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During several ISS missions, there were false alarms at both US and Russian smoke detectors. High local airborne particulate concentrations and interior deposits are considered the causes for such anomalies. Alternatives are proposed to replace or complement these faulty smoke detectors. The entrained zeolite particles may play a role in causing problems with check valves and air save pumps in CDRA and Vozdukh. Another incidence has been the dispersion of particulates out of Metox regeneration oven. Particulate matters with aerodynamic diameter of 15 microns and above, which normally settle down on earth, stay airborne under micro-gravity and thereby cause the above-mentioned nuisances. The motion of such a particle along a gas stream with an initial velocity can be expressed by theoretical equations. Stokes' Law leads to the descriptions of inertial precipitation of aerosols that are important in solving the issues.

NEW WELDING processes are dropping costs while providing improvements in weld quality. This paper describes some of the more promising new developments in pressure and fusion welding and brazing. Included in the discussion are ultrasonic, high frequency resistance, foil seam, magnetic force, percussion, friction, and thermopressure welding and diffusion bonding. The description of adhesive bonding includes the development of glass or ceramic materials as structural adhesives.*

The likelihood of transmission of potential disease agents between animals and man during spaceflight is a real concern. Development of disease exclusion lists for animals and refinement of animal containment units have been the principal means of providing protection to the crew members. Awareness of potential latent infections and a judicious use of the higher risk category of animals such as wild-caught nonhuman primates provides another level of protection. Use of high efficiency filters, gasketing, and differential air pressures have all enabled increasing levels of safety through containment of potential aerosol escape from animal habitats.

This paper describes the testing of a waste management system designed and fabricated for use in a space vehicle. The system provides for the collection and inactivation of urine, feces, emergency diarrheal disorders, vomitus, and debris; the volumetric determination of each micturition; and onboard storage of the inactivated wastes within the waste management system compartment. The zero-gravity test program conducted in a KC-135 aircraft provided the primary verification of the performance of the waste collection and urine volume determination functions prior to actual space flight. The test hardware simulated the actual system to a high degree of fidelity with respect to operational characteristics of the airflow required in collection, mechanical functions and system pressure differentials, in order to minimize simulation errors.

This paper investigates the use of several zero-ozone depleting potential (zero-ODP) HFC refrigerants, including HFC-134a, HFC-227ca, HFC-227ea, HFC-236ea, HFC-236cb, HFC-236fa, HFC-245cb, and HFC-254cb, for centrifugal chiller applications. We took into account the thermodynamic properties of the refrigerant and aerodynamic characteristics of the impeller compression process in this evaluation.. For a given operating temperature lift, there are significant differences in the pressure ratio required by each refrigerant and this variation in pressure ratio directly affects compressor size, efficiency, and performance. A comparison of the HFC refrigerant candidates with CFC-114 shows that HFC-236ea, HFC-227ca and HFC-227ea are viable alternatives for centrifugal water chillers. HFC-236ea has properties closest to CFC-114, and will result in comparible performance, but will require a slightly larger impeller and a purge system.

Design load values are a prime consideration in space suit design. Pressurized garment assemblies can be accurately modeled as a cylindrical shell under pressure to determine the resulting pressure loads. But, the resulting longitudinal loads are not a complete picture of the load environment. The man induced loads generally act longitudinally and are very often the larger loads the space suit restraint system must withstand. This paper presents the data collected to fill out the human strength data base in the glove area along with a short description of how this data was collected. Also, a description of how this data was used in the design and flight certification of the current Shuttle Extravehicular Mobility Unit space suit is included along with a discussion of techniques to extend this model to include future space suit design.

THE X-ray spectrum readily adapts itself to problems in chemical analysis and crystal formation. It is effective on very minute particles which otherwise cannot be segregated. A permanent record is made, and the specimens may be used over and over again, as the X-ray is non-destructive. As a means of inspection, X-ray clearly shows the interior of objects such as weldings castings, forgings, cold-worked metals, and so on. Inhomogeneities that are very slight in width and a fraction of one per cent in thickness are seen easily on a radiograph. Defects thus found may be eliminated summarily by checking various steps in production.

Over the past two decades, various models of “worst case” solar energetic particle event (SPE) spectra have been proposed in order to place an upper bound on the likely doses to critical body organs of astronauts on missions outside Earth’s geomagnetic field. In this work, direct comparisons of organ dose estimates for various models of “worst case” SPE spectra are made by using the same transport code (BRYNTRN) and the same human geometry model (Computerized Anatomical Man). The calculations are made assuming nominal thicknesses of spacecraft aluminum shielding. Discussions of possible acute exposure responses from these exposures are presented.

This specification covers tools used to install tiedown straps on wire bundles and for installing connector accessory shield termination bands (see 6.1).

Results of a recent low-speed wind-tunnel investigation conducted to define the forebody flow on a 16% scale model of the NASA High Angle-of-Attack Research Vehicle (HARV), an F-18 configuration, are presented with analysis. Measurements include force and moment data, oil-flow visualizations, and surface pressure data taken at angles of attack near and above maximum lift (36° to 52°) at a Reynolds number of one million based on mean aerodynamic chord. The results presented identify the key flow-field features on the forebody including the wing-body strake.

Instrumentation that has been used for characterization of mixed-phase and glaciated conditions in the past, like the OAP probes, are subject to errors caused by variations in diffraction on the images away from the object plane and by the discrete nature of their particle detection and sizing. Correction methods are necessary to consider their measurements adequate for high ice water content (IWC) environments judged to represent a significant safety hazard to propellers and turbofan engine operability and performance. For this reason, within the frame of EU FP7 HAIC project, instrumentation characterization and validation is considered a major element need for successful execution of flight tests campaigns. Clearly, instrumentation must be sufficiently reliable to assess the reproducibility of artificial clouds with high ice water content generated in icing tunnels.

This paper shows how the quantity demanded, viewed as an independent variable, interacts with customer values, producer costs and constraints. Failure to analyze Demand as Independent Variable (pronounced “Dave”) increases the chances that new programs will not launch, or once started, will fail. All producers in all markets face demand curves that describe their customers' reaction to price changes. Aggregate market demand curves show how buyers react to price changes within broad product sets, while product demand curves show buyer responses to a specific item. Demand curves relate quantities sold relative to their prices. In several military, transit and fleet cases, minimum quantity requirements form upper price boundaries along demand curves. Allowing prices to go so high that buying authorities cannot acquire the required numbers of units likely means that there may not be sufficient resources to form systems that can accomplish the buyers' goals.

Wet oxidation was used to oxidize a spacecraft model waste under different oxidation conditions. The variables studied were pressure, temperature, duration of oxidation, and the use of one homogeneous and three heterogeneous catalysts. Emphasis is placed on the final oxidation state of carbon and nitrogen since these are the two major components of the spacecraft model waste and two important plant nutrients.

This specification covers one type of nylon webbing.

This document shall be used in conjunction with: - AS6286, Training and Qualification Program for Deicing/Anti-icing of Aircraft on the Ground - AS6286/1, Processes including Methods - AS6286/2, Equipment - AS6286/3, Fluids - AS6286/5, Health, Safety and First Aid - AS6286/6, Aircraft Deicing/Anti-icing Diagrams, No-Spray-Zones

A multi-axial dynamic test instrument was designed to perform wear testing of actual aircraft tires as well as tread/carcass composite specimens under laboratory loading conditions which simulate the elements of take-off, landing and taxiing operations. The wear tester consists of a self-spinning abrading head, mounted on the actuator of a servo-hydraulic test system, which faces either (1) the tread surface of a composite specimen clamped by a horizontal stretch frame or (2) the tread region of actual inflated tires. The test concept has been partially proven in the case of tread/carcass composite specimens by building a proto-type test apparatus and operating it successfully. In the current test set-up, the specimen is subjected to static tension to simulate a circumferential load in the tire footprint and the tread surface is in periodic contact with an abrading head under a specific level of pressure.

When high-intensity discharge (HID) electric lamps are used for plant growth, system inefficiencies occur due to an inability to effectively target light to all photosynthetic tissues of a growing crop stand, especially when it is closed with respect to light penetration. To maintain acceptable crop productivity, light levels typically are increased thus increasing heat loads on the plants. Evapotranspiration (ET) or transparent thermal barrier systems are subsequently required to maintain thermal balance, and power-intensive condensers are used to recover the evaporated water for reuse in closed systems. By accurately targeting light to plant tissues, electric lamps can be operated at lower power settings and produce less heat. With lower power and heat loads, less energy is used for plant growth, and possibly less water is evapotranspired. By combining these effects, a considerable energy savings is possible.

This document establishes the minimum requirements for an environmental test chamber, and test procedures to carry out anti-icing performance tests according to the current materials specification for aircraft deicing/anti-icing fluids. The primary purpose for such a test method is to determine the anti-icing endurance under controlled laboratory conditions of AMS1424 Type I and AMS1428 Type II, III, and IV.