Patent Description:
According to a first aspect of the present invention, there is provided a satellite comprising a bus and a boom having a first end mounted to the bus, and a second end distal from the first end. The satellite further comprises a thruster mounted on the second end of the boom configured to provide thrust to the satellite, and an end effector mounted on the second end of the boom configured to acquire objects.

According to a second aspect of the present invention, there is provided a method of grappling at least one of components and a payload on a satellite as claimed in claim <NUM>.

The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the Background.

Aspects of the present disclosure are illustrated by way of example and are not limited by the accompanying figures for which like references indicate the same or similar elements.

In one embodiment, technology is described for an orbital satellite having a pair of multi-axis booms each including thrusters for course/attitude adjustment and an end effector for grappling payloads and manipulating other tools and objects. The multi-axis booms each include a first end mounted to the bus, and a second end including the thrusters and the end effector, though it is conceivable that end effectors be positioned at one or more other locations between the first and second ends of each boom. The end effectors are positioned relative to the thrusters so as to be outside of the propulsive stream generated by the thrusters.

In embodiments, the end effectors may be multi-functional tools used for grappling payloads and/or making repairs on the bus while the bus is in orbit. For example, the end effectors may be used to remove and relocate secondary payloads affixed to an ESPA ring once the bus is in orbit. Alternatively, the end effector may be used to load expired payloads onto an ESPA ring, or transfer expired payloads to another satellite or tug while acquiring a new payload. The end effectors may further be used to make repairs or take measurements on the bus while in orbit or while on a planetary or lunar surface. Each end effector may be configured to make repairs or take measurements itself, or to grip a variety of tools for making repairs and taking measurements. The acquired components and tools may be configured with a customized structural interface which can be affixed to and detached from the end effector. In embodiments, the end effectors may be powered, and/or they may have their own electrical current source so that tools which connect to the end effector may be powered.

It is understood that the present technology may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the technology to those skilled in the art. Indeed, the technology is intended to cover alternatives, modifications and equivalents of these embodiments. Furthermore, in the following detailed description of the present technology, numerous specific details are set forth in order to provide a thorough understanding of the present technology. However, it will be clear to those of ordinary skill in the art that the present technology may be practiced without such specific details.

The terms "longitudinal" and "transverse," "top" and "bottom," "upper" and "lower" and "vertical" and "horizontal," and forms and synonyms thereof, as may be used herein are by way of example and illustrative purposes only, and are not meant to limit the description of the technology inasmuch as the referenced item can be exchanged in position and orientation.

For purposes of this disclosure, a connection may be a direct connection or an indirect connection (e.g., via one or more other parts). In some cases, when a first element is referred to as being connected, affixed, mounted or coupled to a second element, the first and second elements may be directly connected, affixed, mounted or coupled to each other or indirectly connected, affixed, mounted or coupled to each other. When a first element is referred to as being directly connected, affixed, mounted or coupled to a second element, then there are no intervening elements between the first and second elements (other than possibly an adhesive or melted metal used to connect, affix, mount or couple the first and second elements).

<FIG> is a high-level illustration of a satellite <NUM> in which the present technology may be implemented. Satellite <NUM> includes a bus <NUM> carrying a primary payload <NUM> and one or more secondary payloads <NUM> mounted to an ESPA (evolved expendable launch vehicle (EELV) secondary payload adapter) ring <NUM>. The various payloads <NUM>, <NUM> may each include one or more grappling fixtures <NUM>, the purpose of which are explained below. Grappling fixtures <NUM> may be provided on various other components, including for example ESPA ring <NUM> and other components shown schematically in <FIG>. The number of secondary payloads <NUM> are shown by way of example only and may vary in further embodiments. In some embodiments, the secondary payloads <NUM> may be omitted entirely. The embodiment of satellite <NUM> shown is configured for so-called inverted flight, where the secondary payloads <NUM> are mounted to an earth deck <NUM> at launch. However, in further embodiments, the payloads may be reversed with the secondary payloads mounted at the opposite end of bus <NUM>.

Bus <NUM> may further include a variety of components for the operation of satellite <NUM>, several of which are shown schematically in <FIG>. For example, the bus components include solar panels <NUM> and one or more batteries <NUM> for providing power to the satellite components. The bus <NUM> may further include a system processor <NUM> and T, C & R (telemetry, commands and ranging) communication and processing equipment <NUM>. T, C & R may be referred to by other names, such as T, T & C (tracking, telemetry and control), as is known in the art. T,C & R communication and processing equipment <NUM> includes communication and processing equipment for telemetry, commands from the ground to the satellite and ranging to operate the satellite. System processor <NUM> is used to control and operate satellite <NUM>. An operator on the ground can control satellite <NUM> by sending commands via T,C & R communication and processing equipment <NUM> to be executed by system processor <NUM>.

Bus <NUM> may further include inertial sensors <NUM> and momentum wheels <NUM>. Inertial sensors <NUM> are used to determine the position and three-axis orientation of satellite <NUM>, and momentum wheels <NUM> may be used for three-axis control of the orientation of the satellite <NUM>, based on feedback from the inertial sensors <NUM>. As is known, at some point during their operation, one or more of the momentum wheels may reach their maximum rotational velocity. At this point, the processor <NUM> may spin down the one or more momentum wheels. While momentum wheels are spinning down, orientation control of the satellite <NUM> may be achieved by the thrusters, as is explained below. Bus <NUM> may further include fuel canisters <NUM> for powering the thrusters.

Satellite <NUM> may also have a pair of booms <NUM> affixed to bus <NUM>. The booms <NUM> include proximal ends 130a affixed to the bus <NUM>, and distal ends 130b opposite the proximal ends 130a. The distal ends 130b of booms <NUM> include the thrusters <NUM> and, in accordance with the present technology, further include end effectors <NUM> as explained below. While a pair of thrusters <NUM> are shown at the distal ends 130b of booms <NUM>, each boom may include a single thruster <NUM> or more than two thrusters <NUM> in further embodiments. While the proximal ends 130a of booms <NUM> are shown mounted toward a first end of the bus <NUM>, proximate the primary payload <NUM>, it is understood that the mounting points of the booms <NUM> to the bus <NUM> may be anywhere between the first and second ends of bus <NUM>. In embodiments, the first and second booms may be diametrically opposed to each other on bus <NUM>, though they need not be in further embodiments.

Once brought to its initial or final orbit by a rocket <NUM> (a portion of which is shown in <FIG>), the satellite <NUM> disengages from the rocket <NUM>. If not the final orbit, the thrusters <NUM> are used to move and orient the satellite <NUM> to its final geostationary or non-geostationary orbital location. A geosynchronous orbit is one having a period of rotation synchronous with that of the Earth's rotation in the plane of the Equator so that it remains stationary in relation to a fixed point on the Earth's surface.

Further detail of the booms <NUM> will now be explained with reference to the front and rear perspective view of <FIG> and <FIG>, respectively. <FIG> and <FIG> show a single boom <NUM>, but the following description applies to both booms <NUM>. Each boom may include a shoulder joint <NUM>, and elbow joint <NUM> and a wrist joint <NUM>, which together provide multi-axis pitch, yaw and roll movement of the boom distal end 130b, including for example with <NUM>, <NUM>, <NUM>, <NUM> or <NUM> degrees of freedom of movement. This allows the distal end 130b of the boom <NUM> to be translated to a wide variety of positions and oriented in a wide variety of angular positions. Thus, under the control of the system processor <NUM>, the thrusters <NUM> may be positioned and oriented as needed to accomplish movement and/or reorientation of the satellite. Similarly, under the control of the system processor <NUM>, the end effectors <NUM> may be positioned and oriented as needed to acquire objects or components as explained below.

In one example, shoulder joint <NUM> may include a motor and bearings (not shown) to drive a first arm <NUM> with pitch and yaw rotation relative to the shoulder joint <NUM>. Elbow joint <NUM> may include a motor and bearings (not shown) to drive a second arm <NUM> with yaw and roll rotation relative to the elbow joint <NUM>. And wrist joint <NUM> may include a motor and bearings (not shown) to drive the thrusters <NUM> and end effector <NUM> with pitch and roll rotation relative to the wrist joint <NUM>.

The above-described components of booms <NUM> accomplishing the movements and rotations of distal end 130b are by way of example only. It is understood that booms <NUM> may include a variety of other components configured to move the distal end 130b with multiple degrees of freedom, including <NUM>, <NUM>, <NUM>, <NUM> and <NUM> degrees of freedom. The lengths of booms <NUM> shown in <FIG> are for illustrative purposes only, and the first and second arms <NUM>, <NUM> may be sized so that the booms <NUM> together are able to access any point on satellite <NUM>. It is conceivable that the booms <NUM> have additional arms and joints in further embodiments. The booms <NUM> may be stowed during launch on rocket <NUM> by launch locks <NUM> (<FIG>), which may engage the booms <NUM> anywhere along their lengths.

<FIG> show various perspective views of the distal end 130b of a boom <NUM> including the thrusters <NUM> and an embodiment of the end effector <NUM>. In embodiments, thrusters <NUM> may be ion thrusters which create thrust by accelerating ions using electricity. Other types of thrusters are contemplated. The thrusters <NUM> will create a thrust or propulsion stream in the direction of arrows PS in <FIG> and <FIG> to move or reorient the satellite <NUM>. When thrust is needed, the booms <NUM> will position the thrusters in the correct position and orientation under control of processor <NUM>. When movement is desired, the direction of propulsion stream PS will lie along an axis through a center of gravity of the satellite <NUM>. When a change in orientation of the satellite is desired, the direction of propulsion stream PS will lie along an axis that does not pass through the center of gravity of the satellite <NUM>.

In accordance with aspects of the present technology, the end effector <NUM> may be mounted at the distal end 130b of boom <NUM> opposite side on which the thrusters <NUM> are mounted. In further embodiments, one or more end effectors <NUM> may be mounted elsewhere at distal end 130b outside of the propulsion stream of thrusters <NUM>, and/or elsewhere along the length of boom <NUM>. As such, the thrusters <NUM> have no effect on the end effector <NUM>. However, it is conceivable that a shield be erected between the thrusters <NUM> and the end effector <NUM> in further embodiments.

<FIG> illustrate one embodiment of an end effector <NUM> and a technique for grappling payloads and other satellite components using the end effector <NUM>. As explained below, the end effector <NUM> shown and described is one embodiment of an end effector, and the end effector affixed to boom <NUM> may have a great many other configurations in further embodiments. The end effector <NUM> shown in <FIG> includes three grappling fingers <NUM> pivotally mounted to respective hubs <NUM> in a baseplate <NUM>. Each grappling finger <NUM> includes protruding engagement tines 160a which mate within corresponding recesses in a grappling fixture as explained below. The three grappling fingers <NUM> with their engagement tines 160a are sufficient to define three secure engagement points with a component to be grappled by the end effector <NUM>. However, it is conceivable that the end effector includes two grappling fingers or more than three grappling fingers in further embodiments.

Each grappling finger <NUM> may move between a first, retracted position where a component to be grappled may be freely inserted into the end effector <NUM> and freely removed from the end effector <NUM>, and a second, extended position where the grappling fingers <NUM> secure the component to the end effector. Springs <NUM> are shown biasing the grappling fingers <NUM> into their retracted positions against posts <NUM>. Motors (not shown) within each hub <NUM> may be used to move the grappling fingers from their retracted positions to their extended positions, for example under the control of system processor <NUM>. In further embodiments, the springs may bias the grappling fingers <NUM> into their extended positions, and the respective motors may move them to their retracted positions.

Each of the grappling fingers <NUM> extends through a slot <NUM> formed in a support plate <NUM>, on which support plate <NUM> the posts <NUM> are mounted or otherwise formed. The support plate <NUM> may be bolted or otherwise affixed to the baseplate <NUM>, and defines a surface on which grappled components are supported as explained below. The end effector <NUM> further includes a central hub <NUM> affixed to or otherwise formed on the support plate <NUM>. The end effector <NUM> may be affixed to a voltage source (not shown) which provides current to pins <NUM> on the central hub to enable the end effector to power a component mounted onto the end effector <NUM> as explained below. The pins <NUM> may be pogo pins or the like, which receive current when pressed downward by an acquired object as explained below. The number of pins <NUM> is shown by way of example and there may be more or less pins in further embodiments. Power may be supplied to the end effector by other means in further embodiments, such as for example by a pin <NUM> extending from the baseplate164 through an opening in the support plate <NUM>.

The end effector <NUM> may be affixed to the distal end 130b of the boom <NUM> by a post <NUM>. It is conceivable that the end effector <NUM> be rotationally mounted on the post <NUM> (or the post <NUM> be rotationally to the boom <NUM>) to facilitate proper radial positioning of the tines 160b of the grappling fingers <NUM> within the recesses of a grappling fixture as explained below.

<FIG> shows the end effector <NUM> acquiring an object affixed to a grappling fixture <NUM>. The object being acquired is not shown in <FIG>, but as shown for example in <FIG>, a variety of components on the satellite <NUM> may have affixed grappling fixtures <NUM> so as to enable acquisition of these components by the end effector <NUM>. These components include for example the primary payload <NUM>, the one or more secondary payloads <NUM> and the ESPA ring <NUM>. Other components on the satellite <NUM> may also have grappling fixtures, such as for example the batteries (or battery pack) <NUM>, the momentum wheels <NUM>, the solar panels <NUM> and/or the fuel canisters <NUM>. The grappling fixture <NUM> may include a ring <NUM> which may be bolted, glued or otherwise affixed to a payload or other object to enable acquisition by the end effector <NUM>.

The grappling fixture <NUM> is customized structural interface customized to operate with end effector <NUM> to ensure a secure interface and attachment of an acquired object or component to the end effector <NUM>. As shown in <FIG>, a grappling fixture <NUM> may be spherical, and may include recesses 105a which correspond in number and radial positions to the number and radial positions of the grappling fingers <NUM> around the circumference of the end effector <NUM>. The recesses 105a may have concave contours that match the convex contours of the tines 160a on grappling fingers <NUM>.

As described above, the boom <NUM> is capable of positioning an end effector <NUM> with multiple degrees of freedom, translationally and rotationally. The boom <NUM> may position the end effector <NUM> to approach an object to be acquired along an axis shown by arrow <NUM> concentric with a central axis <NUM> of the grappling fixture <NUM>. Thus, the end effector <NUM> is centered with respect to the grappling fixture <NUM>. The boom <NUM> may also position the end effector <NUM> so as to be square with the grappling fixture <NUM> (i.e., a plane of the support plate <NUM> is perpendicular to the central axis <NUM> of grappling fixture <NUM>).

With this approach, the end effector <NUM> positions itself around the grappling fixture <NUM> of an object or component to be acquired on the end effector. As noted, the satellite <NUM> may include end effector sensors <NUM> (shown schematically in <FIG>) which guide the end effector <NUM> into proper engagement over a grappling fixture <NUM> on an object or component to be acquired on end effector <NUM>. The end effector sensors <NUM> may be any of a variety of sensors, including for example one or more cameras or position detecting sensors (in the end effector <NUM>, in the grappling fixture <NUM> and/or elsewhere on the bus <NUM>). The positioning of the end effector <NUM> over a grappling fixture <NUM> may be accomplished manually, using images sent wirelessly from the end effector sensors <NUM> to terrestrial control station and positioning control signals from the control station. Alternatively, the positioning of the end effector <NUM> over a grappling fixture <NUM> may be accomplished automatedly by system processor <NUM>, using images and/or signals received from the end effector sensors <NUM>.

In addition to proper positioning of the end effector <NUM> over the grappling fixture <NUM>, the end effector may be properly rotationally oriented so that the grappling fingers <NUM> of the end effector radially align with the recesses 105a of grappling fixture <NUM>. The proper rotational orientation may be accomplished by the boom <NUM>. As noted above, the end effector <NUM> may be rotationally mounted on the boom <NUM>. In addition to or instead of proper rotational positioning by the boom, the end effector <NUM> may rotate on the boom to accomplish the proper rotational orientation of the grappling fingers <NUM> to the recesses 105a. Again, the end effector sensors <NUM> may be used to ensure the proper rotational orientation of the grappling fingers <NUM> to the recesses 105a.

Referring now to <FIG>, once properly aligned and positioned over a grappling fixture <NUM>, the grappling fingers <NUM> may be actuated to their extended positions so that the tines 160a of each finger <NUM> engage within recesses 105a of fixture <NUM>. At this point, the grappling fixture <NUM> and the attached object are securely affixed to the end effector <NUM>. In embodiments, the end effector sensors <NUM> may send a signal to the system processor <NUM> confirming proper acquisition.

The end effector <NUM> acquires the grappling fixture <NUM> so that the central hub <NUM> of the end effector is received within a central aperture of the grappling fixture <NUM>. This central aperture may include an electrical connector configured to transfer current from the pins <NUM> (for example) on the central hub <NUM> to the object affixed to the grappling fixture <NUM>. Thus, the end effector <NUM> and grappling fixture <NUM> can power objects or components acquired by end effector <NUM>.

Once affixed to the end effector <NUM> in this manner, a grappled object may be moved by repositioning the end effector <NUM> on boom <NUM>. <FIG> shows an object <NUM> such as a primary payload <NUM> or secondary payload <NUM> secured to the end effector <NUM> on the distal end 130b of boom <NUM>. Prior to being acquired on end effector <NUM>, an attachment mechanism is used to secure the object in its position on the satellite <NUM>. For example, <FIG> schematically shows attachment clips <NUM> affixing secondary payloads <NUM> to the ESPA ring <NUM>. Once the end effector <NUM> has acquired an object <NUM> as shown in <FIG>, the attachment mechanisms previously securing the object in place may be removed or released. This may happen automatedly by the system processor <NUM>. In further embodiments, while the object is held on an end effector <NUM> on a first boom <NUM>, the end effector <NUM> on the second boom <NUM> may remove or release the attachment mechanism. In such embodiments, the end effector <NUM> on the second boom <NUM> may have a removal tool as explained below.

As noted, the end effector <NUM> shown and described above is only one of a wide variety of possible configurations. It is appreciated that the end effector may have any number of other configurations, including a wide variety of jaws, claws, rings, pins, fingers and other engagement structures that are capable of acquiring another object or component. The end effector may acquire objects by purely mechanical means or by electromechanical means. In further embodiments, the end effector may also operate by magnetic means, where the end effector includes a magnet which can attract and hold objects or components. As described below, the end effector may acquire tools used to make repairs or perform other operations. One such tool that can be acquired is another type of end effector. Thus, for example, the end effector <NUM> shown in the figures can itself acquire a differently configured end effector, depending on the operation to be performed.

In the above embodiment, a grappling fixture, customized to the end effector, is affixed to each object or component to be acquired to ensure a proper acquisition interface. In further embodiments, the end effector may acquire objects without a customized grappling fixture on the objects. In the above embodiment, the end effector <NUM> includes an electrical interface to provide power to the end effector and to an acquired object. The end effector may have other interfaces in further embodiments, including for example a communications interface enabling communications between an acquired object and the system processor <NUM>. Other possible interfaces include hydraulic and/or pneumatic interfaces to provide mechanical power to the end effector and/or an acquired object.

There are a wide variety of operations which can be accomplished with an acquired object. One typical object acquired by end effector <NUM> will be the primary and/or secondary payloads affixed to bus <NUM>. Once acquired, the payload may be repositioned on the satellite <NUM>, transferred to a second satellite rendezvousing with the first satellite, or set adrift into space for later acquisition by a tug or other satellite. First and second satellites (or a satellite and another rocket or tug) may rendezvous with each other, and then payloads may be transferred by the end effector to or from the first satellite. For example, an expired payload on the first satellite may be switched out for a new payload, thus effectively extending the life of the first satellite with respect to the function of the expired/new payload.

It is also known to launch a satellite into space with secondary payloads mounted to an ESPA ring, which may be mounted on the earth deck (as shown in <FIG>) or elsewhere on the satellite. In one operation, once in space, the end effector <NUM> on a first boom <NUM> may remove a payload <NUM> from the ESPA ring <NUM> positioned on the earth deck <NUM>. The end effector <NUM> on the second boom <NUM> may then acquire and remove the ESPA ring <NUM>. Thereafter, the payload on the first end effector <NUM> may place the payload on the earth deck where it gets mounted. The ESPA ring <NUM> may be repositioned on the satellite, or acquired by a tug or other satellite.

In addition to payloads, the end effectors <NUM> on booms <NUM> may be used to acquire other components on bus <NUM>. These acquired components may then be repositioned on the satellite <NUM>, transferred to a second satellite rendezvousing with the first satellite, or set adrift into space for later acquisition by a tug or other satellite. First and second satellites (or a satellite and another rocket or tug) may rendezvous with each other, and then satellite components may be transferred by the end effector to or from the first satellite. For example, expired fuel canisters or malfunctioning components on the first satellite may be switched out for new canisters and/or components, thus effectively extending the life of the first satellite with respect to thruster fuel the purpose of the malfunctioning components.

As noted, in addition to grappling payloads and other components, the end effector <NUM> on each boom <NUM> may be used to acquire a tool to perform a desired function. <FIG> shows a simple tool <NUM> acquired by end effector <NUM> for performing maintenance or repairs. The tool may be mounted to a structural interface customized for the end effector <NUM>. In the embodiments of end effector <NUM> shown in the figures, the customized structural interface may be a grappling fixture <NUM>, though other customized structural interfaces are possible. As described, the grappling fixture <NUM> may include a power connector to transfer power from the end effector <NUM> to the tool <NUM>, if needed.

Tools <NUM> affixed to an end effector <NUM> may perform a variety of functions. As noted, the tool may be used to perform maintenance or repairs on the satellite <NUM>, or another satellite rendezvousing with the satellite <NUM>. The tools may also be a senor or measuring tool used for sensing or to take measurements. Here, the boom <NUM> would position the end effector <NUM> and sensor/measuring tool <NUM> proximate an object (on the satellite or not) to be sensed or measured, and then the tool <NUM> can gather the required information.

As noted, the tool <NUM> may itself be another end effector configured to acquire an object or component for transfer, or to acquire a further tool for maintenance, repairs, sensing or measurements. The tool <NUM> in this embodiment may be an end effector, or it may be an end effector affixed to an assembly which may have arms and joints allowing for multiple degrees of freedom of movement of the end effector affixed to end effector <NUM>.

<FIG> shows an example where a variety of different tools <NUM> are stored in a tool caddy <NUM>. The tool caddy <NUM> may be affixed to the bus <NUM>. The end effectors <NUM> on the ends of booms <NUM> can acquire and return tools <NUM> to and from tool caddy <NUM> as needed.

The present technology provides advantages in that it maximizes the utility of a satellite. By adding end effectors to the booms which already exist to carry the thrustors, the utility of the booms and overall satellite is greatly increased. As noted, the thrusters are used only intermittently, so that the end effectors can be used without inhibiting the use of the thrusters. In embodiments, the end effectors would only be used when the thrusters are not in use. However, it is possible that the end effectors and thrusters be used simultaneously, for example where the thrusters provide a force required to use a tool <NUM>.

Claim 1:
A satellite (<NUM>), comprising:
a bus (<NUM>);
a boom (<NUM>) having a first end (130a) mounted to the bus, and a second end (130b) distal from the first end;
a thruster (<NUM>) mounted on the second end (130b) of the boom; and
an end effector (<NUM>) mounted on the second end (130b) of the boom (<NUM>) configured to acquire objects (<NUM>);
characterized in that:
the thruster (<NUM>) mounted on the second end (130b) of the boom (<NUM>) is configured to provide thrust to the satellite.