Stowage, deployment and positioning of rigid antenna reflectors on a spacecraft
A spacecraft includes an aft surface, a forward surface and a main body structure disposed therebetween, a stowage and deployment arrangement (SDA) joined to the main body structure by a first mechanical coupling, and an antenna that includes a respective feed element and a rigid antenna reflector coupled with the main body by way of the SDA. The feed element is joined to the main body structure by a second, different, mechanical coupling. The spacecraft is reconfigurable from a launch configuration, with the reflector is disposed forward of the forward surface, with its aperture plane substantially parallel to the forward surface, to an on-orbit configuration. The SDA repositions the reflector to a second position corresponding to the on-orbit configuration. In the second position, the reflector is disposed, Earth facing, substantially aft of the forward surface and outboard of the main body structure and is illuminated by the respective feed element.
1. A spacecraft, comprising:
a structural interface adapter for mating to a launch vehicle, the launch vehicle having a longitudinal axis;
an aft surface disposed proximate to the structural interface adapter;
a forward surface disposed opposite to the aft surface;
a main body structure disposed between the aft surface and the forward surface;
a stowage and deployment arrangement joined to the main body structure by a first mechanical coupling; and
at least one antenna, including a rigid antenna reflector and a respective feed element, the respective feed element being joined to the main body structure by a second mechanical coupling, and not by the first mechanical coupling, the rigid antenna reflector being coupled with the main body structure by way of the stowage and deployment arrangement and not by the second mechanical coupling;
the spacecraft being reconfigurable from a launch configuration to an on-orbit configuration, wherein:
the reflector has an aperture plane and, in the launch configuration, the antenna reflector is disposed in a first position, undeployed, forward of the forward surface, with the aperture plane substantially parallel to the forward surface and orthogonal to the longitudinal axis of the launch vehicle;
the stowage and deployment arrangement repositions the antenna reflector from the first position to a second position corresponding to the on-orbit configuration; and
in the second position, the antenna reflector is disposed, deployed, so as to be illuminated by the respective feed element and Earth facing from a position substantially aft of the forward surface and outboard of the main body structure.
2. The spacecraft of claim 1 , wherein the stowage and deployment arrangement includes a proximal portion coupled with the first mechanical coupling and a distal portion coupled with a third mechanical coupling, the third mechanical coupling being disposed between the stowage and deployment arrangement and the rigid antenna reflector.
3. The spacecraft of claim 2 , wherein the first mechanical coupling includes a hinge.
4. The spacecraft of claim 2 , wherein the third mechanical coupling is near the center of the antenna reflector.
5. The spacecraft of claim 2 , wherein the third mechanical coupling includes one or more of a hinged joint, an actuator, a two axis positioning mechanism, and a three axis positioning mechanism.
6. The spacecraft of claim 1 , wherein the spacecraft, in the on-orbit configuration is three axis stabilized.
7. The spacecraft of claim 1 , wherein, in the launch configuration, a centroid of the aperture plane is substantially aligned with the longitudinal axis.
8. The spacecraft of claim 1 , wherein, in the launch configuration, the antenna reflector is mechanically attached with the spacecraft main body structure by way of a fourth mechanical coupling.
9. The spacecraft of claim 8 , wherein the fourth mechanical coupling is a launch holddown device.
10. The spacecraft of claim 1 , wherein the first mechanical coupling includes one or more of a hinged joint, an actuator, a two axis positioning mechanism, and a three axis positioning mechanism.
11. A method comprising:
reconfiguring a spacecraft from a launch configuration to an on-orbit configuration, wherein the spacecraft includes:
a structural interface adapter for mating to a launch vehicle, the launch vehicle having a longitudinal axis;
an aft surface;
a forward surface disposed opposite to the aft surface;
a main body structure disposed between the aft surface and the forward surface;
a stowage and deployment arrangement joined to the main body structure by a first mechanical coupling; and
at least one antenna, including a rigid antenna reflector and a respective feed element, the respective feed element being joined to the main body structure by a second mechanical coupling, and not by the first mechanical coupling, the rigid antenna reflector being coupled with the main body structure by way of the stowage and deployment arrangement and not by the second mechanical coupling;
the reflector has an aperture plane and, in the launch configuration, the antenna reflector is disposed in a first position, undeployed, forward of the forward surface, with the aperture plane substantially parallel to the forward surface and orthogonal to the longitudinal axis of the launch vehicle; and reconfiguring includes:
repositioning, with the stowage and deployment arrangement, the antenna reflector from the first position to a second position corresponding to the on-orbit configuration,
illuminating the antenna reflector with the respective feed element, the antenna reflector being disposed, deployed, in the second position so as to be Earth facing from a position substantially aft of the forward surface and outboard of the main body structure.
12. The method of claim 11 , wherein the stowage and deployment arrangement includes a proximal portion coupled with the first mechanical coupling and a distal portion coupled with a third mechanical coupling, the third mechanical coupling being disposed between the stowage and deployment arrangement and the rigid antenna reflector.
13. The method of claim 12 , wherein the first mechanical coupling includes a hinge.
14. The method of claim 12 , wherein the third mechanical coupling is near the center of the antenna reflector.
15. The method of claim 12 , wherein the third mechanical coupling includes one or more of a hinged joint, an actuator, a two axis positioning mechanism, and a three axis positioning mechanism.
16. The method of claim 11 , wherein the spacecraft, in the on-orbit configuration is three axis stabilized.
17. The method of claim 11 , wherein, in the launch configuration, a centroid of the aperture plane is substantially aligned with the longitudinal axis.
18. The method of claim 11 , wherein, in the launch configuration, the antenna reflector is mechanically attached with the spacecraft main body structure by way of a fourth mechanical coupling.
19. The method of claim 18 , wherein the fourth mechanical coupling is a launch holddown device.
20. The method of claim 11 , wherein the first mechanical coupling includes one or more of a hinged joint, an actuator, a two axis positioning mechanism, and a three axis positioning mechanism.