Integrated ion thruster unit for spacecraft

Abstract

To provide ion thruster systems for spacecraft, and more particularly, to an integrated ion thruster unit that may be configured to accommodate payload envelope dimensions associated with a spacecraft.SOLUTION: An integrated ion thruster unit for a spacecraft can include a unit housing including a thrust face, and a plurality of tiles arranged in an array on the thrust face. Each of the tiles can include an emitter and an extractor configured to provide a reference voltage with respect to the emitter. The emitter can include a plurality of tips configured to emit ions in a thrust direction from an ionic liquid propellant in response to an applied voltage.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present technology relates to ion thruster systems for spacecraft, and more particularly to integrated ion thruster units that can be configured to accommodate payload envelope dimensions associated with the spacecraft. [Background technology]

[0002] On-orbit propulsion systems for spacecraft must meet desired thrust and life cycle profiles while minimizing the weight and volume footprint of the propulsion system on the spacecraft as much as possible. To meet these requirements, electrospray emitters operating with capillary-fed ionic liquids have been proposed, as described, for example, in U.S. Patent No. 10,236,154 to Lozano et al. and U.S. Patent No. 10,410,821 to Lozano et al., both of which are incorporated herein by reference in their entireties. Further details regarding the development of electrospray emitters are disclosed in U.S. Patent No. 8,030,621 to Lozano et al., also incorporated herein by reference in their entireties.

[0003] Ionic liquids are molten salts at room temperature and exhibit extremely low vapor pressure. Ionic liquids are composed of positive and negative ions, which can be directly extracted and accelerated to generate thrust when used in bipolar operation. An array of electrospray emitters can be formed, with each emitter in the array having a micron-scale geometry. When the emitter array is supplied with ionic liquid, for example, by capillary action from the base of the array, application of a sufficiently high voltage releases ions (e.g., by direct evaporation of ions from the liquid or by the formation of a Taylor cone at the tip of each emitter). The released high-speed ions can generate net thrust. However, to enable practical and efficient integration into an on-orbit ion thruster unit for a spacecraft, the placement, assembly, and unified control of a large number of micron-scale emitters must be achieved. For example, but not by limitation, in some cases, to function, the ion thruster unit must fit within the spacecraft payload envelope defined by the launch system used to deliver the spacecraft to orbit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 10,236,154 [Patent Document 2] U.S. Patent No. 10,410,821 [Patent Document 3] U.S. Patent No. 8,030,621 Summary of the Invention

[0005] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0006] The present disclosure introduces a novel approach to onboard propulsion systems for spacecraft. In particular, embodiments of the present disclosure include tiles providing hundreds or thousands of emitter tips in spaced-apart relationship with extractors to facilitate ion emission upon application of a threshold voltage. The tiles can be configured to passively wick ionic liquid propellant to the emitter tips. Multiple tiles can be arranged in an array on the thrust face of an integrated ion thruster unit, and the housing of the integrated unit can enclose a reservoir of ionic liquid propellant as a common supply for the tiles in the array.

[0007] Additionally, the configuration of the integrated ion thruster unit may allow the unit to be sized for positioning within a separation ring used to couple the spacecraft to a launch vehicle's payload adapter, thereby allowing more of the launch payload envelope to be allocated to the spacecraft's primary mission rather than the spacecraft's on-orbit propulsion system. Additionally or alternatively, non-propulsion-related components may be enclosed within the integrated unit housing, further conserving space within the payload envelope. Furthermore, the characteristics of the integrated ion thruster unit may facilitate in-orbit retrofitting onto existing orbital spacecraft, for example, if the spacecraft's original on-orbit propulsion system is depleted.

[0008] According to one embodiment of the present disclosure, an integrated ion thruster unit for a spacecraft is provided. The integrated ion thruster unit may include a unit housing including a thrust surface and a plurality of tiles arranged in an array on the thrust surface. Each of the tiles may include an emitter and an extractor configured to provide a reference voltage to the emitter. The emitter may include a plurality of tips configured to eject ions from an ionic liquid propellant in a thrust direction in response to an applied voltage.

[0009] According to another embodiment of the present disclosure, a launch assembly is provided. The launch assembly can include a spacecraft and an integrated ion thruster unit coupled to the spacecraft. The integrated ion thruster unit can include a unit housing including a thrust surface and a plurality of tiles exposed on the thrust surface and configured to eject ions in a thrust direction from an ionic liquid propellant stored in the unit housing. The launch assembly can also include an isolation ring coupled to the spacecraft and configured to couple to the payload adapter and selectively isolate the spacecraft from the payload adapter. The isolation ring can extend from a first edge adjacent to the spacecraft to a second edge and define an isolation ring opening extending therethrough from the first edge to the second edge, and the unit housing can extend into the isolation ring opening and substantially to the payload adapter side of the first edge.

[0010] According to another embodiment of the present disclosure, a method for assembling a launch assembly is provided. The method can include coupling an integrated ion thruster unit to a spacecraft. The integrated ion thruster unit can include a unit housing including a thrust surface and a plurality of tiles exposed on the thrust surface and configured to eject ions in a thrust direction from an ionic liquid propellant stored in the unit housing. The method can also include coupling a separation ring to the spacecraft. The separation ring can be configured to couple to the payload adapter and selectively separate the spacecraft from the payload adapter, the separation ring extending from a first edge adjacent to the spacecraft to a second edge and defining a separation ring opening extending therethrough from the first edge to the second edge, and the unit housing extending into the separation ring opening and extending substantially to the payload adapter side of the first edge.

[0011] According to another embodiment of the present disclosure, a method for retrofitting an integrated ion thruster unit onto a spacecraft is provided. The method can include delivering the integrated ion thruster unit to an orbital rendezvous with the spacecraft. The integrated ion thruster unit can include a unit housing including a thrust surface and a plurality of tiles exposed on the thrust surface and configured to eject ions in a thrust direction from an ionic liquid propellant stored within the unit housing. The method can also include mechanically coupling the integrated ion thruster unit to the spacecraft in orbit.

[0012] To explain how the above problems can be addressed, a more particular description of the principles briefly described above will be given by reference to specific embodiments thereof that are illustrated in the accompanying drawings. With the understanding that these drawings depict only exemplary embodiments of the present disclosure and therefore should not be considered limiting of its scope, the principles herein will be described and explained with additional specificity and detail using the accompanying drawings. [Brief explanation of the drawings]

[0013] [Figure 1A] FIG. 1 is a perspective view of an exemplary electrospray tile according to an embodiment of the present disclosure. [Figure 1B] FIG. 1B is an exploded view of the tile shown in FIG. 1A according to an embodiment of the present disclosure. [Figure 2] 2 is an enlarged detail view of an example emitter of the tile shown in FIG. 1A taken along line 2-2 shown in FIG. 1B, according to an embodiment of the present disclosure. [Figure 3A] FIG. 1 is a schematic elevation view of an exemplary launch assembly including an exemplary spacecraft and an exemplary separation ring coupled to an exemplary payload adapter, in accordance with an embodiment of the present disclosure. [Figure 3B] FIG. 3B is a schematic perspective view of an exemplary spacecraft envelope defined by the launch assembly shown in FIG. 3A, in accordance with an embodiment of the present disclosure. [Figure 4A]3B is a schematic elevation view of an exemplary integrated ion thruster unit mounted on a spacecraft in the launch assembly shown in FIG. 3A in accordance with an embodiment of the present disclosure. [Figure 4B] FIG. 4B is a schematic perspective view of the integrated ion thruster unit shown in FIG. 4A combined with the isolation ring shown in FIG. 4A in accordance with an embodiment of the present disclosure. [Figure 4C] FIG. 4C is a schematic cross-sectional view of an exemplary interior of an integrated ion thruster unit taken along line CC of FIG. 4B, in accordance with an embodiment of the present disclosure. [Figure 5] FIG. 1 is a schematic perspective view of another exemplary integrated ion thruster unit according to an embodiment of the present disclosure. [Figure 6] 1 illustrates an exemplary method of assembling a launch assembly according to an embodiment of the present disclosure. [Figure 7] 1 illustrates an exemplary method for retrofitting a spacecraft with an integrated ion thruster unit, according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] Various exemplary embodiments of the present disclosure are described in detail below. While specific implementations are described, it should be understood that this description is for illustrative purposes only. Those skilled in the art will recognize that other components and configurations may be used without departing from the spirit and scope of the present disclosure. Accordingly, the following description and drawings are illustrative and should not be construed as limiting. Numerous specific details are set forth to provide a thorough understanding of the present disclosure. However, in certain instances, well-known or conventional details are not described to avoid obscuring the description. References to one embodiment or an embodiment in this disclosure may refer to the same embodiment or any embodiment. Such references refer to at least one of the exemplary embodiments.

[0015] Reference to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present disclosure. Appearances of the phrase "in one embodiment" in various places throughout this specification do not necessarily all refer to the same embodiment, nor are they separate or alternative exemplary embodiments mutually exclusive of other exemplary embodiments. Furthermore, various features are described that may be exhibited by some exemplary embodiments but not by other embodiments. Any feature of one example may be combined with or used in conjunction with any other feature of any other example.

[0016] The terms used herein generally have their ordinary meaning in the art within the context of this disclosure and in the specific context in which each term is used. Alternative language and synonyms may be used for any one or more of the terms discussed herein, and no particular importance should be placed on whether a term is detailed or discussed herein. In some cases, synonyms for particular terms are provided. The listing of one or more synonyms does not exclude the use of other synonyms. Examples throughout this specification, including examples of any terms discussed herein, are used as illustrations and are not intended to further limit the scope and meaning of the disclosure or any exemplary term. Similarly, the present disclosure is not limited to the various exemplary embodiments provided herein.

[0017] Although not intended to limit the scope of the present disclosure, examples of devices, apparatuses, methods, and their related results according to exemplary embodiments of the present disclosure are provided below. Please note that titles or subtitles may be used in the examples for the convenience of the reader and in no way limit the scope of the present disclosure. Unless otherwise defined, technical and scientific terms used herein have the meanings commonly understood by those skilled in the art to which this disclosure belongs. In case of conflict, the present document, including definitions, will control.

[0018] Additional features and advantages of the present disclosure will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the principles disclosed herein. The features and advantages of the present disclosure may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the present disclosure will become more fully apparent from the following description and appended claims, or may be learned by practice of the principles as described herein.

[0019] For clarity of explanation, in some instances, the technology may be presented as including individual functional blocks that represent devices, device components, steps, or routines in a software-implemented method or combination of hardware and software.

[0020] The figures may show some structural or method features in a particular arrangement and / or order. However, it should be understood that such a particular arrangement and / or ordering may not be required. Rather, in some embodiments, such features may be arranged in a different manner and / or order than that shown in the illustrative figures. Furthermore, the inclusion of a structural or method feature in a particular figure does not imply that such feature is required in all embodiments, and in some embodiments, it may not be included or may be combined with other features.

[0021] As used herein, ordinal terms (e.g., "first," "second," "third," etc.) used to modify elements such as structures, components, operations, etc. do not in themselves indicate a priority or order of the element relative to another element, but merely distinguish one element from another element having the same name (but excluding the use of the ordinal term).

[0022] While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that there is no intention to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives consistent with the scope of the present disclosure and the appended claims. Electrospray thruster system elements

[0023] 1A is a perspective view of an exemplary embodiment of an electrospray tile 100. FIG. 1B is an exploded view of tile 100. In the exemplary embodiment, tile 100 includes a frame 102 and an emitter 104 and an extractor 106, each coupled to the frame. For example, emitter 104 and extractor 106 may each have a generally flat profile, and frame 102 may be configured to provide primary structural support to tile 100, establish a spaced-apart, oriented relationship between emitter 104 and extractor 106, and facilitate coupling of tile 100 to an integrated ion thruster system, as described in more detail below.

[0024] In an exemplary embodiment, the tile 100 has a generally rectangular outline defining a width 108 and a length 110 in a plane perpendicular to the thrust direction 101. The thrust direction 101 may be the net direction in which ions are ejected during operation. For example, the tile may have a width 108 in the range of approximately 0.25 to 3 centimeters (cm) and a length 110 in the range of approximately 0.25 to 3 cm. As another example, in some embodiments, the tile 100 may have a square outline with the width 108 and length 110 each equal to approximately 1.3 cm. The generally rectangular or square outline may facilitate packing tens, hundreds, or thousands of tiles 100 into an integrated ion thruster, as described in more detail below. Other outline shapes and sizes are also contemplated. In an exemplary embodiment, the tile 100 has a thickness 112 along the thrust direction 101 of approximately 2 to 5 millimeters (mm). Other thicknesses are also contemplated.

[0025] 2 is an enlarged detailed view of one embodiment of the emitter 104 taken along line 2-2 shown in FIG. 1B , illustrating an exemplary embodiment of emitter bodies 114 defined on and extending from a base surface 118 of the emitter 104. The emitter may also include a wetted surface 120 opposite the base surface 118. The base surface 118 and the wetted surfaces 120 may each be perpendicular to the thrust direction 101. Each of the emitter bodies 114 may extend in the thrust direction 101 away from the base surface 118 to a tip 116. The tip 116 is configured to be wetted with an ionic liquid propellant. For example, the emitter 104 may be configured to wick the ionic liquid propellant from the wetted surface 120 to the plurality of tips 116 of the emitter. For example, the emitter 104 may be formed from a porous material, and the pores (not shown) may be sized to allow passive wicking of the ionic liquid by capillary action within the pores.

[0026] The emitter body 114 may be sized to provide a field focusing effect at the tip 116 to emit ions under application of a voltage equal to or greater than the threshold voltage of the emitter 104. For example, the emitter body 114 may taper from a base width 124 at the base surface 118 within a range of 50 to 150 microns (μm) to the tip 116, which may have a radius of curvature of less than 10 μm. Other shapes for the emitter body 114 are also contemplated. The emitter body may have a height 122 from the base surface 118 to the tip 116 within a range of 200 to 500 μm. Other heights for the emitter body 114 are also contemplated. The threshold voltage may be approximately 400 volts or greater. Other threshold voltages are also contemplated.

[0027] In an exemplary embodiment, the emitter 104 may include a number of emitter bodies 114 (and thus tips 116) in the range of 200 to 10,000. In other examples, the emitter 104 may include a number of emitter bodies 114 (and thus tips 116) in the range of 1,000 to 3,000. Other numbers of tips 116 are contemplated. In an exemplary embodiment, the emitter bodies 114 may be arranged in a tip pattern 126 on the base surface 118. For example, the tip pattern 126 may include rows 128 of emitter bodies 114 extending parallel to the width 108 of the tile 100, the rows 128 being spaced apart along the length 110 of the tile 100. Other tip patterns 126 are also contemplated.

[0028] The extractor 106 may be configured to implement a counter electrode of the emitter 104. For example, a power supply such as power supply 410 (FIGS. 4B and 5) may be configured to apply a voltage to an ionic liquid in communication with the emitter 104, and the extractor 106 may be configured as a reference or ground voltage relative to the emitter 104. Note that the "ground" voltage at the extractor 106 may be, but is not limited to, the spacecraft ground. In other words, in some implementations, the reference voltage at the extractor 106 may be biased from the spacecraft ground. The extractor 106 may include an extractor aperture 132 sized and positioned to allow ions extracted from the tip 116 to pass therethrough in the thrust direction 101. The extractor apertures 132 may be arranged in an aperture pattern 130 configured to be aligned with the tip pattern 126. For example, opening pattern 130 may include openings 132 extending parallel to width 108 of tile 100 and spaced apart along length 110 of tile 100, such that each opening 132 is aligned in thrust direction 101 with a corresponding one of rows 128 of exemplary tip pattern 126 described above. In another example, opening pattern 130 may include a grid support bar 139 extending parallel to tile length 110 at a central portion of width 108, and tip pattern 126 may include breaks 129 in rows 128 aligned in thrust direction 101 with grid support bar 139 (such that grid support bar 139 does not block thrust direction 101 emission from any of tips 116). Other opening patterns 130 are also contemplated.

[0029] The frame may include a frame body 140 configured to position the extractor 106 parallel to the emitter 104 and spaced apart from the emitter 104 along the thrust direction 101. For example, the frame body 140 may include a first surface 142 configured to position the emitter 104 thereon. The frame body may also include a second surface 144 positioned beyond the first surface 142 in the thrust direction 101 and configured to position the extractor 106 thereon. For example, the second surface 144 may be defined by a plurality of legs 145 extending from a corner of the frame body 140, and the first surface 142 may be defined by a shelf extending from a portion of the interior of the frame body 140 to the corner. A suitable bonding material, such as epoxy, may be used to attach the emitter 104 and extractor 106 to the frame 102. Other configurations of the frame body 140 are also contemplated.

[0030] The frame body 140 may also define a frame channel 146 extending therethrough and configured to fluidly couple the wetted surface 120 of the emitter 104 with a reservoir 230 of ionic liquid propellant (shown in FIG. 4C ). In an exemplary embodiment, the frame body 140 includes a closed peripheral portion 148, with the frame channel 146 extending centrally through the closed peripheral portion 148 in the thrust direction 101. Other configurations of the frame channel 146 are also contemplated.

[0031] As demonstrated in the patent by Lozano previously incorporated by reference, in some embodiments, each tip 116 can generate a thrust of greater than 0.02 microNewtons (μN) under the application of the above threshold voltage using a suitable ionic liquid propellant. Thus, a single tile 100 having 1,000 tips 116 can generate a thrust in the thrust direction 101 of greater than 20 μN. Other values ​​of thrust per tip and other numbers of tips 116 per tile 100 are contemplated.

[0032] 3A is a schematic elevation view of an example launch assembly 380 including an example spacecraft 350 and an example separation ring 352 coupled to an example payload adapter 300. FIG. 3B is a schematic perspective view of an example spacecraft envelope 306 defined by launch assembly 380. Payload adapter 300 is configured to couple multiple spacecraft, such as spacecraft 350, to a launch vehicle (not shown) for delivering the spacecraft to an initial orbit. Launch assembly 380 defines, for each spacecraft carried by the launch vehicle, a spacecraft envelope 306 within which spacecraft 350 must be contained within launch assembly 380. In other words, spacecraft envelope 306 is the volume within which spacecraft 350 must fit in order to be launched by a launch vehicle using payload adapter 300. For example, the launch vehicle's payload bay may at least partially define the outer shape of the spacecraft envelope 306 for each spacecraft 350. In some implementations, the payload adapter 300 may be ring-shaped and oriented concentrically about the launch vehicle's longitudinal axis 310, with the spacecraft envelope 306 for each spacecraft comprising a circumferentially extending portion of the annular region defined between the payload adapter 300 and the launch vehicle's payload bay's cylindrical outer wall 308. Other configurations of the payload adapter 300 and spacecraft envelope 306 are also contemplated.

[0033] The payload adapter 300 may include a plurality of adapter port rings 302. Each adapter port ring 302 defines an adapter port 304 configured to couple to a corresponding spacecraft 350. The launch assembly 380 may include an isolation ring 352 configured to couple the spacecraft 350 to the corresponding adapter port ring 302. The isolation ring 352 may be further configured to selectively separate the spacecraft 350 from the payload adapter 300, for example, after the launch vehicle delivers the spacecraft 350 to the intended release orbit. The isolation ring 352 may define an isolation ring opening 354 that is substantially aligned with and in fluid communication with the adapter port 302 when the isolation ring is coupled between the adapter port ring 304 and the spacecraft 350. A ring normal 358 may be defined parallel to a central axis L of the isolation ring opening 354.

[0034] For example, payload adapter 300 may be implemented as a standard EELV Secondary Payload Adapter (ESPA) ring developed in connection with the Advanced Expendable Launch Vehicle (EELV) program originally managed by the United States Air Force, with each adapter port 304 having a 15-inch diameter. Further, in this example, separation ring 352 may be implemented as a 15-inch Advanced Lightband (ALB) manufactured by Rocket Lab / Planetary Systems Corporation of Silver Springs, Maryland. In another example, payload adapter 300 may be implemented as a standard Grande ESPA ring, with each adapter port 304 having a 24-inch diameter, and separation ring 352 implemented as a 24-inch ALB. In another example, payload adapter 300 may be implemented as a Compact Launch ESPA ring, with each adapter port 304 having an 8-inch diameter, and separation ring 352 implemented as an 8-inch ALB. Other implementations of payload adapter 300 or separation ring 352 are also contemplated.

[0035] Figure 4A is a schematic elevation view of an integrated ion thruster unit 400 mounted on a spacecraft 350 within a launch assembly 380. Figure 4B is a schematic perspective view of an exemplary embodiment of the integrated ion thruster unit 400 in combination with an isolation ring 352. Figure 4C is a schematic cross-sectional view of an exemplary interior 200 of the integrated ion thruster unit 400 taken along line CC shown in Figure 4B.

[0036] The integrated ion thruster unit 400 may include a unit housing 402 that includes a thrust face 404. A plurality of tiles 100 may be arranged in an array 428 on the thrust face 404. For example, a plurality of tiles 100 may be coupled to the unit housing 402 and oriented such that the tiles are exposed outside the unit housing 402 on the thrust face 404, and such that each tile 100 is in an adjacent edge-to-edge relationship with at least one other tile 100 in the array 428. The tiles may be oriented such that the thrust direction 101 is aligned perpendicular to the thrust face 404 (i.e., the tiles 100 may be oriented in a plane parallel to the thrust face 404). Other orientations and positioning of some or all of the tiles 100 are also contemplated.

[0037] In some embodiments, the array of tiles 100 may have a number of tiles 100 of at least 50. Further, in some embodiments, the array of tiles may have a number of tiles 100 of at least 100. Further, in some embodiments, the array of tiles may have a number of tiles 100 of at least 500. Other numbers of tiles 100 in the array 428 are also contemplated.

[0038] The tiles 100 may be secured to the thrust face 404 in any suitable manner. For example, the integrated ion thruster unit 400 may include a bracket 212 disposed on the thrust face 404 to position the tiles 100 within the array 428 relative to the unit housing 402. More specifically, the bracket 212 may be configured to secure the tiles 100 to the bracket 212. In particular, the bracket 212 may be configured to avoid or limit interference with the transport of ionic liquid propellant to the emitter 104, as described in more detail below. Other implementations for securing the tiles 100 to the thrust face 404 are also contemplated.

[0039] The array of tiles 100 may be sized and arranged to allow the cross-sectional profile of the unit housing 402 to be received through the isolation ring opening 354. Additionally, various other components of the integrated ion thruster unit 400 that may be included within the unit housing 402 are described below, and other components may be disposed within the unit housing 402 to further allow the cross-sectional profile of the unit housing 402 to be received through the isolation ring opening 354. For example, the cross-sectional profile may be the widest cross-sectional area of ​​the unit housing 402 as measured perpendicular to the ring normal 358. Furthermore, in some embodiments, the cross-sectional profile may be further received through the adapter port 304 when the adapter port 304 is in fluid communication with the isolation ring opening 354. In some embodiments, the inner diameter of the adapter port 304 and the inner diameter of the isolation ring opening 354 are each within the range of 11 to 16 inches. For example, in the embodiment shown in FIG. 4B , payload adapter 300 may be implemented as an ESPA with an adapter port 304 having an inner diameter of approximately 13.5 inches, and isolation ring 352 may be implemented as a 15-inch ALB with isolation ring opening 354 having an inner diameter of approximately 12.4 inches. Isolation ring 352 may further include a portion 356 of a release mechanism extending chordwise through isolation ring opening 354 at a minimum distance of approximately 3.8 inches from the center of isolation ring opening 354. As mentioned above, each tile 100 may have a square outline with width 108 and length 110 each equal to approximately 1.3 cm (see FIG. 1A ). To accommodate reception through isolation ring opening 354 (and subsequently through slightly larger adapter port 304), array 428 may include 144 tiles 100 arranged in eight rows of 18 tiles each. Other tile sizes and numbers and arrangements of tiles 100 in array 428 that allow the cross-sectional profile of unit housing 402 to be received through isolation ring opening 354 are also contemplated.

[0040] As is known, spacecraft envelope 306 imposes constraints on the size of spacecraft 350, which can limit the overall capabilities or functions of the spacecraft. For example, if a conventional chemical or ion propulsion system (not shown) were to be included on spacecraft 350 to provide one or more of orbital maneuvers, stationkeeping, or the like, such conventional system would typically occupy a significant portion of spacecraft envelope 306, thereby limiting the remaining volume available for the intended payload of spacecraft 350. In particular, in embodiments in which the component arrangement allows the cross-sectional profile of unit housing 402 to be received through and extend into isolation ring opening 354 (and optionally adapter port 304), integrated ion thruster unit 400 may be positioned in a manner that allows a much larger portion of spacecraft envelope 306 to be allocated to the intended payload of spacecraft 350 compared to the amount of spacecraft envelope 306 occupied by a conventional propulsion system.

[0041] More specifically, the isolation ring 352 can extend from a first edge 360 ​​adjacent the spacecraft 350 to a second edge 362 adjacent the payload adapter 300, such that an isolation ring opening 354 extends through the isolation ring 352 along axis L (in other words, along a ring normal 358) from the first edge 360 ​​to the second edge 362. The first edge 360 ​​can be viewed as a parting plane between a payload adapter side 366 of the first edge and a spacecraft side 368 of the first edge. The launch assembly 380 can include an integrated ion thruster unit 400 positioned relative to the spacecraft 350 such that a unit housing 402 extends into the isolation ring opening 354 and substantially to the payload adapter side 366 of the first edge 360 ​​when the isolation ring couples the spacecraft 350 to the adapter port ring 302 for launch. In this context, "substantially" means that 50% or more of the volume occupied by the integrated ion thruster unit 400 is positioned on the payload adapter side 366 of the first edge 360. Furthermore, in some embodiments, the launch assembly 380 includes an integrated ion thruster unit 400 positioned such that the unit housing 402 extends primarily to the payload adapter side 366 of the first edge 360. In this context, "primarily" means that at least 75% of the volume occupied by the integrated ion thruster unit 400 is positioned on the payload adapter side 366 of the first edge 360, as shown in FIG. 4B .

[0042] Embodiments of launch assembly 380 are also contemplated in which unit 400 is not or cannot be positioned such that unit housing 402 extends substantially to payload adapter side 366 of first edge 360 ​​when spacecraft 350 (to which integrated ion thruster unit 400 is coupled) is attached to adapter port ring 302 for launch. Additionally, embodiments of integrated ion thruster unit 400 are also contemplated in which unit 400 cannot be received within isolation ring opening 354.

[0043] It should be understood that in the exemplary embodiment, the ability of separation ring 352 to separate spacecraft 350 from payload adapter 300 is entirely independent of the function of integrated ion thruster unit 400. However, embodiments are contemplated in which integrated ion thruster unit 400 contributes to the separation of spacecraft 350 from payload adapter 300.

[0044] The integrated ion thruster unit 400 may be configured to include a propellant supply system 210 within the interior 200 of the unit housing 402 that contains a quantity of ionic liquid propellant 234 sufficient to supply the tiles 100 in the array 428 throughout the lifecycle of the unit. The propellant supply system 210 may include one or more reservoirs 230 contained within the unit housing 402. Each reservoir 230 may be configured to contain an amount of ionic liquid propellant 234 used by a subset of the tiles 100 in the array 428 during an operational phase of the integrated ion thruster unit 400. In the illustrated example, one reservoir 230 is shown in fluid communication with a subset of the tiles 100 located in nine columns of the array 428; additional reservoirs 230 (not shown) may be included to provide ionic liquid propellant 234 to other subsets of the tiles 100 in the array 428. Other combinations of reservoirs 230 in fluid communication with different subsets of tiles 100 are also contemplated (including, in some examples, the use of a single reservoir 230 to supply all tiles in the array).

[0045] The one or more reservoirs 230 may be configured to transport the ionic liquid propellant 234 toward the tile 100 in any suitable manner. For example, the reservoir 230 may include a porous material configured to transport the ionic liquid propellant 234 toward the tile 100 by capillary action. Other implementations for the one or more reservoirs 230 are also contemplated.

[0046] As described above, the brackets 212 can be configured to facilitate delivery of the ionic liquid propellant 234 to the tiles 100. For example, each bracket 212 can define a bracket channel 246 extending therethrough in the thrust direction 101 and positioned to align with the frame channel 146 of the tile 100 secured to the bracket 212. More specifically, the bracket channel 246 can be configured to fluidly couple the frame channel 146 of the secured tile (and thus the wetted surface 120 of the emitter 104) with the reservoir 230. In some embodiments, the propellant supply system 210 further includes a wick 238 positioned within the aligned bracket channel 246 and frame channel 146. For example, each of the wicks 238 can extend from the reservoir 230 through the corresponding aligned bracket channel 246 and frame channel 146 to the wetted surface 120. The wick 238 may include fibers configured to wick the ionic liquid propellant 234 from the reservoir 230 through aligned channels to the wetted surface 120. Other implementations for establishing fluid communication between the reservoir 230 and the wetted surface 120 are also contemplated.

[0047] The integrated ion thruster unit 400 also includes one or more electrodes 220 configured to apply a voltage to the ionic liquid propellant 234 extending into the unit housing 402 and in contact with the emitter 104, thereby causing ions to be ejected from the emitter tip 116 (shown in FIG. 2 ) in the thrust direction 101. For example, each electrode 220 can extend into a corresponding one of the one or more reservoirs 230. The one or more electrodes 220 can be operably coupled to a power source, such as power source 410. More specifically, each electrode 220 can be selectively energized by the power source, and the electrode 220 can be positioned to electrically transmit the resulting applied voltage across the ionic liquid propellant 234 in fluid communication between the electrode 220 and the emitter 104 in the subset of tiles 100 in fluid communication with the reservoir 230. Other distributions of the electrodes 220 among the reservoirs 230 are also contemplated. When the electrode 220 is energized, the electric field effect caused by the shape of the tip 116 causes ions to be ejected from the ionic liquid propellant 234 at the tip 116 .

[0048] In the illustrated embodiment, each electrode 220 extends into a corresponding reservoir 230 adjacent the thrust face 404. However, other locations of the electrodes 220 relative to the unit housing 402 are contemplated. The electrodes 220 may be formed from a suitable conductive material, such as, but not limited to, a porous activated carbon fiber (ACF) material.

[0049] The propellant supply system 210 may also include one or more storage tanks 232 enclosed within the unit housing 402 and configured to store ionic liquid propellant 234, for example, during a pre-operational phase. The one or more storage tanks 232 may be selectively coupled in fluid communication with one or more reservoirs 230 via one or more valves 236. In the illustrated embodiment, each reservoir 230 is selectively coupled in fluid communication with a corresponding one of the storage tanks 232 by one valve 236. However, other numbers of and connections between the reservoirs 230, storage tanks 232, and valves 236 are contemplated.

[0050] The inclusion of one or more storage tanks 232 separate from and selectively connectable in fluid communication with the one or more reservoirs 230 allows the ionic liquid propellant 234 to be isolated from the tile 100 until the initiation of thrust operation. For example, the one or more storage tanks 232 can be filled with ionic liquid propellant 234 before the integrated ion thruster unit 400 is coupled to the launch assembly 380. One or more valves 236 can remain closed to prevent the one or more reservoirs 230 from receiving the ionic liquid propellant 234 until on-orbit operation of the integrated ion thruster unit 400 is desired. For example, one or more valves 236 can remain closed throughout phases such as, but not limited to, ground operations (e.g., assembly of the integrated ion thruster unit, coupling of the integrated ion thruster unit to the spacecraft), launch of the spacecraft (including the integrated ion thruster unit) into orbit on a launch vehicle, separation of the spacecraft (including the integrated ion thruster unit) from the launch vehicle, and on-orbit idling of the spacecraft. In response to the spacecraft reaching or approaching an on-orbit operation phase requiring thrust from the integrated ion thruster unit, one or more valves 236 can be opened to supply ionic liquid propellant 234 from one or more tanks 232 to one or more reservoirs 230. By isolating the ionic liquid propellant 234 from the tiles 100 until the start of thrust operation, the risk of unintentional deposition of ionic liquid propellant 234 on the surfaces of the tiles 100 and thrust faces 404, which could create a short circuit path between the emitter 104 and the extractor 106, is significantly reduced.

[0051] Alternatively, one or more valves 236 can be used to supply ionic liquid propellant 234 from tank 232 to reservoir 230 at any suitable time, or ionic liquid propellant 234 can be pre-filled or stored in one or more reservoirs 230, and storage tank 232 can be omitted.

[0052] The volume occupied by the propellant supply system 210 depends on a depth 426 from the thrust face into the unit housing 402, parallel to the thrust direction 101 defined by the tiles. For example, the thrust direction 101 may be parallel to the ring normal 358 when the launch assembly 380 is assembled. As described above, the components of the integrated ion thruster unit 400 may be positioned within the unit housing 402 to allow the cross-sectional profile of the unit housing 402 to be received through the isolation ring opening 354. To that end, in some embodiments, the depth 426 may be less than the depth 424 of the unit housing measured parallel to the thrust direction. Other depths and positioning of the propellant supply system 210 relative to the unit housing 402 are also contemplated.

[0053] The integrated ion thruster unit 400 may include one or more additional components (in addition to the tiles 100, the propellant supply system 210, and the electrodes 220). The unit housing 402 may include one or more additional component areas configured to accommodate the one or more additional components. For example, in this context, considering the thrust face 404 as the front of the integrated ion thruster unit 400, the unit housing 402 may enclose one or more aft additional component areas 406 located aft of the depth 426 of the propellant supply system 210 relative to the thrust direction 101. In another example, the unit housing 402 may enclose one or more adjacent additional component areas 408 located adjacent the propellant supply system 210 relative to the thrust direction 101.

[0054] The one or more additional components may include propulsion-related components 410 (i.e., components specific to the propulsion and operation of the tile 100). For example, as described above, the propulsion-related components 410 may include one or more power sources 410 configured to supply a voltage to the emitters 104 of the tiles 100 in the array 428. For example, the one or more power sources 410 may be configured to supply a voltage that meets or exceeds a threshold voltage of the emitters 104 across the tile 100. In the illustrated example, the propulsion-related components 410 are positioned in the rear additional component region 406, although it is also contemplated that the propulsion-related components 410 may be positioned in the adjacent additional component region 408.

[0055] The one or more additional components may also include non-propulsion-related components 420 (i.e., related to support or mission functions for the spacecraft 350 other than propulsion). The non-propulsion-related components 420 may include one or more suitable implementations of subsystems typically provided on a satellite bus platform. For example, the non-propulsion-related components 420 may include one or more of a guidance, navigation, and control (GNC) subsystem, an avionics subsystem, a command and data processing (C&DH) subsystem, a ground communications subsystem, a gyroscope subsystem, an inertial management unit (IMU) subsystem, a mission data processing subsystem, a radiation sensor subsystem, a positioning, navigation, and timing (PNT) subsystem, an electrical power system (EPS) control subsystem, or a battery subsystem. The non-propulsion-related components 420 may function as a backup or redundant for a corresponding subsystem provided elsewhere on the spacecraft 350, or may function as a primary subsystem. In the illustrated example, the non-propulsion-related components 420 are located in the adjacent additional components area 408, although it is also contemplated to position the propulsion-related components 410 within the aft additional components area 406. In some implementations, the inclusion of one or more non-propulsion-related components 420 within the unit housing 402 allows a correspondingly larger portion of the spacecraft envelope 306 to be allocated to the intended payload of the spacecraft 350, as described above. Additionally or alternatively, the inclusion of one or more non-propulsion-related components 420 within the unit housing 402 may allow the integrated ion thruster unit 400 to be provided as a complete, ready-to-connect unit, enabling faster and less expensive design and manufacturing of the spacecraft 350.

[0056] In addition to requiring less volume within the spacecraft envelope 306 available for launch of the spacecraft 350 than a conventional on-board propulsion system, the features of the integrated ion thruster unit 400 described herein also facilitate retrofitting the integrated ion thruster unit 400 to the spacecraft 350 after the spacecraft 350 is already in orbit. For example, the spacecraft 350 may have previously launched with a conventional on-board propulsion system or an initial integrated ion thruster unit 400 that may have exhausted its available propellant stores or otherwise become unsuitable for further operation. The retrofit integrated ion thruster unit 400 may be delivered to an orbital rendezvous with the spacecraft 350 and mechanically coupled to the spacecraft 350 in orbit. For example, a portion of the separation ring 352 may remain fixed to the spacecraft 350 from the spacecraft's initial deployment, and the integrated ion thruster unit 400 may be positioned within the separation ring opening 354 and coupled to the separation ring 352 in a manner similar to that described above. Other implementations for coupling the integrated ion thruster unit 400 to the spacecraft 350 in connection with an on-orbit retrofit are also contemplated. The retrofitted integrated ion thruster unit 400 may provide a self-contained, turnkey on-board propulsion system that can extend the service life of the spacecraft 350.

[0057] In some embodiments, the retrofitted integrated ion thruster unit 400 may include one or more non-propulsion-related components 420, as described above. For example, the non-propulsion-related components 420 may include a ground communication system configured to enable ground control of the retrofitted integrated ion thruster unit 400. In another example, the non-propulsion-related components 420 may include a replacement subsystem configured to replace the functionality of an original subsystem of the spacecraft 350 that may be degraded. In another example, the non-propulsion-related components 420 may include a subsystem that adds new non-propulsion capabilities to the spacecraft 350.

[0058] 5 is a perspective view of another exemplary integrated ion thruster unit 400. As in the embodiment of FIG. 4B, the integrated ion thruster unit 400 may again include a plurality of tiles 100 that may be arranged in an array (here designated as array 528) on a thrust face 404, the thrust direction 101 may be parallel to the ring normal direction 358, and the volume occupied by the propellant supply system 210 may depend on a depth 426 from the thrust face 404 into the unit housing 402 parallel to the ring normal direction 358. Other elements of the integrated ion thruster unit 400 are numbered the same as in FIG. 4.

[0059] The components of the integrated ion thruster unit 400 may again be disposed within a unit housing 402 such that the cross-sectional profile of the unit housing 402 may be received through the isolation ring opening 354 and further through the adapter port 304. In some embodiments, the inner diameter of the adapter port 304 and the inner diameter of the isolation ring opening 354 are each within a range of 20 to 26 inches. For example, in the embodiment shown in FIG. 5, the payload adapter 300 may be implemented as a Grande ESPA ring, with each adapter port 304 having a nominal 24-inch diameter, and the isolation ring 352 may be implemented as a 24-inch ALB. Each tile 100 may again have a square profile with a width 108 and a length 110 each equal to approximately 1.3 cm (see FIG. 1A).

[0060] To accommodate reception through the isolation ring opening 354 (and then through the slightly larger adapter port 304), the array 528 in this case may include 513 tiles 100 arranged in a central pattern of 225 tiles by 9 columns and 144 tiles in each of two adjacent patterns of 16 rows by 9 columns. Other tile sizes and numbers and arrangements of tiles 100 in the array 528 that allow the cross-sectional profile of the unit housing 402 to be received through the isolation ring opening 354 are also contemplated.

[0061] Additionally, the embodiment of FIG. 5 may again include one or more propulsion-related components 410, non-propulsion-related components 420, or both, housed within unit housing 402 and positioned within either or both of rear add-on component area 406 or adjacent add-on component area 408, as described above.

[0062] As can be seen particularly by comparing the embodiments of FIGS. 4B and 5 , the volume available for an increased number of tiles 100 (and thus a greater maximum available thrust), an increased number or size of reservoirs 230 and storage tanks 232 (and thus a greater propellant payload), and an increased number of propulsion-related components 410 and non-propulsion-related components 420 increases exponentially as the radius of the separation ring opening 354 increases. Accordingly, a correspondingly greater volume within the spacecraft envelope 306 can be reserved for the intended payload of the spacecraft 350 in embodiments in which the unit housing 402 extends substantially or nearly completely to the payload adapter side of the first edge 360 ​​when the spacecraft 350 (with the integrated ion thruster unit 400 coupled thereto) is attached to the adapter port ring 302 for launch, as described above.

[0063] It should be understood that embodiments of the integrated ion thruster unit 400 are not limited to the sizes of the payload adapter 300, adapter port 304, or isolation ring opening 354 described in the examples above. In some embodiments, the inner diameter of the adapter port 304 and the inner diameter of the isolation ring opening 354 are each within a range of 6 to 11 inches. For example, as described above, the payload adapter 300 may be implemented as a small launch ESPA ring, with each adapter port 304 having a nominal 8-inch diameter, and the isolation ring 352 implemented as an 8-inch ALB. In another example, the inner diameter of the adapter port 304 and the inner diameter of the isolation ring opening 354 may each be within a range of 16 to 20 inches. In either case, the array of tiles 100 and the arrangement of the propellant supply system 210 may be similarly constructed to accommodate the unit housing 402 being received through the isolation ring opening 354 of an 8-inch ALB.

[0064] Other sizes and types of payload adapters are contemplated. Furthermore, it should be understood that embodiments of integrated ion thruster unit 400 are not limited to being coupled to a spacecraft in a location that penetrates an isolation ring during payload assembly, but rather may be coupled to a spacecraft in any suitable location (and may have any suitable size).

[0065] 6 illustrates an example method 600 of assembling a launch assembly, such as launch assembly 380. Method 600 can include one or more of the steps of: coupling (604) an integrated ion thruster unit to a spacecraft, the integrated ion thruster unit including a unit housing including a thrust face and a plurality of tiles exposed on the thrust face and configured to eject ions in a thrust direction from an ionic liquid propellant stored in the unit housing; and coupling (608) an isolation ring to the spacecraft, the isolation ring configured to couple to a payload adapter and selectively isolate the spacecraft from the payload adapter, the isolation ring extending from a first edge adjacent to the spacecraft to a second edge and defining an isolation ring opening therethrough from the first edge to the second edge, the unit housing extending into the isolation ring opening and extending substantially to the payload adapter side of the first edge.

[0066] In some embodiments, the steps further include receiving a cross-sectional profile of the unit housing through the isolation ring opening.

[0067] In certain embodiments, the inside diameter of the separator ring opening is in the range of 11 to 16 inches.

[0068] In some embodiments, the inside diameter of the separator ring opening is in the range of 20 to 26 inches.

[0069] In certain embodiments, the steps further include coupling an isolation ring to an adapter port of the payload adapter, the adapter port ring defining an adapter port in fluid communication with the isolation ring opening, and the unit housing extending into the adapter port.

[0070] In some embodiments, the steps further include coupling the separation ring such that the unit housing extends primarily toward the payload adapter side of the first edge.

[0071] In certain embodiments, the steps further include coupling one or more reservoirs within the unit housing, the one or more reservoirs configured to contain an ionic liquid propellant used by the tiles in the array.

[0072] In some embodiments, the steps include coupling one or more storage tanks within the unit housing, the one or more storage tanks configured to store ionic liquid propellant during a pre-operational phase of the spacecraft; and coupling one or more valves between the one or more storage tanks and the one or more reservoirs, the one or more valves configured to selectively couple the one or more storage tanks into fluid communication with the one or more reservoirs.

[0073] In certain embodiments, the integrated ion thruster unit further includes a propellant supply system depending from the thrust face into the unit housing, and the step further includes accommodating at least one additional component area within the unit housing, the at least one additional component area including one or both of one or more aft additional component areas located aft of the propellant supply system relative to the thrust direction and one or more adjacent additional component areas located adjacent to the propellant supply system relative to the thrust direction.

[0074] In some embodiments, the steps further include coupling one or more additional components into the at least one additional component area, the one or more additional components including a first additional component selected from among a Guidance, Navigation, and Control (GNC) subsystem, an Avionics subsystem, a Command and Data Processing (C&DH) subsystem, a Ground Communications subsystem, a Gyroscope subsystem, an Inertial Management Unit (IMU) subsystem, a Mission Data Processing subsystem, a Radiation Sensor subsystem, a Positioning, Navigation, and Timing (PNT) subsystem, an Electrical Power System (EPS) Control subsystem, or a Battery subsystem.

[0075] Additional or alternative steps are contemplated as indicated by the discussion herein.

[0076] 7 illustrates an exemplary method 700 for retrofitting a spacecraft with an integrated ion thruster unit, such as integrated ion thruster unit 400. Method 700 includes delivering the integrated ion thruster unit to an orbital rendezvous with the spacecraft, the integrated ion thruster unit comprising: a unit housing including a thrust surface; and The method may include one or more of delivering (704) an integrated ion thruster unit, the integrated ion thruster unit including a plurality of tiles exposed on the thrust face and configured to eject ions in the thrust direction from an ionic liquid propellant stored within the unit housing; and mechanically coupling (708) the integrated ion thruster unit to the spacecraft in orbit.

[0077] In some embodiments, a portion of the separation ring remains fixed to the spacecraft from the time of initial deployment of the spacecraft, and the steps further include positioning the integrated ion thruster unit within an separation ring opening defined by the portion of the separation ring.

[0078] In certain embodiments, the inside diameter of the separator ring opening is in the range of 6 to 11 inches.

[0079] In some embodiments, the inner diameter of the separator ring opening is in the range of 11 to 16 inches.

[0080] In certain embodiments, the inside diameter of the separator ring opening is in the range of 16 to 20 inches.

[0081] In some embodiments, the inside diameter of the separator ring opening is in the range of 20 to 26 inches.

[0082] In certain embodiments, the steps further include coupling the integrated ion thruster unit to a portion of the isolation ring.

[0083] In some embodiments, the steps further include coupling one or more additional components to the spacecraft, the one or more additional components being housed within at least one additional component region within the unit housing.

[0084] In certain embodiments, the one or more additional components include a first additional component selected from among a Guidance, Navigation, and Control (GNC) subsystem, an Avionics subsystem, a Command and Data Processing (C&DH) subsystem, a Gyroscope subsystem, an Inertial Management Unit (IMU) subsystem, a Mission Data Processing subsystem, a Radiation Sensor subsystem, a Positioning, Navigation, and Timing (PNT) subsystem, an Electrical Power System (EPS) Control subsystem, or a Battery subsystem.

[0085] In some embodiments, the steps further include coupling a ground communication system to the spacecraft, the ground communication system being contained within the unit housing and configured to enable ground control of the integrated ion thruster unit.

[0086] In certain embodiments, the spacecraft includes a lower-performance original non-propulsion-related subsystem, and the steps further include coupling a replacement subsystem to the spacecraft, the replacement subsystem contained within the unit housing and configured to replace the functionality of the original non-propulsion-related subsystem.

[0087] In some embodiments, the steps further include coupling a new subsystem to the spacecraft, the new subsystem contained within the unit housing and configured to add new non-propulsion-related capabilities to the spacecraft.

[0088] Additional or alternative steps are contemplated as indicated by the discussion herein.

[0089] While various examples and other information have been used to describe aspects within the scope of the appended claims, those skilled in the art will be able to derive a wide variety of implementations using these examples, and therefore limitations on the scope of the claims should not be implied based on the specific features or arrangements of such examples. Moreover, while some subject matter may be described in language specific to example structural features and / or method steps, it should be understood that the subject matter defined in the appended claims is not necessarily limited to these described features or acts. For example, such functionality may be differently distributed or performed in components other than those identified herein. Rather, the described features and steps are disclosed as example components of systems and methods within the scope of the appended claims.

[0090] Claim language stating "at least one of" refers to at least one of a set and indicates that one element of the set or multiple elements of the set satisfy the claim. For example, claim language stating "at least one of A and B" means A, B, or A and B.

Claims

1. 1. An integrated ion thruster unit for a spacecraft, said integrated ion thruster unit comprising: a unit housing having a thrust surface; a plurality of tiles arranged in an array on the thrust surface; Equipped with Each of the tiles: an emitter having a plurality of tips configured to emit ions from the ionic liquid propellant in a thrust direction in response to an applied voltage; an extractor configured to provide a reference voltage to the emitter; 1. An integrated ion thruster unit comprising:

2. each of the tiles further comprising a frame coupled to the emitter and the extractor; The integrated ion thruster unit of claim 1 , wherein said frame is configured to establish a spaced-apart, oriented relationship between said emitter and said extractor.

3. The frame is a first surface configured to position the emitter on the first surface; a second surface positioned beyond the first surface in the thrust direction, the second surface configured to position the extractor on the second surface; 3. The integrated ion thruster unit of claim 2, comprising:

4. The emitter is A base surface and a plurality of emitter bodies extending in the thrust direction away from the base surface; Furthermore, The integrated ion thruster unit of claim 1 , wherein each of said emitter bodies extends to a corresponding one of said tips.

5. 5. The integrated ion thruster unit of claim 4, wherein the emitter further comprises a wetted surface opposite the base surface, the emitter configured to wick the ionic liquid propellant from the wetted surface to the tip by capillary action.

6. 10. The integrated ion thruster unit of claim 1, wherein each of said tiles defines a width in the range of approximately 0.25 to 3 centimeters (cm) and a length in the range of approximately 0.25 to 3 cm, and wherein a number of said plurality of tips is in the range of 200 to 10,000 per each of said tiles.

7. 10. The integrated ion thruster unit of claim 1, wherein the number of tiles in the array is at least 50.

8. 10. The integrated ion thruster unit of claim 1, wherein the number of tiles in the array is at least 100.

9. 10. The integrated ion thruster unit of claim 1, wherein the number of said plurality of tiles in said array is at least 500.

10. 10. The integrated ion thruster unit of claim 1, further comprising one or more reservoirs contained within said unit housing and configured to contain said ionic liquid propellant for use by said tiles in said array.

11. 11. The integrated ion thruster unit of claim 10, wherein the one or more reservoirs comprise a porous material configured to transport the ionic liquid propellant toward the tile by capillary action.

12. one or more storage tanks enclosed within the unit housing and configured to store the ionic liquid propellant during a pre-operational phase of the spacecraft; one or more valves configured to selectively couple the one or more storage tanks in fluid communication with the one or more reservoirs; 11. The integrated ion thruster unit of claim 10, further comprising:

13. 11. The integrated ion thruster unit of claim 10, wherein each of the one or more reservoirs is in fluid communication with a different subset of the tiles in the array.

14. 10. The integrated ion thruster unit of claim 1, further comprising a bracket disposed on said thrust face for positioning said tiles in said array relative to said unit housing, said tiles in said array being secured to said bracket.

15. 15. The integrated ion thruster unit of claim 14, further comprising: one or more reservoirs configured to contain the ionic liquid propellant used by the tiles in the array; each of the tiles further comprising a frame coupled to the emitter and the extractor, the emitter including a wetted surface, the frame defining a frame channel therethrough; each of the brackets defining a bracket channel therethrough aligned with the frame channel of the tile secured to each of the brackets, the bracket channel coupling the frame channel and the wetted surface of the secured tile in fluid communication with the one or more reservoirs.

16. 16. The integrated ion thruster unit of claim 15, further comprising a wick positioned within said bracket channel and said aligned frame channel.

17. 10. The integrated ion thruster unit of claim 1, further comprising one or more electrodes configured to apply the applied voltage to the ionic liquid propellant extending into the unit housing and in contact with the emitter of each of the plurality of tiles.

18. 20. The integrated ion thruster unit of claim 17, further comprising one or more reservoirs configured to contain the ionic liquid propellant used by the tiles in the array, each of the one or more electrodes extending into a corresponding one of the one or more reservoirs adjacent the thrust face.

19. a propellant supply system depending from said thrust surface into said unit housing; the unit housing enclosing at least one additional component area; The at least one additional component region: one or more aft add-on component regions aft of the propellant supply system relative to the thrust direction; one or more adjacent additional component regions located adjacent the propellant supply system relative to the thrust direction; 10. The integrated ion thruster unit of claim 1, comprising one or both of:

20. 20. The integrated ion thruster unit of claim 19, further comprising one or more additional components located within the at least one additional component area, the one or more additional components comprising a first additional component selected from among a Guidance, Navigation, and Control (GNC) subsystem, an Avionics subsystem, a Command and Data Processing (C&DH) subsystem, a Ground Communications subsystem, a Gyroscope Subsystem, an Inertial Management Unit (IMU) subsystem, a Mission Data Processing subsystem, a Radiation Sensor subsystem, a Positioning, Navigation, and Timing (PNT) subsystem, an Electrical Power System (EPS) control subsystem, or a battery subsystem.

21. Spaceships and an integrated ion thruster unit coupled to the spacecraft, the integrated ion thruster unit comprising: a unit housing including a thrust surface; and a plurality of tiles exposed on the thrust surface and configured to eject ions in a thrust direction from an ionic liquid propellant stored within the unit housing; a separation ring coupled to the spacecraft and configured to couple to a payload adapter and selectively separate the spacecraft from the payload adapter; Equipped with the isolation ring extends from a first edge adjacent to the spacecraft to a second edge and defines an isolation ring opening extending through the isolation ring from the first edge to the second edge, and the unit housing extends into the isolation ring opening and substantially to a payload adapter side of the first edge. Launch assembly.

22. 22. The launch assembly of claim 21, wherein a cross-sectional profile of the unit housing is receivable through the isolation ring opening.

23. 23. The launch assembly of claim 22, wherein the inside diameter of the isolation ring opening is within the range of 6 to 11 inches.

24. 23. The launch assembly of claim 22, wherein the inside diameter of the isolation ring opening is within the range of 11 to 16 inches.

25. 23. The launch assembly of claim 22, wherein the inside diameter of the isolation ring opening is within the range of 16 to 20 inches.

26. 23. The launch assembly of claim 22, wherein the inside diameter of the isolation ring opening is within the range of 20 to 26 inches.

27. 22. The launch assembly of claim 21, further comprising: the payload adapter coupled to the isolation ring, the payload adapter comprising an adapter port ring defining an adapter port in fluid communication with the isolation ring opening, the isolation ring coupling the spacecraft to the adapter port ring, and the unit housing extending into the adapter port.

28. 22. The launch assembly of claim 21, wherein the unit housing extends primarily on the payload adapter side of the first edge.

29. 22. The launch assembly of claim 21, wherein the integrated ion thruster unit further comprises one or more reservoirs configured to contain the ionic liquid propellant used by the tiles.

30. the integrated ion thruster unit: one or more storage tanks enclosed within the unit housing and configured to store the ionic liquid propellant during a pre-operational phase of the spacecraft; one or more valves configured to selectively couple the one or more storage tanks in fluid communication with the one or more reservoirs; 30. The launch assembly of claim 29, further comprising:

31. the integrated ion thruster unit further comprising a propellant supply system depending from the thrust surface into the unit housing; the unit housing enclosing at least one additional component area; The at least one additional component region: one or more aft add-on component regions aft of the propellant supply system relative to the thrust direction; one or more adjacent additional component regions located adjacent the propellant supply system relative to the thrust direction; 22. The launch assembly of claim 21, including one or both of:

32. 32. The launch assembly of claim 31, further comprising one or more additional components located within the at least one additional component area, the one or more additional components comprising a first additional component selected from among a Guidance, Navigation, and Control (GNC) subsystem, an Avionics subsystem, a Command and Data Processing (C&DH) subsystem, a Ground Communications subsystem, a Gyroscope Subsystem, an Inertial Management Unit (IMU) subsystem, a Mission Data Processing subsystem, a Radiation Sensor subsystem, a Positioning, Navigation, and Timing (PNT) subsystem, an Electrical Power System (EPS) control subsystem, or a Battery subsystem.

33. 1. A method of assembling a launch assembly, comprising: The method comprises: coupling an integrated ion thruster unit to a spacecraft, the integrated ion thruster unit including a unit housing including a thrust surface and a plurality of tiles exposed on the thrust surface and configured to eject ions in a thrust direction from an ionic liquid propellant stored within the unit housing; coupling a separation ring to the spacecraft; Including, the isolation ring is configured to couple to a payload adapter and selectively isolate the spacecraft from the payload adapter, the isolation ring extending from a first edge adjacent to the spacecraft to a second edge and defining an isolation ring opening through the isolation ring from the first edge to the second edge, and the unit housing extending into the isolation ring opening and extending substantially to a payload adapter side of the first edge.

34. 34. The method of claim 33, further comprising receiving a cross-sectional profile of the unit housing through the isolation ring opening.

35. 35. The method of claim 34, wherein the inside diameter of the isolation ring opening is within the range of 6 to 11 inches.

36. 35. The method of claim 34, wherein the inside diameter of the isolation ring opening is within the range of 11 to 16 inches.

37. 35. The method of claim 34, wherein the inside diameter of the isolation ring opening is within the range of 16 to 20 inches.

38. 35. The method of claim 34, wherein the inside diameter of the isolation ring opening is within the range of 20 to 26 inches.

39. 34. The method of claim 33, further comprising coupling the isolation ring to an adapter port of the payload adapter, the adapter port ring defining an adapter port in fluid communication with the isolation ring opening, and the unit housing extending into the adapter port.

40. 34. The method of claim 33, further comprising coupling the isolation ring such that the unit housing extends primarily to the payload adapter side of the first edge.

41. 34. The method of claim 33, further comprising coupling one or more reservoirs within the unit housing, the one or more reservoirs configured to contain the ionic liquid propellant used by the tile.

42. coupling one or more storage tanks within the unit housing, the storage tanks configured to store the ionic liquid propellant during a pre-operational phase of the spacecraft; coupling one or more valves between the one or more storage tanks and the one or more reservoirs, the valves configured to selectively couple the one or more storage tanks in fluid communication with the one or more reservoirs; 42. The method of claim 41, further comprising:

43. the integrated ion thruster unit further includes a propellant supply system depending from the thrust surface into the unit housing; the method further comprising housing at least one additional component region within the unit housing; The at least one additional component region: one or more aft add-on component regions aft of the propellant supply system relative to the thrust direction; one or more adjacent additional component regions located adjacent the propellant supply system relative to the thrust direction; 34. The method of claim 33, comprising one or both of:

44. 44. The method of claim 43, further comprising coupling one or more additional components into the at least one additional component area, wherein the one or more additional components comprise a first additional component selected from among a Guidance, Navigation, and Control (GNC) subsystem, an Avionics subsystem, a Command and Data Processing (C&DH) subsystem, a Ground Communications subsystem, a Gyroscope subsystem, an Inertial Management Unit (IMU) subsystem, a Mission Data Processing subsystem, a Radiation Sensor subsystem, a Positioning, Navigation, and Timing (PNT) subsystem, an Electrical Power System (EPS) Control subsystem, or a Battery subsystem.

45. 1. A method for retrofitting an integrated ion thruster unit onto a spacecraft, comprising: The method comprises: delivering the integrated ion thruster unit to an orbital rendezvous with the spacecraft, the integrated ion thruster unit including a unit housing including a thrust surface and a plurality of tiles exposed on the thrust surface and configured to eject ions in a thrust direction from an ionic liquid propellant stored within the unit housing; mechanically coupling the integrated ion thruster unit to the spacecraft in orbit; A method comprising:

46. 46. ​​The method of claim 45, wherein a portion of an isolation ring remains fixed to the spacecraft from initial deployment of the spacecraft, the method further comprising positioning the integrated ion thruster unit within an isolation ring opening defined by the portion of the isolation ring.

47. 47. The method of claim 46, wherein the inside diameter of the isolation ring opening is within the range of 6 to 11 inches.

48. 47. The method of claim 46, wherein the inside diameter of the isolation ring opening is within the range of 11 to 16 inches.

49. 47. The method of claim 46, wherein the inside diameter of the isolation ring opening is within the range of 16 to 20 inches.

50. 47. The method of claim 46, wherein the inside diameter of the isolation ring opening is within the range of 20 to 26 inches.

51. 47. The method of claim 46, further comprising coupling the integrated ion thruster unit to the portion of the isolation ring.

52. 46. ​​The method of claim 45, further comprising coupling one or more additional components to the spacecraft, wherein the one or more additional components are housed within at least one additional component region within the unit housing.

53. 53. The method of claim 52, wherein the one or more additional components comprise a first additional component selected from among a Guidance, Navigation, and Control (GNC) subsystem, an Avionics subsystem, a Command and Data Processing (C&DH) subsystem, a Gyroscope subsystem, an Inertial Management Unit (IMU) subsystem, a Mission Data Processing subsystem, a Radiation Sensor subsystem, a Positioning, Navigation, and Timing (PNT) subsystem, an Electrical Power System (EPS) Control subsystem, or a Battery subsystem.

54. 46. ​​The method of claim 45, further comprising coupling a ground communication system to the spacecraft, the ground communication system contained within the unit housing and configured to enable ground control of the integrated ion thruster unit.

55. 46. ​​The method of claim 45, wherein the spacecraft includes a lower performance original non-propulsion related subsystem, the method further comprising coupling a replacement subsystem to the spacecraft, the replacement subsystem contained within the unit housing and configured to replace the functionality of the original non-propulsion related subsystem.

56. 46. ​​The method of claim 45, further comprising coupling a new subsystem to the spacecraft, the new subsystem contained within the unit housing and configured to add new non-propulsion related capabilities to the spacecraft.

Images