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

Software Performs Testing, Monitoring, and Control Functions

The Front End Processor (FEP) Real-Time Embedded Software performs command and data-processing functions for an aeronautical MIL-STD-1553B telemetry link and ground support equipment (GSE) in a spacecraft-equipment-testing environment. The FEP is used in the Test, Control, and Monitor System of the Space Station Program for checking out Space-Station modules and payloads as they flow through Kennedy Space Center. Consisting of about 50,000 lines of C-language code, the FEP software runs on Motorola MVME 167 processors in a VersaModule Eurocard (VME) chassis. The software can be re-compiled for execution on other processors. The software interacts with the 1553B telemetry link through commercial VME interface cards and supports as many as four redundant 1553B buses. The GSE interfaces consist of analog, digital, relay, and serial links for controlling the GSE used in testing. The software includes modules that control and monitor the MIL-STD-1553B links of the Space Station and the associated GSE interfaces. Back-end interfaces (user interfaces) to the FEP software are provided through a standard Ethernet network that enables a user or a testing application program to exercise control or to monitor data from the interfaces supported by the FEP software.

Posted in: Briefs, TSP, Software, Embedded software, Telemetry, Embedded software, Telemetry, Test procedures, Spacecraft
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Relatively Simple Atmospheric-CO2 Controller

Temperature of an alkanolamine solution is controlled to make it absorb or desorb CO2.

An apparatus has been developed as a means of controlling the partial pressure of CO2 (pCO2) in air in a closed or semiclosed environmental system. The apparatus takes CO2 from the air in a source chamber and supplies the CO2, at a regulated partial pressure, to the air in a sink chamber. In the original intended application, the chambers would be located aboard a spacecraft: the source chamber would be inhabited by crewmembers, and the sink chamber would be a plant-growth chamber. Apparatuses like this one could also be used to control pCO2 in research plant-growth chambers on Earth.

Posted in: Briefs, Materials, Carbon dioxide, Test equipment and instrumentation
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A Technique for Injecting Ag+ Ions as Biocide into H2O

A simple and reliable technique facilitates the addition of silver ions to water supplies to suppress bacterial contamination. In the original application for which the technique was devised, there is a need for Ag+-ion concentrations at a biocidal levels (0.5 mg/L) in 44-L batches of drinking water. The technique involves the preparation of a solution of concentrated biocide by dissolving 0.66 g of AgF and 1.04 g of NaF in 0.5 L deionized water. Batches of the solution are put into plastic syringes that have volumes of 20 cm3 each and are equipped with fittings for connection to the water supplies to be treated. The syringes are capped and placed in plastic bags for transport and storage. The shelf life of the syringes stored at room temperature is at least two years. When needed, a syringe is simply unpacked and connected to a mating fitting on a water supply. The concentrated solution is then injected into the flowing water, wherein the solution becomes diluted to the desired final concentration.

Posted in: Briefs, TSP, Materials, Water quality
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Breathing-Air and Cooling Apparatus for Protective Suit

Applications can include diving, space, and firefighting suits.

The figure schematically illustrates a portable life-support apparatus for any of a variety of protective suits to be worn in hostile environments. A prototype of the apparatus has been fitted to space suits for use underwater. Astronauts wear these suits during training dives in a tank of warm water, using the neutral buoyancy available in the underwater environment to simulate aspects of the zero gravitation of outer space. The apparatus provides breathing air and adjustable cooling in the suit, while maintaining overall neutral buoyancy. The apparatus is readily adaptable to such related applications as conventional diving and space suits, firefighting suits, and protective garments to be worn in hot, toxic, and/or radioactive environments.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Life support systems, Oxygen equipment, Oxygen equipment, Cooling, Protective clothing
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Thermoelectric Contact Cooler/Freezer

This cooler is efficient and quiet.

A thermoelectric contact cooler/ freezer is designed to utilize thermal conduction to rapidly freeze blood and urine samples in test tubes and syringes. This apparatus is dependable, wastes little energy, contains no moving parts other than a fan, can operate in a wide temperature range and in any orientation (including in zero gravity), is quiet, and emits no chlorofluorocarbons or other greenhouse gases. It is a vast improvement over currently available convection-type cooler/freezers.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Medical equipment and supplies, Cooling
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Molten-Carbonate Electrolyzers for Making CO and O2

Molten-carbonate fuel cells would be operated in reverse.

Electrochemical cells in which molten carbonates would serve as electrolytes have been proposed for use in electrolyzing CO2. The proposal was made in an effort to implement a concept of in situ resource utilization (ISRU) for the exploration of Mars; the basic idea is to generate CO (if needed as a fuel) and O2 (for oxidizing fuel and/or for breathing) by electrolysis of CO2 from the Martian atmosphere. On Earth, molten-carbonate electrolyzers could be used to make breathable O2 for medical use, pure O2 for oxidizing surfaces of semiconductor chips, and CO as a feedstock for synthesis of alcohols and hydrocarbons. In both terrestrial and spacecraft life-support systems, the electrolyzers could be used to regenerate breathable O2 from CO2.

Posted in: Briefs, TSP, Physical Sciences, Carbon dioxide, Carbon monoxide, Oxygen
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Improved Spherical Energy Analyzer

An improved spherical energy analyzer (a type of electrostatic mass spectrometer) is under development for use in analyzing a beam of ions generated by a Hall thruster. The major improvement, relative to a commercial spherical energy analyzer, is the addition of a quadrupole stage (with refocusing electron optics) for separating ions of different charge states. The development work also includes efforts to make the instrument smaller and lighter than the commercial version in order to make it possible to translate and rotate the instrument through the ion beam inside a vacuum chamber that contains the Hall thruster.

Posted in: Briefs, TSP, Physical Sciences, Test equipment and instrumentation
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Redundant Oxygen-Deficiency Monitoring System

An oxygen-deficiency monitoring system (ODMS) has been developed for a ten-room facility in which the use of large amounts of nitrogen and helium could cause an oxygen deficiency severe enough to be hazardous to personnel. The ODMS comprises three subsystems, of which two monitor three rooms each, and one monitors four rooms. The ODMS generates alarms when the oxygen content of the air in a room falls below 19.5 mole percent. Each subsystem includes transport pumps that draw air continuously from each room through two tubes. Each subsystem includes two oxygen analyzers equipped with sampling pumps, plus two programmable-logic controllers (PLCs) and associated hardware that control electrically actuated valves that admit small fractions of the transport flows to the oxygen analyzers. The PLCs cause the valves to connect the two oxygen analyzers to two different sampling tubes, and then to switch the connections to a different pair of sampling tubes after an interval of about 10 seconds, and so forth until the air from all sampling points has been monitored, and then the sequence repeats. If one sampling tube, oxygen analyzer, pump, or PLC fails, it can be repaired while the system continues to operate, albeit at a reduced rate.

Posted in: Briefs, TSP, Physical Sciences, Oxygen, Test equipment and instrumentation
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Theory of Formation-Flying Control for Multiple Spacecraft

A report presents the mathematical basis of a method of controlling multiple spacecraft flying in formation, subject to control constraints. The spacecraft are assumed to be equipped with relative-position-sensing, relative-velocity-sensing, and communication infrastructure, and with maneuvering actuators. The method involves a leader-following control scheme. A graph is used to represent the hierarchy of, and the data dependencies among, the leading and following spacecraft. Graph-theoretic concepts are shown to play a vital role in determining the basic properties of the leader-following control architecture; hence, changes in the hierarchy (represented by changes in the graph) translate directly to the required changes in control.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Mathematical models, Spacecraft
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Self-Organization Based on Quantum Entanglement

A report presents a theoretical study of communication among intelligent agents in the presence of quantum entanglement and the absence of classical (in the sense of non-quantum) communication channels. Several paradigms of self-organization based on quantum entanglement are introduced and discussed. These paradigms include inverse diffusion, transmission of conditional information, decentralized coordination, cooperative computing, competitive games, and topological evolution in active systems.

Posted in: Briefs, TSP, Information Sciences, Research and development
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