1. A satellite constellation forming method comprises a satellite deployment step S2, a spacecraft acceleration step S4, a spacecraft orbiting step S5 and spacecraft deceleration step, and the aforementioned steps are repeated in order. In the satellite deployment step S2, deploying one of the satellites into the circular orbit 2 from the spacecraft 10 on the circular orbit 2. In the spacecraft acceleration step S4, accelerating the spacecraft 10 and switching the orbit from the circular orbit 2 to a spacecraft transfer orbit 3 in the same orbit plane. In the spacecraft orbiting step S5, making the spacecraft 10 orbit along the spacecraft transfer orbit 3 a plurality of times. In the spacecraft deceleration step, decelerating the spacecraft 10 and switching the orbit from the spacecraft transfer orbit 3 to the circular orbit 2 in the same orbit plane.

A spacecraft includes a structural interface adapter for mating to a launch vehicle, an aft surface disposed proximate thereto, and a forward surface disposed opposite thereto, a main body structure, including a plurality of sidewalls, disposed between the aft surface and the forward surface and a plurality of unfurlable antenna reflectors. At least one unfurlable antenna reflector is configured to be illuminated, in an on-orbit configuration, by a respective feed array. The spacecraft is reconfigurable from a launch configuration to the on-orbit configuration. In the launch configuration, the at least one unfurlable antenna reflector is disposed, undeployed, forward of the respective feed array, proximate to and outboard of one of the plurality of sidewalls. In the on-orbit configuration, the forward surface is substantially earth-facing and the at least one unfurlable antenna reflector is disposed, deployed, so as to be earth-facing from a position aft of the respective feed array.

A method for solar array (28a, 28b) deployment includes deploying a first portion of solar cells of a solar array responsive to a first drag condition, charging a battery (26) with the first portion of solar cells, activating an electric thruster (24) at a first power level using the first portion of solar cells, deploying a second portion of solar cells of the solar array responsive to a second drag condition that is lower than the first drag condition, and activating the electric thruster at a second power level that is higher than the first power level using the first portion of solar cells and the second portion of solar cells.

A first spacecraft and a second spacecraft are configured to be disposed together, in a launch configuration, for launch by a single launch vehicle. In the launch configuration, the first spacecraft is mechanically coupled with a primary payload adapter of the launch vehicle, and the second spacecraft is mechanically coupled with the first spacecraft by way of an inter-spacecraft coupling arrangement. The spacecraft are configured to be deployed, following injection into a first orbit by the launch vehicle, by separating the first spacecraft from the primary payload adapter while the second spacecraft is mechanically coupled with the first spacecraft. A first onboard propulsion subsystem of the first spacecraft includes one or more thrusters configured to execute an orbit transfer maneuver from the first orbit to a second orbit. A propellant line arrangement detachably couples the first onboard propulsion subsystem with a second propellant storage arrangement on the second spacecraft.

Apparatus and methods for controlling a spacecraft for a transfer orbit. The spacecraft includes a propulsion subsystem with electric thrusters that are installed with two-axis gimbal assemblies. The spacecraft also includes a controller that identifies a target spin axis for the spacecraft, determines an actual spin axis for the spacecraft during the transfer orbit, determines gimbal angles for the electric thruster(s) that adjust the actual spin axis toward the target spin axis, and initiates a burn of the electric thruster(s) at the gimbal angles.

An electronic pressure regulation system includes an electronic control unit and a fluid assembly, with the fluid assembly including a fluid control branch having a proportional control valve and a heater. The heater may be a strip heater applied to or a coil wrapped around an external surface of the proportional control valve. The system may further include a latching isolation valve. A secondary fluid control branch can be included, and the fluid control branches can be in parallel. The electronic pressure regulation system can be included in an all-electric satellite. Another electronic pressure regulation system includes an electronic control unit and a fluid assembly, with the fluid assembly including a fluid control branch having a proportional control valve, the proportional control valve including two independently-controlled coils for magnetostrictive actuation.

Example methods and systems of deploying a constellation of spacecraft are described. An example method includes releasing a cluster of spacecraft from a launch vehicle at a first orbit, separating spacecraft in the cluster of spacecraft from each other to minimize overlap of visibility periods from a ground station, and raising each of the spacecraft as separated simultaneously in a synchronized ascent to a respective final orbit. An example system includes a cluster of spacecraft in orbit at a first orbit, and a ground station in communication with spacecraft of the cluster of spacecraft when the spacecraft of the cluster are visible to the ground station. The ground station commands each spacecraft to separate from each other and to raise in altitude as separated simultaneously in a synchronized ascent to a respective final orbit.

Satellite systems and methods to perform rendezvous and docking between a servicer satellite and an on-orbit satellite, and specifically to satellite systems and methods to perform rendezvous and docking between a servicer satellite and an on-orbit client satellite using electric propulsion thrusters. In one aspect, a servicer satellite with a set of thruster arms each attached to an electric propulsion thruster performs acceleration, deceleration, and steering maneuvers through six degree of freedom positioning of the thrusters, the same set of thruster arms and thrusters performing station keeping of the docked servicer-client satellite system.

A method of moving a spacecraft from an initial orbit to a final orbit includes providing a spacecraft with thrusters traveling in an initial orbit that has a first RAAN. Thrusters are activated to move the spacecraft into a transfer orbit having more eccentricity than the initial orbit. A RAAN of the transfer orbit changes over time toward a target RAAN. The spacecraft enters an aerobraking orbit wherein the spacecraft is exposed to increased atmospheric drag to reduce orbit energy and reduce an apoapsis radius. Thrusters may be activated to increase the periapsis radius of the aerobraking orbit and cause the spacecraft to move into the final orbit, the final orbit having a final RAAN different from the first RAAN.

Methods for a reusable space vehicle to land at substantially the same location as its launching site. The vehicle traveling in a particular orbit, which is a repeating ground track orbit, allows for launching and landing at the same location once per day. The repeating ground track orbits that allow for launching and landing at the same location once per day overfly the launch and landing site once per day. Launching and landing at the same site provides a number of direct advantages. For example, the just-landed vehicle may be transported a relatively short distance to the launch site, reconditioned relatively quickly, and be ready for a quick turn-around launch.