February 2004

Briefs: Mechanical & Fluid Systems
Miniature Robotic Spacecraft for Inspecting Other Spacecraft

A report discusses the Miniature Autonomous Extravehicular Robotic Camera (Mini AERCam) — a compact robotic spacecraft intended to be released from a larger spacecraft for exterior visual inspection of the larger spacecraft. The Mini AERCam is a successor to the AERCam Sprint...

Briefs: Mechanical & Fluid Systems
Miniature Ring-Shaped Perisaltic Pump

An experimental miniature peristaltic pump exploits piezoelectrically excited flexural waves that travel around a ring: A fluid is carried in the containers formed in the valleys between the peaks of the...

Briefs: Physical Sciences
Electrochemical, H₂O₂-Boosted Catalytic Oxidation System

An improved water-sterilizing aqueous-phase catalytic oxidation system (APCOS) is based partly on the electrochemical generation of hydrogen peroxide (H2O2). This H2O2-boosted system offers significant improvements over prior dissolved-oxygen...

Briefs: Physical Sciences
Permanent Sequestration of Emitted Gases in the Form of Clathrate Hydrates

Underground sequestration has been proposed as a novel method of permanent disposal of harmful gases emitted into the atmosphere as a result of human activity. The method was conceived primarily for disposal of carbon dioxide (CO2, greenhouse gas causing global...

Cube-shaped thermoelectric devices energized by a particles from radioactive decay of 244Cm have been proposed as long-lived sources of power. These power cubes are intended...

An ultraviolet-absorption spectrometer system has been developed as a prototype instrument to be used in continuous, real-time monitoring to detect the growth of biofilms. Such monitoring...

A cylindrical-punch indentation technique has been developed as a means of measuring the nonlinear elastic responses of materials - more specifically, for measuring the moduli of...

Briefs: Manufacturing & Prototyping
Improved Thin, Flexible Heat Pipes

Flexible heat pipes of an improved type are fabricated as layers of different materials laminated together into vacuum-tight sheets or tapes. In comparison with prior flexible heat pipes, these flexible...

A method, now undergoing development, of forming nanochannels in planar substrates is intended to enable the fabrication of advanced fluidic devices that could be integrated with...

As noted in the previous article, the field-induced force density on a magnetic fluid is proportional to the magnetic susceptibility times the gradient of the magnetic field squared. The direction of...

Briefs: Robotics, Automation & Control
Pumping Liquid Oxygen by Use of Pulsed Magnetic Fields

An effort is underway to develop a method of pumping small amounts of liquid oxygen by use of pulsed magnetic fields. This development is motivated by a desire to reduce corrosion and hazards of explosion and combustion by eliminating all moving pump parts in contact with the pumped...

Briefs: Robotics, Automation & Control
A Software Architecture for Semiautonomous Robot Control

A software architecture has been developed to increase the safety and effectiveness with which tasks are performed by robots that are capable of functioning autonomously but sometimes are operated under control by humans. The control system of such a robot designed according to a prior...

Briefs: Robotics, Automation & Control
Compact Plasma Accelerator

A plasma accelerator has been conceived for both material-processing and spacecraft-propulsion applications. This accelerator generates and accelerates ions within a very small volume. Because of its compactness,...

Briefs: Robotics, Automation & Control
Improved Electrohydraulic Linear Actuators

A product line of improved electrohydraulic linear actuators has been developed. These actuators are designed especially for use in actuating valves in rocket-engine test facilities. They are also...

Briefs: Mechanical & Fluid Systems
Autonomous Formation Flight

NASA's Strategic Plan for the Aerospace Technology Enterprise includes ambitious objectives focused on affordable air travel, reduced emissions, and expanded aviation-system capacity. NASA Dryden Flight Research...

Intelligent fasteners with embedded microprocessors remotely controlled by wireless tools or a data network can advance the speed, flexibility, flow, and cost...

Provisions for specification of hazards faced by a robotic vehicle (rover) equipped with a rocker-bogie suspension, for prediction of collisions between the vehicle and the hazards,...

Briefs: Mechanical & Fluid Systems
Wavy-Planform Helicopter Blades Make Less Noise

Wavy-planform rotor blades for helicopters have been investigated for the first time in an effort to reduce noise. Two of the main sources of helicopter noise are blade/vortex interaction (BVI)...

Briefs: Mechanical & Fluid Systems
Expandable Purge Chambers Would Protect Cryogenic Fittings

Expandable ice-prevention and cleanliness-preservation (EIP-CP) chambers have been proposed to prevent the accumulation of ice or airborne particles on quick-disconnect (QD) fittings, or on ducts or tubes that contain cryogenic fluids. In the original application for which the EIP-CP...

An assembly of sensors, denoted an electronic tongue, is undergoing development as a prototype of compact devices for use in measuring concentrations of contaminants in water. Thus...

A two-frequency, polarimetric, spaceborne synthetic-aperture radar (SAR) system has been proposed for measuring the moisture content of soil as a function of depth, even in the presence of...

A modular wireless data-acquisition and control system, now in operation at Kennedy Space Center, offers high performance at relatively low cost. The system includes a central station and...

Briefs: Electronics & Computers
Microwave System for Detecting Ice on Aircraft

A microwave-based system has been developed as a means of detecting ice on aircraft surfaces, with enough sensitivity to provide a warning before the ice accretes to a dangerous thickness. The...

Briefs: Electronics & Computers
Routing Algorithm Exploits Spatial Relations

A recently developed routing algorithm for broadcasting in an ad hoc wireless communication network takes account of, and exploits, the spatial relationships among the locations of nodes, in...

Semiconductor electronic devices and circuits based on silicon carbide (SiC) are being developed for use in high-temperature, high-power, and/or high-radiation conditions under which...

Briefs: Materials
Nonlinear Thermoelastic Model for SMAs and SMA Hybrid

A constitutive mathematical model has been developed that predicts the nonlinear thermomechanical behaviors of shape-memory alloys (SMAs) and of shape- memory-alloy hybrid composite (SMAHC) structures, which are composite-material structures that contain embedded SMA actuators. SMAHC...

Briefs: Electronics & Computers
Two-Finger EKG Method of Detecting Evasive Responses

A system based on acquisition and processing of electrocardiographic (EKG) signals from two fingers has been proposed as a means of determining whether a person is answering questions evasively. The system — in effect, a "lie detector" of sorts, would be used to gauge...

One of the major challenges for NASA's next-generation reusable-launch-vehicle (RLV) program is the design of a cryogenic lightweight composite fuel...

Briefs: Electronics & Computers
Tailoring Ion-Thruster Grid Apertures for Greater Efficiency

A report proposes tailoring the diameters of the apertures in the accelerator grid of an ion thruster to reduce the open grid area through which un-ionized propellant gas can escape. The result would be a reduction in the loss of propellant gas and a corresponding increase in...

Briefs: Electronics & Computers
Lidar for Guidance of a Spacecraft or Exploratory Robot

A report describes the Laser Mapper (LAMP) — a lightweight, compact, low-power lidar system under development for guidance of a spacecraft or exploratory robotic vehicle (rover) at Mars or another planet. The LAMP is intended especially for use during rendezvous of two spacecraft in...

Briefs: Materials
Formulations for Stronger Solid Oxide Fuel-Cell Electrolytes

Tests have shown that modification of chemical compositions can increase the strengths and fracture toughnesses of solid oxide fuel-cell (SOFC) electrolytes. Heretofore, these solid electrolytes have been made of yttria- stabilized zirconia, which is highly conductive for oxygen ions...

Briefs: Software
Simulation Testing of Embedded Flight Software

Virtual Real Time (VRT) is a computer program for testing embedded flight software by computational simulation in a workstation, in contradistinction to testing it in its target central processing unit (CPU). The disadvantages of testing in the target CPU include the need for an expensive test bed,...

Briefs: Software
Updated System-Availibility and Resource-Allocation Program

A second version of the Availability, Cost and Resource Allocation (ACARA) computer program has become available. The first version was reported in "System-Availability and Resource- Allocation Program" (LEW-15713), NASA Tech Briefs, Vol. 19, No. 8 (August 1995), page 54. To...

Briefs: Software
Software for Fault-Tolerant Matrix Multiplication

Formal Linear Algebra Recovery Environment is a computer program for high-performance, fault-tolerant matrix multiplication. The program is based on an extension of the prior theory and practice of fault-tolerant matrix·matrix multiplication of the form C = AB. This extension provides...

Briefs: Software
Routines for Computing Pressure Drops in Venturis

A set of computer- program routines has been developed for calculating pressure drops and recoveries of flows through standard venturis, nozzle venturis, and orifices. Relative to prior methods used for such calculations, the method implemented by these routines offers greater accuracy because it...

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