Docking system and method for satellites
The present invention relates to a service satellite having a body, a controller and a docking unit. The docking unit includes at least two foldable, adjustable gripping arms pivotally mounted on the satellite body, each gripping arm being pivotable relative to the satellite body, and a gripping end at each free end of the gripping arms, wherein the gripping ends are adapted and configured to capture and grip a target portion of an orbiting satellite. Each gripping arm is controllable independently by the controller, which coordinates the motion of the arms. The service satellite also includes a propulsion unit including a first thruster mounted adjacent a Nadir end of the service satellite body, and a balance thruster, the balance thruster being distanced from the first thruster and facing a different direction than the first thruster, propellant for the thruster and the balance thruster; and means for aligning the thrusters so that a thrusting vector passes through a joint center of gravity of the service satellite and the serviced satellite.
1. A service satellite for providing in-orbit services to an orbiting satellite, the service satellite comprising:
a body;
at least two thrusters;
at least two docking arms connected to the body and configured to engage with an interface ring extending from an external surface of the orbiting satellite, each of the at least two docking arms including:
a ring-engaging end configured to couple with the interface ring; and
a four-bar linkage assembly, including:
a first crank pivotably connected to the service satellite;
a second crank pivotably connected to the service satellite and spaced apart from the first crank; and
an operational arm pivotably connected at a first location to the first crank and pivotably connected at a second location to the second crank; and
at least one controller configured to:
move each of the at least two docking arms to enable the ring-engaging end of each of the at least two docking arms to couple with the interface ring at at least two spaced-apart locations on the interface ring, thereby forming an interconnection between the service satellite and the orbiting satellite through the externally extending interface ring, and thereby permitting the service satellite to join with the orbiting satellite, forming a tandem assembly; and
coordinate firing of the at least two thrusters to enable thruster firing on the service satellite to propel the orbiting satellite through forces exerted through the externally extending interface ring.
2. The service satellite of claim 1 , wherein the at least two docking arms are adjustable and wherein the at least one controller is configured to adjust the at least two docking arms to thereby cause a tilt between the service satellite and the orbiting satellite.
3. The service satellite of claim 2 , wherein the at least one controller is configured to cause an angle of tilt of up to about 4° between the service satellite and the orbiting satellite.
4. The service satellite of claim 2 , wherein the at least one controller is configured to initiate the thruster firing to propel the orbiting satellite while the body of the service satellite is tilted relative to the orbiting satellite.
5. The service satellite of claim 1 , wherein the interconnection is non-intrusive into the orbiting satellite.
6. The service satellite of claim 1 , wherein at least one ring-engaging end includes a recess configured to receive the interface ring of the orbiting satellite.
7. The service satellite of claim 6 , wherein the at least one ring-engaging end includes a portion that is rotatable within the recess of the interface ring.
8. The service satellite of claim 6 , wherein at least a portion of the ring-engaging end is urged by a spring against the interface ring.
9. The service satellite of claim 1 , wherein the at least one controller is further configured to adjust a distance between the at least two docking arms to cause the at least two docking arms to cooperate to grasp the interface ring of the orbiting satellite.
10. The service satellite of claim 1 , of between 150 kg and 500 kg and configured to fit within an auxiliary payload space of a launch vehicle.
11. The service satellite of claim 1 , wherein the operational arm is pivotably connected to the first crank at the first location on a first side of the operational arm proximate the body, and the operational arm is pivotally connected to the second crank at a location between the first location and the ring-engaging end.
12. The service satellite of claim 1 , further including at least one solar panel attached to and extendable from the body in an orientation that is tilted at an angle of over about 30 degrees with respect to a north-south axis of the body.
13. The service satellite of claim 12 , wherein the at least one solar panel includes a first solar panel rotatable about a longitudinal axis thereof, and wherein the at least one controller is configured to rotate the first solar panel to avoid casting a shadow of the first solar panel on a second solar panel attached to the orbiting satellite.
14. The service satellite of claim 1 , wherein after coordinating firing of the at least two thrusters to propel the orbiting satellite, the at least one controller is further configured to:
move the at least two docking arms to disengage the ring-engaging end of each of the at least two docking arms from the interface ring of the orbiting satellite;
fire the at least two thrusters to move the service satellite away from the orbiting satellite and to position the service satellite within docking distance of another orbiting satellite; and
move each of the at least two docking arms to enable the ring-engaging end of each of the at least two docking arms to couple with an interface ring of the another orbiting satellite, thereby forming another interconnection between the service satellite and the another orbiting satellite through the externally extending interface ring of the another orbiting satellite, and thereby permitting the service satellite to join with the another orbiting satellite, forming another tandem assembly; and
coordinate firing of the at least two thrusters to propel the another orbiting satellite through forces exerted through the externally extending interface ring of the another orbiting satellite.