Refractory Open-Cell Foam Fuel Matrix for High-Efficiency Nuclear Thermal Propulsion

A fuel form for fission applications is functional at extremely high temperatures with minimal erosion or fission product losses. Marshall Space Flight Center, Alabama A tricarbide foam fuel material has been developed that can operate at temperatures near 3,000 °C, without substantial hydrogen erosion, while providing highly efficient heat transfer to the coolant or propellant. A tricarbide foam fuel matrix of zirconium carbide (ZrC), niobium carbide (NbC), and uranium carbide (UC) has been successfully deposited and hydrogen tested. It shows that high-temperature, high-porosity foams can be produced that resist hydrogen corrosion and prevent the diffusion of fission products from the matrix. Chemical vapor deposition (CVD) technology was applied to nuclear materials systems that may be used in thermal propulsion and very high-temperature gas reactors.

Posted in: Materials, Briefs

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Hydrazine Absorbent/Detoxification Pad

This hydrazine-degrading pad has applications in hazardous-material emergency response situations. Lyndon B. Johnson Space Center, Houston, Texas A new chemistry was developed for existing hydrazine absorbent/detoxification pads. Enhancements include faster reaction rates, weight reduction, a color change that indicates spill occurrence, and another color change that indicates successful hydrazine degradation. The previous spill control pad, using copper oxide on the silica gel substrate as the reactant, affected only 50 percent degradation of hydrazine after 9 hours. The new prototypes have been found to degrade hydrazine from 95 to 99.9 percent in only 5 minutes, and to below detection limits within 90 minutes.

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Nanotechnology Approach to Lightweight, Multifunctional Polyethylene Composite Materials

Potential uses include personal armor, implantable prosthetics, and cut-resistant fabrics such as gloves worn by chefs and scuba divers. Langley Research Center, Hampton, Virginia Of several ideas being pursued by NASA for the reduction of radiation dosage to astronauts, the use of ultra-high-molecular-weight polyethylene (UHMWPE)-based composite materials for both radiation shielding and micrometeorite shielding appears to be particularly appealing. UHMWPE has long been understood to provide superior radiation shielding following encounters with energetic nucleons due to its high hydrogen content. Meanwhile, impacts of micrometeorites with UHMWPE tend to vaporize it, rather than causing spallation of the shield material, which then creates additional potentially damaging micrometeorites. Less widely appreciated is the high specific strength of UHMWPE and UHMWPE fibers, which provide structural integrity to the composite. Amongst thermoplastics, UHMWPE has the highest impact strength and is also highly resistant to abrasion. Despite this highly appealing combination of properties, UHMWPE’s key mechanical properties can be improved by forming composites with other nanostructured materials, leading to further performance increases and weight reductions. Such composites will increase the ability of UHMWPE structures to withstand micrometeorite impacts and maintain the structural integrity of a pressurized environment.

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Electrostrictive Polymers

These lightweight and durable materials enable sensing and actuation devices. Langley Research Center, Hampton, Virginia A new class of electroactive polymeric blend materials has been created that offers both sensing and actuation dual functionality. The blend is comprised of two components where one has sensing capability, and the other has actuating capability. These innovative materials provide significant field-induced strain, high mechanical output force, and exceptional strain energy density. These electrostrictive polymers are conformable, lightweight, and durable. The processing system to fabricate these polymers is simple and can be manipulated to control and optimize the materials’ mechanical and electrical properties.

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COVE: A CubeSat Payload Processor

This processor is a reconfigurable FPGA-based electronics payload for advanced data processing applications. NASA’s Jet Propulsion Laboratory, Pasadena, California The COVE (CubeSat Onboard processing Validation Experiment) Payload Processor is JPL’s first on-orbit demonstration with the Xilinx Virtex-5 FPGA (field-programmable gate array). The electronics payload is designed to provide a platform for advanced data processing applications while conforming to CubeSat specifications. Measuring 9 × 9.5 × 2 cm, COVE carries the new radiation-hardened Virtex-5 FPGA (V5QV), magnetoresistive RAM (MRAM), and phase-change memory. All data access to/from the payload is facilitated through a shared memory interface via a direct serial peripheral interface (SPI). Multiple configuration options enable COVE to be reconfigured in flight with new FPGA firmware.

Posted in: Electronics & Computers, Briefs

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Dynamic Range Enhancement of High-Speed Data Acquisition Systems

Reversible non-linear amplitude compression is used. John H. Glenn Research Center, Cleveland, Ohio The innovation is a technique to overcome hardware limitations of common high-speed data acquisition systems in order to be able to measure electronic signals with high dynamic range, wide bandwidth, and high frequency.

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HALT Technique to Predict the Reliability of Solder Joints in a Shorter Duration

This methodology can reduce product development cycle time for improvements to packaging design qualification. NASA’s Jet Propulsion Laboratory, Pasadena, California The Highly Accelerated Life Testing (HALT) process subjects test articles to accelerated combined environments of thermal, dynamic, voltage, and current to find weak links in a given product design. The technique assesses fatigue reliability of electronic packaging designs used for long-duration deep space missions by testing using a wide temperature range (–150 to +125 °C), and dynamic acceleration range of up to 50g. HALT testing uses repetitive, multiple-axis vibration combined with thermal cycling on test articles to rapidly precipitate workmanship defects, manufacturing defects, and thermal cycling-related weak links in the design. This greatly reduces the product development time by rapidly finding problems and qualifying the packaging design quickly. Test vehicles were built using advanced electronic package designs using the surface mount technology process.

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