Patent Description:
A spacecraft often uses solar arrays for electric power generation. A solar array generally is comprised of solar panels connected together, wherein each solar panel is populated with solar cells to generate the electric power. Usually, there is wiring across the solar panels to carry the electric power to the spacecraft.

Solar cells and their assemblies need to radiate heat away from the Sun to cool. As solar cells are built up into a solar array, the solar cells need to maintain high thermal conductivity to a radiating surface.

It is also desirable to build solar cells onto a thin substrate to achieve low cost manufacturing. This substrate could be a plastic sheet such as polyimide, a thin fiber composite, or thin metal sheet. This substrate has lateral strength, but is thin, lightweight, and likely flexible.

In addition, it is desirable to have a solar array based on rigid solar panels. This panel has more strength to deliver the rigidity and frequency response needed for the program. The panel is often an aluminum (Al) honeycomb with carbon composite face sheets. Thus, it is desirable to attach the thin substrate with the solar cells to a rigid panels.

However, this attachment requires a large area adhesive bond to ensure thermal contact to the rigid panel radiating surface. The large area adhesive bond is a large mass of material, which is undesirable for space applications.

Also, it is difficult to attach two flat surfaces of the substrate and rigid panel together without having trapped air. This trapped air will cause delamination or blowout when this assembly goes into a vacuum environment of space.

What is needed, then, is a means for simplifying the design and manufacturing, of solar arrays.

Document <CIT>, according to its abstract, states a deployable structure that may include a slit-tube longeron and a flat panel coupled with the slit-tube longeron. The slit-tube longeron may include a tubular member having a slit that runs along the longitudinal length of the slit-tube longeron. The deployable structure may be configured to couple with a satellite. And the deployable structure may be configured to transform between a stowed state and a deployed state where the tubular member is substantially straight when the deployable structure is in the deployed state, and the tubular member is wrapped around the satellite when the deployable structure is in the stowed state.

Document <CIT> discloses solar cell panels mounted on hatch covers that are used for covering an outdoor treatment tank. The hatch covers can be moved into each other in a sliding direction.

There is provided an apparatus, comprising at least first and second solar panels, wherein each of the first and second solar panels is comprised of a substrate having one or more solar cells bonded thereto, and a frame for supporting the substrate and the solar cells; the frame has a cutout or opening in a center of the frame and, when deployed, the cutout or opening enables cooling of the solar cells through the substrate by exposing a back side of the substrate and the solar cells for transferring or radiating heat directly through the cutout or opening of the frame; and the frame of the first solar panel is configured to be nested inside the cutout or opening of the frame of the second solar panel when the first and second solar panels are stowed in a stacked configuration; wherein the substrate and the solar cells for the first and second solar panels are positioned on opposite sides of the frames for the first and second solar panels, wherein the substrate and the solar cells for the first and second solar panels positioned on opposite sides of the frames for the first and second solar panels face a same direction when deployed, and/or the substrate and the solar cells for the first and second solar panels positioned on opposite sides of the frames for the first and second solar panels are positioned adjacent each other when stowed.

Further, there is provided a method, comprising stowing at least first and second solar panels, wherein each of the first and second solar panels is comprised of a substrate having one or more solar cells bonded thereto, and a frame for supporting the substrate and the solar cells; the frame has a cutout or opening in a center of the frame and, when deployed, the cutout or opening enables cooling of the solar cells through the substrate by exposing a back side of the substrate and the solar cells for transferring or radiating heat directly through the cutout or opening of the frame; and the frame of the first solar panel is configured to be nested inside the cutout or opening of the frame of the second solar panel when the first and second solar panels are stowed in a stacked configuration; wherein the substrate and the solar cells for the first and second solar panels are positioned on opposite sides of the frames for the first and second solar panels, wherein the substrate and the solar cells for the first and second solar panels positioned on the opposite sides of the frames for the first and second solar panels face a same direction when deployed, and/or the substrate and the solar cells for the first and second solar panels positioned on opposite sides of the frames for the first and second solar panels are positioned adjacent each other when stowed.

In the following description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration a specific example in which the disclosure may be practiced. It is to be understood that other examples may be utilized and structural changes may be made without departing from the scope of the present disclosure.

This disclosure provides a "flex on frame" concept for solar arrays, wherein a solar array includes at least one solar panel comprised of one or more solar cells bonded onto a substrate, which may be a flexible substrate, and the substrate and the solar cells are then attached to a support frame having a cutout or opening in a center of the frame under the solar cells. The substrate is thin to facilitate heat flow and thus it has a low stiffness that may bend and warp making it unsuitable for flight alone. The substrate is attached to the frame that provides the stiffness for the structure to be used as a solar panel.

The "flex on frame" concept for solar arrays has a number of advantages. For example, the "flex on frame" concept has both cost and cycle time advantages, as compared to solar arrays with solid solar panels.

Another advantage of the "flex on frame" concept for solar arrays is the cutout or opening in the frame. The cutout or opening enables the substrate to become the radiator into space, thus eliminating the typical thick rigid panel from the heat flow to the radiating surface. Solid solar panels have to integrate features to facilitate removing heat from the solar arrays, which can add complexity and weight to the assembly.

In the "flex on frame" concept, thermal connection to the frame is not required, but is permissible, simplifying attachment of the circuit to the panel (e.g., simple mechanical fasteners or clamps). This differs from a solid panel using a necessary solid substrate or other material (e.g., metal plate) meant to transfer heat away from the solar cells laterally.

Moreover, by having such a cutout or opening, the frame can, but need not, take part in thermal transport from the solar cells like a solid solar panel. Primarily, the frame provides mechanical support for the substrate with the solar cells bonded thereon. This enables separation of thermal and mechanical roles as compared to solid solar panels, if desired.

The "flex on frame" concept for solar arrays may result in a less rigid structure than solid solar panels, for equivalent thickness structures. There is a correlation between stiffness and the fundamental mode or frequency of a solar panel, which is modified when a solar panel is solid as opposed to when it is a only a frame having a cutout or opening. Solid solar panels have high stiffness to have a higher fundamental mode or frequency, while the "flex on frame" concept has a lower fundamental mode or frequency than a solid solar panel of the same thickness.

The vibrational frequency of the solar panels is an important metric. A more rigid structure having a higher fundamental mode or frequency results in a more stable spacecraft.

This disclosure provides the "flex on frame" concept in a stacked configuration comprising at least two frames, each having a thickness, wherein a first frame is configured to nest with a second frame. A cutout or opening in a center of the frame allows multiple frames to be stacked inside of each other. This allows the frames to be thicker than a solid solar panel and therefore increases the rigidity in the stacked configuration during launch and transport, while reducing weight and enabling efficient thermal dissipation when deployed and operating.

These and other novel aspects to the "flex on frame" concept are described in more detail below.

<FIG> is a schematic of a spacecraft <NUM> with one or more solar arrays <NUM> comprised of one or more solar panels <NUM>. In this example, the spacecraft <NUM> comprises a satellite, and there are two (<NUM>) solar arrays <NUM>, and four (<NUM>) solar panels <NUM>, wherein each of the solar arrays <NUM> is comprised of two of the solar panels <NUM>, and the solar arrays <NUM> and solar panels <NUM> extend on both sides of the spacecraft <NUM>. The solar arrays <NUM> are attached to the spacecraft <NUM> by means of triangular trusses <NUM> or other mechanisms, and each of the solar panels <NUM> is attached to an adjacent solar panel <NUM> by means of hinges <NUM> or other mechanisms, wherein the triangular trusses <NUM> and hinges <NUM> allow the solar arrays <NUM> and solar panels <NUM> to be folded and stacked for storage during launch, and then extended and deployed during operation.

<FIG> and <FIG> are top-view, top-view and cross-sectional side-view schematics, respectively, illustrating the components and assembly of one of the solar panels <NUM>, including a solar power module (SPM) <NUM> and a frame <NUM>.

<FIG> shows the SPM <NUM>, which is comprised of an array of solar cells <NUM> bonded to a substrate <NUM>. In one example, the substrate <NUM> is a flexible substrate, namely a flex circuit comprised of a laminate of one or more Kapton™ insulating layers and one or more metal layers providing electrical interconnects.

<FIG> shows the frame <NUM> for supporting the solar cells <NUM> and substrate <NUM>, wherein the frame <NUM> is a rectangular structure formed, for example, of joined pieces defining a perimeter around a cut-out or opening in a center of the frame <NUM> under the solar cells <NUM>.

<FIG> shows the SPM <NUM> mounted on and attached to the frame <NUM>, wherein the substrate <NUM> is attached to the frame <NUM> at a perimeter of the frame <NUM> along one or more edges of the substrate <NUM>. Once mounted and attached, the SPM <NUM> and frame <NUM> comprise a solar panel <NUM>.

A conventional rigid solar panel is a solid shape, often rectangular, but can be any shape. In this disclosure, the solar panel <NUM> is largely hollow due to the configuration of the frame <NUM>.

In this example, the substrate <NUM> is a thermal structure for radiating heat from the solar cells <NUM> into outer space, and the frame <NUM> is a mechanical structure for supporting the solar cells <NUM> and the substrate <NUM>. Specifically, the cutout or opening at the center of the frame <NUM> enables cooling of the solar cells <NUM> through the substrate <NUM> by exposing a back side of the substrate <NUM> for radiating heat directly through the cutout or opening of the frame <NUM>. The goal is for the radiated heat flow of the solar cells <NUM> and the substrate <NUM> to outer space to be minimally shadowed by the mechanical structure of the frame <NUM>.

In another example, it is possible to have reinforcing materials and/or supporting members (not shown) inside the frame <NUM> to increase stiffness, wherein the reinforcing materials could be mesh, honeycomb material, or the like, and the supporting members could be various bars, channels, or the like. This is described in more detail below in conjunction with <FIG> and <FIG>.

<FIG> are a cross-sectional side-view schematic and a top-view schematic, respectively, of the SPM <NUM>, frame <NUM>, solar cells <NUM> and substrate <NUM>, wherein the substrate <NUM> is attached to the frame <NUM> using one or more fasteners <NUM> and reinforced areas <NUM>.

A wide variety of fasteners <NUM> can be used, including pins, posts, rivets or other structures, and the fasteners <NUM> may be comprised of metal, polymer, or other types of materials. Adhesives of various types could be used with the fasteners <NUM>, or as an alternative to the fasteners <NUM>, with continuous or spot application.

The fasteners <NUM> may attach to a single surface of the frame <NUM> or extend through the frame <NUM>. It may be desirable that the fasteners <NUM> are reversible to allow disassembly for repairs, and reversing the fasteners <NUM> could involve destroying them, such as in cutting or drilling the fasteners <NUM>, which should not be a major concern due to their low cost.

As shown in <FIG>, the fasteners <NUM> may be placed in reinforced areas <NUM> of the substrate <NUM> near the edges of the substrate <NUM>, or in other areas of the substrate <NUM>, to prevent tearing of the substrate <NUM>. The reinforced areas <NUM> may be comprised of additional Kapton™ insulating layers, carbon fiber, Kevlar™, and/or metal layers, or some other combination of layers, or some other material. It would be rather straightforward to pattern a copper (Cu) trace layer as a reinforcement. Additionally, the frame <NUM> material may also be reinforced in proximity to the fasteners <NUM>.

In this example, four (<NUM>) or five (<NUM>) of the fasteners <NUM> are positioned on each of the four (<NUM>) sides of the frame <NUM>, around the perimeter of the frame <NUM>, and near the edges of the substrate <NUM>. In other examples, it may only be necessary to attach the SPM <NUM> to two (<NUM>) opposing sides of the frame <NUM>. On the other hand, attaching the SPM <NUM> to all four (<NUM>) sides of the frame <NUM> does offer assurances regarding the security of the attachment of the SPM <NUM> to the frame <NUM>.

<FIG> are a cross-sectional side-view schematic and a top-view schematic, respectively, of the SPM <NUM>, frame <NUM>, solar cells <NUM>, substrate <NUM>, fasteners <NUM> and reinforced areas <NUM>, wherein the substrate <NUM> is attached to the frame <NUM> using one or more bars <NUM> located along one or more sides of the frame <NUM>, for example, in the reinforced areas <NUM> near the edges of the substrate <NUM> and between at least some of the fasteners <NUM> and the substrate <NUM>. These bars <NUM> serve to spread the force applied by the fasteners <NUM> and thus minimize the risk of tearing the substrate <NUM>. These bars <NUM> could be rectangular or another shape, preferably matching the geometry of the frame <NUM>. The bars <NUM> could also be comprised of a series of one or more shorter segments. <FIG> illustrates reinforcement at a single attachment position, while <FIG> illustrates reinforcement that spans multiple attachment positions.

<FIG>, <FIG>, <FIG> and <FIG> are top-view schematics and <FIG> is a cross-sectional side-view schematic providing greater detail on electrical connections to the solar cells <NUM>. It is preferred that wiring for the electrical connections to the solar cells <NUM> be on a back side of the substrate <NUM>, so that as much area as possible on the front side of the solar cells <NUM> is used to collect the Sun's energy.

<FIG> is a top-view schematic of the SPM <NUM>, solar cells <NUM> and substrate <NUM>, before being mounted on and attached to the frame <NUM>, wherein the substrate <NUM> has one or more tabs <NUM> extending from one or more sides of the substrate <NUM>. Each of the tabs <NUM> may be comprised of the same materials as the substrate <NUM>, and may be contiguous portions of the substrate <NUM>. Each of the tabs <NUM> may include one or more electrical conductors <NUM>, patterned from one or more metal layers deposited on a surface of the tabs <NUM> and/or buried within the layers of the tabs <NUM>, for making electrical connections to at least one of the solar cells <NUM>.

<FIG> is a top-view schematic of the SPM <NUM>, frame <NUM>, solar cells <NUM>, substrate <NUM>, fasteners <NUM>, reinforced areas <NUM>, and bars <NUM>, wherein the substrate <NUM> is attached to the frame <NUM> with fasteners <NUM> at the reinforced areas <NUM> and bars <NUM>, and the tabs <NUM> and electrical conductors <NUM> extend beyond the frame <NUM>.

<FIG> is a top-view schematic of the SPM <NUM>, frame <NUM>, solar cells <NUM>, substrate <NUM>, fasteners <NUM>, reinforced areas <NUM>, and bars <NUM>, wherein the tabs <NUM> and electrical conductors <NUM> are folded around and under the frame <NUM>.

<FIG> is a bottom-view schematic of the frame <NUM>, substrate <NUM>, fasteners <NUM>, and bars <NUM>, wherein the tabs <NUM> and electrical conductors <NUM> are folded around and under the frame <NUM>, and the tabs <NUM> are attached to the back side of the substrate <NUM>, for example, with adhesive, fasteners, bars, or the like. The tabs <NUM> could also be attached to one or more sides of the frame <NUM>, including the bottom side, front side and perimeter sides of the frame <NUM>.

In this example, the tabs <NUM> extend around the outside of the frame <NUM>, and then pass under and are secured by the bars <NUM>. Another option could be to pass the tabs <NUM> through a slot or channel in the frame <NUM>. In yet another option, the substrate <NUM> could be structured to end at the opening of the frame <NUM>, which would allow the tabs <NUM> to fold down inside the frame <NUM>, instead of outside the edge of the frame <NUM>. In still another option, the tabs <NUM> could also be attached to one or more sides of the frame <NUM> and simply extend back away from the Sun.

The electrical conductors <NUM> may be electrically connected to conductors or traces (not shown) deposited on the back side of the substrate <NUM> and/or buried within the substrate <NUM>, through the use of exposed conductors or traces, vias and the like.

<FIG> is a cross-sectional side-view schematic of the SPM <NUM>, frame <NUM>, solar cells <NUM>, substrate <NUM>, fasteners <NUM>, bars <NUM> and tabs <NUM>, wherein the tabs <NUM> are wrapped around the frame <NUM> to the back side of the substrate <NUM>. Here, the substrate <NUM> is visible on the top side of the frame <NUM> and bends around the outside of the frame <NUM>. Preferably, the tabs <NUM> are positioned to have minimal shadowing of the radiation from the back side of the substrate <NUM>. For example, the tabs <NUM> could be positioned behind the structure of the frame <NUM> to minimize shadowing.

The ends of the tabs <NUM> are available to make connections to other electrical conductors, such as a wiring harness (not shown), to carry power to adjacent frames <NUM>, panels <NUM>, arrays <NUM>, other structures, and the spacecraft <NUM> itself. For example, the wiring harness may be positioned along the back of the substrate <NUM>, the back of the frame <NUM>, or the side of the frame <NUM>. The wiring harness may extend partially or completely inside the frame <NUM> when the frame <NUM> is comprised of hollow members. The electrical conductors in the wiring harness may form part of the frame <NUM> when the frame <NUM> is constructed as a composite or through additive manufacturing.

<FIG> is a top-view schematic and <FIG> is a cross-sectional side-view schematic illustrating reinforcing materials <NUM> that may be used to fill the center of the frame <NUM>, wherein <FIG> shows only the frame <NUM> and the reinforcing materials <NUM>, and <FIG> shows the SPM <NUM> mounted on and attached to the frame <NUM>, with the substrate <NUM> attached to both the frame <NUM> and the reinforcing materials <NUM>, the solar cells <NUM> bonded to the substrate <NUM> above the reinforcing materials <NUM>.

In one example, these reinforcing materials <NUM> may be designed to allow radiation at normal incidence to reach the solar cells <NUM>, and to block radiation at non-normal incidence from reaching the solar cells <NUM>. For example, space radiation (e.g., electrons, protons, gamma rays) bombards the solar array <NUM> and solar panels <NUM> at all angles. The use of a honeycomb structure as the reinforcing materials <NUM> in the frame <NUM> can be used to block the space radiation at non-normal incidence, and thus shield the solar cells <NUM> from damage, while allowing radiative cooling <NUM> to occur at normal incidence.

It is important for the solar panel <NUM> to pass acoustic and vibration testing. Attachment of the substrate <NUM> to the reinforcing materials <NUM> below the substrate <NUM> can limit vibrations and improve survivability. Acoustic and vibration environment occurs during the launch phase while the solar panels <NUM> are folded and stowed against the side of the spacecraft <NUM>. In this condition, the solar cells <NUM> from one panel <NUM> may be facing the reinforcing materials <NUM> from a second panel <NUM>. Their mechanical engagement should be designed to withstand the acoustic and vibration requirements. Employing shock absorbing or soft materials such as foam between the solar cells <NUM> or substrate <NUM> and the reinforcing materials <NUM> of the next panel <NUM> would be advantageous.

<FIG> and <FIG>, that do not fall under the claimed scope, are cross-sectional side-view schematics of the solar panels <NUM>, wherein <FIG> shows a pair of solar panels <NUM> that are connected by a hinge <NUM> and stacked together, and <FIG> shows the pair of solar panels <NUM> extended into position while connected to the hinge <NUM>. Also shown are the SPM <NUM>, solar cells <NUM>, substrate <NUM>, frame <NUM>, fasteners <NUM>, bars <NUM>, and tabs <NUM>.

The thickness of the stack formed by the pair of solar panels <NUM> comprises the thickness of each of the solar panels <NUM> panels and the spacing between them. One or more snubbers <NUM> may be positioned between the stacked solar panels <NUM>, wherein the snubbers <NUM> are soft, shock absorbing materials such as foam that maintain pressure and contact between the solar panels <NUM> to minimize bow and vibration of the solar panels <NUM>.

<FIG>, <FIG> and <FIG>, that do not fall under the claimed scope, are top-view, cross-sectional side-view, and side-view schematics, respectively, illustrating another configuration for the solar panels <NUM>. While the frames <NUM> in <FIG> and <FIG> are the same size, in this example there are different sizes for the frames <NUM> that provide for a different stowed configuration. Specifically, a smaller one or more of the frames 16A can be stacked inside a larger one or more of the frames 16B, as shown in <FIG>, wherein each of the frames 16A, 16B have slightly different widths. <FIG> shows a cross-sectional side-view with the solar panels <NUM> stowed together in a stacked configuration, and <FIG> shows a side-view with the solar panels <NUM> deployed. In this example, the SPM <NUM>, solar cells <NUM> and substrate <NUM> are positioned on the same side of the smaller frame 16A as compared to the SPM <NUM>, solar cells <NUM> and substrate <NUM> on the larger frame 16B. Also shown is the hinge <NUM> connecting the solar panels <NUM>, although the mechanism of the hinge <NUM> to accomplish the stacking and deployment of the solar panels <NUM> is not detailed here.

The retracted solar array <NUM> is given a specific volume to occupy in the spacecraft <NUM> design. The conventional folding in <FIG> apportions less than half the height of the space to each solar panel <NUM>. The new design shown in <FIG> shows how both panels <NUM> can be more than half the height of the space. The new design allows the panels <NUM> to have a greater height within the allowed space. This increased height increases its stiffness resulting in a more stable spacecraft <NUM>.

<FIG>, <FIG> and <FIG>, that fall under the claimed scope, are top-view, cross-sectional side-view, and side-view schematics, respectively, illustrating yet another configuration for the solar panels <NUM>. In this example, the SPM <NUM>, solar cells <NUM> and substrate <NUM> are positioned on an opposite side of the smaller frame 16A as compared to the SPM <NUM>, solar cells <NUM> and substrate <NUM> on the larger frame 16B. <FIG> is a top-view showing a smaller one or more of the frames 16A stacked inside a larger one or more of the frames 16B, wherein each of the frames 16A, 13B have slightly different widths. <FIG> is a cross-sectional side-view with the solar panels <NUM> stowed together in a stacked configuration, and <FIG> is a side-view with the solar panels <NUM> deployed.

As noted above, in this configuration the substrate <NUM> is on the opposite side of the smaller frame 16A, which is the side opposite the Sun. As shown in <FIG>, the solar cells <NUM> are inside the frame 16A facing the Sun when deployed. When stowed, as shown in <FIG>, the SPMs <NUM>, solar cells <NUM> and substrates <NUM> of the respective solar panels <NUM> are positioned close together. The spacing and vibration can be controlled by one or more snubbers <NUM> or other mechanisms. This assembly is more rigid when stowed, and more robust against vibration and acoustic loads present during launch.

The smallest panel <NUM> may incorporate reinforcing materials <NUM> and/or supporting members (not shown) inside the frame 16A to increase stiffness, wherein the reinforcing materials <NUM> could be mesh, honeycomb material, or the like, and the supporting members could be various bars, channels, or the like.

<FIG> and <FIG>, that do not fall under the claimed scope, are cross-sectional side-view schematics illustrating yet another configuration involving solar panels <NUM> mounted on a spacecraft <NUM>, wherein <FIG> is a cross-sectional side-view with the solar panels <NUM> stowed together in a stacked configuration, and <FIG> is a cross-sectional side-view with the solar panels <NUM> deployed.

In this example, a thin panel <NUM> is attached to a body of the spacecraft <NUM>, as shown in <FIG>, and a solar panel <NUM> is attached to the thin panel <NUM>. The other solar panels <NUM>, which fold out when deployed, are stacked against the solar panel <NUM> attached to the thin panel <NUM> when stowed together. Thus, all of the solar panels <NUM> are stacked over the thin panel <NUM> and the body of the spacecraft <NUM> when stowed together. One or more snubbers <NUM> can be installed to protect the spacecraft <NUM> and solar panels <NUM> during launch. This stacked configuration provides a thicker structure, which increases the fundamental mode, thereby providing for a more stable spacecraft <NUM>.

Examples of the disclosure may be described in the context of a method <NUM> of fabricating an apparatus comprising the solar array <NUM> for the spacecraft <NUM>, the method <NUM> comprising steps <NUM>-<NUM>, as shown in <FIG>, wherein the resulting spacecraft <NUM> having the solar array <NUM> is shown in <FIG>.

As illustrated in <FIG>, during pre-production, exemplary method <NUM> may include specification and design <NUM> of the spacecraft <NUM> and/or solar array <NUM>, and material procurement <NUM> for same. During production, component and subassembly manufacturing <NUM> and system integration <NUM> of the spacecraft <NUM> and/or solar array <NUM> takes place, which include fabricating the spacecraft <NUM> and/or solar array <NUM>, including bonding one or more solar cells <NUM> to the substrate <NUM>, and then attaching the substrate <NUM> and the solar cells <NUM> to a frame <NUM> for support. Thereafter, the spacecraft <NUM> and/or solar array <NUM> may go through certification and delivery <NUM> in order to be placed in service <NUM>. The spacecraft <NUM> and/or solar array <NUM> may also be scheduled for maintenance and service <NUM> (which includes modification, reconfiguration, refurbishment, and so on), before being launched.

For the purposes of this description, a system integrator can include without limitation any number of solar cell <NUM>, solar panel <NUM>, solar array <NUM> or spacecraft <NUM> manufacturers and major-system subcontractors; a third party may include without limitation any number of venders, subcontractors, and suppliers; and an operator may be a satellite company, military entity, service organization, and so on.

As shown in <FIG>, a spacecraft <NUM> fabricated by exemplary method <NUM> can include systems <NUM>, a body <NUM>, one or more solar arrays <NUM>, and one or more antennae <NUM>. Examples of the systems <NUM> included with the spacecraft <NUM> include, but are not limited to, one or more of a propulsion system <NUM>, an electrical system <NUM>, a communications system <NUM>, and a power system <NUM>. Any number of other systems <NUM> also may be included.

<FIG> is an illustration of a method of stowing, deploying and operating the solar array <NUM>, in the form of a functional block diagram, according to one example.

When stowed and deployed, the solar array <NUM> is comprised of at least first and second solar panels <NUM>, wherein each of the first and second solar panels <NUM> includes one or more of the SPMs <NUM> and each of the SPMs <NUM> is comprised of a substrate <NUM>, which may be a flexible substrate <NUM>, having one or more solar cells <NUM> bonded thereto; and a frame <NUM> for supporting the substrate <NUM> and the solar cells <NUM>. The frame <NUM> has a cutout or opening under the solar cells <NUM> and, when deployed, the cutout or opening enables cooling of the solar cells <NUM> through the substrate <NUM> by exposing a back side of the substrate <NUM> for transferring or radiating heat directly through the cutout or opening of the frame <NUM>. The frame <NUM> of the first solar panel <NUM> is configured to be nested inside the cutout or opening of the frame <NUM> of the second solar panel <NUM> when the first and second solar panels <NUM> are stowed in a stacked configuration.

When operating, each of the solar cells <NUM> absorbs light <NUM> from a light source <NUM> and generates an electrical output <NUM> in response thereto, which results in excess heat being generated by the solar cells <NUM>.

The frame <NUM> of the first solar panel <NUM> may have a thickness different from the frame <NUM> of the second solar panel <NUM>, to increase rigidity of the first solar panel <NUM> and the second solar panel <NUM> in the stacked configuration, while reducing weight and enabling efficient thermal dissipation when deployed for operation.

The first and second solar panels <NUM> may be connected by a hinge for stacking the first and second solar panels <NUM> together when stowed, and for extending the first and second solar panels <NUM> into position when deployed.

One or more snubbers <NUM> may be positioned between the spacecraft <NUM>, first and second solar panels <NUM> when stowed in a stacked configuration.

The frames <NUM> for the first and second solar panels <NUM> may be different sizes, such that a smaller one of the frames <NUM> can be stacked inside a larger one of the frames <NUM> when stowed in a stacked configuration.

The substrate <NUM> and solar cells <NUM> for the first and second solar panels <NUM> are positioned on opposite sides of the frames <NUM> for first and second solar panels <NUM>. The substrate <NUM> and solar cells <NUM> for the first and second solar panels <NUM> positioned on opposite sides of the frames <NUM> for first and second solar panels <NUM> face a same direction when deployed and/or the substrate <NUM> and solar cells <NUM> for the first and second solar panels <NUM> positioned on opposite sides of the frames <NUM> for first and second solar panels <NUM> are positioned adjacent each other when stowed.

The solar array <NUM> may include a third solar panel <NUM>, wherein the third solar panel <NUM> is comprised of a substrate <NUM> having one or more solar cells <NUM> bonded thereto, and a frame <NUM> for supporting the substrate <NUM> and the solar cells <NUM>; the third solar panel <NUM> is attached to a panel <NUM> on a body of a spacecraft <NUM>; and the first and second solar panels <NUM> are stacked against the third solar panel <NUM> when stowed together.

Claim 1:
An apparatus, comprising:
at least first and second solar panels (<NUM>), wherein:
each of the first and second solar panels (<NUM>) is comprised of a substrate (<NUM>) having one or more solar cells (<NUM>) bonded thereto, and a frame (<NUM>) for supporting the substrate (<NUM>) and the solar cells (<NUM>);
the frame (<NUM>) has a cutout or opening in a center of the frame (<NUM>) and, when deployed, the cutout or opening enables cooling of the solar cells (<NUM>) through the substrate (<NUM>) by exposing a back side of the substrate (<NUM>) and the solar cells (<NUM>) for transferring or radiating heat directly through the cutout or opening of the frame (<NUM>); and
the frame (<NUM>) of the first solar panel (<NUM>) is configured to be nested inside the cut-out or opening of the frame (<NUM>) of the second solar panel (<NUM>) when the first and second solar panels (<NUM>) are stowed in a stacked configuration;
wherein the substrate (<NUM>) and the solar cells (<NUM>) for the first and second solar panels (<NUM>) are positioned on opposite sides of the frames (<NUM>) for the first and second solar panels (<NUM>),
wherein the substrate (<NUM>) and the solar cells (<NUM>) for the first and second solar panels (<NUM>) positioned on opposite sides of the frames (<NUM>) for the first and second solar panels (<NUM>) face a same direction when deployed, and/or the substrate (<NUM>) and the solar cells (<NUM>) for the first and second solar panels (<NUM>) positioned on opposite sides of the frames (<NUM>) for the first and second solar panels (<NUM>) are positioned adjacent each other when stowed.