Engineering topics

Marshall, Craig

Publications and source records attributed to Marshall, Craig.

3 records

NASA NTRS2005

Multifunctional Deployment Hinges Rigidified by Ultraviolet

Multifunctional hinges have been developed for deploying and electrically connecting panels comprising planar arrays of thin-film solar photovoltaic cells. In the original intended application of these hinges, the panels would be facets of a 32-sided (and approximately spherical) polyhedral microsatellite (see figure), denoted a PowerSphere, that would be delivered to orbit in a compact folded configuration, then deployed by expansion of gas in inflation bladders. Once deployment was complete, the hinges would be rigidified to provide structural connections that would hold the panels in their assigned relative positions without backlash. Such hinges could also be used on Earth for electrically connecting and structurally supporting solar panels that are similarly shipped in compact form and deployed at their destinations. As shown in section A-A in the figure, a hinge of this type is partly integrated with an inflation bladder and partly integrated with the frame of a solar panel. During assembly of the hinge, strip extensions from a flexible circuit harness on the bladder are connected to corresponding thin-film conductors on the solar panel by use of laser welding and wrap-around contacts. The main structural component of the hinge is a layer of glass fiber impregnated with an ultraviolet-curable resin. After deployment, exposure to ultraviolet light from the Sun cures the resin, thereby rigidifying the hinge.

Kerslake, Thomas W.↗

NASA NTRS2005

Development of a Thin-Film Solar Cell Interconnect for the Powersphere Concept

Dual junction amorphous silicon (a-Si) solar cells produced on polyimide substrate have been selected as the best candidate to produce a lightweight solar array for the PowerSphere program. The PowerSphere concept features a space-inflatable, geodetic solar array approximately 0.6 meters in diameter and capable of generating about 20W of electrical power. Trade studies of various wiring concepts and connection methods led to an interconnect design with a copper contact that wraps around the edge, to the back of the solar cell. Applying Plasma Vapor Deposited (PVD) copper film to both sides and the edge of the solar cell produces the wrap around contact. This procedure results in a contact pad on the back of the solar cell, which is then laser welded to a flex circuit material. The flex circuit is constructed of copper in a custom designed routing pattern, and then sandwiched in a Kapton insulation layer. The flex circuit then serves as the primary power distribution system between the solar cells and the spacecraft. Flex circuit material is the best candidate for the wiring harness because it allows for low force deployment of the solar cells by the inflatable hinges on the PowerSphere. An additional frame structure, fabricated and assembled by ILC Dover, will reinforce the wrap around contact-flex blanket connection, thus providing a mechanically robust solar cell interconnect for the PowerSphere multifunctional program. The PowerSphere team will use the wraparound contact design approach as the primary solution for solar cell integration and the flex blanket for power distribution.

Simburger, Edward J.↗

NASA NTRS1994

Fiber Optical Solar Simulator

A new solar simulator is described whose output closely matches a desired solar spectrum for testing photovoltaic cells. The accurate simulation of the spectrum is attained by combining three light beams, each tailored to have suitable spectral content. The three light beams, derived from two sources, are filtered and 'mixed' by means of a trifurcated, randomized fiber cable so that when superimposed they add up to the desired solar spectrum. The fiber optic solar simulator (FOSS) simplifies solar cell testing by greatly reducing measurement time, obviating need for spectral mismatch corrections, and improving the accuracy of measurement. Other applications of FOSS are also described.

Sopori, Bhushan L.↗