Articulating Radiator System

An Application Data Sheet (ADS) is filed concurrently with this specification as part of the present application. Each application that the present application claims benefit of or priority to as identified in the concurrently filed Application Data Sheet is incorporated by reference herein in its entirety and for all purposes.

Thermal management of systems and apparatuses in non-terrestrial environments, such as space and lunar environments, pose unique and diverse challenges. Temperatures can range between 18 Kelvin (K) and 393 K, and maintaining equipment, such as spacecraft or satellites, within a desired operational temperature range can be challenging in the non-terrestrial environments. Traditional thermal management methods and control systems may be nonviable in these non-terrestrial environments. Further, in some non-terrestrial environments, equipment may be exposed to dust, debris, or other particles that can damage or reduce functionality of the equipment. For instance, Moon dust can accumulate on and infiltrate equipment on the lunar surface. It is desirable to control equipment temperatures in non-terrestrial environments to within the desired operating temperature range.

Details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims. The following, non-limiting implementations are considered part of the disclosure; other implementations will be evident from the entirety of this disclosure and the accompanying drawings as well.

In some embodiments, a radiation system may be provided. The radiator system may include a housing having a support structure, one or more stationary panels connected to the support structure and having insulation, and an internal volume at least partially defined by the one or more stationary panels, by a first opening, and by a second opening, a plurality of articulating radiator panels, in which each articulating radiator panel is movably connected to the support structure, has an inner surface with one or more coolant channels and/or one or more heat pipes, has an exterior surface opposite the inner surface, and has insulation, and a movement mechanism connected to the support structure and the plurality of articulating radiator panels, and configured to move each of the articulating radiator panels with respect to the support structure. A first articulating radiator panel may be positioned adjacent to the first opening, the first articulating radiator panel may be configured to be positioned in a first open position and a first closed position, in the first closed position, the first articulating radiator panel may cover the first opening, faces the interior volume, and may be configured to thermally insulate the interior volume at the first opening, in the first open position, the first articulating radiator panel may not cover the first opening, the one or more coolant channels and/or one or more heat pipes of the first articulating radiator panel may be configured to radiate heat into the environment outside the housing, and the internal volume may be exposed to the environment outside the housing through the first opening, a second articulating radiator panel may be positioned adjacent to the second opening, the second articulating radiator panel may be configured to be positioned in a second open position and a second closed position, in the second closed position, the second articulating radiator panel may cover the second opening, may face the interior volume, and may be configured to thermally insulate the interior volume at the second opening, and in the second open position, the second articulating radiator panel may not cover the second opening, the one or more coolant channels and/or one or more heat pipes of the second articulating radiator panel may be configured to reject heat into the environment outside the housing, and the internal volume may be exposed to the environment outside the housing through the second opening.

In some embodiments, in the first closed position, the one or more coolant channels and/or one or more heat pipes of the first articulating radiator panel may be configured to radiate heat into the interior volume, and in the second closed position, the one or more coolant channels and/or one or more heat pipes of the second articulating radiator panel may be configured to radiate heat into the interior volume.

In some of the above embodiments, in the first closed position, the first articulating radiator panel may be configured to reduce thermal energy in the internal volume from exiting through the first opening, and in the second closed position, the second articulating radiator panel may be configured to reduce thermal energy in the internal volume from exiting through the second opening.

In some embodiments, in the first open position, the housing may be configured such that thermal energy is configured to exit through the first opening to the environment outside the housing, and in the second open position, the housing may be configured such that thermal energy is configured to exit through the second opening to the environment outside the housing.

In some of the above embodiments, the movement mechanism may be configured to move the first articulating radiator panel and the second articulating radiator panel at the same time.

In some of the above embodiments, the movement mechanism may be configured to move the first articulating radiator panel independently of the second articulating radiator panel.

In some of the above embodiments, the first articulating radiator panel may be configured to move between the first open position and the first closed position by rotating about a first axis by about 130 degrees.

In some of the above embodiments, the second articulating radiator panel may be configured to move between the second open position and the second closed position by rotating about a second axis by about 60 degrees.

In some of the above embodiments, the first articulating radiator panel may be configured to be positioned by the movement mechanism in a plurality of partially open first positions, and the second articulating radiator panel may be configured to be positioned by the movement mechanism in a plurality of partially open second positions.

In some of the above embodiments, when the first articulating radiator panel is in the first closed position and the second articulating radiator panel is in the second closed position, the interior volume may be insulated such that less than 10% of heat loss occurs between the interior volume and the environment outside housing.

In some embodiments, the system may further include one or more second coolant channels and/or one or more second heat pipes positioned in the interior volume. In the first open position, the one or more second coolant channels and/or one or more second heat pipes may be configured to radiate heat into the environment outside the housing through the first opening, and in the second open position, the one or more second coolant channels and/or one or more second heat pipes may be configured to radiate heat into the environment outside the housing through the second opening.

In some such embodiments, the system may further include a module positioned in the interior volume. The module may have a radiative external surface configured to radiate heat into the interior volume, the one or more second coolant channels and/or one or more second heat pipes may be in contact with the radiative external surface of the module, in the first open position, the module may be configured to radiate heat into the environment outside the housing through the first opening, and in the second open position, the module may be configured to radiate heat into the environment outside the housing through the second opening.

In some of the above embodiments, the first articulating radiator panel may be configured to rotate back and forth between a first partially open position and a second partially open position, and the second articulating radiator panel may be configured to rotate back and forth between a third partially open position and a fourth partially open position.

In some such embodiments, the rotating back and forth by the first articulating radiator panel and the second articulating radiator panel may be configured to shake off dust and debris.

In some of the above embodiments, the movement mechanism may include one or more shape memory alloys.

In some of the above embodiments, the inner surface of each articulating radiator panel may have the one or more coolant channels.

In some of the above embodiments, the inner surface of each articulating radiator panel may have the one or more heat pipes.

In some of the above embodiments, in the first closed position, the first articulating radiator panel may be configured to cover and seal the first opening and thereby reduce the ingress of dust or debris through the first opening, and in the second closed position, the second articulating radiator panel may be configured to cover and seal the second opening and thereby reduce the ingress of dust or debris through the second opening.

Like reference numbers and designations in the various drawings indicate like elements.

Non-terrestrial planetary and solar system body surfaces pose unique and challenging thermal, debris, and dust environments that make traditional thermal management methods and control systems nonviable. For most equipment used in non-terrestrial environments, it is desirable that the equipment be able to operate for long periods of time (e.g., years) and continuously for long durations (e.g., months or years). To operate properly in non-terrestrial environments, such as space or the Moon, some equipment requires thermal and/or dust management systems that are capable of withstanding thermal ranges of non-terrestrial environments, such as between 18 K and 393 K or higher, as well as surface operations having dust and other debris that can damage or impair functionality of the equipment. It also desirable to provide thermal and/or dust management that allows for the equipment to maintain its desired functional and performance capabilities, including with minimal to no use of consumables or human interaction.

In some space or lunar operations, some equipment will be positioned in and between shadowed and sunlit areas. For example, some regions of the Moon have permanently shadowed regions (PSRs) which are always in shadow. The temperature within these regions can be as low as 18 K, for example. Whereas in some areas exposed to solar radiation (e.g., sunlit areas), the temperature can be as high as 393 K. In a further example, some lunar missions may begin in a sunlit area, enter a PSR, and then exit the PSR to a sunlit area. Further, some equipment traversing the lunar surface can be exposed to lunar dust which can damage or reduce functionality of the equipment. To withstand operating in such non-terrestrial environments, it is desirable to have heat rejection turndowns that are up to 25:1, 50:1, or 100:1, or that range from 100:1 to 400:1. Provided herein are novel apparatuses and techniques for thermal management and/or dust management in various environments, such as non-terrestrial, lunar, and space.

A radiator system with articulating radiator panels is provided herein. The movable radiator panels are capable of varying the overall radiation view factor to provide variable heat rejection rates and high thermal turndown rates. In some embodiments, a subset of the movable radiator panels can be selectively adjusted to provide for multiple view factors in order to reject heat in one direction while protecting the internal environment of the system from solar radiation or dust/debris in another direction. The movable radiator panels are also configured to expand the effective radiator surface area beyond a traditional radiator of the same form factor. In other words, the movability of the radiator panels increases or expands the total radiator area. When in a closed position, the movable radiator panels can both thermally insulate hardware and equipment inside the system and protect the system from dust and debris intrusion. In some instances, dust or debris that can accumulate on the surfaces of the radiator system can be shaken off by movement of the radiator panels.

depicts an off-angle view of a radiator system according to various embodiments. The radiator systemhas a housingthat has a support structureand two stationary panelsA andB that are connected to the support structure. These stationary panelsA andB are configured to remain in position and not move, in contrast to the articulating radiator panels described below. The housinghas an interior volumethat is at least partially defined by the support structureand two stationary panelsA andB. This interior volumeis encompassed by the dashed and lightly shaded shape. The interior volumeis configured to receive and hold a payload, such as equipment or modules. For example, a cold trap tank for collecting water can be positioned inside the interior volume.

As provided herein, the radiator systemis configured to partially and fully thermally insulate the interior volume, as well as reject heat at various form factors, including form factors greater than the surface area of interior volumeitself. For example, as provided herein, the movability of the articulating radiator panels increases or expands the total radiator area. The radiator systemis configured to provide a turndown of up to 25:1, 50:1, or 100:1, or between 100:1 and 400:1, as provided herein. In some such embodiments, the stationary panelsA andB, and the articulating radiator panels, have insulation that is configured to thermally insulate the interior volume, including rejecting heat external to the housingand retaining heat inside the housing. The radiator system is also configured to provide very low heat rejection in a closed configuration, such as less than 10%, 5%, or 1% of heat loss to an external environment. This includes maintaining such low heat rejection when exposed to external temperatures ranging from 18 K to over 300 K.

The radiator systemalso has a plurality of articulating radiator panelsA-D. Each articulating radiator panelA-D has an inner surface having a plurality of coolant channels that are configured to flow a coolant fluid therein and to reject heat. In some embodiments there may be only one coolant channel and in other embodiments there may be other means of delivering heat to each articulating radiator panel for rejection via radiation, such as a thermally conductive pathways via thermal contact with non-fluid materials, or other means. For instance, each articulating radiator panel may have one or more heat pipes that are configured to transfer heat from inside the interior volumeto the panel. Some heat pipes are heat transfer devices that use phase transition to transfer heat between two solid surfaces. Each heat pipe may have a hot interface where a volatile liquid is in contact with a thermally conductive surface that is caused to turn into a vapor by absorbing heat from that surface. The vapor may travel along the heat pipe to a cold interface of the heat pipe where the vapor condenses back into a liquid and thereby releasing latent heat. The liquid may return to the hot interface by capillary action, centrifugal force, or gravity. In some instances, the condensed liquid returns to the evaporator by a wick that exerts a capillary action on the liquid phase of the fluid. This cycle may be repeated. In some embodiments, one or more coolant channels and one or more heat pipes may be used.

As illustrated in, articulating radiator panelA has a first surfaceA, e.g., an inner surface, with a first plurality of coolant channelsA, and articulating radiator panelB has a second surfaceB, e.g., another inner surface, with a second plurality of coolant channelsB. In some other embodiments, one or more of itemsmay be a heat pipe instead of a coolant channel. Each articulating radiator panelA-D is configured to be moved into a plurality of positions with respect to the housingand/or support structure. In some embodiments, these positions include a closed position and various open positions. In some embodiments, when in such open positions, heat can be rejected by the coolant channels of each articulating radiator panel, heat may be rejected from the interior volumeto the environment outside the housing, heat may be transferred to the coolant channels of an open articulating radiator panel from the environment outside the housing, and/or heat may be transferred to the interior volumefrom the environment outside the housing.

Each articulating radiator panelA-D may also have insulation configured to act as a thermal barrier for the inner surface. In some instances, the insulation is installed on a backside of the articulating radiator panel and serve as the exterior surface of the panel. In some embodiments, the exterior surface or surfaces of the articulating radiator panels may be configured with emissivity properties configured to reflect or reject heat or solar radiation incident of the surfaces. For example, when in a closed position, each articulating panel may provide thermal insulation to a portion of the interior volume. In another example, the exterior surface of each articulating panel may reject heat or radiation from a source external to the housing, such as the Sun.depicts the radiator system ofin a closed configuration according to various embodiments. Here, each articulating radiator panelA-D is in a closed position or closed configuration. Each articulating radiator panel has an exterior surface, one of which is visible for articulating radiator panelA and labeled asA. As noted, the articulating radiator panels may have insulation which may be an external surface of the articulating radiator panel, or the insulation may be arranged such that it provides a thermal barrier or thermal break is provided between the interior and exterior surfaces of each articulating radiator panel.

This exterior surfaceA may also be configured to have a low emissivity. This low emissivity may an effective emittance (e*) of about 0.05 or 0.02, for example. In some embodiments, the interior surface of the articulating radiator panels may have a high emissivity surface. This may include an emissivity of about 0.9, for example. By having high emissivity, the interior surfaces effectively radiate heat.

As further seen in, the interior volumeis enclosed by at least the articulating radiator panelsA-D and the stationary panelsA andB. This enclosure by these components may provide thermal insulation for the interior volumesuch that less than 20%, 15%, 10%, 5%, or 1% of heat loss may occur between the interior volumeand the environment outside the housing. This thermal insulation of the interior volumemay be from the insulation and from the emissivity of the articulating radiator panelsA-D and the stationary panelsA andB.

In some embodiments, the housingmay have one or more openings through which thermal heat can enter or exit the interior volume.depicts a side view of the radiator system ofanddepicts the off-angle view of. Here in, the housinghas a first openingA and a second openingB adjacent to the first openingA. Each boundary of an opening is illustrated with a dash-dot-dot boundary line and the first openingA has dark shading while the second openingB has light shading. The first openingA is also marked in. In some instances, like in, at least two openings may not be separated by a physical barrier or boundary. Each articulating radiator panel is adjacent to a corresponding opening of the housing. In some embodiments, each articulating radiator panel is configured to cover or fill the corresponding opening when in a closed position. In some instances, each articulating radiator panel is configured to partially cover or partially fill the corresponding opening when in a partially open, not fully open, position. When in a closed and some partially open configurations, an articulating radiator panel may face the interior volumeand its inner surface, like surfaceA, may reflect heat from the interior volumeback into interior volume.

For example, in, articulating radiator panelA is adjacent to the first openingA and articulating radiator panelB is adjacent to the second openingB. When the articulating radiator panelA is in the closed position as illustrated in, articulating radiator panelA covers and fills the first openingA, and thermally insulates the interior volumeat this first opening. Further, when the articulating radiator panelB is in the closed position as illustrated in, articulating radiator panelB covers and fills the second openingB, and thermally insulates the interior volumeat this second opening.

When an articulating radiator panel is in a partially open or fully open position, the interior volume is thermally connected to the environment outside the housing such that heat can be exchanged between the interior volume and exterior environment. The more open the articulating radiator panel is with respect to the corresponding opening, the more thermal connection occurs. In these partially open or fully open positions, heat can also be rejected or absorbed by the coolant channels on each articulating radiator panel, in some embodiments. The positioning of the articulating radiator panels is therefore capable of changing the view factor of the radiator system and providing for large turndowns.

depict side views of the reactor system ofin various configurations, according to disclosed embodiments. In, the four articulating radiator panelsA-D are in fully open positions. The first and second openingsA andB are represented by dash-dot-dot lines and as can be seen, they are fully uncovered by the corresponding articulating radiator panelsA andB, respectively. A third openingC corresponding to articulating radiator panelC and a fourth openingD corresponding to articulating radiator panelD are also shown as dash-dot-dot lines similar to the other openings. Here, the interior volume (not labeled) is in thermal communication with the environment outside the housingthrough all four openingsA-D such that heat can be exchanged with the external environment through all four openings. Further, heat can also be exchanged between the coolant channels of all four articulating radiator panelsA-D and the external environment. As illustrated, the view factor of the radiator systemmay therefore include the coolant channels of all four articulating radiator panelsA-D as well as all four openingsA-D of the housing. As also illustrated, the view factor of the radiator systemin this position ofis greater than the view factor of the radiator system in the closed position.

In some embodiments, a payload or module positioned inside the internal volume may also have one or more coolant channels. To provide thermal management and control of the payload or module, heat may be exchanged using the coolant channels of the payload/module, using the coolant channels of the articulating radiator panels, or both. Using both the coolant channels of the payload/module and the coolant channels of the articulating radiator panels can provide thermal management of the payload/module and the interior volume with a high turndown, such as up to 25:1, 50:1, or 100:1, or range between 100:1 and 400:1. For example, when the articulating radiator panels are in the fully open positions of, the form factor of the radiator system is larger than it would be if the articulating radiator panels were stationary in the closed position, e.g., of.

depicts the radiator system ofhaving a payload in the interior volume, according to disclosed embodiments. Here, a payloadis positioned inside the interior volumeof the housing. In some embodiments, additional coolant channels may be positioned inside the internal volume, such as on the payload itself to provide for thermal management of the payload. In this illustration, payloadhas a plurality of coolant channelsas represented by box. These coolant channelsmay be positioned internal to the payload, in the exterior walls of the payload, or on the exterior surface of the payload. These coolant channelsare configured to exchange heat with, e.g., reject heat to, the environment external to the housing, depending on the position of the articulating radiator panels.

In, the four articulating radiator panelsA-D are in a partially open position. Here, the four panels are less open than inand the interior volume (not labeled) is in thermal communication with the environment outside the housingthrough all four openingsA-D such that heat can be exchanged with the external environment through all four openings, but to a lesser degree or amount than in. Further, heat can also be exchanged between the coolant channels of all four articulating radiator panelsA-D and the external environment, but again less so than in. These partially open positions still provide for thermal exchange with the external environment through the interior volume and coolant channels of the articulating panels, but less so than in a fully open position. These partially open positions also provide for adjusting the amount of heat exchanged with, e.g., rejected to, the external environment. In some instances, in partially open positions some heat from the interior volume or the articulating radiator panels may be exchanged with the external environment and some heat may be reflected back into the interior volume by the articulating radiator panels.

In, two articulating radiator panels are fully open while other articulating radiator panels are closed. Here, articulating radiator panelsA andB are in their fully open positions, while articulating radiator panelsC andD are closed. The interior volume is still in thermal communication with the external environment through openingsA andB, but not through openingsC andD. In some embodiments, some such configurations may advantageously insulate the interior volume. For example, if solar radiation is striking the side of the housingwith the articulating radiator panelsC andD, this solar radiation can be blocked or reflected by positioning these panels in their closed positions to prevent the solar radiation from heating the interior volume. Concurrently, the opening of the other two articulating radiator panelsA andB allows for thermal exchange, e.g., cooling, of the interior volume to the external environment without the solar radiation via thermal exchange using the articulating radiator panelsA andB, coolant channels in the interior volume, or both.

The radiator system herein may provide an overall effective view to space (i.e., to the environment outside the housing) for the interior volume. When all articulating radiator panels are in the closed position, like in, the effective view to space is zero. As the articulating radiator panels open from their closed position, the collective view to space increases. For example, in the fully open position of, the collective view to space may be 100%. In the partially open position of, the collective view to space may be less, such as 40%.

Some additional or alternative features of the articulating radiator panels will now be discussed. In some implementations, each articulating radiator panel is configured to move or rotate about an axis, such as at a hinge joint. Given this rotational movement, the coolant channels may have various fluidic connections to a reservoir of the system having the coolant fluid. For example, flexible hoses may be used to fluidically connect each articulating radiator panel to the reservoir. These flexible hoses may be made of a stainless-steel braid. In another example, a rotary union may be used in which a stationary inlet permits fluid to flow from a stationary inlet to a rotating output.

The articulating radiator panels may be rotatable to different degrees. For example, the upper articulating radiator panelsA andC may be configured to rotate about an axis, respectively, by at least 90 degrees, 100 degrees, 115 degrees, 130 degrees, 145 degrees, 165 degrees, 180 degrees, 200 degrees, or 240 degrees, for example. In another example, the lower articulating radiator panelsB andD may be configured to rotate about an axis, respectively, by at least 45 degrees, 60 degrees, 75 degrees, 90 degrees, and 100 degrees, for instance.

In some embodiments, the movement mechanism may be configured to move two or more articulating radiator panels at the same time using one actuation driver or mechanism. This can advantageously save weight and cost by using only one actuation driver, e.g., a motor or piston, to actuate multiple panels instead of one actuation driver per panel.depict side views of a movement mechanism and articulating panels in two configurations. In, the radiator system has articulating radiator panelsA andC in the closed position. The movement mechanismincludes a single actuator, a first linkdirectly connected at its middle to the actuator, a second linkconnected to one end of the first linkand to the articulating radiator panelA, and a third linkconnected to the other end of the first linkand to the articulating radiator panelC. Each articulating radiator panelA andC has a separate hinge pointA andC, respectively, separate from the connection point to the corresponding link. As the actuatormoves upwards, the articulating radiator panelsA andC are simultaneously pushed upwards by the second and third linksandand caused to rotate simultaneously about their hinge pointsA andC, as shown in.

In some embodiments, the movement mechanism may be configured to move four articulating radiator panels at the same time.depicts a side view of another radiator system with another movement mechanism. This systemincludes the four articulating radiator panelsA-D that can be moved simultaneously using one actuator of the movement mechanism. In this embodiment, the movement mechanism has an actuatorthat moves a first linkvertically, or in a direction parallel to axis. The first linkis slidably connected at a first endA to a first slotted linkA at a first connection pointA, and connected at a second endB to a second slotted linkB at a second connection pointB. The first slotted linkA is rotatably connected to a frameat a rotation pointA that remains stationary with respect to the links and panels. A second linkA is slidably and rotatably connected at the first connection pointA to the first linkand to the first slotted linkA. The second linkA is also rotatably connected to a first articulating radiator panelA at a rotation pointA, and the first articulating radiator panelA is rotatably connected to a rotation pointA on a framewhich may have a payloadadjacent to it.

A third linkB is slidably and rotatably connected at the second connection pointB to the first linkand to the second slotted linkB. The second slotted linkB is rotatably connected to the frameat a rotation pointB that remains stationary with respect to the links and panels. The third linkB is also rotatably connected to a third articulating radiator panelC at a rotation pointB, and the third articulating radiator panelB is rotatably connected to a rotation pointB on the frame. As the first linkmoves in the direction parallel to axis, the first slotted linkA rotates about its rotation pointA and the connection pointA slides within the slotA of the first slotted linkA which causes the second linkA to move the first articulating radiator panelA about the rotation pointA. Similarly, as the first linkmoves in the direction parallel to axis, the second slotted linkB rotates about its rotation pointB and the connection pointB slides within the slotB of the second slotted linkB which causes the third linkB to move the third articulating radiator panelB about the rotation pointB.

The rotations of the first slotted linkA and the second slotted linkB also cause two other articulating radiator panels to rotate. A fourth linkA is rotatably connected at a rotation pointA to an end of the first slotted linkA and connected at a rotation pointA to a second articulating radiator panelB. The second articulating radiator panelB is rotatably connected to the frameat a rotation pointA. A fifth linkB is rotatably connected at a rotation pointB to an end of the second slotted linkB and connected at a rotation pointB to a fourth articulating radiator panelD. The fourth articulating radiator panelD is rotatably connected to the frameat a rotation pointB. As the first linkmoves in the direction parallel to axis, the first slotted linkA rotates about its rotation pointA and the connection pointA with the fourth slotted linkA causes the fourth linkA to move the third articulating radiator panelC about the rotation pointA. Similarly, at the same time, as the first linkmoves in the direction parallel to axis, the second slotted linkB rotates about its rotation pointB and the connection pointB with the fifth slotted linkB causes the fifth linkB to move the fourth articulating radiator panelD about the rotation pointB. The movement of the first linkis configured to cause movement of all four of the articulating radiator panelsA-D to move with respect to the frame.

In some other embodiments, the movement mechanism may be configured to move at least one articulating radiator panel independently from another articulating radiator panel. This may include different motors or actuators for each panel.

In some embodiments, the movement mechanism may have one or more actuation mechanisms that are shape memory alloys. The shape memory alloys may be configured to be in one position, e.g., a deformed position, to retain at least one articulating radiator panel in one position, such as a first position or a closed position. When heated to higher temperature, the shape memory alloy is configured to move to another position, e.g., a pre-deformed or remembered position, and thereby move the articulating radiator panel to a second position, such as a partially or fully opened configuration. In some embodiments, the movement mechanism may have multiple shape memory alloys that are configured to move an articulating radiator panel to multiple positions as the shape memory alloys increase in temperature. For example, the movement mechanism may have two different shape memory alloys configured to move one articulating radiator panel. At a first temperature, both shape memory alloys are in their deformed position such that the articulating radiator panel is in a closed position. At a second higher temperature, one shape memory alloy changes to its pre-deformed shape which in turn causes the articulating radiator panel to move to a partially open position while the second shape memory alloy remains deformed. At a third temperature higher than the first and second temperatures, the second shape memory alloy changes to its pre-deformed shape which in turn causes the articulating radiator panel to move to a different partially open, or fully open, position.

The embodiments provided herein are also configured to prevent or reduce dust or debris from entering the interior volume and affecting the functionality of radiator panels. For example, when one or more of the articulating radiator panels are closed, such as all of them closed in, dust may not be able to enter the interior volume, or its entry may be reduced. In some embodiments, each articulating radiator panel may seal off the corresponding opening. In some embodiments, there may be a soft seal or overlap between adjacent panels, such as the edges where panels meet, like between panelsA andB. This may be advantageous if the radiator system is on a movable vehicle, such as on the lunar surface where it may encounter lunar dust. During transport, the interior volume may be protected from such dust when the articulating radiator panels are in the closed positions. In another example, when in an open position, dust may accumulate on the articulating radiator panels which may reduce the functionality of the coolant channels, e.g., their heat rejection or absorption may be reduced by the collection of dust. This dust may be removed by moving the articulating radiator panels, or by repeatedly moving the panels up and down to effectively shake off the dust. In some embodiments, the dust may also be removed by electrostatic or vibrational forces.