Gossamer apparatus and systems for use with spacecraft

Gossamer apparatus and systems for use with spacecraft may include a deployable gossamer apparatus. The deployable gossamer apparatus may include a plurality rib members and gossamer material extending therebetween and may be configured in a stowed configuration and a deployed configuration. The rib members of the deployable gossamer apparatus store potential energy used for deployment of the deployable gossamer apparatus.

BACKGROUND

The present disclosure relates generally to gossamer apparatus and systems for use with spacecraft to increase a surface area (e.g., to form a drag surface defining the suface area) of the spacecraft and/or to decelerate a spacecraft, e.g., to modify the spacecraft's orbit, to de-orbit the spacecraft, for aerobraking the spacecraft, to lower the apogee of the orbit of the spacecraft, for providing a solar sail, etc.

An increasing number of spacecraft are located in low earth orbit. With spacecraft fragmentation, a growing population of orbital debris has been created. Spacecraft may be de-orbited at the end of their operational lives to lower the amount orbital debris. Various standards may require spacecraft to de-orbit within 25 years of the end of their operational life. Traditionally, chemical propulsion systems have been used to de-orbit spacecraft from low-earth orbit at the end of their operational life.

To reduce propellant requirements on spacecraft entering orbit around a planetary body with an atmosphere such as, e.g., Earth, Mars, etc., an “aerobraking” approach may be used. “Aerobraking” reduces the velocity of the spacecraft when initially arriving at a planetary body by using drag created by the atmosphere of the planetary body to reduce the eccentricity of the orbit (e.g. to change the orbit from a hyperbolic to an elliptical trajectory, or to circularize the orbit). In other words, a spacecraft may use aerobraking to reduce the velocity of the spacecraft. For example, the surface area of appendages already used by the spacecraft such as, e.g., solar arrays, etc., may be used for aerobraking.

Some space missions may require a spacecraft to lower its orbit without fully de-orbiting the spacecraft, e.g., reducing apogee to circularize an orbit. Traditionally, chemical propulsion systems may be used for orbit transfers such as, e.g., a partial Hohmann transfer.

Spacecraft may currently deorbit from low Earth orbit using chemical propulsion, electro-dynamic drag, electric propulsion, and natural orbit decay. Chemical propulsion systems are expensive and heavy, and must be integrated into the spacecraft design from conception. In addition, not all satellites require station keeping, orbital maneuvering, or propulsion based attitude control, and therefore, a need for a propulsion system apart from for de-orbiting may not exist. Propulsion systems are often high cost, and thus may represent a large investment for a part of the mission that does not directly contribute to operations.

Electro-dynamic tethers have been developed to de-orbit spacecraft. Electro-dynamic tethers may, however, require complex deployment and may have reliability issues. Further, each of chemical propulsion, electro-dynamic drag, and electric propulsion systems may require functions of the spacecraft systems to be operational at end of life. If the spacecraft systems fail during operations (e.g., prior to de-orbit), then de-orbit may not be able to be accomplished.

Natural orbit decay from atmospheric drag has also been used to de-orbit spacecraft, but the rate of decay is proportional to the surface area of the spacecraft. Most spacecraft in appreciably high orbits (e.g., about 600 kilometers to about 1000 kilometers) may not have a large enough surface area to produce sufficient drag to de-orbit the spacecraft within a 25 year period.

SUMMARY

The problems with modifying orbits of spacecraft with other approaches may be addressed by the exemplary gossamer apparatus and systems described herein. For example, the exemplary gossamer apparatus and systems may be low mass, low cost, scalable, modular, etc. and/or may have few integration requirements.

One exemplary system or apparatus for use on, or with, a spacecraft (e.g., for de-orbiting the spacecraft, for modifying the orbit of the spacecraft, for aerobraking the spacecraft, for decelerating the spacecraft, for increasing the drag of the spacecraft, etc.) may include a deployable gossamer apparatus (e.g., a gossamer structure) and a storage apparatus. The deployable gossamer apparatus may include a central mount portion (e.g., triangular-shaped, circular-shaped, ring-shaped defining an opening such that the central portion is couplable around a docking or separation system of the spacecraft, etc.), a plurality of rib members (e.g., spaced at equal angles around the central mount portion) extending from a proximal end portion to a distal end portion, and gossamer material coupled to and extending between at least two of the plurality of rib members. The proximal end portion of each rib member of the plurality of rib members may be coupled to the central mount portion, and each rib member of the plurality of ribs may be biased to extend along a rib axis (e.g., predisposed to lie along the rib axis).

The deployable gossamer apparatus may be configurable in at least a stowed configuration and a deployed configuration. The plurality of rib members may be wrapped around the central mount portion when the deployable gossamer apparatus is in the stowed configuration, and the plurality of rib members may be positioned to form a drag surface defining a surface area greater than the spacecraft's independent surface area to create a drag force on the spacecraft when the deployable gossamer apparatus is in the deployed configuration.

In at least one embodiment, the gossamer apparatus and systems may further include an electronic circuit chip that executes, or initiates, deployment (e.g., a transition of the deployable gossamer apparatus from the stowed configuration to the deployed configuration) at a certain date and/or time (e.g., after a selected amount of time has elapsed, etc.), at a command from the spacecraft, or based on a watchdog timer (e.g., to allow deployment without a functioning spacecraft). For example, the watchdog timer may be independent from other systems of the spacecraft, and therefore, may be self-reliant. In other words, the watchdog timer may operate independently from the rest of the spacecraft. The watchdog timer may be configured to start a clock, or timer, and “count down” a selected time period until deployment should occur. When the watchdog timer reaches the end of the selected time period, the watchdog timer may initiate a transition of the deployable gossamer apparatus from the stowed configuration to the deployed configuration. Further, in at least one embodiment, the entire exemplary gossamer apparatus and systems may be described as operating independently from the spacecraft (although the gossamer apparatus and systems may be coupled to the spacecraft). In at least one embodiment, may be activated by a signal from an operator.

The storage apparatus may be couplable to the spacecraft and configured to hold the deployable gossamer apparatus and to restrict deployment (e.g., movement of the rib members in the direction in which the rib members are biased, restricting the potential energy stored by the rib members, etc.) of the deployable gossamer apparatus when the deployable gossamer apparatus is in the stowed configuration.

In at least one embodiment, the gossamer apparatus may have the capability to detach from the spacecraft which may allow for modification of the spacecraft's orbit without completing a deorbit maneuver (e.g. detach after completing an orbit change maneuver, detach after lowering the spacecraft's orbit).

In one or more embodiments, each rib member of the plurality of rib members may include at least one lenticular spring (e.g., a carpenter's tape-shaped spring, lens-shaped spring, etc.), and each rib member may be configurable in at least a deployed, linear configuration and a stowed, nonlinear configuration. Each rib member may extend along a rib axis when in the deployed, linear configuration, and each rib member may extend nonlinearly when in the stowed, nonlinear configuration. For example, each rib member may be in the deployed, linear configuration when the deployable gossamer apparatus is in the deployed configuration and/or each rib member may be in the nonlinear configuration when the deployable gossamer apparatus is configured in the stowed configuration. In at least one embodiment, each rib member of the plurality rib members may include two lenticular springs, and each of the two lenticular springs may define or have a concave surface and a convex surface on the side opposite the concave surface (e.g., a carpenter's tape shape). The concave surface of each of the two lenticular springs of each rib member may be positioned such that the concave surfaces of each lenticular spring face each other, or face away from each other. In at least one embodiment, the lenticular springs may be coupled to each other (e.g., about an edge region of the springs, about a central region of the springs, etc.). Additionally, the lenticular springs may be coupled to each along the entire length of the springs or one or more portions of the length of the springs.

In one or more embodiments, the plurality of ribs portions may extend radially from the central mount portion when the deployable gossamer apparatus is configured in the deployed configuration. Further, in at least one embodiment, the plurality of ribs may store potential energy when the deployable gossamer apparatus is configured in the stowed configuration, and the stored potential energy of the plurality of ribs may provide forces that affect the deployment (e.g., kinetic movement) of the deployable gossamer apparatus from the stowed configuration to the deployed configuration when the storage apparatus releases the deployable gossamer apparatus. In one or more embodiments, each of the plurality of ribs may include one or more of steel alloys, titanium alloys, aluminum alloys, copper-beryllium alloys, glass fiber composites, carbon fiber composites, and polymer composites. In at least one embodiment, each of the plurality of rib members may be rotatably coupled to the central portion about a coupling axis perpendicular to the central axis. In at least one embodiment, the plurality of rib members may include at least three rib members.

In one or more embodiments, a gap may be defined between two rib members, which, in turn, may provide a gap in the gossamer material when the deployable gossamer apparatus is in a deployed configuration (e.g., the gap may simplify the wrapping of the ribs and gossamer material about the central mount portion using at least one of a variety of fold patterns such as, e.g., Chinese fan fold). The rib members and gossamer material may be wrapped around the central mount portion when in the stowed configuration. In at least one embodiment, the gossamer material may include polyimide material.

In one or more embodiments, the deployable gossamer apparatus, when in the deployed configuration, may offset the center of pressure from the center of gravity of the spacecraft to stabilize the spacecraft.

In at least one embodiment, the storage apparatus may include one or more wall portions to restrain the deployable gossamer apparatus in the stowed configuration. Further, the storage apparatus may include actuation apparatus configured to release the deployable gossamer apparatus from being restrained by the storage apparatus so as to be configured in the deployed configuration (e.g., the actuation apparatus may release the one or more wall portions of the storage apparatus such that the one or more wall portions may move about hinges and release the deployable gossamer apparatus and/or move out of the way of the deployable gossamer apparatus). In at least one embodiment, the actuation apparatus may include a shape-memory-alloy actuator.

In one or more embodiments, a central axis may extend through the central mount portion, and the plurality of ribs portions may be wrapped around the central mount portion about the central axis when the deployable gossamer apparatus is in the stowed configuration.

In one or more embodiments, the deployable gossamer apparatus may lie along a storage plane when in the stowed configuration, and the deployable gossamer apparatus may extend outside of the storage plane when in the deployed configuration.

One exemplary deployable gossamer apparatus may include a thin polyimide film (e.g. MYLAR or KAPTON blanket) that is folded and stowed during spacecraft operations and deployed at End-of-Life (EOL) of spacecraft. In at least one embodiment, lenticular springs may be used as structure for the gossamer material. Further, the deployable gossamer apparatus may use a simple release mechanism such as, e.g., a shape-memory alloy mechanism actuated by simple drive circuit powered by a primary battery or spacecraft power, a burn wire, frangible or exploding nut, etc.

One or more exemplary systems described herein may be single-fault tolerant for on-demand deployment and for prevention of premature deployment. In at least one embodiment, a deployable gossamer apparatus gossamer sail may wrap around a central mount portion with a “Chinese fan-fold” configuration and/or using any other folding technique. In at least one embodiment, lenticular springs may provide structure to the deployable gossamer apparatus (e.g., the gossamer material when the deployable gossamer apparatus is configured in a deployed configuration).

In at least one embodiment, the storage apparatus may be configured to stow the deployable gossamer apparatus, to restrain the deployable gossamer apparatus in a stowed configuration, and to restrict the deployable gossamer apparatus from moving into a deployed configuration. In at least one embodiment, a shape memory alloy actuator may affect the release of the deployable gossamer apparatus from the stowed configuration. After being released, the deployable gossamer apparatus may unfold, or deploy, independently. In other words, the deployable gossamer apparatus may provide energy (e.g., stored potential energy) to deploy itself after being released. In at least one embodiment, rib members of the deployable gossamer apparatus may store the potential energy and may deploy the deployable gossamer apparatus when released (e.g., released from being restrained).

In at least one embodiment, the system may include storage apparatus to stow the deployable gossamer apparatus such as, e.g., a cover coupled, or tethered, to the system to prevent orbital debris impact on the ribs, gossamer portions, actuator, and drive circuit. In at least one embodiment, the only interfaces to the spacecraft, e.g., a satellite, rocket body, etc., may be a structural attachment interface and a signal interface for sending/receiving an I/O release signal.

In at least one embodiment, the I/O release signal may include a status signal from the spacecraft computer and a watchdog timer. The status signal may be repeated on a regular interval. The watchdog timer may be reset each time it receives the signal. If the spacecraft fails, then, after a selected, or specified, length of time, the watchdog timer may expire and the system will be automatically deployed. Alternatively, the spacecraft can initiate, command, or direct deployment.

In at least one embodiment, the gossamer portions may include gossamer material such as, e.g., DUPONT KAPTON, polyimide film. In at least one embodiment, when in the stowed configuration, the deployable gossamer apparatus may have a folding approach to maximize the packing ratio. In at least one embodiment, the central mount portion may be triangular. In at least one embodiment, when in the deployed configuration, the deployable gossamer apparatus may have a diameter of about 10 meters and a surface area of about 75 meters squared. Other embodiments may be sized to match the requirements of the spacecraft mission. In at least one embodiment, the deployable gossamer apparatus may wrap around a small specific structure. For example, the deployable gossamer apparatus may be configured to wrap around an existing structure like a launch vehicle separation system, e.g., a Marman clamp, Lightband, etc.

In at least one embodiment, the deployable gossamer apparatus may define shuttlecock-like design when in the deployed configuration such that it may provide a center of pressure offset from the center of gravity offset. Further, the exemplary system may apply a stabilizing moment to the spacecraft, assuring the cross-section is perpendicular to the velocity vector, minimizing de-orbit time, etc.

One exemplary system for increasing the surface area (e.g., to form a drag surface defining the suface area) of a spacecraft may include a deployable gossamer apparatus. The deployable gossamer apparatus may include a central mount portion, a plurality of rib members, and gossamer material. The plurality of rib members may extend from a proximal end portion to a distal end portion. The proximal end portion of each rib member of the plurality of rib members may be coupled to the central mount portion and each rib member of the plurality of rib members may be biased to extend along a rib axis to deploy the deployable gossamer apparatus. The gossamer material may be coupled to and extend between at least two of the plurality of rib members. The deployable gossamer apparatus may be configurable in at least a stowed configuration and a deployed configuration.

In at least one embodiment, the plurality of rib members may be positioned to provide a surface area greater than the spacecraft when in the deployed configuration.

In at least one embodiment, the exemplary system may include storage apparatus couplable to the spacecraft and configurable in a storage configuration and a released configuration. The storage apparatus may be configured to restrict deployment of the deployable gossamer apparatus from the stowed configuration to the deployed configuration when in the storage configuration. Further, the storage apparatus may be configured to allow deployment of the deployable gossamer apparatus from the stowed configuration to the deployed configuration without providing energy to the deployable gossamer apparatus for deployment when in the released configuration.

In at least one embodiment, when in the stowed configuration, the plurality of rib members may be wrapped around the central mount portion and store potential energy to provide movement of the deployable gossamer apparatus from the stowed configuration to the deployed configuration.

In at least one embodiment, the plurality of rib members may be wrapped around the central mount portion and lie along a storage plane when in the stowed configuration where the storage plane is perpendicular to a central axis, and the plurality of rib members may be positioned to provide a surface area greater than the spacecraft and extends outside of the storage plane when in the deployed configuration.

The above summary is not intended to describe each embodiment or every implementation of the present disclosure. A more complete understanding will become apparent and appreciated by referring to the following detailed description and claims taken in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary embodiments shall be described with reference toFIGS. 1-12. It will be apparent to one skilled in the art that elements (e.g., apparatus, structures, parts, portions, regions, configurations, functionalities, method steps, materials, etc.) from one embodiment may be used in combination with elements of the other embodiments, and that the possible embodiments of such apparatus and systems using combinations of features set forth herein is not limited to the specific embodiments shown in the figures and/or described herein. Further, it will be recognized that the embodiments described herein may include many elements that are not necessarily shown to scale. Still further, it will be recognized that the size and shape of various elements herein may be modified but still fall within the scope of the present disclosure, although certain one or more shapes and/or sizes, or types of elements, may be advantageous over others.

Exemplary system for increasing the surface area of a spacecraft are described herein. Generally, the exemplary system may include a deployable gossamer apparatus that may be stowed until it is deployed. For example, the deployable gossamer apparatus may be stowed using a storage apparatus until the spacecraft is ready to be decelerated (e.g., for de-orbit, for aerobraking, etc.) and then the deployable gossamer apparatus may be released by the storage apparatus and deployed to increase the surface area of the spacecraft.

The exemplary system may be described in terms of various configurations or states. For example, when the deployable gossamer apparatus, or structures, of the exemplary system are stowed and thus may not be configured to increase the surface area of the spacecraft, it may be described herein the deployable gossamer apparatus is in, or configured in, a stowed configuration. Further, when the deployable gossamer apparatus, or structures, of the exemplary system are deployed and thus increasing the surface area of the spacecraft, it may be described herein that the deployable gossamer apparatus is in, or configured in, a deployed configuration.

As described herein, the exemplary system may include storage apparatus generally configured to store, protect, etc. the deployable gossamer apparatus and to restrict the deployable gossamer apparatus from deploying (e.g., transitioning from the stowed configuration to the deployed configuration). The storage apparatus may also be described in terms of configurations or states. For example, the storage apparatus may be described as being in, or configured in, a storage configuration when containing, enclosing, housing, etc., the deployable gossamer apparatus and restricting the deployable gossamer apparatus from deploying. Further, when the storage apparatus releases (e.g., stops restricting) the deployable gossamer apparatus from the stowed configuration to transition (e.g., deploy, transform, move, etc.) from the stowed configuration to the deployed configuration, the storage apparatus may be described as being in, or configured in, a released configuration.

The deployable gossamer apparatus of the exemplary system for increasing the surface area or projected area (e.g., to form a drag surface) of a spacecraft may be configured to store potential energy that provides the transition from the stowed configuration to the deployed configuration. The deployable gossamer apparatus may be described as being energy independent from other portions of the system and/or the spacecraft the system is attached thereto. For example, the deployable gossamer apparatus may not require energy from the other portions of the system and/or the spacecraft. Instead, for example, other portions of the exemplary system may provide restriction, or inhibition, of the stored potential energy of the deployable gossamer apparatus from releasing such that the deployable gossamer apparatus does not deploy until a selected time (e.g., end of life, directed to be deployed by a user, etc.). In some of the embodiments described herein, the deployable gossamer apparatus may include lenticular springs to store potential energy to deploy the deployable gossamer apparatus (e.g., to transition the deployable gossamer apparatus from a stowed configuration to a deployed configuration).

To increase the surface area of a spacecraft, the deployable gossamer apparatus may change shape and size when transitioning from the stowed configuration to the deployed configuration. For example, the deployable gossamer apparatus may be described as lying (or extending along) a plane when in the stowed configuration (e.g., so as to occupy less space, etc.) and may be described as extending outside of the plane when in the deployed configuration to, e.g., define a shuttlecock-like shape to increase the surface area of the spacecraft and stabilize the trajectory and/or attitude of the spacecraft.

Multiple views of an exemplary system10for increasing the surface area of a spacecraft are depicted inFIGS. 1-3. As shown inFIG. 1, the exemplary system10may be coupled to, or attached to, a spacecraft20. In other embodiments, the exemplary system10may be integral, or part of the spacecraft20. The spacecraft20may be described as lying along a central axis34. In this example, the exemplary system10is also shown centered on central axis34. The central axis34may also be the direction of travel, or trajectory, of the spacecraft20. For example, the spacecraft20may be described as moving along central axis34in direction35.

As shown, the exemplary system10is mounted (e.g., attached, coupled) to a rear surface22of the spacecraft20. In other embodiments, the exemplary system10may be mounted on any side, face, surface, appendage, portion, region, or any other suitable location on, within, or extending from the spacecraft20. The spacecraft20may be any spacecraft, target object, or space object on which the exemplary system10may be used to increase the surface area of the spacecraft20. The exemplary system10may be attached to the spacecraft20by rivets, bolts, welds, adhesives, brazed joints, and/or any other fastening technique known to one skilled in the art.

The exemplary system10for increasing the surface area or projected area of a spacecraft20may include a deployable gossamer apparatus30and a storage apparatus80. The storage apparatus80may be the portion of the system10that may be coupled, or attached, to the external face22of spacecraft20. As shown inFIG. 1, the storage apparatus80may be configured in the storage configuration such that the deployable gossamer apparatus30is restrained and enclosed, covered, wholly or partially etc. by the storage apparatus80. In this embodiment, the storage apparatus80may completely enclose the deployable gossamer apparatus30when in the storage configuration, and thus the deployable gossamer structure30may not be visible inFIG. 1. Since the deployable gossamer apparatus30is configured in the stowed configuration (e.g., and restrained by the storage apparatus in the storage configuration), the surface area of the spacecraft is not increased by the system10inFIG. 1. Further, the attachment of the system10to the spacecraft20may be made between the storage apparatus80(or portion thereof) and/or the deployable gossamer apparatus30and the spacecraft20.

When the surface area of the spacecraft is to be increased (e.g., for deceleration, for aerobraking, for de-orbiting, or for modifying an orbit etc.), the deployable gossamer apparatus30may be transitioned from the stowed configuration to the deployed configuration. The deployable gossamer apparatus30is depicted inFIGS. 2A-2Cin the deployed configuration. As shown inFIG. 2C, the surface area defined by deployable gossamer apparatus30when deployed increases the surface area or projected area of spacecraft20when taken, or viewed, along the central axis34. It is to be understood that prior to deployment of the deployable gossamer apparatus30, the spacecraft20may not be traveling along axis34, but after the deployable gossamer apparatus30is deployed, the spacecraft20may settle into a flight path or trajectory along the axis34due to the configuration (e.g., shape of the draft surface, shuttle-cock shape, etc.) provided by the deployed deployable gossamer apparatus30. Further, although the entire surface area of the spacecraft may be is described as being increased, in particular, it may be described that the deployable gossamer structure30increases the surface area perpendicular to the axis34. In other words, if the spacecraft20and deployable gossamer structre30, when deployed in the deployed configuration, are viewed along the axis34and planarized, or flattened, (such as when depicted on a sheet of paper as inFIG. 2C), the surface area of the spacecraft20and deployable gossamer structure30will have increased. In other words, the area defined by an orthographic projection of the spacecraft20and deployable gossamer structre30, when deployed in the deployed configuration, onto a plane perpendicular to the central axis34(e.g., as inFIG. 2C), will have increased.

The deployable gossamer apparatus30may include a plurality of rib members40and gossamer material51extending between the rib members40as shown inFIG. 2A. The gossamer material51may be coupled (e.g., adhered, welded, fastened, glued, etc.) to the rib members40(e.g., continuously, at multiple points along the rib members40, etc.). In at least one embodiment, the gossamer material51may be coupled to the rib members40at only the proximal and distal end portions42,44. The deployable gossamer apparatus30may further include a central mount portion60that may be described in further detail herein with respect toFIGS. 3B, 3D and 7A-7B. The plurality of rib members40may be configured to provide structural support to gossamer material51extending between the rib members40. For example, the gossamer material51may be flexible, non-resilient material that may provide the surface area (e.g., drag surface, etc.) increase with the support of the rib members40. In at least one embodiment, the gossamer material51may also have some limited stiffness to it, e.g., provided by creases in the material, which may help to maintain the shape of the deployed gossamer apparatus when in the deployed configuration. Further, as will be described further herein, the rib members40may be configured to provide the energy (e.g., potential energy, strain energy) for deployment (e.g., for passive deployment) of the deployable gossamer apparatus40.

Generally, the storage apparatus80may be used to restrict, or hold, the deployable gossamer apparatus30in the stowed configuration. In the embodiment depicted inFIGS. 1-3, the storage apparatus80includes a plurality of wall portions. As shown inFIGS. 3A-3D, the plurality of wall portions may include side wall portions90, top wall portions82,84, and back wall portions88. In at least one embodiment, the back wall portion88may not be included in the storage apparatus80, and instead, the storage apparatus80may be directly attached to the spacecraft20without a back wall portion88. The storage apparatus80may further include hinges92coupling the side wall portions90to the top wall portions82,84. Hinges92may also couple side wall portions90to back wall portion88, if present. The wall portions82,84,90may include (e.g., be formed of, be manufactured of, etc.) one or more metallic materials, one or more polymeric materials, one or more composite materials, and/or any combination of suitable materials.

The exemplary system10may further include actuation apparatus70that is configured to unlock or release the storage apparatus80from the storage configuration to transition to the released configuration thereby releasing the deployable gossamer apparatus30, which allows the deployable gossamer apparatus30to move from the stowed configuration to the deployed configuration. In essence, the actuation apparatus70releases the deployable gossamer apparatus30to deploy into the deployed configuration. The actuation apparatus70will be described further herein with respect toFIGS. 3A-3D.

As described, the deployable gossamer apparatus30may be configurable in at least a stowed configuration as shown inFIG. 1and a deployed configuration as shown inFIGS. 2A-2C. As shown in the exemplary system10, the deployable gossamer apparatus may include four rib members (e.g., two rib members extend adjacently to provide a break in the gossamer material51to provide the folding as will be described further herein). In other embodiments, any number of rib members40may be included as part of the deployable gossamer apparatus30to, e.g., support the gossamer material51. For example, the deployable gossamer apparatus30may include one or more rib members, two or more rib members, three or more rib members, four or more rib members, six or more rib members, eight or more rib members, ten or more rib members, twelve or more rib members, twenty or more rib members, etc. and/or four or less rib members, six or less rib members, eight or less rib members, ten or less rib members, twelve or less rib members, twenty or less rib members, thirty or less rib members, forty or less rib members, fifty or less rib members, etc.

The rib members40of the deployable gossamer apparatus30may be described as extending from a proximal end portion42that may be coupled to a central mount portion60(e.g., as shown and described with reference toFIGS. 7A-7B) to a distal end portion44. As described herein, each rib member40may be biased to extend along a rib axis41,41′,41″, etc. In other words, the rib members40may be predisposed to lie, or extend, along the rib axis. For example, the “natural” or lowest energy state of the rib members40may be extending, or lying, along their respective rib axis. Further, the rib members40may be described as storing potential energy when not extending along their respective rib axis may be described as having released their stored potential energy when extending along their respective rib axis. As such, if the rib members40are unrestricted or unrestrained by any other portion or object, the rib members40may move (e.g., unwind, unfurl, etc.) as will be described herein with respect toFIGS. 5A-5C.

As shown inFIG. 2C, the plurality of rib members40may be spaced equidistantly and equilaterally about the central mount portion60and/or central axis34. In other embodiments, the plurality of rib members40may not be spaced equidistantly and equilaterally and instead may be unequally spaced. Additionally, the rib members40may extend radially (e.g., as opposed to tangentially) from the central mount portion60and/or central axis34. In other embodiment, the rib members40may extend in a partially radial direction, or have a radial component to the extension direction, from the central mount portion60and/or central axis34.

The rib members40may include (e.g., be formed of, be manufactured or fabricated using, etc.) one or more of steel alloys, titanium alloys, copper-beryllium alloys, glass fiber composites, polymer composites, carbon fiber composites, polymer composites, or any other suitable material.

When in the stowed configuration as shown inFIG. 1, the deployable gossamer apparatus30(and portions/components therefore) may be described as being located (e.g., lying) substantially in a plane perpendicular to the central axis34. Although the deployable gossamer apparatus30is in the deployed configuration, the storage plane36may be represented by a dotted line inFIG. 2B. When in the deployed configuration, the deployable gossamer apparatus30(and portions/components therefore) may be described as extending outside of the storage plane36in a plane perpendicular to the central axis34.

In the deployed configuration, the rib portions40may form an angle α between the storage plane36and the rib axes41′,41″,41′″ to create a “shuttlecock” design or shape. Although in this embodiment, each rib member40has the same angle α, in other embodiments each rib member40may have a different angle α from each other. Additionally, this “shuttlecock” shape, or any shape that the exemplary deployable gossamer apparatus30may take in the deployed configuration, may be maintained at least partially by the gossamer material51extending between the rib members40. For example, the rib members40may extend into their biased, lowest energy state pulling the gossamer material51therebetween into the proper or desired shape configuration (e.g., shuttlecock shape) upon deployment (further, e.g., the gossamer material51may also restrain the movement of the rib members40as they deploy or restrict to their position when in the deployed configuration such that a desired angle α is achieved). In another embodiment, the rib members40may assume an out-of-plane orientation by means of a torsional spring or linear spring at or near their attachment point to the central mount portion60.

When in the deployed configuration, the deployable gossamer stricture30may passively stabilize spacecraft20by utilizing drag forces resultant from interaction of the gossamer material51and the rarified upper atmosphere of a planetary body. More specifically, the plurality of rib members40are positioned to form a drag surface with gossamer material51defining a surface area (e.g., a surface area when viewed along the axis34as shown inFIG. 2C) greater than the spacecraft20to decelerate the spacecraft20when in the deployed configuration. The surface area may be taken perpendicular to the central axis34. In other words, when looking at the spacecraft from either end of central axis34such as when looking atFIG. 2C, the surface area of the spacecraft will have increased when the deployable gossamer apparatus30is in the deployed configuration.

The deployed deployable gossamer apparatus30may be described as offsetting the center of pressure from the center of gravity of the spacecraft20to stabilize the spacecraft20. For example, as shown inFIG. 2B, prior to the deployment of the deployable gossamer apparatus30, both the center of gravity and center of pressure may be located proximate area11. After full deployment of the deployable gossamer apparatus30in the deployed configuration as shown inFIG. 2B, the center of gravity may remain proximate area11while the center of pressure may be located proximate area12. In other words, the center of pressure may have moved to an area, or location,11in a direction13opposite the trajectory direction35(i.e., the direction that the spacecraft20may settle into after deployment of the deployable gossamer structure).

When the deployable gossamer apparatus30is in the stowed configuration, the plurality of rib members40and the gossamer material51may occupy a smaller space than when in the deployed configuration. In this embodiment, the plurality of rib members40and the gossamer material51may be wrapped around the central mount portion60when the deployable gossamer apparatus30is in the stowed configuration as shown inFIG. 3BandFIG. 3D. Although the deployable gossamer apparatus30is shown in the stowed configuration inFIG. 3Deven though the storage apparatus80is in the released configuration, it is to be understood that the deployable gossamer apparatus30may begin, or initiate, transitioning (e.g., moving, unfurling, unwinding, deploying, etc.) into the deployed configuration as soon as the storage apparatus80is in the released configuration. In other words, the rib members40of the deployable gossamer apparatus30may begin to immediately move out of their stowed configuration upon opening or releasing of the storage apparatus80, and therefore,FIGS. 3B and 3Dmay not depict the actual deployment dynamics of the deployable gossamer apparatus30.

The gossamer material51may include, e.g., one or more polyimides, MYLAR®, DUPONT KAPTON®, or other film, etc.). The material may be selected to withstand a folding requirement and to meet a packing factor needed to fit the deployable gossamer apparatus30in the storage apparatus80. As described herein, the gossamer material51may be coupled to and extend between at least two of the plurality of rib members40. As shown, a gossamer portion50may be a portion of the gossamer material51that extends between two rib members40. Further, the gossamer material51may be reflective or non-reflective. For example, if the deployable gossamer apparatus30is configured to be used in an aerobraking or de-orbiting operation, the gossamer material51may be non-reflective. Further, for example, if the deployable gossamer apparatus30is configured to be used in a solar sail operation, the gossamer material51may be reflective.

The deployed configuration of the deployable gossamer apparatus30may be described as forming a deployed sail54that may include a roughly, or substantially circular, projection as shown inFIG. 2C. Further, the shape of the deployed sail54may be maintained by tension between the rib members40. Also, in at least one embodiment, the deployable gossamer apparatus30may include a stiffener around the distal perimeter, or circumference, of the deployed sail54. Further, wrinkles in the gossamer material51and/or any other methods known to one skilled in the art of deployable gossamer apparatus may provide the shape of the deployed sail54.

Although as depicted, the deployable gossamer apparatus30includes three gossamer portions50, it is to be understood that the deployable gossamer apparatus30may include plurality of gossamer portions50to form a deployed sail54that may provide a triangular, rectangular, pentagular, etc. projection. In at least one embodiment, each gossamer portion50may be an ellipsoidal segment.

As described herein, the storage apparatus80of the exemplary system10may be configured in at least the storage configuration as shown inFIGS. 3A and 3Cand the released configuration as shown inFIG. 3D. When the deployable gossamer apparatus30is in the stowed configuration, the rib members40and gossamer material51are wrapped around the central mount portion60as shown inFIG. 3Band may be contained, or enclosed, wholly or partially within the storage apparatus. The rib members40and gossamer material51may be held (e.g., restricted or restrained) in the stowed configuration by storage apparatus80when the storage apparatus80is configured in the storage configuration as shown inFIGS. 3A and 3C. More specifically, the wall portions (e.g., panels or other suitable surface, enclosure or cover pieces) such as that side wall portions90, top wall portions82,84, and back wall portion88of the storage apparatus80may prevent deployment of the deployable gossamer apparatus30from the stowed configuration. For example, the wall portions may restrict movement (e.g., unwinding, unfurling, movement out of the storage plane, etc.) of the rib members40. More specifically, as described herein, the rib members40may be biased, or predisposed, to extend along their respective rib axes41′,41″,41′″ and the wall portions of the storage apparatus80may not allow the rib members40(may restrict rib members40) from moving to extend along their respective rib axes41′,41″,41′″. As such, the potential energy stored by the rib members40when in the stowed configuration may be restricted, or stopped, from being released, by the storage apparatus80.

Although the storage apparatus80depicted herein includes a plurality of wall portions to restrict or stop the deployable gossamer apparatus30from deploying to the deployed configuration, it is to be understood that the storage apparatus80may include, or utilize, any portion or member arranged in any configuration to restrict or stop the deployable gossamer apparatus30from deploying to the deployed configuration.

To release the storage apparatus80from the storage configuration to the released configuration, and in turn, release the deployable gossamer apparatus from the stowed configuration to the deployed configuration, the exemplary system10may further include actuation apparatus70that configured to restrict or hold the storage apparatus80in the storage configuration. When the deployable gossamer apparatus30is to be deployed, the actuation apparatus70may release the storage apparatus80from the storage configuration as shown inFIG. 3B. When the storage apparatus80is released from the storage configuration, the wall portions82,84,90may unfold releasing and exposing the deployable gossamer apparatus30so as to allow the deployable gossamer apparatus30to expand (e.g., move, be configured, transform, expand, change) into the deployed configuration as shown inFIGS. 2A-2C.

In other words, the wall portions82,84,90(and in some embodiments, back wall portion88) cover and contain the deployable gossamer apparatus30, and the actuation apparatus70holds the storage apparatus80in the storage configuration until released by operation of the actuation apparatus70into the released configuration. When released, the storage apparatus80can transition into the released configuration.

Although three top wall portions82,84are used in this embodiment, any number of top wall portions82,84may be provided such as, e.g., one or more top wall portions, two or more top wall portions, three or more top wall portions, four or more top wall portions, etc. In this embodiment, one top wall portion82may be referred to as the restraining top wall portion82, and the other two top wall portions84may be referred to as the restrained top wall portions84because the restraining top wall portion82may overlap the retrained top wall portions84to restrict movement of the restrained top wall portions84when in the storage configuration. In essence, the top wall portions82,84(e.g., panels, enclosure or cover pieces, etc.) may serve either a restraining function (e.g., configured to restrain another top wall portion) or may be restrained by another top wall portion (e.g., configured to be restrained by another top wall portion). As shown, the restraining top wall portion82retrains the other two top wall portions84.

More specifically, the restraining top wall portion82may include one or more overlap regions86(e.g., ridges) configured to overlap corresponding regions87(e.g., edges, ridges, etc.) of the restrained top wall portions84to restrict, or restrain, movement of the restrained top wall portions84(e.g., such that the restrained top wall portions84are “held down” by the restraining top wall portion82). In this embodiment, all of the top wall portions82,84may be restricted or restrained from movement (e.g., held closed in the storage configuration) by the actuation apparatus70, which will be described further herein within respect to the actuation apparatus70. Further, the overlap regions86,87may be configured to prevent unintentional deployment or shifting of the wall portions82,84,90during exposure to high-g forces or extreme vibrational environments. The overlap regions86,87(e.g., using grooves, ridges, etc.) may provide a simplified interface between the top wall portions82,84and the actuation apparatus70because only one top wall portion82directly interfaces with the actuation apparatus70for releasing the entire storage apparatus80.

As shown inFIGS. 3A-3D, each side wall portion90and top wall portions82,84may be pivotally coupled together, e.g., by hinges92(e.g., piano hinges, living hinges, or any other suitable hinges). In one or more embodiments, the hinges92may include a piano hinge with a metallic or polymeric pin, polymeric spacers (e.g., DELRIN), and metallic, polymeric, or a composite barrel. The hinges92may be integrated into the wall portions82,84,90, with the barrel formed of the same piece of material, or it may be fastened (bolt, adhesive, etc.) to the wall portions82,84,90and may be made of a different material. Additional hinges92may pivotally connect side wall portions90to either the spacecraft structure or the storage apparatus back wall portion88, if present. In at least one embodiment, a single hinge and pin may be located along the length of the side portion(s)90, while in another embodiment there may be a plurality of co-linear hinges.

As described, the actuation apparatus70may be configured to restrict, and subsequently release, the storage apparatus80from the storage configuration. In the particular embodiments depicted inFIGS. 1-3, the actuation apparatus70is configured to restrict, and subsequently, release the restraining top wall portion82, which as described herein, release the other wall portions84,90. The actuation apparatus70may include a first portion72and a second portion76. The first portion72of actuation apparatus70may be fastened to or integrated within the restraining top wall portion82. The restrained top wall portions84may each define a restraining tab74(e.g., a u-shaped, c-shaped, or otherwise shaped tab or mechanism) that may be configured to interface partially around a portion of the actuation apparatus70(e.g., release mechanism). The restraining tabs74may be configured to help, prevent, reduce, and/or limit movement of the restrained top wall portions84(e.g., in high-g and vibrational environments by preventing motion of the wall portions82,84,90).

The second portion76of the actuation apparatus70(e.g., an actuator) may be coupled (e.g., mounted) to the storage apparatus80(e.g., to the back wall portion) and/or the central mount portion60. The second portion76may be selectively coupled to the first portion72such that when the second and first portions76,72are coupled together, the actuation apparatus70may be configured to restrict the storage apparatus80in the storage configuration. Likewise, when the first and second portions72,76are uncoupled, the actuation apparatus70may release the storage apparatus80from the storage configuration to the released configuration.

In the embodiment depicted inFIGS. 6-7, the second portion76of the actuation apparatus70may be shape-memory alloy actuator. For example, the actuator may include an actuator pin76′ extending from the top towards the storage apparatus80that interfaces with the first portion72of the actuation apparatus70(e.g., a release nut or other suitable release mechanism) that is integrated into the restraining top portion82(or any other suitable component) of the storage apparatus80. In some embodiments, before actuation, the first portion72may be held in place on a pin76′ on top of the second portion76(e.g., shape memory alloy actuator) by a latch mechanism that is held by second portion76. The first portion72may be, for example, a release nut, and the second portion76may be, for example, a shape memory alloy actuator. When actuated by an applied voltage, the second portion76(e.g., shape memory alloy actuator) may release the first portion72(e.g., release nut), at which point the first portion72release the second portion76(e.g., the second portion76may slide off actuator pin76′). In at least one embodiment, the second portion76may be propelled away from, or off of, the actuator pin76′ by a spring that may be configured to provide an initial push to separate the first portion72from the second portion76immediately after actuation.

The gossamer apparatus30is shown in the stowed configuration while the storage apparatus80is deploying into the released configuration inFIG. 3B. After the actuation apparatus70is released, the storage apparatus80may transition (e.g., open) to a released configuration. The energy to open the storage apparatus80may come from potential energy that is stored in the storage apparatus80. In at least one embodiment, the energy may be supplied by torsional springs in the hinges92or near the hinges92that are compressed (e.g., storing potential energy) when the storage apparatus80is in the storage configuration and are at a lower energy state (e.g., extended state) when the storage apparatus80is in the released configuration. Any suitable mechanism configured to provide potential energy at or near the hinge92location may be provided. Thus, the wall portions82,84,90may be configured to open without any external motors or other devices.

Another exemplary system410for increasing the surface area of a spacecraft is depicted inFIGS. 4A-4C. The exemplary system410includes storage apparatus480that is different than the storage apparatus80described herein with reference toFIGS. 1-3. In this embodiment, the hinges492of the storage apparatus480are springs (e.g., lenticular springs or any other type of spring) that are configured to store potential energy when bent but naturally straighten when unrestrained. As such, when actuation apparatus470releases the storage apparatus480from the storage configuration, the hinges492may release the stored potential energy to transition the storage apparatus480from the storage configuration as shown inFIG. 4Ato the released configuration as shown inFIG. 4C. As shown inFIG. 4A, the deployable gossamer apparatus430may not be fully enclosed (e.g., at least a portion of the deployable gossamer apparatus430may be visible, exposed, and/or unprotected) and the total mass of the system410may be reduced.

As shown inFIG. 3B, the side wall portions90may be selected to have a height to accommodate the height of the stowed deployable gossamer apparatus30, and wide enough (e.g., from one end to the other end along the storage plane36) to allow the stowed deployable gossamer apparatus30to be located in the storage plane36. Further, the top wall portions82,84may be configured to cover at least enough area in the storage plane36so that, when taken in combination, the plurality of top wall portions82,84may completely enclose the deployable gossamer apparatus30when in the stowed configuration. In another embodiment, the wall portions82,84,90may leave openings in the storage apparatus80and not completely enclose the deployable gossamer apparatus30. In some embodiments, the wall portions82,84,90may be selected and sized to be large enough to restrain the deployable gossamer apparatus30in the stowed configuration but to not completely enclose the deployable gossamer apparatus30(e.g., not necessarily protect the deployable gossamer apparatus30from the surrounding environment).

Further, the maximum width of the folded deployable gossamer apparatus30may influence the height of the side wall portions90. The general shape of the deployable gossamer apparatus30may be configured such that each gossamer material51may be folded and wrapped between two adjacent rib members40. Due to the gossamer material51being wider at the distal end portions44of the rib members40than at the proximal end portions42of the rib members40, the deployable gossamer apparatus30may increases in width/height as the deployable gossamer apparatus30wraps from the central mount portion60to the distal end portions44of the rib members40. In other words, an outer region of39of the deployable gossamer apparatus30, when in the stowed configuration, may be taller (e.g., have greater height) and may be thicker (e.g., due to more material) than an inner region37as shown inFIG. 3B. As such, a maximum width of the deployable gossamer apparatus30may determine the height of the side wall portions90of the storage apparatus80.

The deployable gossamer apparatus30may deploy (e.g., transition from the stowed configuration to the deployed configuration) simultaneously, or nearly simultaneously within the storage apparatus80, when the storage apparatus80moves from the storage configuration to the released configuration. For example, the actuation apparatus70may essentially be the only mechanism restraining the deployable gossamer apparatus30from deploying. When the storage apparatus80is in the released configured, the storage apparatus80may be configured so that it does not interfere with the position or configuration of the deployable gossamer apparatus30. In other embodiments, the storage apparatus80may interfere with the deployment of the deployable gossamer apparatus30, so that storage apparatus80may facilitate a desired deployment trajectory (e.g., provide a reaction surface for the deployable gossamer apparatus30, or a portion of the structure to react against in order to guide the direction, speed or dynamics of the deployment).

In one or more embodiments, the storage apparatus80may be shaped like a triangular prism. However, in other embodiments the storage apparatus80may be shaped like a circle, ring, hexagon, octagon, parallelogram, a random or irregular shape, or any other suitable shape.

Diagrammatic representations of exemplary rib members40deploying while the deployable gossamer apparatus30is transitioning from the stowed configuration to the deployed configuration are depicted inFIGS. 5A-5C. For example, the deployable gossamer apparatus30may be wrapped around a central mount portion60to collapse the deployable gossamer apparatus30from the deployed configuration to the stowed configuration as shown inFIG. 5A. In one or more embodiments, it may be described that the gossamer material51and rib members40may be folded like a Chinese fan (e.g., a flattened accordion fold). As shown, the central mount portion60is triangular and the deployable gossamer apparatus30is wrapped around the central mount portion60in a triangular path around the central axis34(e.g., may be a central axis which extends through the central portion60). The deployment process of the rib members40is depicted inFIGS. 5B-5C. As shown, the distal end portion44may rotated around the center mount portion60and central axis34in a counterclockwise direction.

The deployable gossamer apparatus30wrapped about a triangular central mount portion60is shown in further detail inFIGS. 6 and 7A-7B. The gossamer material51is depicted being folded up with the rib members40about the central mount portion60. The gossamer material51may be bonded (e.g., vibration welding, adhesive, mechanical fasteners, etc.) to the rib members40. The gossamer material51may be bonded on either side of each rib member40.

As shown, two rib members40′,40″ may be located in close proximity (e.g., adjacent one another) to each other (e.g., parallel, co-linear, co-extensive, co-axial, extending along adjacent paths) without gossamer material51extending therebetween. Instead, gossamer material51may only extend from the opposing sides of the two rib members40′,40″. A gap43may be defined between the two rib members40′,40″ to allow the rib members40′,40″ to be wrapped around the central mount portion60when in the stowed configuration. In other words, the rib members40′,40″ arrangement may provide a split in an otherwise continuous deployable gossamer apparatus30that allows the two adjacent rib members40′,40″ to slide past each other when being folded (when the deployable gossamer apparatus30is transitioned into the stowed configuration from the deployed configuration). The gap, or split,43may prevent ripping of the gossamer material51during packing and deployment. In other embodiments, the deployable gossamer apparatus30may include two rib members40for each gossamer portion50, allowing each to fold independently of the others, or only one rib member40per gossamer portion, which may require that all the gossamer portions50fold and unfold simultaneously.

As shown inFIGS. 6 and 7A-7B, the central mount portion60may include a base structure66and a plurality of geometric protrusions64coupled to the base structure66. The geometric protrusions64may be configured to provide a guiding surface about which the rib members40may be wrapped around. The geometric protrusions64may be shaped in any suitable manner for wrapping (e.g., packing, folding, or otherwise stowing) rib members40and gossamer material51about the central mount portion60. Additionally the geometric protrusions64may facilitate wrapping about the central mount portion60along a circular, triangular, square, hexagonal, or irregular orientation or facilitate wrapping in any other suitable manner. The central mount portion60may include any suitable number of geometric protrusions64in order to facilitate wrapping such as, e.g., one or more geometric protrusions, two or more geometric protrusions, three or more geometric protrusions, four or more geometric protrusions, etc.

The plurality of rib members40may be rotatably coupled to the geometric protrusions64about a coupling axes68′,68″,68′″ that may be perpendicular to the central axis34. The rib member40may be attached to the geometric protrusions64using any suitable coupling means that provides rotation, or pivotable motion, about the coupling axes68′,68″,68′″. As shown, pins are used to couple the rib members40to the geometric protrusions64. The rib members40may be configured (e.g., by the rotatable coupling with the geometric protrusions64) to rotate out of the original or storage plane36and up into the shuttlecock configuration in an out-of-plane orientation as described herein with references toFIGS. 2A-2C. To restrict rotation about the coupling axes68′,68″,68′″, the central mount portion60may further include rotation restriction bars69positioned so that they define a maximum angle α out of the storage plane36that the rib members40can move as shown inFIG. 7B. More specifically, the rotation restriction bars69may contact, or abut, the rib members40stopping the rib members40from rotating any more out of the storage plane.

A proximal end portion42of an exemplary rib member40is depicted inFIG. 8. As shown, the rib member40may include two lenticular springs48. As shown in this embodiment, each of the two lenticular springs48may define a concave surface77and a convex surface78. In the embodiment shown, the two lenticular springs48may be opposed to each other. In other words, the two lenticular springs48may be positioned such that the concave surfaces77face each other. In other embodiments, the two lenticular springs48may be positioned such that the concave surfaces77face away from each other (and the convex surfaces78face each other). In some embodiments, one or more spacers may be located between the two opposed lenticular springs48at one or more locations along the rib members40. The two lenticular spring48configuration may provide structural stiffness to the rib member40in its deployed configuration. Further, a hole49(e.g., an opening or any other suitable attachment feature) may be defined through each of the lenticular springs48that may be used to rotatably couple the rib member40to the central mount portion60using, e.g., a pin. As shown, the holes49are located at, or near, the proximal end portion47of the rib member40.

Although a particular orientation of the lenticular springs48is disclosed in this embodiment, other embodiments of rib member40may include a different orientation of the lenticular springs48such as those described herein with reference toFIGS. 11A-11H.

The plurality of rib members40may be configured to store potential energy when the deployable gossamer apparatus30is configured in the stowed configuration. The stored potential energy of the plurality of rib members40may provide the movement of the deployable gossamer apparatus30from the stowed configuration to the deployed configuration when the storage apparatus80releases the deployable gossamer apparatus30. More specifically, the lenticular springs48of the rib members40may store the potential energy and, when released, generate forces to straighten the rib members40to extend along a rib axis (e.g., the way a carpenter's tape naturally straightens itself out). When bent, or wrapped about the central mount portion60, the lenticular springs48may store potential energy, which may be subsequently spent to straighten out the lenticular springs48during the transition from the stowed configuration, or state, to the deployed configuration, or state. The lenticular springs48may be selected and/or configured so as to generate a sufficient force for deploying the deployable gossamer apparatus30(e.g., to deploy the deployable gossamer apparatus30in a passive manner based on the rib members40own potential energy, without the aid or addition of energy from other components such as a motor).

In another embodiment, the velocity generated by the lenticular springs48may be higher than required for deployment. In this embodiment, a damping device may be used to dampen the motion of the rib members40as they deploy, preventing them from moving too quickly. The damping may come from a passive or active damping device. Passive damping may include wrinkles in the gossamer material of the gossamer portions50, passive damping provided by spacer material46installed between the two lenticular springs48as shown inFIG. 8and/or from a rotary or linearly viscous damper.

The exemplary system10for increasing the surface area of a spacecraft20may also be configured to achieve stability in the shuttlecock formation when the deployable gossamer apparatus30is in the deployed configuration. The aerodynamic forces on the deployed sail54(e.g., the gossamer portions50as supported by the rib members40when the deployable gossamer apparatus30is in the deployed configuration) may be configured to provide a force-moment, and the damping device may be configured to dampen any oscillations such that the exemplary system10and/or spacecraft20could achieve stability. Additionally, if the spacecraft20already has a passive damping device, the exemplary system10may be configured to utilize the already provided damping device to provide damping. Passive damping may also be provided using a passive damping device such as magnetic hysteresis rods. The hysteresis rods are for damping the attitude change of the spacecraft that may result from aerodynamic forces once the device is deployed.

A side, elevation view of the exemplary system10including storage apparatus80in a storage configuration and actuation apparatus70is depicted inFIG. 9Aand a side, elevation view of the exemplary system10with the storage apparatus80transitioning from the storage configuration to a released configuration is depicted inFIG. 9B. Only one of three of groups of wall portions82,88,90of the storage apparatus80is shown for clarity. As shown, as the second portion76of the actuation apparatus70decouples, or disengages, from the first portion72of the actuation apparatus70, the wall portions82,90may move away from the central mount portion60when the storage apparatus80transitions from the storage configuration to released configuration. As shown, the storage apparatus80may begin to unfold immediately after the actuation apparatus70(e.g., first portion72and second portion76) is actuated. Further, as the pressure, or restriction, on the stowed deployable gossamer apparatus30is released and the side wall portions90of the storage apparatus80move away, the deployable gossamer apparatus30may also begin to deploy.

The exemplary system10may be configured to interface with the spacecraft's computer system. The interface may be used to transmit (send/receive) a signal that deploys the exemplary system10. One method for sending a deploy signal may be a single I/O command to a drive circuit.

Another exemplary method of deployment may be to inhibit deployment until a watchdog timer expires, or runs out. For example, the spacecraft may periodically (e.g., once a day, once an hour, etc.) send a command to reset a watchdog timer within the electronics of the exemplary system10. The nature of the timer may be such that when it expires, the timer may connect the circuit that provides the electrical energy used to actuate the actuation apparatus70and effect/cause the deployment of the deployable gossamer apparatus30. The watchdog timer may be configured to continuously listen for a signal from the spacecraft computer. The signal from the spacecraft computer, when received by the watchdog timer, may reset the timer, preventing the deployment of the deployable gossamer apparatus30. The signal maybe sent by the spacecraft computer to the watchdog timer regularly on an interval significantly shorter than the duration of the timer. Further, the timer may be have a time period that is long enough to prevent accidental activation of the actuation apparatus70in the case of a computer restart or planned spacecraft shut-down time. The use of the watchdog timer and the deployment signal may ensure that the deployable gossamer apparatus30can deploy at the end of a satellite's life (e.g., when the spacecraft computer of the satellite may have stopped functioning). In the case of a computer failure and unexpected end of the spacecraft's useful life, the timer may expire (e.g., since the time will not receive a reset signal from the failed computer) and the deployable gossamer apparatus30will deploy, safely deorbiting the spacecraft.

In at least one embodiment, the exemplary system10may supply its own power source by means of a primary battery, batteries, solar cells, or any other energy storage device. In at least one other embodiment, the exemplary system10may be supplied power by the spacecraft's20power system.

In at least one other embodiment, the only interface between the exemplary system10may be structural. In this case, the exemplary system10may include an internal timer and battery. Before launch, the timer may be configured, or set, to connect a battery to provide power to the actuation apparatus70after a selected period of time has elapsed or upon a certain date and time, which may ensure that the spacecraft20may deorbit at a later time (e.g., to prevent an extension of the mission or early disposal of the spacecraft20in the case of an early end of the spacecraft's life).

In at least one embodiment, the structural interface between any portion of the exemplary system10(e.g., the deployable gossamer apparatus30and/or the storage apparatus80) and the spacecraft20may be considered permanent (e.g., where the interface is not designed to be severed). In at least one other embodiment, the structural interface between any portion of the exemplary system10and the spacecraft20may be considered to be temporary, where the interface may be designed such that it can be separated at a specified time or may be designed such that it can be separated at any time. In other words, any portion of the exemplary system10, whether structural or communicative, may be removably coupled to (decouplable from) the spacecraft20.

The spacecraft20may include a separation system. The separation system may include pyrotechnically severed fasteners, a latch device or devices, or any other fastening device that can be released. A separation event may be initiated by the spacecraft20and may require no action (e.g., command, input) by the deployable gossamer apparatus30and/or the storage apparatus80. Such a command could originate in the spacecraft's computer logic, or could originate as a command from the ground. Further, a separation event may be initiated by the exemplary system10and may require no action by the spacecraft20. Still further, a separation event may be initiated by either the spacecraft20or the exemplary apparatus10and may be executed by either.

Another exemplary system110for increasing the surface area of a spacecraft is depicted inFIGS. 10A-10C. Several features and/or portions of the exemplary system110may be similar to the exemplary system10described herein with reference toFIGS. 1-9. For example, the rib members140, the gossamer material151, the central mount portion160, the actuation apparatus170, portions of the storage apparatus180including hinges192and the subcomponents thereof, may be similar to the rib members40, the gossamer material51, the central mount portion60, and the actuation apparatus70, portions of the storage apparatus80including hinges92, and the subcomponents thereof of the system ofFIGS. 1-9. Further, for example, the storage and deployment mechanisms and systems and the deployment dynamics of the exemplary system110may be similar to the storage and deployment mechanisms and systems and the deployment dynamics of exemplary system10. As such, such features and/or portions may not be further described herein or may not be described in the same level of detail, and it is to be understood that one or more such features and/or portions may be used interchangeably between each and every embodiment described herein.

As shown inFIGS. 10A-10C, the exemplary system110may include a central mount portion160that is ring-shaped (e.g., hollow in the middle, may be circular, but also may be a hollow triangle, square, hexagon etc.) about a central axis134. The deployable gossamer apparatus130may fold and wrap around the central mount portion160when in the stowed configuration. The storage apparatus180may include four restraining wall portions182and four restrained wall portions184. The system110may further include four actuation apparatuses170that correspond to the four restraining portions182. When the actuation apparatuses170are actuated (e.g., released), the storage apparatus180may transition (e.g., unfolds) from the storage configuration as shown inFIG. 10Ato the released configuration as shown inFIG. 2-10Cto allow, or release, the deployable gossamer apparatus130to transition from the stowed configuration to the deployed configuration as shown inFIG. 10B-10C.

The central ring portion may be ring-shaped defining an opening such that the central portion160is couplable around a separation system of a spacecraft20. The ring-shape of the central mount portion160may allow the system110to make efficient use of space on the spacecraft20by mounting around an already existing circular object such as a docking or launch vehicle interface ring (e.g., Lightband, Marman clamp, etc.).

The wall portions of the storage apparatus180may include a side wall portion190, a top wall portions182,184, and hinges192. When in the storage configuration as shown inFIG. 10A, the restraining wall portions182may overlap and restrain the restrained wall portions184. The restraining, or overlap, feature may additionally be incorporated into one or more of the side wall portions190, such as the side wall portions90that correspond to (e.g., are hinged to) the restraining wall portions182. The use of an overlap configuration with restraining wall portions182and restrained top wall portions184may reduce the number of actuators needed by half as only the restraining portions182may need to be released for the storage apparatus180to transition from the storage configuration to the released configuration. In other ring-shaped embodiments, the storage apparatus may only include one restraining top wall portion and one or more restraining top wall portions.

The rib members140may be coupled to the central mount portion160in such a way as to allow them to rotate at least partially out of a storage plane when the deployable gossamer apparatus130is in a stowed configuration to an out-of-plane orientation in the deployed configuration as shown inFIG. 10B(e.g., a shuttlecock configuration or out-of-plane configuration).

Another exemplary system210for increasing the surface area of a spacecraft is depicted inFIGS. 11A-11H. Several features and/or portions of the exemplary system210may be similar to the exemplary systems10,110described herein with reference toFIGS. 1-9andFIGS. 10A-10C, respectively. For example, the rib members240, the gossamer material251, the central mount portion260, the actuation apparatuses270, portions of the storage apparatus280, and the subcomponents thereof, may be similar to the rib members40,140, the gossamer material51,151, the central mount portions60,160, and the actuation apparatuses70,170, portions of the storage apparatus80,180, and the subcomponents thereof of the exemplary systems10,110. Further, for example, the storage and deployment mechanisms and systems and the deployment dynamics of exemplary system210may be similar to the storage and deployment mechanisms and systems and the deployment dynamics of exemplary systems10and110. As such, such features and/or portions may not be further described herein or are not described in the same level of detail, and it is to be understood that one or more such features and/or portions may be used interchangeably between each and every embodiment described herein.

The exemplary system210ofFIGS. 11A-11Hmay be configured to be mounted inside a docking ring298(e.g., a separation or connection system) of a spacecraft20. The ability to mount the system210inside the docking ring298may provide an efficient use of space on the spacecraft20since, e.g., the area inside the docking ring298is an already existing and potentially unoccupied area on the spacecraft20.

The exemplary system210may include a storage apparatus280including a plurality of wedge-shaped, or pie-slice-shaped, top wall portions282,284. As in previous embodiments described herein, one or more the top wall portions282may be configured to restrain the other top wall portions. For example, one of the top walls portions282may include a tab portion272that may interface with the actuation apparatus270and may restrain the remaining top wall portions.

As described, the top wall portions282of the storage apparatus280may be pie-shaped or triangular-shaped. The top wall portions282may be arranged such that the edges most distal from the central axis234are attached to side wall portions of the storage apparatus280. In at least one embodiment, the exemplary system210may be integral, or built into, the spacecraft20, and as such, the wall portions of the storage apparatus280may be directly coupled to the docking ring298(not shown). When the storage apparatus280is in the released configuration as shownFIGS. 11C-11E, the top wall portions282of the storage apparatus280may pivot away from a central mount portion260and/or actuation apparatus270to form a star-like geometry.

The storage apparatus280is depicted in the released configuration while the deployable gossamer apparatus230is shown in the stowed position inFIG. 11Cfor the purposes of clarity. As shown, the deployable gossamer apparatus230may include rib members240and gossamer material251that are wrapped around the central mount portion260.

The central mount portion260may define an angle or curved surface290(e.g., the surface290may not be parallel to the storage plane, the surface290may be at an angle to the storage plane, etc.) configured to assist the transition of the deployable gossamer apparatus230from the stowed configuration to the deployed configuration of the deployable gossamer apparatus230when in the stowed configuration. More specifically, potential energy stored in the rib members240, when released, may allow the rib members240to not only unwrap and extend radially outward (e.g., along a rib axis) but the rib members240may also react (e.g., abut, contact, engage, etc.) with the surface290causing the rib members240to move out of the storage plane. As shown inFIGS. 11E-11H, the rib members240may move out of the storage plane and into the out-of-plane or shuttlecock orientation with the rib members240lying along rib axes without the need for providing additional energy to the rib members for deployment. In other words, the stored potential energy provides all the energy necessary to deploy the deployable gossamer apparatus230from the stowed configuration to the deployed configuration.

As shown inFIG. 12, the rib members240may be include (e.g. be formed of) one or more lenticular springs248. In contrast to the rib members40described with reference toFIGS. 1-9, the two lenticular springs248of the rib members240may be configured, or oriented, such that the convex surfaces277face each other (e.g., an opposite configuration from the rib members40ofFIGS. 1-9). Additionally, the concave surfaces278of each lenticular spring248may face away (e.g., in an opposing direction), at least in part, from each other. In at least one embodiment, the two lenticular springs248of each rib member240may further be connected along one edge245. Further, the proximal end portion242of the rib member240may define an aperture249to be used to attach, or couple (e.g., rotatably or pivotably couple) the rib member240to the central portion portion260. An exemplary rib member may be described in U.S. Pat. No. 7,895,795 to Murphey et al. entitled “TRIANGULAR ROLLABLE AND COLLAPSIBLE BOOM,” which is incorporated herein by reference in its entirety.

All patents, patent documents, and references cited herein are incorporated in their entirety as if each were incorporated separately. This disclosure has been provided with reference to illustrative embodiments and is not meant to be construed in a limiting sense. As described previously, one skilled in the art will recognize that other various illustrative applications may use the techniques as described herein to take advantage of the beneficial characteristics of the system and methods described herein. Various modifications of the illustrative embodiments, as well as additional embodiments of the disclosure, will be apparent upon reference to this description.