Space Systems/loral, LLC

Howard E Pollard

Robert E Neff

Michael J McVey

Christopher F Hoeber

Cheryl J Ajluni

Improved solar cell circuit layouts and cell structures that protect solar arrays located on spacecraft disposed in geosynchronous earth orbit from electrostatic discharge. An insulating material, such as RTV adhesive, for example, is used as a barrier that disposed in intercell gaps between solar cells. The use of the insulating material modifies sparking in the gaps caused by electrostatic discharge so that, while the spark still occurs, it has different non-destructive characteristics. The use of the insulating material causes no damage to other solar cell materials, such as a Kapton insulating layer or substrate used to support the solar cells. Furthermore, unique solar cell wiring schemes are provided that limit the voltage between adjacent solar cells to 50 volts or less.

Solar array augmented electrostatic discharge for spacecraft in geosynchronous earth orbit

A solar cell assembly with current limiting protection comprises a rectangular planar solar cell having four corner locations including first and second opposed surfaces and a beveled edge at one of the corner locations. Parallel spaced longitudinally extending conductors are provided on a first opposed surface and a metallic coating overlies an entire second opposed surface. Interconnect members mount a protective bypass diode, electrically intermediate and in series with the first and second conductor members, on the solar cell in a mutually coplanar relationship proximate to but spaced from the beveled edge, accommodating relative in-plane motion between the bypass diode and the solar cell. The interconnect members include an upper interconnect member extending between and fixed, respectively, to a first metallic pad member on the first opposed surface adjacent the beveled edge and electrically connected to the bus member and to a first surface of the bypass diode and a lower interconnect member extending between and fixed, respectively, to a second metallic pad member mounted adjacent the beveled edge and electrically connected to the metallic coating and to a second surface of the bypass diode. A protective glass sheet overlies and is bonded to the first opposed surface of the solar cell and the bypass diode in a generally coextensive relationship. A supplemental reinforcement sheet member may overlie a portion of the second opposed surface of the solar cell and the bypass diode and be bonded thereto in a generally coextensive relationship.

Solar cell assembly

An optical inspection system for detecting cracks in a crystalline substrate. The crystalline substrate that is to be inspected is located in a test plane in the field of view of a video camera. A first collimated light source projects light which is passed through a long pass filter. The filtered collimated light is projected onto the reflective surface of a panel that contains surface irregularities in the same order as the wavelength of the filtered, collimated light. The light is diffused by the panel surface and reflected onto the crystalline substrate at a plurality of various angles. The light passes through the crystalline substrate and is reflected into the path of the field of view of the video camera and forms an object image from which a real image is created and may be viewed on a control monitor. Cracks in the solar cell silicon layer or glass covers can be observed on the control monitor, and printed by a video graphics printer or stored via a VCR for permanent documentation purposes.

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Saratoga, CA, United States of America

Howard E Pollard