Manufacturing & Prototyping

Damage-Free Finishing of Silicon X-Ray Optics Using Magnetic Field-Assisted Finishing

Goddard Space Flight Center, Greenbelt, Maryland

Thin, segmented mirrors have been fabricated from monocrystalline silicon blocks. The material is economically viable, and is virtually free of internal stress because of its nearly perfect crystalline structure. The mirror surfaces will first be accurately figured and finished on thick silicon blocks, then sliced off at the desired thickness by wire electro-discharge machining. A finishing process has been conceived in which existing mirror-finishing processes are adapted to be capable of quickly and accurately figuring and finishing damage-free, segmented, monocrystalline silicon mirrors in a cost-efficient manner.

Posted in: Briefs, TSP, Manufacturing & Prototyping, Optics, Optics, Finishing

Smart Crucibles and Heat Pipes

Molybdenum and molybdenum alloys are the leading candidates for making the new heat pipe modules.

Marshall Space Flight Center, Alabama

Near-net-shape vacuum plasma spray (VPS) forming techniques were developed to produce advanced components with internal features such as smart heat pipes and crucibles. The initial results demonstrated the ability to incorporate features such as channels and a porous layer within the wall of a smart crucible.

Posted in: Briefs, Manufacturing & Prototyping, Forming, Parts

Multi-Step DRIE Process to Fabricate Silicon-Based THz Components

Commercial applications include airport screening systems, explosives detectors, nondestructive testing, and wireless communications.

Terahertz (THz) frequency radiometers, spectrometers, and radars are promising instruments for the remote sensing of planetary atmospheres such as Mars, Venus, Jupiter, and Saturn, and their moons such as Titan, Europa, Ganymede, and others. For these long-term planetary missions, severe constraints are put on the mass and power budget for the payload instruments.

Posted in: Briefs, TSP, Manufacturing & Prototyping, Radar, Radar, Semiconductors, Test equipment and instrumentation

Plasma Reduction of Lunar Regolith for In-Space Fabrication

Plasma processing effectively produced agglutinate and glassy spherules — analog particles similar to those found on the lunar surface.

Marshall Space Flight Center, Alabama

The in situ production of vital gases and raw materials on the lunar surface is an integral part of NASA’s exploration vision. Development of processes for extraction of oxygen and metallics from the lunar regolith will be vital not only for life support on the lunar surface, but also for spacecraft propulsion to travel further beyond low Earth orbit. This will have a direct impact on cost reduction associated with minimizing the raw material mass from Earth. Aside from utilization of in situ resources, one of the significant limitations of current simulant is the lack of constituents, such as agglutinates. These agglutinates are typically mineral fragments of the lunar regolith that are held together by glass and, depending on location, may constitute 60% to 70% of the lunar regolith.

Posted in: Briefs, Manufacturing & Prototyping, Human factors, Fabrication, Gases, Metals, Spacecraft

Method for Determining Self-Reacting Friction Stir Weld Schedules

This new process is quicker and more effective.

Lyndon B. Johnson Space Center, Houston, Texas

This invention establishes a process to define a viable self-reacting friction stir weld (SR-FSW) schedule (parameter settings) for a given material combination. The focus of this process results in a SR-FSW schedule that is insensitive to intentional changes or normal process variation in pin force at a given rotation and travel speed. Viable is defined as a weld schedule that is usable in a production environment and is able to accommodate normal production variations.

Posted in: Briefs, Manufacturing & Prototyping, Welding, Test procedures

Flexible, Lightweight Vacuum Shell for Load-Responsive Multilayer Insulation for High Thermal Performance

There are substantial reductions in weight and improvements in performance.

Goddard Space Flight Center, Greenbelt, Maryland

Better thermal insulation is needed to insulate cryogenic propellants used by NASA for launch vehicles, spacecraft, and orbiting fuel depots. In particular, cryotank insulation during in-air pre-launch and launch ascent stages currently uses spray-on foam insulation (SOFI), which is extremely problematic.

Posted in: Briefs, TSP, Manufacturing & Prototyping, Propellants, Insulation, Launch vehicles, Spacecraft

Bulk Separation and Manipulation of Carbon Nanotubes by Type

Lyndon B. Johnson Space Center, Houston, Texas

The utility of this invention is to extract metals (semi-metals) or semiconductors from bulk nanotube samples. The bulk material is a mixture of the two. These materials can then be used to clone a particular type of nanotube, place a particular type in a device, generate smart materials, or make sensing elements.

Posted in: Briefs, Manufacturing & Prototyping, Materials identification, Metals, Nanomaterials, Semiconductors

Durable Joining Technology for Uniformly-Curved Composite Sandwich Structures

An insert improves distribution of load through the joint, increasing safety.

NASA’s next-generation launch vehicles will be enabled by high-performance composite materials and innovative manufacturing methods. As such, NASA uses adhesively bonded joints where possible instead of mechanically fastened (bolted) joints to design and manufacture structures. The adhesive joints typically are lighter and distribute loads more efficiently across an interface, while mechanically fastened joints are prone to stress concentrations around the bolts.

Posted in: Briefs, Manufacturing & Prototyping, Joining, Adhesives and sealants, Composite materials, Launch vehicles

Ohmic Contact to N- and P-Type Silicon Carbide

Ohmic contact can be formed in one process step.

Electrical ohmic contacts can be simultaneously formed on silicon carbide (SiC) semiconductors having donor and acceptor impurities (n- and p-type doping, respectively). This implies that such contacts can be formed on SiC layers in one process step during the fabrication of the semiconductor device. This also means that the multiple process steps for fabricating contacts onto n- and p-type surfaces, which is characteristic of the prior art, will be greatly reduced, thereby reducing time and cost, and increasing yield (more process steps and complexity increases chances for lower yields). Another significance of this invention is that this scheme can serve as a non-discriminatory, universal ohmic contact to both n- and p-type SiC, without compromising the reliability of the specific contact resistivity when operated at temperatures in excess of 600 °C.

Posted in: Briefs, Manufacturing & Prototyping, Semiconductor devices, Semiconductor devices, Product development, Fabrication

Flap Edge Noise Reduction Fins

This innovation has applications in aircraft leading edge slats and rotor tips for propulsion components on both aircraft and rotorcraft, as well as on wind turbines.

Aircraft noise is a significant problem with both economic and public health implications, especially for communities near airports. As a result, increasingly stringent constraints are being placed on aircraft carriers worldwide to reduce this noise. The current disclosure focuses on airframe noise generated at or near the surface of the flap-side edge.

Posted in: Briefs, Manufacturing & Prototyping, Airframes, Wings, Noise, Noise

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