Special Coverage

Soft Robot “Walks” on Any Terrain
Defense Advanced Research Projects Agency
Using Microwaves to Produce High-Quality Graphene
Transducer-Actuator Systems for On-Machine Measurements and Automatic Part Alignment
Wide-Area Surveillance Using HD LWIR Uncooled Sensors
Heavy Lift Wing in Ground (WIG) Cargo Flying Boat
Technique Provides Security for Multi-Robot Systems
Bringing New Vision to Laser Material Processing Systems
NASA Tests Lasers’ Ability to Transmit Data from Space
Converting from Hydraulic Cylinders to Electric Actuators
Automating Optimization and Design Tasks Across Disciplines

System for Measuring Flexing of a Large Spaceborne Structure

An optoelectronic metrology system is used for determining the attitude and flexing of a large spaceborne radar antenna or similar structure. The measurements are needed for accurate pointing of the antenna and correction and control of the phase of the radar signal wavefront. The system includes a dual-field-of-view star tracker; a laser ranging unit (LRU) and a position-sensitive-detector (PSD)-based camera mounted on an optical bench; and fiducial targets at various locations on the structure.

Posted in: Briefs, Electronics & Computers, Calibration, Measurements, Antennas, Radar, Antennas, Radar

VHF Wide-Band, Dual-Polarization Microstrip-Patch Antenna

A dual-stacked-patch design incorporates several improvements over a basic design.

The figure depicts selected aspects of a very-high-frequency (VHF) microstrip-patch antenna designed and built to satisfy requirements specific to an airborne synthetic-aperture radar system for measuring the thickness of sea ice. One of the requirements is that the antenna be capable of functioning over the relatively wide frequency band of 127 to 172 MHz — corresponding to a fractional bandwidth of about 30 percent relative to a nominal mid-band frequency of 149.5 MHz. Another requirement is that the antenna be capable of functioning in either or both of two orthogonal linear polarizations. In addition, the antenna is required to be as compact and lightweight as possible.

Posted in: Briefs, Electronics & Computers, Antennas, Architecture, Radar, Antennas, Architecture, Radar, Weather and climate

Using LDPC Code Constraints To Aid Recovery of Symbol Timing

Performance would approach within ≈ 0.2 dB of that of perfect timing.

A method of utilizing information available in the constraints imposed by a low-density parity-check (LDPC) code has been proposed as a means of aiding the recovery of symbol timing in the reception of a binary-phase- shift-keying (BPSK) signal representing such a code in the presence of noise, timing error, and/or Doppler shift between the transmitter and the receiver. This method and the receiver architecture in which it would be implemented belong to a class of timing-recovery methods and corresponding receiver architectures characterized as pilotless in that they do not require transmission and reception of pilot signals.

Posted in: Briefs, Electronics & Computers, Architecture, Architecture

Integrated Formation Optical Communication and Estimation System

Formation estimation couples estimation algorithms, sensing topology, and communication topology.

An architecture has been designed that integrates formation estimation methodologies, precision formation sensing, and high- bandwidth formation communication into a robust, strap-on system that meets knowledge and communication requirements for the majority of planned, precision formation missions. Specifically, the integrated system supports (a) sub- millimeter metrology, (b) multiple >10 Mbps communication channels over a large, 10° field-of-view (FOV), and (c) generalized formation estimation methodologies. The sensing sub-system consists of several absolute, metrology gauges with up to 0.1 mm precision that use amplitude-modulated lasers and a LISA-heritage phase meter. Since amplitude modulation is used, inexpensive and robust diode lasers may be used instead of complex, frequency-stabilized lasers such as for nanometer-level metrology. The metrology subsystem laser transceivers consist of a laser diode, collecting optics, and an avalanche photo diode (APD) for detecting incoming laser signals. The APD is necessary since received power is small due to the large (for optical applications) FOV. The phase meter determines the phase of the incoming amplitude modulations as measured by the APD. This phase is equivalent to time-of-flight and, therefore, distance.

Posted in: Briefs, Electronics & Computers, Architecture, Communication protocols, Lasers, Architecture, Communication protocols, Lasers

Making Superconducting Welds Between Superconducting Wires

Parts of a superconducting circuit can be made from different metals.

A technique for making superconducting joints between wires made of dissimilar superconducting metals has been devised. The technique is especially suitable for fabrication of superconducting circuits needed to support persistent electric currents in electromagnets in diverse cryogenic applications. Examples of such electromagnets include those in nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) systems and in superconducting quantum interference devices (SQUIDs).

Posted in: Briefs, TSP, Manufacturing & Prototyping, Electromagnetic compatibility, Wiring, Electromagnetic compatibility, Wiring, Fabrication, Welding, Conductivity

Method for Thermal Spraying of Coatings Using Resonant-Pulsed Combustion

High-volume, high-velocity surface deposition allows protective metal coatings to be applied to otherwise vulnerable surfaces.

A method has been devised for high-volume, high-velocity surface deposition of protective metallic coatings on otherwise vulnerable surfaces. Thermal spraying is used whereby the material to be deposited is heated to the melting point by passing through a flame. Rather than the usual method of deposition from the jet formed from the combustion products, this innovation uses non-steady combustion (i.e. high- frequency, periodic, confined bursts), which generates not only higher temperatures and heat transfer rates, but exceedingly high impingement velocities an order of magnitude higher than conventional thermal systems. Higher impingement rates make for better adhesion. The high heat transfer rates developed here allow the deposition material to be introduced, not as an expensive powder with high surface-area-to-volume, but in convenient rod form, which is also easier and simpler to feed into the system. The nonsteady, resonant combustion process is self-aspirating and requires no external actuation or control and no high-pressure supply of fuel or air.

Posted in: Briefs, TSP, Manufacturing & Prototyping, Heat transfer, Heat transfer, Spraying, Metals, Combustion and combustion processes

Coating Reduces Ice Adhesion

Developed for the space shuttle, this coating may be used on aircraft and automobiles.

The Shuttle Ice Liberation Coating (SILC) has been developed to reduce the adhesion of ice to surfaces on the space shuttle. SILC, when coated on a surface (foam, metal, epoxy primer, polymer surfaces), will reduce the adhesion of ice by as much as 90 percent as compared to the corresponding uncoated surface. This innovation is a durable coating that can withstand several cycles of ice growth and removal without loss of anti-adhesion properties.

Posted in: Briefs, Materials, Coatings Colorants and Finishes, Coatings, colorants, and finishes, Durability, Durability, Icing and ice detection, Reusable launch vehicles and shuttles

Hybrid Multifoil Aerogel Thermal Insulation

Aerogel used in place of astroquartz makes lighter, more efficient insulation.

This innovation blends the merits of multifoil insulation (MFI) with aerogel-based insulation to develop a highly versatile, ultra-low thermally conductive material called hybrid multifoil aerogel thermal insulation (HyMATI). The density of the opacified aerogel is 240 mg/cm3 and has thermal conductivity in the 20 mW/mK range in high vacuum and 25 mW/mK in 1 atmosphere of gas (such as argon) up to 800 ºC. It is stable up to 1,000 ºC. This is equal to commercially available high-temperature thermal insulation. The thermal conductivity of the aerogel is 36 percent lower compared to several commercially available insulations when tested in 1 atmosphere of argon gas up to 800 ºC.

Posted in: Briefs, TSP, Materials, Conductivity, Insulation, Nanomaterials

XML-Based SHINE Knowledge Base Interchange Language

The SHINE Knowledge Base Interchange Language software has been designed to more efficiently send new knowledge bases to spacecraft that have been embedded with the Spacecraft Health Inference Engine (SHINE) tool. The intention of the behavioral model is to capture most of the information generally associated with a spacecraft functional model, while specifically addressing the needs of execution within SHINE and Livingstone. As such, it has some constructs that are based on one or the other.

Posted in: Briefs, TSP, Information Sciences, Communication protocols, Computer software / hardware, Computer software and hardware, Data exchange, Communication protocols, Computer software / hardware, Computer software and hardware, Data exchange

SHINE Virtual Machine Model for In-flight Updates of Critical Mission Software

This software is a new target for the Spacecraft Health Inference Engine (SHINE) knowledge base that compiles a knowledge base to a language called Tiny C — an interpreted version of C that can be embedded on flight processors. This new target allows portions of a running SHINE knowledge base to be updated on a “live” system without needing to halt and restart the containing SHINE application. This enhancement will directly provide this capability without the risk of software validation problems and can also enable complete integration of BEAM and SHINE into a single application.

Posted in: Briefs, TSP, Information Sciences, Computer software / hardware, Computer software and hardware, Computer software / hardware, Computer software and hardware, Spacecraft

The U.S. Government does not endorse any commercial product, process, or activity identified on this web site.