Space Systems/loral, LLC

California Institute of Technology

David Younghee Oh

Dan M Goebel

Lenny Low

Peter W Lord

Bao Hoang

Christopher Bryan Stell

Jorge Delgado

Thomas Randolph

Lee Charles Rotlisberger

Gregory Alan Carr

Fischer Guenter

Denis Trofimov

A spacecraft includes a power train that includes a solar array, an electric propulsion subsystem, and a power conversion module. The power conversion module receives power from the solar array at a voltage, V; and delivers power to the electric propulsion subsystem at a voltage, V. The spacecraft is configured to operate at a varying distance, D, from the sun within the range of Dto D, Dbeing at least 1.3&#xd7;D. The solar array is configured to deliver power to the power conversion module at a voltage approximately equal to Vwhen the spacecraft is proximate to D.

Power train for deep space solar electric propulsion

An electric propulsion (EP) device is used to enable, a stationkeeping satellite to track a prescribed stationkeeping Earth orbit. EP propellant and electric power are throttled to vary the thrust and specific impulse of the EP device. A solar array provides electrical power during each Earth day cycle with excess power above that needed by the spacecraft stored by a battery. Software control manages the voltage, current and burn time to minimize propellant usage and impact to the system.

Energy managed electric propulsion methods and systems for stationkeeping satellites

Systems and methods for launching a satellite into orbit that optimize the mass of the satellite delivered into orbit. A satellite carrying one or more chemical propulsion devices and one or more electric propulsion devices is launched into a transfer orbit using a launch vehicle. In one embodiment, a selected chemical propulsion device is fired to raise the orbit of the satellite from the transfer orbit to an intermediate orbit. One or more electric propulsion device is fired to raise the orbit of the satellite from the intermediate orbit to final geosynchronous orbit and the one or more electric propulsion device is throttled to produce variable thrust levels so as to operate at all optimum specific impulse level to optimize the mass of the satellite delivered into orbit. In another embodiment, the electric propulsion device may deliver the satellite into a near-geosynchronous orbit instead of final geosynchronous orbit. In this case, a selected chemical propulsion device is fired to place the satellite in its final orbit. In yet another embodiment, the launch vehicle may be used to deliver the satellite into the intermediate starting orbit after which the electric propulsion device is used to achieve final orbit. In this case, the transfer orbit raising step is omitted.

Electric orbit raising with variable thrust

Systems and methods that employ a phase change material to provide thermal control of electric propulsion devices (thrusters). A spacecraft is configured to have an electric propulsion thruster. The electric propulsion thruster is surrounded with a phase change material. Suitable phase change materials include high-density polyethylene (HDPE), waxes, paraffin materials, and eutectic salts. The spacecraft is launched into orbit. The electric propulsion thruster is fired for a predetermined period of time. Heat generated by the electric propulsion thruster is absorbed and stored in the phase change material while the thruster is firing. The stored heat is dissipated into space after the thruster has stopped firing.

Phase change material thermal control for electric propulsion

A charging sensor that uses photoemission to directly measure the electrical potential of a spacecraft in orbit relative to the space environment. The photoemission based charging sensor uses photoemission from a photoemitting conductive plate of a charge probe as a reference point for voltage readings and provides direct measurements of spacecraft charging.

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La Canada, CA, United States of America

David Younghee Oh