Particle dispersion layer having persistent magnetic field

A spacecraft includes a body defining an interior payload region and a particle dispersion layer disposed between the interior payload region and one or more exterior surfaces of the body. The particle dispersion layer is formed of one or more magnets having a persistent magnetic field. The spacecraft including the particle dispersion layer may be manufactured by obtaining a particle dispersion layer having a persistent magnetic field, identifying a directionality of the persistent magnetic field of the particle dispersion layer, and installing the particle dispersion layer between an interior payload region formed by a body of a spacecraft and one or more exterior surfaces of the body according to the identified directionality of the persistent magnetic field.

FIELD

The invention relates generally to a particle dispersion layer protecting a payload of a spacecraft from external radiation sources.

BACKGROUND

Ionizing radiation produced by high-energy particles may cause a variety of issues in spacecraft electronics. Galactic cosmic rays (GCRs) are an example source of high-energy particles commonly encountered by spacecraft. Single-event effects (SEEs) may occur when a high-energy particle strikes a spacecraft and produces a shower of secondary particles that penetrate the spacecraft. This burst of secondary particles created from the high-energy particle may generate ions of sufficient quantity in a vicinity of an electronic component on-board the spacecraft to cause an SEE. SEEs may result in permanent damage or transient disruption of function of the electronic component. For example, a logic element of an electronic circuit may experience an SEE in the form of upset, latchup, gate rupture, or burnout.

One potential solution aimed at reducing the occurrence of SEEs is the use of mass shielding. This approach places thick and/or dense layers of material between the external radiation environment and an electronic circuit to be protected from SEEs. However, the inventor has recognized that mass shielding by its very nature relies on its mass to provide protection from SEEs, which if used on-board a spacecraft has the potential to significantly increase the total mass of the spacecraft.

Another potential solution aimed at reducing the occurrence of SEEs is the creation of an external magnetic field outside the spacecraft by an electromagnet. This external magnetic field has the potential to deflect at least some charged particles away from the spacecraft. However, the inventor has also recognized several disadvantages of this approach. For example, a magnetic field generator used to produce an external magnetic field can be heavy and consume significant power on-board the spacecraft during operation. Additionally, the inventor has further recognized that the magnetic field produced by the electromagnet may interfere with electronics or instruments on-board the spacecraft. Furthermore, the inventor has recognized that an external magnetic dipole produced by the electromagnet may interact with the magnetic field of another object, such as the magnetic field of Earth or other astronomical object to create torque on the spacecraft, which may negatively impact operation of the spacecraft. Further still, the inventor has also recognized that the external magnetic field generated by the electromagnet may not block or deflect neutral particles like gamma ray photons or charged particles of sufficiently high energy.

Yet another potential solution aimed at reducing the occurrence of SEEs on-board a spacecraft is the use of radiation hardened (rad-hard) electronics. This approach utilizes electronics that are less susceptible to ionizing radiation. The inventor has recognized a number of potential disadvantages of rad-hard electronics, including higher costs and lower performance for the same amount of power, mass, or semiconductor real estate as compared to electronic components not specifically designed to accommodate high-energy radiation environments.

SUMMARY

According to an example of the present disclosure, a spacecraft includes a body defining an interior payload region and a particle dispersion layer disposed between the interior payload region and one or more exterior surfaces of the body. The particle dispersion layer is formed of one or more magnets having a persistent magnetic field.

According to another example of the present disclosure, a method of manufacturing a spacecraft includes obtaining a particle dispersion layer having a persistent magnetic field, identifying a directionality of the persistent magnetic field of the particle dispersion layer, and installing the particle dispersion layer between an interior payload region formed by a body of a spacecraft and one or more exterior surfaces of the body according to the identified directionality of the persistent magnetic field.

According to another example of the present disclosure, a spacecraft includes a body defining an interior payload region, a particle dispersion layer disposed between the interior payload region and one or more exterior surfaces of the body, and a mass shielding layer disposed between the particle dispersion layer and the one or more exterior surfaces of the body. The particle dispersion layer is formed of multiple particle dispersion layer portions, in which each particle dispersion layer portion includes a sheet magnet producing a persistent magnetic field. The persistent magnetic field of each particle dispersion layer portion has a different directionality than each other particle dispersion layer portion along a midplane of the particle dispersion layer.

The features and techniques that have been discussed can be provided independently in various embodiments or may be combined in yet other embodiments, further details of which are described in further detail with reference to the following description and drawings.

DETAILED DESCRIPTION

A particle dispersion layer having a persistent magnetic field is disclosed, which may be used to reduce the likelihood or severity of SEE-based faults created in spacecraft electronics by ionizing radiation. Secondary particles produced by a high energy particle striking the spacecraft may be effectively distributed over a larger region as compared to the use of mass shielding due to the influence of the persistent magnetic field on the secondary particles. This influence by the persistent magnetic field varies with the secondary particle's charge, mass, and speed. For example, secondary particles exhibiting a charge experience a centripetal force within the persistent magnetic field that curves the path of the charged secondary particles, while the path of neutral particles is not curved by the magnetic field from an initial trajectory. Distributing secondary particles over a greater region as compared to mass shielding has the potential to reduce the harmful effects of ionizing radiation on spacecraft components, even if the same total energy is delivered by the secondary particles. The particle dispersion layer may be disposed between an exterior of the spacecraft and a payload to disperse the paths of the secondary particle through the spacecraft and reduce the density of ions created by the secondary particles near sensitive electronic components, thereby reducing the likelihood or severity of SEE.

As discussed briefly above, the inventor has recognized that mass and size limitations of spacecraft may place limits on the use of mass shielding, external magnetic shielding generated by electromagnets, or rad-hard electronics as techniques for reducing SEE risk. The disclosed particle dispersion layer may provide similar or increased dispersion of secondary particles as compared to many of these techniques, but with a lower mass and/or volume of material that is advantageous to spacecraft design and operation. Additionally, the disclosed particle dispersion layer does not rely on electrical power for its operation, as compared to external magnetic fields produced by electromagnets. Furthermore, the particle dispersion layer disclosed herein may be configured to maintain magnetic flux primarily within the particle dispersion layer, thereby reducing or eliminating magnetically-induced torque on the spacecraft or interference with spacecraft components as compared to external magnetic fields generated by electromagnets. The disclosed particle dispersion layer may also enable cheaper or more efficient electronic components to be used on-board a spacecraft as compared to rad-hard electronics.

FIG. 1depicts an example interaction of a particle100with a spacecraft110. Spacecraft110includes a body112defining an interior payload region114represented schematically inFIG. 1. Body112includes one or more exterior surfaces116, an example of which includes exterior surface116A. Spacecraft110may further include a mass shielding layer118, an example of which includes mass shielding layer portion118A. Mass shielding layer portion118A is disposed between exterior surface116A and payload region114. In at least some examples, exterior surface116A may form part of mass shielding layer portion118A. In another example, mass shielding layer118may be omitted.

Spacecraft110includes a particle dispersion layer120, an example of which includes particle dispersion layer portion120A. Particle dispersion layer portion120A is disposed between payload region114and exterior surface116A of body112. In examples where mass shielding layer portion118A is included in spacecraft110, particle dispersion layer portion120A may be disposed between payload region114and mass shielding layer portion118A. In at least some examples, particle dispersion layer120may additionally provide mass shielding as a primary mass shielding layer of the spacecraft, such as where mass shielding layer118is omitted. Some materials suitable for particle dispersion layer120may be of sufficient density to serve as a primary mass shielding layer, such as samarium cobalt, neodymium-iron-boron, Alnico, nickel, iron, cobalt-platinum, or ferrites, as examples.

Particle dispersion layer portion120A is formed of one or more magnets122having a persistent magnetic field124, which is represented schematically inFIG. 1by example magnetic field vector124A. As an example, particle dispersion layer120has a magnetic flux density within a range of 0.1 Tesla to 2.0 Tesla, and more specifically within a range of 0.4 Tesla to 1.3 Tesla. One or more magnets122of particle dispersion layer120may include one or more sheet magnets, as an example. Particle dispersion layer portion120A producing persistent magnetic field124may be referred to as a permanent magnet, in contrast to a magnetic field generated by an electromagnet through application of electrical current.

In the example depicted inFIG. 1, magnetic field vector124A produced by particle dispersion layer portion120A points orthogonally into the page. Magnetic field vector124A represents the direction of persistent magnetic field124as measured along a midplane126of particle dispersion layer portion120A. By orientating magnetic field vector124A along particle dispersion layer portion120A, the persistent magnetic field may be confined to the greatest extent to the particle dispersion layer in contrast to other magnetic shielding approaches that seek to externalize a magnetic field produced by an electromagnet outside of the spacecraft. However, persistent magnetic field124may include different directionality from that of magnetic field vector124A in other examples.

InFIG. 1, a particle100traveling along particle path102at a velocity “v” relative to spacecraft110strikes exterior surface116A of the spacecraft. Particle path102is initially colinear with an incident axis104. Particle100may travel through at least a portion of mass shielding layer portion118A where the particle may be broken into multiple secondary particles130. Secondary particles130may include one or more positively charged secondary particles, one or more negatively charged secondary particles, and/or one or more secondary particles having a neutral charge. Examples of secondary particles130include kaons, protons, and gamma rays, among other forms of secondary particles.

At least some of secondary particles130may be dispersed from incident axis104by interaction with mass shielding layer portion118A. Example particle paths140-148are depicted inFIG. 1for secondary particles130. A path of ions may be formed by secondary particles130travelling along particle paths140-148. A density of the ions produced by secondary particles130along a secondary cone formed by particle paths140-148may be much greater as compared to particle100. This increase in ion density from secondary particles130increases the likelihood of SEEs.

Secondary particles130passing through mass shielding layer portion118A may continue along their respective trajectories until striking particle dispersion layer portion120A. At least some of secondary particles130may be further dispersed from incident axis104and/or from each other by interaction with persistent magnetic field124produced by particle dispersion layer portion120A. Secondary particles130passing through particle dispersion layer portion120A may continue along their respective trajectories until striking a payload150located within payload region114.

Secondary particles130striking payload150may be distributed over a distance152along an external surface154of the payload, as measured orthogonally to incident axis104.FIG. 1further depicts an example distance156over which secondary particles130would have otherwise been distributed along external surface154in the absence of persistent magnetic field124produced by particle dispersion layer portion120A. Thus, the presence of persistent magnetic field124may increase a distance over which secondary particles130are distributed with respect to payload150.

Persistent magnetic field124produced by particle dispersion layer portion120A exerts a magnetic force on secondary particles130in the form of a centripetal force “Fc”. This centripetal force “Fc” on an individual secondary particle traveling through magnetic field124at a relative velocity “vrel” to the magnetic field may be represented by the following equation: Fc=(q) vrel×B, where “q” represents a charge of the secondary particle, “B” represents the magnetic field vector124A, and “x” represents the cross product of the relative velocity “vrel” and the magnetic field vector “B”.

In view of the above relationship between charge “q”, relative velocity “vrel” of the secondary particle in relation to the magnetic field, and magnetic field vector “B”, the centripetal force “Fc” on an individual secondary particle varies in direction based on a charge of the secondary particle. According to application of the right-hand rule, negatively charged secondary particles132of secondary particles130are deflected along a curved path in a first direction (toward the left-hand side ofFIG. 1) by magnetic field vector124A pointing into the page. Example particle paths140and142of negatively charged secondary particles132are depicted inFIG. 1. Positively charged secondary particles134of secondary particles130are deflected along a curved path in a second direction (toward the right-hand side ofFIG. 1) by magnetic field vector124A pointing into the page. Example particle paths146and148of positively charged secondary particles134are depicted inFIG. 1. Neutral secondary particle136of secondary particles130is not deflected by magnetic field vector124A, as depicted by example particle path144.

Ions of secondary particles130follow a curved trajectory in the presence of persistent magnetic field124that has a radius referred to as the gyroradius. The gyroradius “R” of a secondary particle may be represented by the following equation: R=(mion*vrel)/(q*B), where “mion” is the mass of the secondary particle (including relativistic effects). For example, for a 1 Giga electron-volt (GeV) kaon, which is a typical secondary particle from a GCR impact, mass “mion” is given by: mion=493.7 MeV rest mass+1 GeV kinetic energy=1.494 GeV×1.783×10−27kg/GeV=2.66×10−27kg. Continuing with this example, charge “q” is 1.6×10−19Coulomb (C), and relative velocity is approximately 0.9 c=2.7×108m/sec, where “c” is the speed of light. If the magnetic field intensity is 0.1 Tesla (T), the gyroradius R is given by: R=(2.66×10−27kg×2.7×108m/sec)/(1.6×10−19C×0.1 T)=44.9 meters.

If, for example, the kaon is in the magnetic field for a distance of only 1.0 millimeter, its path is bent by 10−3m/45 m=22.3 microradians. Assuming that two kaons are produced in an impact, one being positive, the other being negative, each traveling with 1.0 GeV of kinetic energy, and each kaon strikes an electronic circuit one centimeter beyond the magnetic particle dispersion layer, the path of each kaon will have deflected by 10−2m×22.3×10−6rad=223×10−9m (223 nm). Since the kaons have opposite charge, they deflect in opposite directions, so their separation when they reach the circuit is 2×223 nm=446 nm. This deflection may be sufficient to avoid a double strike by the kaons on an electronic gate or other electronic component.

FIG. 1further depicts example dimensions as measured along incident axis104. Mass shielding layer portion118A has a thickness160as measured along incident axis104. Thickness160of mass shielding layer118may be selected based on expected operating conditions of the spacecraft, but may be limited by weight and size limitations. In the example depicted inFIG. 1, midplane126of particle dispersion layer portion120A overlaying payload150is parallel to external surface154of the payload. Particle dispersion layer portion120A has a thickness162as measured along incident axis104. In an example, thickness162of particle dispersion layer120may be at least 0.3 millimeters and less than 2 centimeters. However, other suitable range for thickness162may be used depending on implementation.

In the example depicted inFIG. 1, mass shielding layer portion118A is spaced apart from particle dispersion layer portion120A by a distance164. In another example, mass shielding layer portion118A adjoins particle dispersion layer portion120A. Furthermore, in the example depicted inFIG. 1, particle dispersion layer portion120A is spaced apart from payload150by a distance166. Particle dispersion layer120may be separated from the payload by a free space on some or all sides of the payload. As an example, distance166may be 1.0 centimeter to increase a distribution of secondary particles130across distance152by approximately 446.0 nanometers, assuming based on the above example that secondary particles130have a kinetic energy of 1.0 GeV and the particle dispersion layer has a magnetic field of 0.1 Tesla. As another example, distance166may be scaled down to 1.0 millimeter to provide an increase in the distribution of secondary particles130across distance152of approximately 44.6 nanometers, which is sufficient to reduce SEE risk to logic gates having a size of approximately 14.0 nanometers. In another example, particle dispersion layer portion120A may adjoin payload150, such as where components sensitive to SEEs are located within an interior volume of payload150.

FIG. 2depicts an example spacecraft110A in the form of a communications satellite. Spacecraft110A is one example of previously described spacecraft110ofFIG. 1. Spacecraft110ofFIG. 1may take other forms, including a space vehicle transporting human passengers or other payloads, a sensor-based probe, or other space-based platform.

As previously described with reference toFIG. 1, spacecraft110A includes body112defining interior payload region114represented schematically inFIG. 1. Body112includes exterior surfaces116, examples of which include exterior surfaces116B,116C,116D, etc., surrounding payload region114. Payload150represented schematically inFIG. 2is located within a volume formed by payload region114. Additional components may be mounted to body112, including solar panels210and communications antennas220, as an example.

Spacecraft110A further includes mass shielding layer118, examples of which include mass shielding layer portions118B,118C,118D, etc. Mass shielding layer portions118B,118C, and118D are disposed between payload region114and exterior surfaces116B,116C, and116D, respectively. In this example, mass shielding layer118completely surrounds payload region114. However, in another example, mass shielding layer118may be provided on only some of the sides of the spacecraft. For example, inFIG. 2, solar panels210may be oriented towards a source of solar radiation230to gather energy, and mass shielding layer118may be provided on one or more sides of the spacecraft that are configured to face towards the source of solar radiation, such as example mass shielding layer118B. By contrast, communications antennas220may be orientated away from the source of solar radiation and towards a target object (e.g., Earth), and one or more sides of the spacecraft that are configured to face away from the source of solar radiation may omit the mass shielding layer.

Spacecraft110A further includes particle dispersion layer120, examples of which include particle dispersion layer portions120B,120C,120D, etc. Particle dispersion layer120is formed of one or more magnets having a persistent magnetic field, as previously described with reference toFIG. 1. Particle dispersion layer portions120B,120C, and120D are disposed between payload region114and exterior surfaces116B,116C, and116D, respectively. Particle dispersion layer120may span at least a portion of a three-dimensional projection of the volume formed by interior payload region114toward an outward-facing side of the one or more exterior surfaces116of body112. In this example, particle dispersion layer120forms a continuous layer that completely surrounds payload region114. However, in another example, particle dispersion layer120may be provided on only some of the sides of the spacecraft and may partially surround the interior payload region in three-dimensions, such as depicted with respect to particle dispersion layer portions120B,120C, and120D. For example, particle dispersion layer120may be provided on one or more sides of the spacecraft that are configured to face towards a source of solar radiation, such as example particle dispersion layer portion120B, and one or more sides of the spacecraft that are configured to face away from the source of solar radiation may omit the particle dispersion layer. In the example depicted inFIG. 2, particle dispersion layer120adjoins mass shielding layer118to form a combined mass shielding/magnetic shielding wall structure.

FIG. 3depicts an example distribution300of secondary particles130striking surface154of payload150in relation to incident axis104. Surface154of payload150is depicted in a plan view inFIG. 3as viewed along incident axis104in a direction of travel of particle100ofFIG. 1. Distribution300of secondary particles130is represented inFIG. 3by an intersection of particle paths140-148with surface154.

A coordinate system defined in relation to payload150is also depicted inFIG. 3, including a first axis310and a second axis312that is orthogonal to the first axis. In this example, incident axis104is orthogonal to both first axis310and second axis312. An example orientation of magnetic field vector124A of persistent magnetic field124produced by particle dispersion layer portion120A ofFIG. 1is depicted inFIG. 3in relation to first axis310and second axis312. In this example, magnetic field vector124A is orthogonal to first axis310and is parallel to second axis312. An axis that is orthogonal to magnetic field vector124A may be referred to as a primary dispersion axis320over which secondary particles130are distributed. In the example depicted inFIG. 3, primary dispersion axis320is parallel to first axis310.

Secondary particles130are distributed over distance152in a first dimension as measured along first axis310due to interaction with magnetic field vector124A. Secondary particles130may also be dispersed from incident axis104in a second dimension as measured along second axis312due to interaction with mass shielding layer118and/or particle dispersion layer120. In this example, secondary particles130are distributed over a distance330as measured along second axis312. Secondary particles130are distributed over a greater distance measured along primary dispersion axis320as represented by distance152than distance330measured along second axis312due to the influence of magnetic field vector124A.

FIG. 3further depicts an example region340within which secondary particles130would have otherwise been distributed in the absence of persistent magnetic field124having magnetic field vector124A. Distance156is depicted inFIG. 3corresponding to a width of region340along first axis310. Distance156in the absence of magnetic interaction is again depicted as being less than distance152in the presence of magnetic interaction with particle dispersion layer120. Distance330also corresponds to a width of region340, since dispersion of secondary particles130due to interaction with magnetic field vector124A is along primary dispersion axis320that is orthogonal to the magnetic field vector.

By changing a relative orientation between magnetic field vector124A and payload150, an orientation of primary dispersion axis320may be likewise changed.FIG. 4depicts an example distribution400of secondary particles130striking surface154of payload150in relation to incident axis104. In contrast to the example distribution300ofFIG. 3, magnetic field vector124A is orientated at an angle410measured relative to second axis312. Angle410in this example corresponds to an angle of 45 degrees in relation to second axis312. Primary dispersion axis320, which is defined as being orthogonal to magnetic field vector124A is orientated at an angle of 45 degrees relative to first axis310, in contrast to the example ofFIG. 3.

A payload, such as example payload150, may include one or more regions within which components of the payload are more sensitive to secondary particles130distributed along one primary dispersion axis than along another. For example, an electronic circuit may include at least one conductive channel and may have a shape of a rectangle that is many times longer along first axis310than along second axis312, which is a common configuration used in electronic circuit design. By way of example, a first and second dimension may be the length and width of a printed circuit board (PCB), a length and width of a microprocessor, other integrated circuit, or other electronic component mounted to such a PCB, etc. Electronic circuit designs commonly include many conductive channels that are aligned with either the first dimension or the second dimension, like lines in a rectangular grid. By reducing alignment of a primary dispersion axis with first axis310and with second axis312, the number of secondary particles striking close to a conductive channel from a single primary particle may be reduced. Within the context of electronic circuits, this configuration has the potential to reduce incidents of SEEs.

FIG. 5depicts the example distribution400of secondary particles130ofFIG. 4in relation to an electronic circuit500. Electronic circuit500is one example of payload150. In this example electronic circuit500includes conductive channels represented schematically at510and512inFIG. 5. Conductive channels510are orientated parallel to first axis310, and conductive channels512are orientated parallel to second axis312.

A region of an electronic circuit may be defined as having a grid orientation such that a majority of the conductive channels within the region of the electronic circuit is either parallel to or perpendicular to the grid orientation. For example, withinFIG. 5, a grid orientation of conductive channels may be parallel to first axis310because a majority of conductive channels510and512are parallel to or perpendicular to first axis310. A grid orientation has fourfold rotational symmetry, i.e., a grid orientation of 0° is equivalent to 90°, 180°, and 270°. Thus, a grid orientation parallel to first axis310also has a grid orientation parallel to second axis312.

In this example, magnetic field vector124A is again angled relative to first axis310and second axis312, as previously described with reference toFIG. 4. Accordingly, magnetic field vector124A residing within a midplane of particle dispersion layer120overlaying the region of electronic circuit500depicted inFIG. 5is orientated at an angle relative to the primary grid orientation corresponding to first axis310and second axis312. Further, in this example, both magnetic field vector124A and primary dispersion axis320are therefore angled relative to conductive channels510and512. Angle410is depicted in relation to second axis312, which is parallel to the grid orientation in this example. Angle410may, for example, be 20-70 degrees relative to the grid orientation. For example, angle410may be 45 degrees relative to the grid orientation to provide an equal angular misalignment between first axis310and second axis312of the grid orientation. By reducing alignment of magnetic field vector124A with conductive channels510and512, clustering of secondary particles130along conductive channels510and512in a dimension that is parallel to magnetic field vector124A is reduced.

FIG. 6depicts another example of particle dispersion layer120in a plan view. In this example, particle dispersion layer120includes multiple particle dispersion layer portions120E,120F,120G, and12011that collectively form a continuous particle dispersion layer.FIG. 7depicts particle dispersion layer ofFIG. 6in a section view through section620.

Particle dispersion layer portions120E,120F,120G, and12011each produce a persistent magnetic field having a different directionality as represented by magnetic field vectors124E,124F,124G, and12411, respectively. Magnetic field vectors124E,124F,124G, and12411each represent a respective directionality of the persistent magnetic field produced by particle dispersion layer portions120E,120F,120G, and12011at a midplane710of particle dispersion layer120, such as previously described with reference to midplane126ofFIG. 1.

Magnetic field vectors124E,124F,124G, and12411are angled relative to each other (e.g., 90 degrees) in a step-wise manner moving along particle dispersion layer portions120E,120F,120G, and12011in a clock-wise direction. Collectively, magnetic field vectors124E,124F,124G, and12411angled relative to each other in a step-wise manner to create a closed loop may increase confinement of the persistent magnetic fields to within particle dispersion layer120. This configuration has the potential to reduce magnetic interference with other components located on-board a spacecraft.

In this example, portion120E interfaces with portions120F,120G, and12011along boundaries610,612, and614, respectively. Portion120F interfaces with portions120E and120G along boundaries610and616, respectively. Portion120G interfaces with portions120E,120F, and120G along boundaries612,616, and618, respectively. Portion12011interfaces with portions120E and120G along boundaries614and618, respectively. Furthermore, in this example, boundaries610,614,616, and618are each angled (e.g., 45 degrees) relative to boundary612. Portions120E,120F,120G, and12011may originate from a common particle dispersion layer material having a common directionality of a persistent magnetic field. As an example, portions120E,120F,120G, and12011may be cut from the particle dispersion layer material (e.g., a sheet magnet) to a target size and shape based on the directionality of the persistent magnetic field to obtain multiple portions having their respective magnetic field orientations. For example, particle dispersion layer120may be formed from multiple sheet magnets corresponding to particle dispersion layer portions120E,120F,120G, and120H distributed across the particle dispersion layer. Two or more sheet magnets of the multiple sheet magnets corresponding to particle dispersion layer portions120E,120F,120G, and12011each have a magnetic field vector along midplane710of particle dispersion layer120that is angled relative to each of the other two or more sheet magnets.

FIG. 8schematically depicts additional aspects of spacecraft110ofFIG. 1in further detail. Spacecraft110includes body112defining interior payload region114. Spacecraft110includes particle dispersion layer120formed of a set of one or more magnets822having a persistent magnetic field. For example, the set of magnets822may include previously described magnets122ofFIG. 1, which produces persistent magnetic field124having previously described magnetic field vector124A.

Particle dispersion layer120is disposed between payload region114and one or more exterior surfaces116of body112. In an example, particle dispersion layer120may be mounted to or integrated with body112. Spacecraft110may include mass shielding layer118disposed between particle dispersion layer120and the one or more exterior surfaces116of body112. However, mass shielding layer118may be omitted in at least some examples.

Example payloads850are located within payload region114inFIG. 8, including an equipment enclosure852containing an electronic circuit854, and a human habitat856containing one or more human passengers858. Payloads850are examples of previously described payload150ofFIG. 1. Particle dispersion layer120produces persistent magnetic field124having a relative orientation810with respect to payloads850. As previously described with reference toFIGS. 3-5, relative orientation810may be selected, for example, to reduce alignment of a magnetic field vector produced by particle dispersion layer120with a primary orientation of sensitive components of payloads850, thereby reducing the density of secondary particle strikes along the sensitive components.

FIG. 9depicts a flow diagram of example operations900that may be performed with respect to manufacturing a spacecraft including a particle dispersion layer having a persistent magnetic field. Some or all of operations900may be performed as part of a method of manufacturing the spacecraft. The spacecraft manufactured by one or more of operations900may include any of the previously described spacecraft configurations disclosed herein, including spacecraft110ofFIG. 1, for example.

A particle dispersion layer material having a persistent magnetic field is obtained at910. Obtaining the particle dispersion layer material at910may include manufacturing the particle dispersion layer material at912. As part of manufacturing the particle dispersion layer material, the particle dispersion layer material may be magnetized at914to obtain a persistent magnetic field having a target directionality. As an example, a sheet of the particle dispersion layer material may be magnetized so that the persistent magnetic field has a target directionality that is within a plane of the sheet, such as previously described with reference to magnetic field vector124A orientated along midplane126ofFIG. 1. The particle dispersion layer material may be magnetized by applying a magnetic field to the particle dispersion layer, such via operation of an electromagnet. Examples of particle dispersion layer materials that may be suitable for magnetization include ferromagnetic materials that maintain a persistent magnetic field responsive to an applied magnetic field.

At920, a directionality of a persistent magnetic field of the particle dispersion layer material is identified. Operation920may be performed to confirm that the directionality of the persistent magnetic field of the particle dispersion layer material is within a threshold range of the target directionality. In an example, the magnetic field produced by the particle dispersion layer material may be measured using a multi-axis magnetic field sensor, enabling the directionality and/or strength of the magnetic field to be measured in two or three dimensions.

At930, the particle dispersion layer material may be cut to a target size and shape based on the identified directionality of the persistent magnetic field to obtain one or more particle dispersion layer portions. Each particle dispersion layer portion obtained by operation930may have a target directionality of the persistent magnetic field in relation to the shape of that portion.FIG. 2depicts an example of particle dispersion layer portions at120B,120C, and120D that may be produced by operation930.FIGS. 6 and 7depict another example of particle dispersion layer portions at120E,120F,120G, and12011that may be produced by operation930.

At940, two or more particle dispersion layer portions may be combined based on the directionality of the persistent magnetic field identified for each portion to obtain a particle dispersion layer. For example, as previously described with reference toFIGS. 6 and 7, multiple particle dispersion layer portions may be combined to provide a step-wise change in directionality among magnetic field vectors throughout the particle dispersion layer. Operation940may be omitted in some examples, such as where the particle dispersion layer is formed of an individual particle dispersion layer portion.

At950, a directionality of the persistent magnetic field of the particle dispersion layer may be identified. Operation950may be performed to confirm that the directionality of the persistent magnetic field of the particle dispersion layer is within a threshold range of a target directionality. The magnetic field produced by the particle dispersion layer may be measured, for example, using a multi-axis magnetic field sensor, enabling the directionality and/or strength of the magnetic field to be measured in two or three dimensions.

The spacecraft may be assembled at960, which may include one or more of operations962-968. At962, a body of the spacecraft is assembled to form an interior payload region. At964, a mass shielding layer may be installed between the payload region and one or more exterior surfaces of the body. Operation964may be omitted where a mass shielding layer is not included in the spacecraft. At966, the particle dispersion layer obtained at operation940or the particle dispersion layer portions obtained at operation930are installed between the payload region and the one or more exterior surfaces of the body to obtain an installed particle dispersion layer. In examples where a mass shielding layer is included in the spacecraft, the particle dispersion layer obtained at operation940or the particle dispersion layer portions obtained at operation930may be installed between the payload region and the mass shielding layer.

At968, a directionality of a persistent magnetic field of the installed particle dispersion layer may be identified. Operation968may be performed to confirm that the directionality of the persistent magnetic field of the installed particle dispersion layer is within a threshold range of a target directionality, particularly with respect to an intended orientation of payload components to be installed within the spacecraft. The magnetic field produced by the particle dispersion layer may be measured, for example, using a multi-axis magnetic field sensor, enabling the directionality and/or strength of the magnetic field to be measured in two or three dimensions. In some examples, magnetization of the particle dispersion layer material previously described at operation914may be performed following installation at operation966. For example, operation960may additionally include magnetizing the particle dispersion layer installed in the spacecraft to obtain the persistent magnetic field having a target directionality.

At970, a payload is installed within the payload region at a relative orientation that is based on the identified directionality of the persistent magnetic field of the installed particle dispersion layer. At980, the spacecraft may be launched carrying the payload.

Examples of the subject matter of the present disclosure are described in the following enumerated paragraphs.

A1. A spacecraft, comprising: a body defining an interior payload region; and a particle dispersion layer formed of one or more magnets having a persistent magnetic field, the particle dispersion layer disposed between the interior payload region and one or more exterior surfaces of the body.

A2. The spacecraft of paragraph A1, wherein the interior payload region forms a volume; and wherein the particle dispersion layer spans at least a portion of a three-dimensional projection of the volume toward an outward-facing side of the one or more exterior surfaces of the body.

A3. The spacecraft of any of paragraphs A1-A3, wherein the particle dispersion layer forms a continuous layer that at least partially surrounds the interior payload region in three-dimensions.

A4. The spacecraft of any of paragraphs A1-A3, further comprising: the payload located within the interior payload region; and wherein the particle dispersion layer is mounted to or integrated with the body.

A5. The spacecraft of paragraph A4, wherein the particle dispersion layer is separated from the payload by a free space that has a thickness of at least 1 millimeter as measured between the payload and the particle dispersion layer.

A6. The spacecraft of paragraph A4, wherein the payload includes an electronic circuit.

A7. The spacecraft of paragraph A6, wherein a region of the electronic circuit has a grid orientation of electronic components defined by an orientation of a majority of the electronic components within the region of the electronic circuit; and wherein a magnetic field vector of the particle dispersion layer within a midplane of the particle dispersion layer overlaying the region of the electronic circuit is orientated at an angle relative to the grid orientation.

A8. The spacecraft of paragraph A4, wherein the interior payload region includes a human habitat.

A9. The spacecraft of any of paragraphs A1-A8, wherein the particle dispersion layer additionally provides mass shielding as a primary mass shielding layer of the spacecraft; and wherein the particle dispersion layer has a thickness of at least 0.3 millimeters and less than 2 centimeters.

A10. The spacecraft of any of paragraphs A1-A9, further comprising: a mass shielding layer disposed between the particle dispersion layer and the one or more exterior surfaces of the body.

A11. The spacecraft of any of paragraphs A1-A10, wherein the particle dispersion layer has a magnetic field vector residing within the particle dispersion layer along a midplane of the particle dispersion layer.

A12. The spacecraft of any of paragraphs A1-A11, wherein the one or more magnets include multiple sheet magnets; wherein the particle dispersion layer is formed from the multiple sheet magnets distributed across the particle dispersion layer; and wherein two or more sheet magnets of the multiple sheet magnets each have a magnetic field vector along a midplane of the particle dispersion layer that is angled within the midplane relative to each of the other two or more sheet magnets.

A13. The spacecraft of any of paragraphs A1-A12, wherein the particle dispersion layer has a magnetic flux density within a range of 0.4 Tesla to 1.3 Tesla.

B1. A method of manufacturing a spacecraft, the method comprising: obtaining a particle dispersion layer having a persistent magnetic field; identifying a directionality of the persistent magnetic field of the particle dispersion layer; and installing the particle dispersion layer between an interior payload region formed by a body of a spacecraft and one or more exterior surfaces of the body according to the identified directionality of the persistent magnetic field.

B2. The method of paragraph B1, further comprising: installing a payload within the interior payload region at a relative orientation to the particle dispersion layer that is based on the identified directionality of the persistent magnetic field installed within the spacecraft.

B3. The method of any of paragraphs B1-B2, further comprising: obtaining a particle dispersion layer material having the persistent magnetic field; identifying a directionality of the persistent magnetic field of the particle dispersion layer material; and cutting the particle dispersion layer material to a target size and shape based on the identified directionality of the persistent magnetic field material to obtain the particle dispersion layer.

B4. The method of paragraph B3, further comprising: magnetizing the particle dispersion layer material to obtain the persistent magnetic field having a target directionality prior to cutting the particle dispersion layer material.

B5. The method of any of paragraphs B1-B2, wherein the identified directionality of the persistent magnetic field includes a target directionality; and wherein the method further comprises magnetizing the particle dispersion layer installed in the spacecraft to obtain the persistent magnetic field having the target directionality.

C1. A spacecraft, comprising: a body defining an interior payload region; a particle dispersion layer disposed between the interior payload region and one or more exterior surfaces of the body, the particle dispersion layer formed of multiple particle dispersion layer portions, each particle dispersion layer portion including a sheet magnet producing a persistent magnetic field, the persistent magnetic field of each particle dispersion layer portion having a different directionality than each other particle dispersion layer portion along a midplane of the particle dispersion layer; and a mass shielding layer disposed between the particle dispersion layer and the one or more exterior surfaces of the body.

C2. The spacecraft of paragraph C1, wherein the particle dispersion layer forms a continuous layer that spans a three-dimensional projection of a volume of the payload region toward an outward-facing side of the one or more exterior surfaces of the body.

The present disclosure includes all novel and non-obvious combinations and subcombinations of the various features and techniques disclosed herein. The various features and techniques disclosed herein are not necessarily required of all examples of the present disclosure. Furthermore, the various features and techniques disclosed herein may define patentable subject matter apart from the disclosed examples, and may find utility in other implementations not expressly disclosed herein.