CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application is an international PCT patent application claiming priority benefit of ET.S. provisional patent application Ser. No. 62/663,321, filed on April 27, 2018 and entitled“FURLABLE SAIL DEVICES, SYSTEMS, AND METHODS,” the entire disclosure of which is herein incorporated by reference for all purposes.

BACKGROUND

[0002] Deployable sails may have a variety of applications, such as deorbit sails, solar sails, and general planar apertures. A variety of issues may face deployable sail systems and/or devices, such as sail support, stowage, and/or deployment. There may be a need for new tools and techniques to address these different issues.

SUMMARY

[0003] Furlable sail devices, systems, and methods are provided in accordance with various embodiments. Embodiments may be configured for a variety of applications, such as deorbit sails, solar sails, RF applications, or other general deployable planar apertures. For example, some embodiments include a system and/or device that may include: a furlable boom; a furlable sail coupled with a distal end of the furlable boom; and/or a shear take-up

mechanism coupled with a root end of the furlable sail.

[0004] In some embodiments, the shear take-up mechanism applies tension to the furlable sail. The shear take-up mechanism may include one or more springs coupled with the root end of the furlable sail.

[0005] In some embodiments, the furlable sail includes a structural sheet. In some embodiments, the structural sheet includes a fiber-reinforced polymer composite. The structural sheet may include one or more areas with bending stiffness. The structural sheet may be fabricated to be self-supporting. In some embodiments, the furlable sail is configured such that a distal end of the furlable sail remains partially furled after deployment. [0006] Some embodiments include one or more rails coupled with the furlable sail to avoid telescoping during deployment or while stowed. The one or more rails coupled with the furlable sail may provide one or more hard stops with respect to one or more edges of the furlable boom in a stowed state.

[0007] Some embodiments include a hold down and release mechanism (HDRM) that may include a restraint strap to hold down the furlable boom and the furlable sail in a co-furled state. The restraint strap may be configured to curl away from furlable sail at least during or after deployment. The restraint strap may be tensioned and contain compliance to allow for a varying diameter for the furlable boom and the furlable sail in the co-furled state.

[0008] In some embodiments, the furlable sail is allowed to move with respect to the furlable boom during deployment. In some embodiments, the furlable sail includes a laminate structure to avoid ballooning. In some embodiments, furlable boom and the furlable sail are tip rolled. In some embodiments, the furlable boom is configured for self- deployment. In some embodiments, the furlable boom and the furlable sail are co-furled.

[0009] In some embodiments, the system and/or device is configured as a deorbit sail. In some embodiments, the system and/or device may be configured as a solar sail or other deployable planar aperture structures.

[0010] In some embodiments, the furlable boom includes a slit-tube boom. The slit-tube boom may include a high-strain composite material. The high-strain composite laminate geometry and/or material may be tailored along the slit-tube axial length to vary the deployment energy, authority and/or behavior. For example, at least the high-strain composite material or a high strain-composite laminate geometry of the slit-tube boom may be tailored along an axial length of the slit-tube boom to vary a deployment energy.

[0011] Some embodiments include one or more kickoff spring components configured to facilitate deployment of the furlable boom and the furlable sail from a stowed state. Some embodiments include a cylindrical component coupled with a distal end of the furlable boom. In some embodiments, the cylindrical component is coupled with the distal end of the furlable boom such that the distal end of the furlable boom remains at least flat or open during stowage and deployment. In some embodiments, the cylindrical component is coupled with the distal end of the furlable boom to facilitate at least consolidation or preloading of the furlable sail and the furlable boom. [0012] Some embodiments include methods, systems, and/or devices as described in the specification and/or shown in the figures.

[0013] The foregoing has outlined rather broadly the features and technical advantages of embodiments according to the disclosure in order that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter. The conception and specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Such equivalent constructions do not depart from the spirit and scope of the appended claims. Features which are believed to be characteristic of the concepts disclosed herein, both as to their organization and method of operation, together with associated advantages will be better understood from the following description when considered in connection with the accompanying figures. Each of the figures is provided for the purpose of illustration and description only, and not as a definition of the limits of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] A further understanding of the nature and advantages of different embodiments may be realized by reference to the following drawings. In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.

[0015] FIG. 1 A shows a device and/or a system in accordance with various embodiments.

[0016] FIG. 1B shows a device and/or a system in accordance with various embodiments.

[0017] FIG. 2A shows a device and/or a system in accordance with various embodiments.

[0018] FIG. 2B shows a device and/or a system in accordance with various embodiments.

[0019] FIG. 3 A shows a device and/or a system in accordance with various embodiments.

[0020] FIG. 3B shows a device and/or a system in accordance with various embodiments.

[0021] FIG. 4A shows a device and/or a system in accordance with various embodiments.

[0022] FIG. 4B shows a device and/or a system in accordance with various embodiments. [0023] FIG. 5 shows a device and/or a system in accordance with various embodiments.

[0024] FIG. 6A shows a device and/or a system in accordance with various embodiments.

[0025] FIG. 6B shows a device and/or a system in accordance with various embodiments.

[0026] FIG. 6C shows a device and/or a system in accordance with various embodiments.

[0027] FIG. 7A shows a device and/or a system in accordance with various embodiments.

[0028] FIG. 7B shows a device and/or a system in accordance with various embodiments.

[0029] FIG. 7C shows a device and/or a system in accordance with various embodiments.

[0030] FIG. 7D shows a device and/or a system in accordance with various embodiments.

[0031] FIG. 7E shows a device and/or a system in accordance with various embodiments.

[0032] FIG. 7F shows a device and/or a system in accordance with various embodiments.

[0033] FIG. 8A shows a device and/or a system in accordance with various embodiments.

[0034] FIG. 8B shows a device and/or a system in accordance with various embodiments.

[0035] FIG. 8C shows a device and/or a system in accordance with various embodiments.

[0036] FIG. 8D shows a device and/or a system in accordance with various embodiments.

[0037] FIG. 8E shows a device and/or a system in accordance with various embodiments.

[0038] FIG. 8F shows a device and/or a system in accordance with various embodiments.

[0039] FIG. 9A shows a flow diagram of a method in accordance with various

embodiments.

[0040] FIG. 9B shows a flow diagram of a method in accordance with various

embodiments.

DETAILED DESCRIPTION

[0041] This description provides embodiments, and is not intended to limit the scope, applicability or configuration of the disclosure. Rather, the ensuing description will provide those skilled in the art with an enabling description for implementing embodiments of the disclosure. Various changes may be made in the function and arrangement of elements. [0042] Thus, various embodiments may omit, substitute, or add various procedures or components as appropriate. For instance, it should be appreciated that the methods may be performed in an order different than that described, and that various stages may be added, omitted or combined. Also, aspects and elements described with respect to certain embodiments may be combined in various other embodiments. It should also be appreciated that the following systems, devices, and methods may individually or collectively be components of a larger system, wherein other procedures may take precedence over or otherwise modify their application.

[0043] Furlable sail devices, systems, and methods are provided in accordance with various embodiments. The furlable sail devices, systems, and/or methods may be applicable to a variety of applications, such as deorbit sails, solar sails, solar arrays, deployable antennas, RF shielding, and/or deployable planar apertures in general. Some embodiments provide a variety of stowage and deployment configurations. In general, the systems, devices, and/or methods provided may include a furlable boom and furlable sail that may utilize a shear take- up mechanism. Some embodiments provide for a deployed furlable sail without the need for traditional lateral supports, such as battens. For example, some embodiments utilize a furlable sail that may include a structural sheet that may be self-supporting. Some embodiments help avoid creep and/or telescoping with respect to the furlable sail and/or furlable boom in a stowed state during long term stowage, for example. The furlable boom and the furlable sail may be coupled with each other with respect to the distal ends of each component while the furlable sail may be coupled with the shear take-up mechanism at a root end of the furlable sail. Some embodiments tip roll the furlable boom and/or furlable sail.

[0044] Turning now to FIG. 1A, a device 100 is provided in accordance with various embodiments. Device 100 may be referred to as a furlable sail device and/or system in some embodiments. Device 100 may include a furlable boom 110, a furlable sail 120 coupled with a distal end of the furlable boom 110, and/or a shear take-up mechanism 130 coupled with a root end of the furlable sail 120.

[0045] In some embodiments, the shear take-up mechanism 130 applies tension to the furlable sail 120. The shear-take up mechanism 130 may include one or more springs coupled with the root end of the furlable sail 120. Some shear take-up mechanisms 130 may utilize other components, such as elastic members and/or motors, to facilitate shear take-up. [0046] In some embodiments, the furlable sail 120 includes a structural sheet. In some embodiments, the structural sheet includes a fiber-reinforced polymer composite. The structural sheet may include one or more areas with bending stiffness. The structural sheet may be fabricated to be self-supporting. In some embodiments, the furlable sail is configured such that a distal end of the furlable sail remains partially furled after deployment.

[0047] Some embodiments include one or more rails coupled with the furlable sail 120 to avoid telescoping during deployment or while stowed. The one or more rails coupled with the furlable sail 120 may provide one or more hard stops with respect to one or more edges of the furlable boom 110 in a stowed state. In some embodiments, the one or more rails may be integrated into the construction of the furlable sail 120; in some embodiments, the one or more rails may be coupled with the furlable sail 120.

[0048] Some embodiments include a hold down and release mechanism that may include a restraint strap to hold down the furlable boom 110 and the furlable sail 120 in a co-furled state. The restraint strap may be configured to curl away from furlable sail 120 at least during or after release or deployment; the restraint strap may be configured for self-reverse coiling. The restraint strap may be tensioned and contain compliance to allow for a varying diameter for the furlable boom 110 and the furlable sail 120 in the co-furled state.

[0049] In some embodiments, the furlable sail 120 is allowed to move with respect to the furlable boom 110 during deployment. In some embodiments, the furlable sail 120 includes a laminate structure to avoid ballooning. In some embodiments, furlable boom 110 and the furlable sail 120 are tip rolled. In some embodiments, the furlable boom 110 is configured for self-deployment. In some embodiments, the furlable boom 110 and the furlable sail 120 are co-furled.

[0050] In some embodiments, device 100 is configured as a deorbit sail. In some embodiments, the device 100 may be configured as a solar sail or other deployable planar aperture structures for applications such as solar arrays and/or RF applications (e.g., antennas and/or shield).

[0051] In some embodiments, the furlable boom 110 includes a slit-tube boom. The slit- tube boom may include a high-strain composite material. The high-strain composite laminate geometry and/or material may be tailored along the slit-tube axial length to vary the deployment energy, authority, and/or behavior. For example, by varying the deployment energy, the boom’s authority or behavior may be adapted for different uses.

[0052] Some embodiments one or more kickoff spring components configured to facilitate deployment of the furlable boom 110 and the furlable sail 120 from a stowed state. Some embodiments include a cylindrical component coupled with a distal end of the furlable boom 110. In some embodiments, the cylindrical component is coupled with the distal end of the furlable boom 110 such that the distal end of the furlable boom 110 remains at least flat or open during stowage and deployment. In some embodiments, the cylindrical component is coupled with the distal end of the furlable boom 1 10 to facilitate at least consolidation or preloading of the furlable sail 120 and/or the furlable boom 110.

[0053] FIG. IB includes a system 101 in accordance with various embodiments. System 101 may include a furlable sail device lOO-a, which may be an example of device 100 of FIG. 1 A. System 101 may also include a hold down and release mechanism 140, which may include a restraint strap 141. System 101 may also include a cradle 150. System 101 may include other components, including, but not limited to, a kickoff spring 142, for example.

[0054] In some embodiments, the hold down and release mechanism (HDRM) 140 may include the restraint strap 141 to hold down the furlable boom and the furlable sail of device lOO-a in a co-furled state. The restraint strap 141 may be configured to curl away from furlable sail of the device lOO-a at least during or after deployment. The restraint strap 141 may be tensioned and contain compliance to allow for a varying diameter for the furlable boom and the furlable sail of device lOO-a in the co-furled state.

[0055] When furled or stowed, the furlable sail device lOO-a may be held in the cradle 150 with the restraint strap 141 of the HDRM 140. The kickoff spring 142 may facilitate the deployment of the furlable sail device lOO-a; for example, the kickoff spring 142 may be coupled with the cradle such that the kickoff spring may push against the furlable sail device lOO-a when in a furled state to facilitate deployment of the furlable sail device lOO-a from its furled state with the release of the restraint strap 141 of the HDRM 140. Some embodiments may utilize a leaf spring as kickoff spring 142; other embodiments may utilize a compression spring or the kickoff spring components.

[0056] Turning now to FIG. 2A and FIG. 2B, two perspectives of a system lOl-b in accordance with various embodiments. System lOl-b may include a furlable sail device 100- b, which may include a furlable boom 1 lO-b, a furlable sail l20-b, and a shear take-up mechanism l30-b. System lOl-b may also show a cradle l50-b and a hold down and release mechanism l40-b with restraint strap 141 -b . System lOl-b may also show a kickoff spring l42-b. System lOl-b is shown in a furled state. The furlable boom 1 lO-b and the furlable sail l20-b may be tip rolled and/or co-furled. System lOl-b may be an example of system 101 of FIG. 1B; device lOO-b may be an example of device 100 of FIG. 1A and/or device lOO-a of FIG. 1B.

[0057] In some embodiments, the shear take-up mechanism l30-b may apply tension to the furlable sail l20-b. The shear take-up mechanism l30-b may include one or more springs coupled with the root end or edge 131 of the furlable sail l20-b; other mechanisms may be utilized such as general elastic members and/or motors. In some embodiments, the shear take-up mechanism l30-b utilizes an offset constant force spring mechanism, which may enable sail tensioning; the tensioning may occur during stowage, during deployment, and/or at full deployment. In some embodiments, the shear take-up mechanism l30-b utilizes a cantilevered rod with Delrin dowel, for example. The shear take-up mechanism l30-b may also utilize an interface to couple with the deployable sail l20-b. In some embodiments, coupling the shear take-up mechanism l30-b with the furlable sail l20-b may involve reinforcing a portion of the furlable sail l20-b or utilize a reinforcement component. In some embodiments, the furlable sail l20-b includes structural reinforced areas at the interface or attachment points between the deployable sail l20-b and the shear take-up mechanism l30-b. For example, additional laminate layers of the furlable sail l20-b may provide such reinforcement. In some embodiments, the furlable sail l20-b is allowed to move with respect to the furlable boom 1 lO-b during deployment. In some embodiments, the furlable sail l20-b may form a structural sheet, which may include a fiber-reinforced polymer composite, for example.

[0058] In some embodiments, the HDRM l40-b utilizes a Frangibolt neck, where a Frangibolt preload path may be independent of the restraint strap l4l-b tightening. In some embodiments, the HDRM l40-b may be configured with a Frangibolt body capture cap and bolt capture plate. In some embodiments, the restraint strap l4l-b is coupled with a strap preload spring 143, which may allow for significant travel. In some embodiments, the cradle l50-b provides a V-groove kinematic interface, which enable defined preload for the furled sail l20-b and boom l lO-b. [0059] FIG. 3A and FIG. 3B show side perspectives of system lOl-b in a stowed state (FIG. 3 A) and a deployed state (FIG. 3B). For example, FIG. 3 A shows the stowed state for system lOl-b with a restraint strap l4l-b and HDRM l40-b are set to hold the furlable sail device lOO-b, with furlable boom 1 lO-b and furlable sail l20-b, in a furled or stowed state. FIG. 3B may show a deployed state, where the HDRM l40-b has released the restraint strap 141 -b . The restraint strap l4l-b may coil away from the furlable sail l20-b and the furlable boom 1 lO-b when they are deployed. The released restraint strap l4l-b as may be shown in FIG. 3B may be back bent to enable a curling geometry once a preload is eliminated. Kickoff spring l42-b may facilitate deployment of the furlable sail device lOO-b; FIG. 3A shows kickoff spring l42-b as a leaf spring in a stowed state.

[0060] FIG. 4A and FIG. 4B show two further perspectives of system lOl-b in a deployed state in accordance with various embodiments. These figures, for example, may show the deployed sail l20-b such the shear take-up mechanism l30-b, as constant force spring, provides tension to the deployed sail l20-b. FIG. 4A may also show the furlable boom 1 lO-b as a slit-tube boom, having gone from a furled and rolled flat state to a tubular deployed state.

[0061] FIG. 5 shows system lOl-b in a deployed state in accordance with various embodiments. FIG. 5 may focus on show the fully deployed furlable sail l20-b and fully deployed furlable boom 1 lO-b. System lOl-b may include other components 102, such as a shear take-up mechanism, HDRM, restraint strap, and/or cradle, though not specifically called out.

[0062] In some embodiments, the furlable sail l20-b includes a structural sheet. In some embodiments, the structural sheet includes a fiber-reinforced polymer composite. The structural sheet may include one or more areas with bending stiffness. The structural sheet may be fabricated to be self-supporting as may be shown in FIG. 5. For example, the furlable sail l20-b may generally fabricated as a laminate structure. For example, the furlable sail l20-b may include a fiber laminate, which may have axial and/or lateral fibers. In some embodiments, the furlable sail l20-b includes a glass/Mylar laminate. In some embodiments, the furlable sail l20-b includes a laminate structure to avoid ballooning.

[0063] The furlable boom 1 lO-b may include a slit-tube boom, which may include a high- strain composite material in some embodiments. The high-strain composite laminate geometry and/or material may be tailored along the slit-tube axial length to vary the deployment energy, authority and/or behavior. For example, by varying the deployment energy, the boom’s authority or behavior may be adapted for different uses. In general, the furlable boom 1 lO-b and the furlable sail l20-b may be coupled with each other at the distal end of the furlable boom 1 lO-b. At their root ends, the furlable boom 1 lO-b may be coupled with a cradle, while the furlable sail l20-b may be coupled with a shear take-up mechanism. In some embodiments, the furlable sail l20-b is allowed to move with respect to the furlable boom 1 lO-b during deployment. As shown in FIG. 5, the furlable sail l20-b may be completely unfurled when deployed, though in some embodiments, the furlable sail l20-b is configured such that the distal end of the furlable sail l20-b may remain partially furled after deployment.

[0064] In some embodiments, the furlable boom 1 lO-b is configured for self-deployment. In some embodiments, the furlable boom 1 lO-b may be fabricated as a neutrally-stable structure (or architecture), a mono-stable structure, or a variable combination of both neutrally-stable structure sections and mono-stable structure sections. For example, the furlable boom 1 lO-b may be fabricated such a root portion may be formed as a neutrally- stable structure, while the distal portion may be formed as a mono-stable structure.

[0065] Turning now to FIG. 6A, FIG. 6B, and FIG. 6C, three perspectives of a system lOl-c in accordance with various embodiments are provided. System lOl-c may be an example of system 101 of FIG. 1B. System lOl-c may include a furlable sail device 100-C, which may be an example of furlable sail device 100 of FIG. 1 A and/or device lOO-a of FIG. 1B. System lOl-c may an include aspects of system lOl-b of FIG. 2 A and/or FIG. 2B. Device 100-C may include a furlable boom 1 lO-c, a furlable sail 120-C, and a shear take-up mechanism 130-C. System lOl-c may also show a cradle 150-C and a hold down and release mechanism 140-C with restraint strap 141-C. System lOl-c may also show a kickoff spring 142-C. System lOl-c may also include a cylindrical component 111, which may be referred to as a hub. System lOl-c is shown in a furled state in FIG. 6A and FIG. 6B; system lOl-c is shown in FIG. 6C after the restraint strap 141-C has been released from the hold down and release mechanism 140-C, where the restraint strap 141-C has curled away from the furlable sail 120-C. FIG. 6C may also show rail component(s) 121, which may provide a variety of functions as may be described in more detail with respect to FIG. 7A or FIG. 7B, for example. The furlable boom 1 lO-c and the furlable sail 120-C may be tip rolled and/or co- furl ed. [0066] In some embodiments, the shear take-up mechanism 130-C applies tension to the furlable sail 120-C. The shear take-up mechanism 130-C may include one or more springs coupled with the root end or edge of the furlable sail l20-c; in some embodiments, this involves reinforcing a portion of the furlable sail 120-C or utilize a reinforcement component. For example, the shear take-up mechanism 130-C may utilize an offset constant force spring mechanism, which may enable sail tensioning upon deployment. In some embodiments, the shear take-up mechanism 130-C may utilize a cantilevered rod with Delrin dowel, for example. The shear take-up mechanism 130-C may also utilize an interface to couple with the deployable sail 120-C. In some embodiments, the furlable sail 120-C is allowed to move with respect to the furlable boom 1 lO-c during deployment.

[0067] In some embodiments, the HDRM 140-C utilizes a Frangibolt neck, where a Frangibolt preload path may be independent of the restraint strap 141-C tightening. In some embodiments, the HDRM 140-C is configured with a Frangibolt body capture cap and bolt capture plate. In some embodiments, the restraint strap 141-C is coupled with a strap preload spring 143-C, which may provide tension to strap 142-C and allow for significant travel. The restraint strap 141-C may be tensioned and contain compliance, such as with spring 143-C and/or HDRM 140-C, to allow for a varying diameter for the furlable boom 1 lO-c and the furlable sail 120-C in the co-furled state.

[0068] In some embodiments, the cradle 150-C provides a V-groove kinematic interface, which enable defined preload for the furled sail 120-C and the furlable boom 1 lO-c. System lOl-c may also include kickoff spring 142-C, configured with a compression spring that may push a sliding component that may make contact with the furlable boom 1 lO-c and/or furlable sail 120-C. The sliding component may provide a sliding surface that may be push against the furlable sail 120-C during stowage and/or during deployment. Other similar configurations may be utilized for the kickoff spring 142-C, such as a plug and boot configuration with a compression spring between the plug and boot components. In some embodiments, the compression spring includes a stainless-steel compression spring that may provide a low kickoff force.

[0069] The cylindrical component 111 may couple with a distal end of the furlable boom 1 lO-c and/or furlable sail 120-C. The cylindrical component 111 may be formed as a separate hub element; in some embodiments, the cylindrical component 111 is formed as part of the distal end of the furlable boom 1 lO-c. The cylindrical component 111 may facilitate furling the furlable boom 1 lO-c and the furlable sail 120-C. The cylindrical component 111 may allow for proper consolidation of the furlable sail 120-C and furlable boom 1 lO-c and for preloading in the stowed configuration. The cylindrical component 111 may be coupled with the furlable boom 1 lO-c such that the distal end of the furlable boom 1 lO-c remains flat and/or open during both stowage and deployment. In some embodiments, furlable boom 1 lO-c and the furlable sail 120-C are tip rolled around the cylindrical component 111. Some embodiments are configured such that the distal end of the furlable sail 120-C may remain furled after deployment; this may work as an alternative configuration to the use of the cylindrical component 111 or may be utilized in conjunction with the cylindrical component 111

[0070] FIG. 7A and FIG. 7B show aspects of device lOO-d in accordance with various embodiments. Device lOO-d may be an example of aspects of device 100 of 1A, FIG. 1B, FIG. 2 A, FIG. 2B, FIG. 3A, FIG. 3B, FIG. 4A, FIG. 4B, FIG. 5, FIG. 6A, FIG. 6B, and/or FIG. 6C. Device lOO-d may show a furlable sail l20-d and one or more rails l2l-d. Device lOO-d may also show a cylindrical element 11 l-d that may be coupled at the distal edge of the furlable sail 1 lO-d along with a furlable boom; see FIG. 7B.

[0071] The one or more rails 12 l-d may be coupled with the furlable sail l20-d to avoid telescoping during deployment or while stowed. For example, the one or more rails l2l-d coupled with the furlable sail l20-d may provide one or more hard stops with respect to one or more edges of the furlable boom in a stowed state. This may help prevent relative motion between the furlable sail l20-d and the furlable boom in a stowed configuration. The cylindrical component 11 l-d may be coupled with a distal end of the furlable boom and/or furlable sail l20-d. FIG. 7B may show cylindrical component 11 l-d to represent how the furlable boom may fit between the two rows of rails l2l-d such that the rails provide one or more hard stops for the furlable boom in a stowed state later shown in FIG 7C. In some embodiments, the cylindrical component 11 l-d is coupled with the distal end of the furlable boom such that the distal end of the furlable boom remains at least flat or open during stowage and deployment. In some embodiments, the cylindrical component 11 l-d is coupled with the distal end of the furlable boom to facilitate consolidation of the furlable sail l20-d and the furlable boom. [0072] The furlable sail l20-d may include one or more reinforced regions along its distal edge to facilitate coupling with the cylindrical component 11 l-d and/or a furlable boom.

This reinforcement may include additional layers or aspects of the furlable sail l20-d.

[0073] FIG. 7C and FIG. 7D show aspects of device lOO-e in accordance with various embodiments. Device lOO-e may be an example of aspects of device 100 of 1A, FIG. 1B, FIG. 2 A, FIG. 2B, FIG. 3A, FIG. 3B, FIG. 4A, FIG. 4B, FIG. 5, FIG. 6A, FIG. 6B, FIG. 6C, FIG. 7A, and/or FIG. 7B. In particular, device lOO-e may be an example of device lOO-d of FIG. 7A and/or 7B. Device lOO-e may show a furlable sail l20-e, a furlable boom 1 lO-e, one or more rails l2l-e, and a cylindrical component 11 l-e. The cylindrical element 11 l-e may be coupled at the distal edge of the furlable sail l20-e and the furlable boom 1 lO-e.

[0074] The cylindrical component 11 l-e may couple with a distal end of the furlable boom 1 lO-e and/or furlable sail l20-e. The cylindrical component 11 l-e may be formed as a separate hub element; in some embodiments, the cylindrical component 11 l-e may be formed as part of the distal end of the furlable boom 1 lO-e. The cylindrical component 11 l-e may facilitate furling the furlable boom 1 lO-e and the furlable sail l20-e. The cylindrical component 11 l-e may be coupled with the furlable boom 1 lO-e such that the distal end of the furlable boom 1 lO-e remains flat and/or open during both stowage and deployment. In some embodiments, furlable boom 1 lO-e and the furlable sail 1 lO-e are tip rolled around the cylindrical component 11 l-e.

[0075] The furlable sail l20-e may include one or more reinforced regions along its distal edge to facilitate coupling with the cylindrical component 11 l-e and/or a furlable boom 110- e. This reinforcement may include additional layers or aspects of the furlable sail l20-e.

[0076] The one or more rails l2l-e (see, e.g., FIG.7C) may be coupled with the furlable sail l20-e to avoid telescoping during deployment or while stowed. For example, the one or more rails 12 l-e coupled with the furlable sail l20-e may provide one or more hard stops with respect to one or more edges of the furlable boom 1 lO-e in a stowed state. This may help prevent relative motion between the furlable sail l20-e and the furlable boom 1 lO-e in a stowed configuration.

[0077] FIG. 7E and FIG. 7F show two views of a system lOl-e-l in a deployed state in accordance with various embodiments. FIG. 7E and FIG. 7F may focus on showing the deployed furlable sail l20-e-l and deployed furlable boom l lO-e-l . System lOl-e-l may include other components l02-e, such as a shear take-up mechanism, HDRM, restraint strap, and/or cradle, though not specifically called out. FIG. 7F may also show one or more rails l2l-e-l. Furlable sail l20-e-l may be an example of furlable sail l20-d and/or l20-e, for example. System lOO-e-l may be an example of system 101 of FIG. 1B and/or lOl-c of FIG. 6 A, FIG. 6B, and/or FIG. 6C.

[0078] In some embodiments, the furlable sail l20-e-l may include a structural sheet. In some embodiments, the structural sheet includes a fiber-reinforced polymer composite. The structural sheet may include one or more areas with bending stiffness. The structural sheet may be fabricated to be self-supporting as may be shown in FIG. 7E and/or FIG. 7F. For example, the furlable sail l20-e-l may generally fabricated as a laminate structure. For example, the furlable sail l20-e-l may include a fiber laminate, which may have axial and/or lateral fibers. In some embodiments, the furlable sail l20-e-l may include a glass/Mylar laminate. In some embodiments, the furlable sail l20-e-l includes a laminate structure to avoid ballooning.

[0079] The furlable boom 1 lO-e-l may include a slit-tube boom, which may include a high-strain composite material in some embodiments. The high-strain composite laminate geometry and/or material may be tailored along the slit-tube axial length to vary the deployment energy, authority and/or behavior. For example, by varying the deployment energy, the boom’s authority or behavior may be adapted for different uses. In general, the furlable boom 1 lO-e-l and the furlable sail l20-e-l may be coupled with each other at the distal end of the furlable boom 1 lO-e-l . At their root ends, the furlable boom 1 lO-e-l may be coupled with a cradle, while the furlable sail l20-e-l may be coupled with a shear take-up mechanism. In some embodiments, the furlable sail l20-e-l is allowed to move with respect to the furlable boom 1 lO-e-l during deployment. As shown in FIG.7E and/or FIG. 7F, the furlable sail l20-e-l may not be completely unfurled when deployed, though in some embodiments, the furlable sail l20-e-l may be configured such that the distal end of the furlable sail l20-e-l may be completely unfurled after deployment.

[0080] In some embodiments, the furlable boom 1 lO-e-l is configured for self-deployment. In some embodiments, the furlable boom 1 lO-e-l may be fabricated as a neutrally-stable structure (or architecture), a mono-stable structure, or a variable combination of both neutrally-stable structure sections and mono-stable structure sections. For example, the furlable boom 1 lO-e-l may be fabricated such a root portion may be formed as a neutrally- stable structure, while the distal portion may be formed as a mono-stable structure.

[0081] Turning now to FIG. 8 A, FIG. 8B, and FIG. 8C, a system 103 in accordance with various embodiments are shown from different perspectives in a stowed or furled state.

System 103 may include one or more furlable sail devices lOO-f and/or furlable sail systems lOl-f, which may be shown in a furled state. System 103 may show two furlable sail devices lOO-f and/or systems lOl-f; some embodiments may include more or fewer devices lOO-f and/or systems lOl-f. The furlable sail device lOO-f and/or furlable sail system lOl-f may be coupled with a spacecraft 160. Furlable sail device lOO-f may be an example of devices 100 of FIG. 1 A, FIG. 1B, FIG. 2A, FIG. 2B, FIG. 3 A, FIG. 3B, FIG. 4A, FIG. 4B, FIG. 5, FIG.

6 A, FIG. 6B, FIG. 6C, FIG. 7A, FIG. 7B, FIG. 7C, FIG. 7D, FIG. 7E, and/or FIG. 7F;

furlable sail system lOl-f may be an example of systems 101 of FIG. 1B, FIG. 2A, FIG. 2B, FIG. 3 A, FIG. 3B, FIG. 4A, FIG. 4B, FIG. 5, FIG. 6A, and/or FIG. 6B. FIG. 8D, FIG. 8E, and FIG. 8F show system 103 from different perspectives in accordance with various embodiments. The one or more furlable sail devices lOO-f and/or furlable sail systems lOl-f may be shown in a deployed state. System 103 may provide an example where the furlable sail devices lOO-f and/or furlable sail systems lOl-f may be configured as deorbit sails, though may be configured for other purposes as noted elsewhere herein.

[0082] Turning now to FIG. 9A, a flow diagram of a method 900 is shown in accordance with various embodiments. Method 900 may be implemented utilizing a variety of systems and/or devices such as those shown and/or described with respect to FIG. 1 A, FIG. 1B, FIG.

2 A, FIG. 2B, FIG. 3A, FIG. 3B, FIG. 4A, FIG. 4B, FIG. 5, FIG. 6A, FIG. 6B, FIG. 6C, FIG.

7 A, FIG. 7B, FIG. 7C, FIG. 7D, FIG. 7E, FIG. 7F, FIG. 8A, FIG. 8B, FIG. 8C, FIG. 8D, FIG. 8E, and/or FIG. 8F. In FIG. 9A, the specific selection of steps shown and the order in which they are shown is intended merely to be illustrative. It is possible for certain steps to be performed in alternative orders, for certain steps to be omitted, and for certain additional steps to be added according to different embodiments. Some but not all of these variants are noted in the description that follows.

[0083] At block 910, a furlable sail coupled with a distal end of a furlable boom may be tip rolled together. In some embodiments, the furlable sail and the furlable boom may be tip rolled around a cylindrical component, such as a hub. At block 920, the tip rolled furlable sail and furlable boom may be positioned with respect to a cradle and restraint strap coupled with a hold down and release mechanism. At block 930, the restraint strap may be tensioned and contain compliance with respect to the positioned tip rolled furlable sail and furlable boom. In some embodiments, a shear take-up mechanism may be coupled with a root end of the furlable sail; this may occur at a variety of different times such as before the furlable sail is tip rolled, before the tip rolled furlable sail is positioned with respect to the cradle; before the restrain strap is tensioned, and/or after the restraint strap is tensioned. A root end of the furlable boom may be coupled with the cradle. The device and/or system may be coupled with a spacecraft in some embodiments.

[0084] Turning now to FIG. 9B, a flow diagram of a method 901 is shown in accordance with various embodiments. Method 901 may be implemented utilizing a variety of systems and/or devices such as those shown and/or described with respect to FIG. 1 A, FIG. 1B, FIG.

2 A, FIG. 2B, FIG. 3A, FIG. 3B, FIG. 4A, FIG. 4B, FIG. 5, FIG. 6A, FIG. 6B, FIG. 6C, FIG.

7 A, FIG. 7B, FIG. 7C, FIG. 7D, FIG. 7E, FIG. 7F, FIG. 8A, FIG. 8B, FIG. 8C, FIG. 8D, FIG. 8E, and/or FIG. 8F. In FIG. 9B, the specific selection of steps shown and the order in which they are shown is intended merely to be illustrative. It is possible for certain steps to be performed in alternative orders, for certain steps to be omitted, and for certain additional steps to be added according to different embodiments. Some but not all of these variants are noted in the description that follows.

[0085] At block 950, a hold down and release mechanism may be released to deploy a tip rolled furlable sail coupled with a distal end of a furlable boom. At block 960, the tip rolled furlable sail and furlable boom may be self-deployed. A root end of the furlable sail may be tensioned with a shear take-up mechanism; this may occur at a variety of different times such as during stowage, during deployment, and/or after deployment.

[0086] These embodiments may not capture the full extent of combination and

permutations of materials and process equipment. However, they may demonstrate the range of applicability of the method, devices, and/or systems. The different embodiments may utilize more or fewer stages than those described.

[0087] It should be noted that the methods, systems and devices discussed above are intended merely to be examples. It must be stressed that various embodiments may omit, substitute, or add various procedures or components as appropriate. For instance, it should be appreciated that, in alternative embodiments, the methods may be performed in an order different from that described, and that various stages may be added, omitted or combined. Also, features described with respect to certain embodiments may be combined in various other embodiments. Different aspects and elements of the embodiments may be combined in a similar manner. Also, it should be emphasized that technology evolves and, thus, many of the elements are exemplary in nature and should not be interpreted to limit the scope of the embodiments.

[0088] Specific details are given in the description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, well-known circuits, processes, algorithms, structures, and techniques have been shown without unnecessary detail in order to avoid obscuring the embodiments.

[0089] Also, it is noted that the embodiments may be described as a process which may be depicted as a flow diagram or block diagram or as stages. Although each may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process may have additional stages not included in the figure.

[0090] Having described several embodiments, it will be recognized by those of skill in the art that various modifications, alternative constructions, and equivalents may be used without departing from the spirit of the different embodiments. For example, the above elements may merely be a component of a larger system, wherein other rules may take precedence over or otherwise modify the application of the different embodiments. Also, a number of stages may be undertaken before, during, or after the above elements are considered. Accordingly, the above description should not be taken as limiting the scope of the different embodiments.