interface ring 1402b at a second end opposing the first end. The spring tapes 1408a-1408d are attached to the interface rings 1402a, 1402b via connections at attachment points <NUM>. The spring tapes 1408e-<NUM> are attached to interface ring 1402b at a first end and to interface ring 1402c at a second end opposing the first end. The spring tapes 1408e-<NUM> are attached to the interface rings 1402b, 1402c via connections at attachment points <NUM>. The spring tapes <NUM> are attached to the interface rings <NUM> such that the spring blades <NUM> are arranged axisymmetrically about a boom axis.

As described herein, an extendable element (or extendable section or extendable unit), unless otherwise stated, refers to a plurality of spring tapes <NUM> and the interface ring <NUM> to which those spring tapes <NUM> are attached which deploys in deployment direction <NUM> under the translational force of the spring tapes <NUM>. For example, interface ring 1402a and spring tapes 1408a-1408d form an extendable element as interface ring 1402a deploys in deployment direction <NUM> under the translational force of spring tapes 1408a-1408d upon release of the stored potential energy in spring tapes 1408a-1408d.

Generally, in the stowed configuration, the spring tapes 1408a-1408d are constrained in a folded configuration by and between interface rings 1402a, 1402b and the spring tapes 1408e-<NUM> are constrained in a folded configuration by and between interface rings 1402b, 1402c. The interface rings 1402a, 1402b are retained in the stowed position by a retaining device (not shown). Upon release of the retaining device (e.g. by an actuator component of a launcher), the interface rings 1402a and 1402b are freed and the spring tapes 1408a-<NUM> extend. Interface ring 1402c may also deploy similarly to interface rings 1402a, 1402b if interface ring 1402c has spring tapes attached thereto below the interface ring 1402c (opposite the deployment direction <NUM>).

Referring now to <FIG>, <FIG>, and <FIG>, shown therein are cross-sectional views of the antenna assembly <NUM> in the deployed configuration <NUM> (as in <FIG>). <FIG> illustrates antenna assembly <NUM> in deployed configuration <NUM>, while <FIG> is a close-up view of <FIG> in which a segment <NUM> of the extendable section <NUM> of the antenna assembly <NUM> is omitted. Certain components described in reference to <FIG> are not repeated here but are shown using the same reference numerals. In particular, the antenna assembly <NUM> includes deployable boom <NUM> in the deployed configuration including interface rings <NUM> and spring tapes <NUM>. The launch tube <NUM> is constrained geometrically in the axial and radial directions both in the stowed configuration and the deployed configuration.

When all of the extendable elements are in the deployed configuration the deployable boom <NUM> is fully extended and the extendable helical radiating element <NUM> is fully deployed. The deployment of the extendable helix <NUM> occurs in the axial direction along a deployment axis <NUM>, with minimal movement in the radial directions <NUM> along the radial axis <NUM> (radial directions <NUM> and radial axis <NUM> are illustrated in <FIG>). The extendable helix 901may have nearly free deployment along the axial direction <NUM>. The helical radiating element <NUM> may have a high gain radiating pattern when deployed.

In some embodiments, the helical radiating element <NUM> is a thin membrane. This may to provide flexibility for both deployment and stowing. The thin membrane may also allow for a bonding surface of the fixed helix portion <NUM> to the rigid helix support <NUM>. The antenna cross section of the helical radiating element <NUM> provides a radiating surface to achieve the antenna axial RF gain.

The extendable helix <NUM> is constrained along the deployment (axial) axis <NUM> and the radial axis <NUM> by skate blades (not shown) when the extendable helix <NUM> is in the stowed configuration. The constraining provides support and rigidity while the extendable helix 901is stowed. The extendable helix <NUM> is constrained along the (axial) deployment axis <NUM> and the radial axis <NUM> by a skirt <NUM>. The skirt <NUM> provides support and rigidity while the extendable helix <NUM> is deployed. The helical radiating element <NUM> cross-section away from the antenna base plane is parallel to the radial direction of the radial axis <NUM>. The parallel positioning may reduce the stack height of the helical radiating element <NUM> when stowed. The helical radiating element <NUM> transitions from a vertical plane (being parallel to the axial plane/direction <NUM>) to being a helical shape along the radial plane (i.e. from the fixed helix <NUM> to the extendable helix <NUM>). The axial (vertical plane) portion of the helical radiating element <NUM> allows for attachment of the fixed helix <NUM> to the fixed section <NUM> (cylindrical stiff base <NUM>). The radial plane portion of the helical radiating element <NUM> provides flexibility to the helix assembly for deployment.

The skirt <NUM> is configured to provide support to the extendable helix <NUM> in the radial direction <NUM> once deployed. The skirt <NUM> has minimal flexibility in the axial direction <NUM> in the stowed state to minimize the potential energy required for deployment. In some embodiments, the skirt <NUM> is coated or surface treated with a conductive coating. The conductive coating may include a Ge coating or a carbon-loaded coating.

<FIG> illustrates a segment <NUM> (shown in <FIG>) of antenna assembly <NUM> in deployed configuration <NUM> in isolation. The segment <NUM> illustrates a plurality of extendable elements in the deployed configuration including interface rings <NUM> and spring tapes <NUM> (fully extended). The segment <NUM> also includes extendable radiating element <NUM> and skirt elements <NUM>. When the plurality of extendable elements <NUM> are in the deployed configuration the helical radiating element <NUM>, and in particular extendable helix <NUM>, is deployed and fills the RF functionality. When stowed, the helical radiating element <NUM> is optimized for minimum volume and the stiffness of the helical radiating element <NUM> is negligible along the deployment axis <NUM> so the force required for extension of the extendable helix <NUM> is minimal. When deployed, the extendable helix <NUM> is constrained by the skirt <NUM> to ensure the out-of-axis positioning of the extendable helix <NUM>.

In some embodiments, the deployment of the deployable boom <NUM> is sequential to limit the maximal shock generated at the end of each stage of deployment (where a stage of deployment refers to the deployment of an extendable element). The launch tube <NUM> ensures that the deployment occurs along a single degree of freedom to ensure a reproducible behavior for the deployment dynamics. The deployable boom <NUM> extends in the axial direction <NUM> along the interior of the helical radiating element <NUM>. The STES <NUM> are positioned around the periphery of each extendable element <NUM> and extend simultaneously together in the axial direction. The spring tapes <NUM> allow for an efficient structure for the extendable pillar because the spring tapes <NUM> fulfill both functions of energy storage when stowed and assembly stiffness when deployed.

The helix shape of the helical radiating element <NUM> requires minimal mass for support both when stowed and deployed. The actuators used for initiating the conversion between the stowed and deployed configurations are of minimal mass because the power that is needed to be delivered is reduced over conventional designs. The skirt <NUM> secures the off-axis positioning of the helical radiating element <NUM> between the halo <NUM> and the fixed section <NUM>. The launcher <NUM> manages the release of the stored potential energy in the spring tapes <NUM> when the extendable elements <NUM> convert from the stowed to the deployed configuration. The launch tube <NUM> directs the extension of the deployable boom <NUM> in the axial direction <NUM> during deployment.

In some embodiments, the deployment dynamics and shocks produced by the parts when deploying can be restrained using linear dampers. In some embodiments, any form of dampener may be used to reduce the shock produced during deployment.

Referring to <FIG>, illustrated therein is a schematic representation of a system <NUM> for sequentially deploying an extendable structure, according to an embodiment. The system <NUM> may be implemented, for example, in the deployable antenna assembly <NUM> of <FIG> and <FIG>. The system <NUM> may be implemented by the system <NUM> of <FIG>. The system <NUM> includes an extendable structure comprising a plurality of extendable elements 1705a, 1705b, <NUM> (collectively referred to as extendable elements <NUM>, and generically as extendable element <NUM>). The extendable elements <NUM> store potential energy in a stowed configuration. The system <NUM> can be used to sequentially deploy the extendable elements <NUM> along a deployment axis <NUM> in a direction <NUM> of deployment through the release of the stored potential energy in the extendable elements <NUM>.

The system <NUM> also includes a launch tube <NUM>, an inner shaft <NUM> disposed in an interior cavity of the launch tube <NUM>, ball bearings <NUM>, a pin <NUM>, and a pin puller <NUM>. The pin <NUM> is connected to the inner shaft <NUM> at a first end of the pin <NUM> and the pin puller <NUM> at a second end of the pin <NUM>. The pin puller <NUM> is configured to pull or draw the pin <NUM> along the deployment axis <NUM> in the direction opposite the deployment direction <NUM>. As the pin <NUM> is connected to the inner shaft <NUM>, the pulling of the pin <NUM> by the pin puller <NUM> also draws the inner shaft <NUM> towards the pin puller <NUM>. The inner shaft <NUM> includes thick and thin sections. Thick section <NUM> and thin section <NUM> are shown as examples in <FIG>. The thick and thin sections are sized and spaced along the length of the inner shaft <NUM> such that each extendable element 1705a, 1705b, 1705c can be released sequentially. The thick and thin sections alternate along the length of the inner shaft <NUM>. The length of the thick sections of the inner shaft <NUM> increase incrementally along the length of the inner shaft <NUM> opposite deployment direction <NUM>, such that each thick section is longer than the previous thick section. The length of the thin sections of the inner shaft <NUM> decrease incrementally along the length of the inner shaft <NUM> opposite deployment direction <NUM>. The thin sections may be considered spaced cavities along the length of the inner shaft <NUM>.

Generally, the ball bearings <NUM> are constrained between the inner shaft <NUM> and the launch tube <NUM>. The ball bearings <NUM> include multiple subsets of ball bearings <NUM> where each subset is designed to retain an extendable element <NUM>. While in <FIG> two ball bearings <NUM> are shown per subset (i.e. per extendable element <NUM>), fewer or more ball bearings may be used.

The ball bearings <NUM> include a first position and a second position. In the first position, the ball bearings contact a thick section <NUM> of the inner shaft <NUM> and contact the extendable element <NUM> (e.g. an interface ring or annular member of the extendable element). By the ball bearings <NUM> contacting the extendable element <NUM>, the extendable element <NUM> is retained in the stowed configuration. In the second position, the ball bearings <NUM> contact a thin section of the inner shaft <NUM> and do not contact the extendable element (thereby enabling release of the extendable element <NUM>). The movement or displacement of the ball bearings from the first position to the second position is caused by the actuation of the inner shaft <NUM> (i.e. the pin puller pulling the pin connected to the inner shaft <NUM>), which causes the ball bearing <NUM> to contact a thin section of the inner shaft instead of a thick section of the inner shaft.

The sequential deployment system <NUM> is shown at four stages of deployment <NUM>, <NUM>, <NUM>, <NUM>. At deployment stage <NUM>, all of the extendable elements <NUM> are in a stowed configuration. The pin <NUM> is connected to a pin puller <NUM> which pulls the pin <NUM>, pulling the inner shaft <NUM> towards the pin puller <NUM> (along the deployment axis <NUM>, opposite the direction of deployment <NUM>). The inner shaft <NUM> includes spaced cavities along the length of the inner shaft <NUM>. The ball bearings <NUM> are all in the first position in which the ball bearings <NUM> contact the respective extendable elements <NUM> and a thick section <NUM> of the inner shaft <NUM>, constraining the extendable elements <NUM> in the stowed configuration. In the stowed configuration, potential energy is stored in the extendable elements <NUM> that can be released to provide a translational force for extending the extendable element <NUM> along the deployment axis <NUM> in direction <NUM>.

At deployment stage <NUM>, the inner shaft <NUM> has been pulled by the pin puller <NUM> along the deployment axis <NUM> towards the pin puller <NUM>. The pulling of the pin <NUM> also pulls the inner shaft <NUM>. The displacement of the inner shaft <NUM> causes a first subset of the ball bearings <NUM> to move from the first position to the second position as the ball bearings slide along the inner shaft from a thick section <NUM> to a thin section <NUM>. Once in the second position, the first subset of the ball bearings <NUM> no longer contact the first extendable element 1705a. As the first extendable element 1705a is no longer retained, the first extendable element 1705a deploys and extends along the deployment axis <NUM> in direction <NUM>.

At deployment stage <NUM>, the second extendable element 1705b is deployed.

The pin puller <NUM> pulls the pin <NUM> further along the deployment axis <NUM> towards the pin puller <NUM>. This draws the inner shaft <NUM> further towards the pin puller <NUM>. By drawing the inner shaft <NUM> further towards the pin puller <NUM>, a second subset of ball bearings <NUM> (previously retaining the second extendable element 1705b) is displaced from the first position to the second position, such that the ball bearings come into contact with a thin section of the inner shaft <NUM> and out of contact with the second extendable element 1705b. As the extendable element 1705b is no longer retained by the second subset of the ball bearings <NUM>, the extendable element 1705b deploys and extends along the deployment axis <NUM> in the direction <NUM>.

At deployment stage <NUM>, the third expandable element 1705c is deployed and the extendable pillar is fully deployed and extended. The pin puller <NUM> pulls the pin <NUM> further along the deployment axis <NUM> towards the pin puller <NUM>. This draws the inner shaft <NUM> further towards the pin puller <NUM>. By drawing the inner shaft <NUM> further towards the pin puller <NUM>, a third subset of ball bearings <NUM> (previously retaining the third extendable element 1705c) is displaced from the first position to the second position, such that the ball bearings <NUM> come into contact with a thin section of the inner shaft <NUM> and out of contact with the third extendable element 1705c. As the third extendable element 1705c is no longer retained by the third subset of ball bearings <NUM>, the third extendable element 1705c deploys and extends along the deployment axis <NUM> in the direction <NUM>.

Note that the sizing and the spacing of the thick sections of the inner shaft <NUM> are dimensioned such that subsets of ball bearings <NUM> for retaining extendable elements <NUM> later in the sequential deployment remain in contact with a thick section of the inner shaft <NUM> for longer as the pin <NUM> is pulled to deploy earlier-deployed extendable elements <NUM>. This is so the subset of ball bearings <NUM> maintains contact with the extendable element <NUM> to retain the extendable element <NUM>. Similarly, the sizing and spacing of the thin sections of the inner shaft <NUM> are dimensioned such that subsets of ball bearings <NUM> displaced into the second position (where they are not in contact with the extendable element <NUM>) remain in the second position as the other extendable elements <NUM> are deployed.

The potential energy stored in the spring tapes is sufficient to ensure deployment under various scenarios, including without limitation, friction and parasitic loads. The launch tube or telescopic post ensures that the deployment occurs along a single degree of freedom to ensure the reproducible behavior of the deployment dynamics.

The simultaneous or sequential deployment is managed through the release of a ball bearings <NUM> captured between the camshaft <NUM>, launch tube <NUM> and each ring of the extendable element <NUM>. In some embodiments the ball bearings <NUM> may be replaced by another suitable retaining device. The retaining device may be configured to hold the interface rings in a stowed position until deployed. In some embodiments, the deployment may be simultaneous where the cavities are spaced and sized to allow the ball bearings <NUM> retaining multiple sets of expandable elements <NUM> to release simultaneously. Once all bearings <NUM> are freed from the interface ring of the extendable element <NUM>, the extendable element <NUM> initiates its deployment under the force of the spring blade.

An actuator provides the force necessary to exert the relative movement between the camshaft and the launch tube to achieve the controlled deployment of each extendable element <NUM>. The order of interface ring deployment allows all of the extendable elements <NUM> to deploy in a controlled fashion, including the last deployed extendable element. Deployment simplicity is achieved with potential energy stored in the stowed system. Other systems may require a motor to provide the energy to the system to drive deployment. The actuator power required to release each stage sequentially is relatively low as actuation friction loads are minimized. The sequential deployment provides relatively low shocks compared to non-sequential deployment and improved control along the axial direction.

Referring now to <FIG>, illustrated therein is a system <NUM> for simultaneous deployment of an extendable structure, according to an embodiment. The system <NUM> may be implemented by the system <NUM> of <FIG>. In <FIG>, the system <NUM> is shown in a stowed configuration <NUM> and a deployed configuration <NUM>. The system <NUM> is configured to extend an extendable structure <NUM> along a deployment axis <NUM> defined by the extendable structure <NUM> in a direction of deployment <NUM>. The system <NUM> includes the extendable structure <NUM> which includes interface rings (annular members) <NUM> and spring tapes <NUM> attached to the interface rings <NUM>. The system <NUM> also includes a telescopic post <NUM> (including components 1875a, 1875b, 1875c), and a support structure including a skirt <NUM> and a halo <NUM>. The halo <NUM> is attached to the telescopic post <NUM>, the skirt <NUM>, and the spring tapes <NUM>. The skirt <NUM> is extendable, having a stowed configuration and a deployed configuration (i.e. the skirt <NUM> is longer along the deployment axis <NUM> in the deployed configuration).

The system <NUM> also includes a retaining device for retaining the extendable structure <NUM> in the stowed configuration <NUM> including a retaining wire <NUM>, first and second retaining pins <NUM>, <NUM> at opposing ends of the retaining wire <NUM>, and a releasing component <NUM> for holding and releasing the second retaining pin <NUM>. The releasing component <NUM> may be a frangibolt ®, sepnut, or the like. Each spring tape <NUM> is connected to at least one interface ring <NUM>. The spring tapes <NUM> that are furthermost in the extendable structure <NUM> in the deployment direction <NUM> connect to an interface ring <NUM> and to the halo <NUM>. The spring tapes <NUM> furthermost in the extended structure <NUM> in the opposite direction of the deployment direction <NUM> connect to an interface ring <NUM> and a fixed base support structure <NUM> (which is attached to a fixed section <NUM>, described below). The base support <NUM> may be a component of the telescopic post <NUM>. The other <NUM> in the extendable structure <NUM> are connected to interface rings <NUM> at both ends of the <NUM>.

The system <NUM> includes a deployable mass, which in the embodiment of <FIG> is a helical radiating element ("helix"). The helix <NUM> is extendable (i.e. axially translatable along the deployment axis <NUM>) and includes a stowed configuration and a deployed configuration. The helix <NUM> is attached to the skirt <NUM> at a plurality of attachment points. The extension of the skirt <NUM> upon deployment of the extendable structure <NUM> causes the extension of the extendable helix <NUM>. The system <NUM> also includes a fixed section <NUM>. The fixed section <NUM> may be cylindrical. The fixed section may be a rigid helix support. The fixed section <NUM> includes an interior cavity <NUM> in which at least a section of the extendable structure <NUM>, telescopic post <NUM>, and other components are disposed in the stowed configuration <NUM>. The telescopic post <NUM> is mounted to the fixed section <NUM> via the base support <NUM>. The fixed section <NUM> includes a fixed helical radiating element <NUM> mounted to an exterior surface of the fixed section <NUM>. The fixed helix <NUM> connects to the extendable helix <NUM> such that RF signals are transmittable between the extendable helix <NUM> and the fixed helix <NUM>.

Referring now to the stowed configuration <NUM>, the system <NUM> stores potential energy in the spring tapes <NUM> (which are in a folded or bent configuration) between the interface rings <NUM>. The retaining wire <NUM> connects to the halo <NUM> via the first retaining pin <NUM>. The first retaining pin <NUM> is secured to the halo <NUM> via a bolt <NUM>. The retaining wire <NUM> connects via the second retaining pin <NUM> to the releasing component <NUM>, which is fixed to the base support <NUM>. The releasing component <NUM> may be capable of supporting a tension of 100lbs. The helical radiating element <NUM> is stowed for storage and transport.

Referring now to the deployed configuration <NUM>, the connection between the second retaining pin <NUM> and the releasing component <NUM> is disengaged, releasing the second retaining pin <NUM> and releasing the tension in the retaining wire <NUM>. Release of the retaining wire <NUM> enables extension of the spring tapes <NUM> through release of the stored potential energy. Extension of the spring tapes <NUM> extend the extendable structure <NUM>, driving the halo <NUM> in the direction of deployment <NUM>. The skirt <NUM>, which is connected to the halo <NUM>, extends as the halo <NUM> is axially translated in the deployment direction <NUM>. The extendable helix <NUM>, which is connected to the skirt <NUM>, extends as the skirt <NUM> extends to deploy the extendable helical radiating element <NUM> to its full length. Extending the extendable helix <NUM> to its full length provides maximal RF gain.

The deployment simplicity of the system <NUM> is achieved using the potential energy stored in the stowed system <NUM>. In contrast, conventional systems may require a motor to provide the energy to deploy the system, which can increase mass and cost. The stored potential energy required to release the boom (i.e. the extendable structure <NUM>) is relatively low because actuation friction loads are minimized. In some embodiments, actuation friction is minimized by using low friction surface finishes on the sliding surfaces, such as a surface coating with a low friction coefficient. In some embodiments, the friction between contacting elements is minimized geometrically by increasing the lever arm and thus decreasing the normal-to-contact surface loads acting against the external moments.

The extendable elements <NUM> include interface rings 1902a, 1902b, and 1902c. Interface rings 1902a, 1902b, 1902c are referred to collectively as interface rings <NUM> and generically as interface ring <NUM>. Each interface ring <NUM> includes an aperture <NUM> through which a launch tube (e.g. launch tube <NUM> of <FIG>) is disposed. The extendable elements <NUM> include spring tape extendable structures (or spring tapes) 1908a, 1908b, 1908c, 1908d, 1908e, 1908f, <NUM>, <NUM>, 1908i, 1908j, <NUM>, <NUM>, <NUM> referred to collectively as spring tapes <NUM> and generically as spring tape <NUM>. The spring tapes <NUM> are in a stowed configuration in which the spring tapes <NUM> are folded or bent. In the stowed configuration, the spring tapes <NUM> store potential energy that can be released to extend the extendable elements <NUM> in deployment direction <NUM>. The spring tapes <NUM> are attached to the interface rings <NUM> such that the spring blades <NUM> are arranged axisymmetrically about a boom axis.

As described herein, an extendable element (or extendable section or extendable unit), unless otherwise stated, refers to a plurality of spring tapes <NUM> and the interface ring <NUM> to which those spring tapes <NUM> are attached which deploys in deployment direction <NUM> under the translational force of the spring tapes <NUM>. For example, interface ring 1902a and the eight spring tapes 1908a, 1908b, 1908f, <NUM>,1908i (three spring tapes not shown) form an extendable element. Interface ring 1902a deploys in deployment direction <NUM> under the translational force of spring tapes 1908a, 1908b, 1908f, <NUM>,1908i and the three spring tapes which are not shown upon release of the stored potential energy in spring tapes 1908a, 1908b, 1908f, <NUM>,1908i and the three not shown.

Generally, in the stowed configuration, the spring tapes <NUM> are constrained in a folded configuration by and between interface rings <NUM>. The interface rings <NUM> are retained in the stowed position by a retaining device (not shown). Upon release of the retaining device (e.g. by an actuator component of a launcher), the interface rings <NUM> are freed and the spring tapes <NUM> extend.

Claim 1:
A system for a deployable antenna assembly (112a, b, c) comprising:
an extendable pillar (<NUM>, <NUM>) configured to extend in an axial direction along a deployment axis of the deployable antenna assembly to deploy an antenna, the extendable pillar comprising:
at least one extendable element (310a, b, c, <NUM>, <NUM>, <NUM>, <NUM>) configured to convert between a stowed configuration and a deployed configuration, wherein the extendable element in a deployed configuration is longer in the axial direction than the extendable element in a stowed configuration; and
a launcher (<NUM>, <NUM>) configured to initiate conversion of the at least one extendable element (310a, b, c, <NUM>, <NUM>, <NUM>, <NUM>) from the stowed configuration to the deployed configuration, thereby extending the extendable pillar and deploying the antenna, the launcher comprising a retaining device (<NUM>) configured to retain each extendable element in the stowed configuration in which extension of the respective extendable element is constrained and the extendable element is operable to store potential energy that is releasable to extend the extendable element along the deployment axis, characterized in that
the retaining device comprises ball bearings (<NUM>) positioned to contact each extendable element, and the ball bearings are configured such that movement thereof initiates conversion of each extendable element from the stowed configuration to the deployed configuration.