Special Coverage

Supercomputer Cooling System Uses Refrigerant to Replace Water
Computer Chips Calculate and Store in an Integrated Unit
Electron-to-Photon Communication for Quantum Computing
Mechanoresponsive Healing Polymers
Variable Permeability Magnetometer Systems and Methods for Aerospace Applications
Evaluation Standard for Robotic Research
Small Robot Has Outstanding Vertical Agility
Smart Optical Material Characterization System and Method
Lightweight, Flexible Thermal Protection System for Fire Protection

Generating Commands for the Mars Polar Lander Robotic Arm

A report discusses the use of the Web Interface for Telescience (WITS) for visualization and command sequence generation in the Mars Polar Lander (MPL) mission. WITS, which has been described in prior articles in NASA Tech Briefs, is an Internet-based software system that enables geographically dispersed scientists and engineers to participate in sequence generation for planetary lander and rover missions. Public outreach versions of WITS enable the general public to use WITS to view mission images and plan and simulate their own missions. WITS enables scientists to view mission data and generate command sequences from their home institutions, making it unnecessary for them to travel to a mission control center to participate in the mission. The present report describes how WITS fits in the MPL mission operations architecture and how it was used for Robotic Arm and Robotic Arm Camera sequence generation.

Posted in: Briefs, TSP, Information Sciences, Architecture, Communication protocols, Electronic control systems, Robotics, Spacecraft


The Future of Electronic Device Design

An article discusses anticipated advances in the design of increasingly capable integrated circuits containing ever smaller electronic devices. The article emphasizes the emergence of technology computer-aided design (TCAD) — a discipline in which computer-aided design is combined with computational simulation (based on underlying physics) of the operation and fabrication of devices. The article describes challenges that must be met to expand the role of TCAD as a means of overcoming obstacles to further miniaturization and of shortening integrated-circuit-development cycles. One challenge is to develop better mathematical models of the device physics and fabrication processes to enable the more accurate simulation of what happens as circuit features shrink toward molecular dimensions; meeting this challenge will likely involve development of capabilities for "virtual fabrication," in which all aspects of production processes and devices produced could be computationally simulated. Another challenge is to develop new, generally applicable TCAD software with the flexibility and functionality needed to perform increasingly complex and accurate computations. A third challenge is to obtain the enormous computational power needed for advanced TCAD by setting up an Internet-based distributed-computing grid, which would utilize thousands or even millions of computers while they were idle.

Posted in: Briefs, Electronics & Computers, Mathematical models, Electronic equipment, Integrated circuits


Multi-Shock Blankets for Protecting Spacecraft

A report discusses multi-shock blankets, which are under investigation for use in protecting spacecraft against orbiting debris from prior spacecraft missions. Multi-shock blankets are described in comparison with early protective metallic "bumpers" and with a somewhat more recent invention called the "multi-shock shield." A multi-shock blanket is a stand-alone, self-contained shield system that includes several layers of ceramic (or equivalent) shields separated by a flexible foam material.

Posted in: Briefs, TSP, Materials, Particulate matter (PM), Ceramics, Fabrics, Foams, Impact tests, Spacecraft


Airlocks for Pressurized Rovers

A report presents a survey of the design engineering and scientific literature on airlocks and on planetary-exploration vehicles ("rovers"), from the perspective of evaluating existing and potential design concepts for airlocks for pressurized rovers. The airlocks are the key to designing a pressurized rover that is useful and productive for the full range of activities and operational requirements. The report presents a representative embodiment of each of these three airlock types through illustrations of a "simplified rover." The report concludes with a cogent set of design recommendations and characteristics for the three types of airlocks that would be particularly relevant to the design of a highly capable pressurized planetary rover.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Design processes, Autonomous vehicles


Spacecraft-Facility Microbes Tolerate H2O2, NaCl, and Heat

A report describes experiments that were performed to isolate and characterize microbes that survive conditions of controlled circulation of air, desiccation, low nutrient concentrations, and moderately high temperatures in a spacecraft-assembly facility. These conditions are more severe than those to which the natural strains of the same microbial species are ordinarily exposed. This study is part of continuing research on related issues of (1) efficacy of sterilization (e.g., by use of H2O2 and/or heat) of spacecraft to be used in planetary exploration, (2) the use of selected microbes as indicators of the effectiveness of sterilization, and (3) the feasibility of commercial utilization of enzymes produced by microbes that tolerate severe conditions.

Posted in: Briefs, TSP, Bio-Medical, Medical, Assembling, Spacecraft


Study of High-Performance Polyimide Foams

This report describes an experimental study of thermal-stability, mechanical, and flammability properties of foams of several different densities made of three different polyimides. The study was performed because (1) prior such studies were performed on polyimide films rather than foams and (2) the synthesis of polyimide foams is a relatively recent development. There is a need to determine the suitability of each foam for potential applications — for example, as flame retarders, thermal and acoustic insulators, gaskets, seals, vibration-damping pads, spacers in adhesives and sealants, extenders, and flow and leveling aids.

Posted in: Briefs, TSP, Materials, Foams, Materials properties, Performance tests


Subgrid Analysis of Mixing Layer With Evaporating Droplets

This report presents an analysis of a database from computational simulations of a droplet-laden mixing layer (i.e., evaporating droplets of a liquid fuel in air) undergoing a transition to turbulence. The basic governing equations were those of transport of discrete droplets through a flowing gas; the droplets were followed in a Lagrangian frame whereas the gas was followed in an Eulerian frame. The analysis involved the extraction of subgrid scale (SGS) models from flow fields generated using the direct numerical simulation (DNS) approach, in which the governing equations are solved directly at the relevant length scales.

Posted in: Briefs, TSP, Physical Sciences, Analysis methodologies, Simulation and modeling, Gases


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