Tech Briefs

Balloon for Long-Duration, High-Altitude Flight at Venus

A document describes a 5.5-m-diameter, helium-filled balloon designed for carrying a scientific payload having a mass of 44 kg for at least six days at an altitude of about 55 km in the atmosphere of Venus. The requirement for floating at nearly constant altitude dictates the choice of a mass-efficient spherical super-pressure balloon that tracks a constant atmospheric density. Therefore, the balloon is of a conventional spherical super-pressure type, except that it is made of materials chosen to minimize solar radiant heating and withstand the corrosive sulfuric acid aerosol of the Venusian atmosphere.

Posted in: Briefs, TSP, Physical Sciences, Test equipment and instrumentation

Wide-Temperature-Range Integrated Operational Amplifier

A document discusses a silicon-oninsulator (SOI) complementary metal oxide/ semiconductor (CMOS) integrated- circuit operational amplifier to be replicated and incorporated into sensor and actuator systems of Mars- explorer robots. This amplifier is designed to function at a supply potential ≤5.5 V, at any temperature from –180 to +120 °C. The design is implemented on a commercial radiationhard SOI CMOS process rated for a supply potential of ≤3.6 V and temperatures from –55 to +110 °C. The design incorporates several innovations to achieve this, the main ones being the following:

Posted in: Briefs, TSP, Electronics & Computers, Amplifiers, Architecture, Integrated circuits, Sensors and actuators, Robotics, Spacecraft

Dual-Beam Atom Laser Driven by Spinor Dynamics

A Bose-Einstein condensate is adiabatically compressed to drive coherent spin-mixing evolution.

NASA’s Jet Propulsion Laboratory, Pasadena, California

An atom laser now undergoing development simultaneously generates two pulsed beams of correlated 87Rb atoms. (An atom laser is a source of atoms in beams characterized by coherent matter waves, analogous to a conventional laser, which is a source of coherent light waves.) The pumping mechanism of this atom laser is based on spinor dynamics in a Bose-Einstein beam running-wave dipole trap that has been formed by focusing of a CO2-laser beam. By a technique that is established in the art, the trap is loaded from an ultra-high-vacuum magneto-optical trap that is, itself, loaded via a cold atomic beam from an upstream two-dimensional magneto-optical trap that resides in a rubidium-vapor cell that is differentially pumped condensate. By virtue of the angular-momentum conserving collisions that generate the two beams, the number of atoms in one beam is correlated with the number of atoms in the other beam. Such correlations are intimately linked to entanglement and squeezing in atomic ensembles, and atom lasers like this one could be used in exploring related aspects of Bose-Einstein condensates, and as components of future sensors relying on atom interferometry.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics, Architecture, Lasers, Product development, Pumps

Active Correction of Aberrations of Low-Quality Telescope Optics

Relatively inexpensive optical components could be used in free-space optical communications.

NASA’s Jet Propulsion Laboratory, Pasadena, California

A system of active optics that includes a wavefront sensor and a deformable mirror has been demonstrated to be an effective means of partly correcting wavefront aberrations introduced by fixed optics (lenses and mirrors) in telescopes. It is envisioned that after further development, active optics would be used to reduce wavefront aberrations of about one wave or less in telescopes having aperture diameters of the order of meters or tens of meters. Although this remaining amount of aberration would be considered excessive in scientific applications in which diffraction-limited performance is required, it would be acceptable for free-space optical-communication applications at wavelengths of the order of 1 μm.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics, Mirrors, Calibration, Optics, Wireless communication systems

Rugged, Tunable Extended-Cavity Diode Laser

This laser is relatively insensitive to vibration.

NASA’s Jet Propulsion Laboratory, Pasadena, California

A rugged, tunable extended-cavity diode laser (ECDL) has been developed to satisfy stringent requirements for frequency stability, notably including low sensitivity to vibration. This laser is designed specifically for use in an atomic-clock experiment to be performed aboard the International Space Station (ISS). Lasers of similar design would be suitable for use in terrestrial laboratories engaged in atomic-clock and atomic-physics research.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics, Calibration, Lasers, Vibration, Durability, Spacecraft

Advanced Systems for Monitoring Underwater Sounds

Versatile units can be deployed at depths as great as 1 km.

The term “Passive Acoustic Monitoring System” (PAMS) describes a developmental sensing and data-acquisition system for recording underwater sounds. The sounds (more precisely, digitized and preprocessed versions from acoustic transducers) are subsequently analyzed by a combination of data processing and interpretation to identify and/or, in some cases, to locate the sources of those sounds. PAMS was originally designed to locate the sources such as fish of species that one knows or seeks to identify. The PAMS unit could also be used to locate other sources, for example, marine life, human divers, and/or vessels.

Posted in: Briefs, Electronics & Computers, Data acquisition and handling, Product development, Acoustics, Marine vehicles and equipment

Wireless Data-Acquisition System for Testing Rocket Engines

Time-consuming, error-prone wiring tasks are eliminated.

A prototype wireless data-acquisition system has been developed as a potential replacement for a wired data-acquisition system heretofore used in testing rocket engines. The traditional use of wires to connect sensors, signal-conditioning circuits, and data acquisition circuitry is time-consuming and prone to error, especially when, as is often the case, many sensors are used in a test.

Posted in: Briefs, Electronics & Computers, Sensors and actuators, Wireless communication systems, Product development, Rocket engines, Test equipment and instrumentation

Processing Raw HST Data With Up-to-Date Calibration Data

On-the-Fly Reprocessing (OTFR) is a collection of data-processing routines that work within the context of the Hubble Space Telescope (HST) pipeline data-flow system. The purpose served by OTFR is to generate, on demand, scientifically useful data products from raw HST data stored in an archive. First, on the basis of the requested final data products, OTFR retrieves the corresponding sets of raw data from the archives. Next, OTFR processes the raw data sets to remove artifacts and to establish proper header and other template information. Finally, the calibration routines appropriate to the specific data sets are invoked to produce the requested data products, and the data products are released to an archive distribution system for transmission to the requesting party. OTFR offers two notable advantages: (1) Inasmuch as calibrated data occupy about 8 times as much storage space as do raw data, by obviating storage of calibrated data, OTFR reduces the storage capacity needed by the archive; and (2) the calibration routines can be updated to give requesters the benefit of the most recent calibrations.

Posted in: Briefs, Electronics & Computers, Calibration, Architecture, Data management

System for Secure Integration of Aviation Data

Data can be analyzed without compromising security or anonymity.

The Aviation Data Integration System (ADIS) of Ames Research Center has been established to promote analysis of aviation data by airlines and other interested users for purposes of enhancing the quality (especially safety) of flight operations. The ADIS is a system of computer hardware and software for collecting, integrating, and disseminating aviation data pertaining to flights and specified flight events that involve one or more airline(s). The ADIS is secure in the sense that care is taken to ensure the integrity of sources of collected data and to verify the authorizations of requesters to receive data. Most importantly, the ADIS removes a disincentive to collection and exchange of useful data by providing for automatic removal of information that could be used to identify specific flights and crew members. Such information, denoted sensitive information, includes flight data (here signifying data collected by sensors aboard an aircraft during flight), weather data for a specified route on a specified date, date and time, and any other information traceable to a specific flight. The removal of information that could be used to perform such tracing is called “de-identification.”

Posted in: Briefs, Electronics & Computers, Failure analysis, Computer software and hardware, Aircraft operations, Data management, Identification

Mobile Collection and Automated Interpretation of EEG Data

Diagnoses could be performed while subjects engaged in ordinary activities.

A system that would comprise mobile and stationary electronic hardware and software subsystems has been proposed for collection and automated interpretation of electroencephalo- graphic (EEG) data from subjects in everyday activities in a variety of environments. By enabling collection of EEG data from mobile subjects engaged in ordinary activities (in contradistinction to collection from immobilized subjects in clinical settings), the system would expand the range of options and capabilities for performing diagnoses.

Posted in: Briefs, TSP, Bio-Medical, Medical, Computer software and hardware, Data acquisition and handling, Sensors and actuators, Diagnosis, Nervous system, Test equipment and instrumentation

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