Sri International

Other

Richard Cosmo Adamo

Victor M Aguero

Paolo G Sechi

Robert A Brown

Richard C Honey

Karen Marie Nashold

The chassis of a spacecraft has one side exposed to ultraviolet photons and another side shielded from the ultraviolet photons. An electrically conductive surface is disposed on the exposed side of the chassis and is electrically isolated from the chassis. A field-emission array device has a gate, an emitter array, a first terminal electrically connected to the gate, and a second terminal electrically connected to the emitter array. The first terminal electrically couples the gate to the electrically conductive surface on the exposed side of the chassis, and the second terminal electrically couples the emitter array to a surface on the shielded side of the chassis. The emitter array discharges electrons from the surface on the shielded side when a voltage difference in excess of a threshold voltage develops between the gate and the emitter array because of differential charging of the exposed and shielded sides of the chassis.

Solar powered excess electron emission device

Described are a system and method for monitoring and characterizing a stimulus in order to detect transient phenomena. An analog signal represents the stimulus. Conversion circuitry receives the analog signal and continuously converts the analog signal into digital data. Digital circuitry continuously receives the digital data from the conversion circuitry and dynamically computes from the digital data a value that characterizes a parameter of the stimulus while the digital circuitry continuously receives new digital data from the conversion circuitry. The digital circuitry can be reconfigured to characterize a different parameter for the same type or for a different type of stimulus.

Real-time transient pulse monitoring system and method

A sensor and method for measuring an electrical potential difference are described. The sensor includes a micro-fabricated field emission device situated in a space plasma environment. The field emission device has an emitter terminal and a gate terminal. A voltage source applies a voltage across the gate and the emitter terminals to induce current to flow from the emitter terminal A first current monitor measures current flowing from the emitter in response to the applied voltage. A second current monitor measures current flowing to the gate. A control system correlates applied voltages and measured gate and emitter currents with electrical potential differences between the field emission device and the space plasma environment. The control system obtains the gate and emitter currents from the current monitors. A processor computes a value from the gate and emitter current measurements based on a predetermined functional relationship.

System and method for sensing and controlling potential differences between a space object and its space plasma environment using micro-fabricated field emission devices

A system and method for altering an orbit of a space object are described. An electrodynamic tether is deployed from an orbiting space object such that the electrodynamic tether is capable of producing electrical charge. A micro-fabricated charge-emitting device is placed at one end of the electrodynamic tether and has at least two terminals. One of the terminals is electrically connected to the tether to receive the electrical charge produced by the tether. A voltage source applies a voltage across the two terminals of the charge-emitting device to induce the charge-emitting device to emit the charge received from the tether. Depending in part upon the end at which the charge emission device is placed and upon the polarity of the charge emitted, emission of the charge raises or lowers the orbit of the space object.

System and method for adjusting the orbit of an orbiting space object using an electrodynamic tether and micro-fabricated field emission device

A computer-based transient pulse monitoring system and method are described. A general-purpose computer system having a processor, memory, and a digital signal bus for conveying digital signals, also includes a circuit board for measuring certain parameters associated with transient phenomena. The circuit board includes analog circuitry for receiving an analog input signal representing transient phenomena. The analog circuitry continuously measures a characteristic of the transient phenomena and produces an analog output signal representing the measured characteristic. The circuit board also includes a digital interface in communication with the analog circuitry and the digital signal bus. The digital interface converts the analog output signal into a digital signal representing the measured characteristic and transmits the digital signal onto the digital signal bus. The computer system can be connected to a network, such as the Internet. Other systems connected to this network can access the measurements obtained by the computer system of the invention using standard browser technology or file transfer protocols.

Computer-based real-time transient pulse monitoring system and method

A controller for controlling an electrical potential of an object with respect to its environment is described. The controller includes a micro-fabricated charge-emitting device connected to a space object situated in a space plasma environment. The charge-emitting device has a gate and an emitter. A voltage source applies a voltage across the gate and the emitter of the charge-emitting device to induce the emitter to emit into the environment electrical charge drawn from the object. In general, the magnitude of the applied voltage can be less than 100 volts. A control system varies the voltage applied between the gate and the emitter of the charge-emitting device. Varying the voltage adjusts the amount of electrical charge that is emitted by the emitter. Thus, by controlling the voltage, the control system can control the electrical potential of the space object with respect to the space plasma environment.

System for emitting electrical charge from a space object in a space plasma environment using micro-fabricated gated charge emission devices

Method and apparatus for limiting optical radiation to an optical sensor are disclosed for protecting the sensor against damage from high intensity optical radiation. A fixed electric field is established between a pair of spaced electrodes by connection of the electrodes to a DC voltage source. Small solid particles oscillate back and forth in the electric field between the electrodes. Incident optical radiation is focused at a focal plane at the oscillating solid particles, and energy transmitted through the oscillating particles is focused at the optical sensor. The transmittance of the particle-containing space is substantially constant for incident optical radiation intensity up to a threshold level below which the sensor is undamaged by the radiation. Above the threshold, oscillating particles are heated to a high temperature for vaporization, ionization and thermal expansion thereof for increased scatter and absorption thereby limiting optical radiation to the sensor to an intensity below which damage to the sensor occurs.

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Palo Alto, CA, United States of America

Richard Cosmo Adamo