The Boeing Company

Jeffrey Scott Noel

Andrew Henry Giacobe

Yiu-Hung Monte Ho

Sadek W Mansour

Gary E Lemke

Jason D Flathom

Rainier Pio Roda

A method for providing optimized power balanced low thrust transfer orbits utilizing split thruster execution to minimize an electric orbit raising duration of an apparatus includes monitoring an electric power balance on the apparatus. The method also includes firing a first thruster in response to the apparatus exiting an eclipse and based on the electric power balance. The method additionally includes firing a second thruster at a predetermined time delay after firing the first thruster based on the electric power balance. The method additionally includes ending firing one of the first thruster or the second thruster after a predetermined time duration based on the electric power balance. The method further includes ending firing another of the first thruster or the second thruster in response to the apparatus entering a next eclipse.

Optimized power balanced low thrust transfer orbits utilizing split thruster execution

Systems and methods for launching a plurality of spacecraft, provided in a stack of spacecraft, from a launch vehicle traveling along an in-track path include releasing, in a first separation event occurring at a first time, a first spacecraft from the stack of spacecraft using a first separation force having a first separation force in-track component along the in-track path. Subsequently, in a second separation event occurring at a second time, a second spacecraft is released from the stack of spacecraft using a second separation force having a second separation force in-track component along the in-track path, wherein the second time occurs a first time delay after the first time. The first and second separation in-track components may be different, such as by varying a magnitude of the separation force or an angle at which the spacecraft is launched.

Systems and methods for launching a plurality of spacecraft

A method for autonomously controlling electric power supplied to a thruster of a spacecraft during electric orbit raising includes determining a state of charge of a battery onboard the spacecraft at an entry into an eclipse during each orbit of a plurality of orbits during the electric orbit raising of the spacecraft. The method also includes determining an electric power level used to fire each thruster of a plurality of thrusters during each orbit beginning after the eclipse, based at least on the state of charge of the battery, and that will provide a shortest electric orbit raising duration and minimize thruster propellant usage during electric orbit raising.

Autonomous control of electric power supplied to a thruster during electric orbit raising

An apparatus for providing optimized power balanced variable thrust transfer orbits to minimize an electric orbit raising duration is disclosed. The electric orbit raising includes a first transfer orbit and a target orbit. The apparatus includes control electronics configured to transfer to a second transfer orbit to reach the target orbit. A variable thrust based on a current electric power balance is determined. The control electronics are further configured to execute a maneuver to transfer from the first transfer orbit to the second transfer orbit according to the determined variable thrust and a predetermined maneuver plan. The predetermined maneuver plan includes a set of compound steering parameters. The set of compound steering parameters are based on an optimized variable thrust and an associated electrical power balance to the optimized variable thrust. An optimized series of transfer orbits minimizes the electric orbit raising duration.

Optimized power balanced variable thrust transfer orbits to minimize an electric orbit raising duration

Apparatus and methods for stationkeeping in a satellite. The satellite includes a north electric thruster and a south electric installed on a zenith side, an east chemical thruster installed on an east side, and a west chemical thruster installed on a west side. An orbit controller detects a failure of one of the electric thrusters. In response to the failure, the orbit controller controls a burn of the remaining electric thruster proximate to an orbital node. The orbit controller controls a burn of one of the chemical thrusters at 90&#xb0;&#xb1;5&#xb0; from the burn of the remaining electric thruster, and controls a burn of the other one of the chemical thrusters at 270&#xb0;&#xb1;5&#xb0; from the burn of the remaining electric thruster.

Efficient stationkeeping design for mixed fuel systems in response to a failure of an electric thruster

Apparatus and methods for stationkeeping in a satellite. The satellite includes a north electric thruster and a south electric installed on a zenith side. An orbit controller selects a duration of a burn of the north electric thruster proximate to an ascending node that differs from a duration of a burn of the south electric thruster proximate to a descending node. The orbit controller is configured to select an offset of the burn of the north electric thruster in relation to the ascending node that differs from an offset of the burn of the south electric thruster in relation to the descending node.

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Torrance, CA, United States of America

Jeffrey Scott Noel