Special Coverage

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
Vibration Tables Shake Up Aerospace and Car Testing
Supercomputer Cooling System Uses Refrigerant to Replace Water
Computer Chips Calculate and Store in an Integrated Unit
Electron-to-Photon Communication for Quantum Computing

Ground Facility for Vicarious Calibration of Skyborne Sensors

This is an automated facility that generates Web-accessible data.

An automated ground facility, for vicarious radiometric calibration of airborne and spaceborne sensors of visible and infrared light has been established. In the term “vicarious calibration,” “vicarious” is used in the sense of “in place of another,” signifying “in place of laboratory calibration.” Vicarious calibration involves the use of ground truth in the form of measurements by ground-viewing radiometers, a Sun- viewing photometer, and meteorological instruments positioned in a ground target area. Typically, the target is a dry lakebed or other relatively homogeneous area. (The value of a relatively homogeneous target is that it minimizes effects of errors of registration between the target and the fields of view of sensors.) The measurement data are processed by a radiative- transfer computer code to estimate spectral radiances at the position of a sensor known to be overhead at the time of the measurements. These radiances can be compared with the sensor readings to calibrate the sensor.

Posted in: Briefs, TSP, Physical Sciences, Calibration, Computer software and hardware, Sensors and actuators, Wireless communication systems, Ground support, Aircraft

Impact-Locator Sensor Panels

Panels can be electronically daisy-chained and assembled to cover large areas.

Electronic sensor systems for detecting and locating impacts of rapidly moving particles on spacecraft have been invented. Systems of this type could also be useful on Earth in settings in which the occurrence of impacts and/or the locations of impacts are not immediately obvious and there are requirements to detect and quickly locate impacts to prevent or minimize damage. For example, occupants of a military vehicle could know immediately that someone was shooting at it and which side of the vehicle was taking fire. For another example, commercial transportation companies using these systems for remote monitoring of valuable cargo could know when and from what direction impacts were jeopardizing the cargo, whether the impacts were from hailstones, burglary tools, vehicular collisions, or firearms.

Posted in: Briefs, Electronics & Computers, Sensors and actuators, Particulate matter (PM), Materials handling, Collision warning systems, Military vehicles and equipment, Spacecraft

Low-Temperature Supercapacitors

Electrolyte compositions are designed to extend the low-temperature operational limit.

An effort to extend the low-temperature operational limit of supercapacitors is currently underway. At present, commercially available non-aqueous supercapacitors are rated for a minimum operating temperature of –40 °C. A capability to operate at lower temperatures would be desirable for delivering power to systems that must operate in outer space or in the Polar Regions on Earth.

Posted in: Briefs, TSP, Semiconductors & ICs, Ultracapacitors and supercapacitors, Performance upgrades

MEMS/ECD Method for Making Bi₂₋ₓSbₓTe₃ Thermoelectric Devices

Devices containing diverse materials in complex three-dimensional shapes can be fabricated.

A method of fabricating Bi2–xSbxTe3-based thermoelectric microdevices involves a combination of (1) techniques used previously in the fabrication of integrated circuits and of microelectromechanical systems (MEMS) and (2) a relatively inexpensive MEMS-oriented electrochemical- deposition (ECD) technique. The devices and the method of fabrication at an earlier stage of development were reported in “Sub milli meter-Sized Bi2–xSbxTe3 Thermoelectric Devices” (NPO-20472), NASA Tech Briefs, Vol. 24, No. 5 (May 2000), page 44. To recapitulate: A device of this type generally contains multiple pairs of n- and p-type Bi2–xSbxTe3 legs connected in series electrically and in parallel thermally. The Bi2–xSbxTe3 legs have typical dimensions of the order of tens of microns. Metal contact pads and other non-thermoelectric parts of the devices are fabricated by conventional integrated-circuit and MEMS fabrication techniques. The Bi2–xSbxTe3 thermoelectric legs are formed by electrodeposition, through holes in photoresist masks, onto the contact pads.

Posted in: Briefs, Semiconductors & ICs, Architecture, Integrated circuits, Microelectromechanical devices, Fabrication

Compact, Single-Stage MMIC InP HEMT Amplifier

This amplifier exhibits gain of 5 dB at 340 GHz.

Figure 1 depicts a monolithic microwave integrated-circuit (MMIC) single-stage amplifier containing an InP-based high- electron-mobility transistor (HEMT) plus coplanar-waveguide (CPW) transmission lines for impedance matching and input and output coupling, all in a highly miniaturized layout as needed for high performance at operating frequencies of hundreds of gigahertz. This is one in a series of devices that are intermediate products of a continuing effort to develop advanced MMIC amplifiers for sub-millimeter-wavelength imaging systems, scientific instrumentation, heterodyne receivers, and other applications.

Posted in: Briefs, TSP, Semiconductors & ICs, Amplifiers, Architecture, Integrated circuits, Transistors, Waveguides

Making a Back-Illuminated Imager With Back-Side Contact and Alignment Markers

Metal plugs provide both electrical contact and alignment.

A design modification and a fabrication process that implements the modification have been conceived to solve two problems encountered in the development of back-illuminated, back-side-thinned complementary metal oxide/semiconductor (CMOS) image-detector integrated circuits. With respect to such an integrated circuit to be fabricated on a silicon substrate, the two problems are (1) how to form metal electrical-contact pads on the back side that are electrically connected through the thickness in proper alignment with electrical contact points on the front side and (2) how to provide alignment keys on the back side to ensure proper registration of backside optical components (e.g., microlenses and/or color filters) with the frontside pixel pattern. (In this special context, “front side” signifies that face of the substrate upon which the pixel pattern and the associated semiconductor devices and metal conductor lines are formed.)

Posted in: Briefs, TSP, Electronics & Computers, Calibration, Imaging and visualization, Integrated circuits, Fabrication

Green Energy for the Battlefield

The amount of energy the United States consumes increases every year and this growth in energy consumption outpaces energy production. To fill this gap, the U.S. imports 35% of its energy. More importantly, the U.S. imports over 60% of its total oil consumption. Added to this, 70% of this energy is from non-renewable sources.

Posted in: Articles, Energy, Green Design & Manufacturing, Energy consumption, Military vehicles and equipment

Miniature Control Chip Drives James Webb Telescope Signal

SIDECAR ASIC microprocessor-controlled chip Teledyne Imaging Sensors Camarillo, CA 805-373-4545 www.teledyne-si.com

The electronics that will convert analog signals to digital signals on the James Webb Space Telescope (JWST), being built by Northrop Grumman and managed by NASA’s Goddard Space Flight Center, have been miniaturized to take up less space and to weigh less. The electronics also will provide better images of objects in space when they are sent back to scientists on Earth.

Posted in: Application Briefs, Electronics, Sensors, Imaging and visualization, Sensors and actuators

NASA Satellite Data Interpreted for Medical and Public Health Use

Laboratory for Global Health Observation University of Alabama at Birmingham, School of Public Health Birmingham, AL 205-934-4993 www.regardsstudy.org

A partnership between NASA’s National Space Science and Technology Center (NSSTC) and the School of Public Health at the University of Alabama at Birmingham (UAB) is using NASA satellite imagery and data to determine how environmental factors influence diseases such as malaria and childhood asthma.

Posted in: Application Briefs, Medical, Data Acquisition, Data acquisition and handling, Medical, health, and wellness, Satellites

Low-Loss Waveguides for Terahertz Frequencies

Low-loss, flexible conduits of terahertz power would be developed.

Hollow-core, periodic bandgap (HCPBG) flexible waveguides have been proposed as a means of low-loss transmission of electromagnetic signals in the frequency range from about 300 GHz to 30 THz. This frequency range has been called the “terahertz gap” because it has been little utilized: Heretofore, there has been no way of low-loss guiding of terahertz beams other than by use of fixed- path optical beam guides with lenses and mirrors or multimode waveguides that cannot maintain mode purity around bends or modest discontinuities.

Posted in: Briefs, Electronics & Computers, Waveguides, Wireless communication systems

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