Abstract: A method of making a thin gallium arsenide solar cell having a reflecting back surface and coplanar electrical contacts. A photovoltaic cell comprising gallium arsenide is produced in a self-supporting thickness by conventional methods. A pattern of contact lines and a bus contact are formed on the front surface of the cell and a transparent coverslide is bonded thereover. The back of the cell is chemically etched away until the minimum effective thickness is reached, then etching in the bus contact region is continued until the bus is exposed. Any stop-etch material used to prevent excessive etching of the cell material is removed and a reflective contact material is applied to the back of the cell. The resulting solar cell is light in weight and both front and back connections can be made from the back of the cell, making it particularly suitable for use in space-based arrays.

Abstract: An automated assembly, maintenance, and repair system for the construction of a large space structure. The space structure comprises a plurality of trusses and truss junctions that in turn are made up of a plurality of individual struts and nodes. The truss assemblies are progressively built by an assembler trolley as the trolley crawls along the constructed truss. The trolley comprises a forward crawler and a rear crawler joined by an articulated coupler. The crawlers are carried along the structure by belt transports incorporating grippers that engage the truss structure at the nodes. Manipulator arms for strut and node assembly are located on the forward crawler, and the majority of control, power, and communication systems are located in the rear crawler. Cargo canisters filled with component parts for constructing the space structure are carried by the forward crawler. The space structure configuration is determined by the arrangement of the individual struts and nodes during the assembly process.

Abstract: An ultrasonic welding energy concentrating chain comprising a plurality of relatively flat members integrally formed from a flat stock of energy concentrating material having a predetermined thickness and joined together adjacent their peripheries by integral portions to interconnect adjacent members into a longitudinally extending chain, said integral portions being formed as to permit each manual separation of adjacent members, said members being adapted to being interposed between sheets of thermoplastic material and upon application of ultrasonic energy to the sandwich of thermoplastic sheets, the shape of the weld of such thermoplastic sheets generally approximating the shape of said flat members.

Abstract: A tool for installing shrink fit parts formed of a material which is dimensionally stable over a wide range of temperatures having a locating surface on which a part to be shrunk is clamped and having a chamber adjacent the locating surface, which is filled with a cooling media as the part is being shrunk in a source or vat of cooling media, to maintain the part in its shrunken condition after removal from the cooling media. A valve is provided for removing the cooling media from the chamber after the shrunken part is positioned precisely in a second part so that the shrunken part will warm and expand into the second part to form a shrink fit therewith.