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NIM and CAMAC standards were evaluated for use in Space Shuttle experiment payloads. Six payloads were studied, and it was found that 30 to 90% of the electronic functions could be performed with standard, commercially available modules. Only minor modifications are required to adapt the standards to the Shuttle requirements.
The accuracy and long-term stability of currently available NBS radiometric source standards are described. Current research efforts and expected results in this area are outlined. There are over ten NBS radiometric source standards currently available or under development that are of interest for solar measurements or for remote sensing of the earth. The standards and sources are classified and described in terms of the radiometric quantities they represent -- spectral radiance, spectral irradiance and irradiance.
General conceptual requirements for standard levels of documentation and for application of these requirements to intended usages. These standards encourage the policy to produce only those forms of documentation that are needed and adequate for the purpose. Documentation standards are defined with respect to detail and format quality. Classes A through D range, in order, from the most definitive down to the least definitive, and categories 1 through 4 range, in order, from high-quality typeset down to handwritten material. Criteria for each of the classes and categories, as well as suggested selection guidelines for each are given.
A secondary working standard of flow calibration has been developed to be used in place of a primary weight-time standard, and which can thereby effect a 75 percent reduction in calibration time while maintaining acceptable accuracies. The secondary standard uses six previously calibrated turbine-type flowmeters built into two manifold systems containing automatically switched flow valves. The pair of systems is capable of covering the flow range of 0.0004 to 19 l/s (0.007 to 300 gpm) with the uncertainty in volume flow rate not exceeding + or - 0.25 percent over the range of 0.06 to 19 l/s and not exceeding + or - 0.5 percent over the range 0.0004 to 0.06 1/s. Data reduction and plotting of results are by computer.
Comparisons are made between the NP series and the NX series of hydrogen masers. A field operable hydrogen maser (NR series) is also described. Atomic hydrogen primary frequency standards are in development stages. Standards are being developed for a hydrogen beam frequency standard and for a concertina hydrogen maser.
The network operations control center standard interface has been adopted as a standard computer interface for all future minicomputer based subsystem development for the Deep Space Network. Discussed is an intercomputer communications link using a pair of coaxial cables. This unit is capable of transmitting and receiving digital information at distances up to 600 m with complete ground isolation between the communicating devices. A converter is described that allows a computer equipped with the standard interface to use the twin coaxial link.
A study of the comparative program costs associated with use of various standardized spacecraft for Air Force space test program missions to be flown on the space shuttle during the 1980-1990 time period is reviewed. The first phase of the study considered a variety of procurement mixes composed of existing or programmed NASA standard spacecraft designs and a Air Force standard spacecraft design. The results were briefed to a joint NASA/Air Force audience on July 11, 1976. The second phase considered additional procurement options using an upgraded version of an existing NASA design. The results of both phases are summarized.
The comparative program costs associated with use of various standardized spacecraft for Air Force space test program missions to be flown on the space shuttle were studied in two phases. In the first phase, a variety of procurement mixes composed of existing or programmed NASA standard spacecraft designs and an Air Force standard spacecraft design were considered. The second phase dealt with additional procurement options using an upgraded version of an existing NASA design. The results of both phases are discussed.
A miniature argon arc has been designed and tested as a new transfer standard of spectral radiance for the wavelength range from 114 nm to 330 nm. Calibration has been performed using two primary standard sources: the hydrogen arc from 130 nm to 330 nm and the blackbody line radiator from 114 nm to 130 nm. The mini-arc provides an intense, stable, and reproducible UV continuum with dc power requirements of less than 1.5 kW. The arc characteristics have been investigated, and the sensitivity of the radiant power output to various operating parameters has been measured. The rms uncertainty in the spectral radiance is estimated to be 5.3% above 140 nm and 10.1% between 114 nm and 140 nm, due primarily to uncertainties in the primary standard sources.
A secondary working standard of flow calibration has been developed to be used in place of a primary weight-time standard, and which can thereby effect a 75 percent reduction in calibration time while maintaining acceptable accuracies. The secondary standard uses six previously calibrated turbine-type flowmeters built into two manifold systems containing automatically switched flow valves. The pair of systems is capable of covering the flow range of 0.0004 to 19 1/s (0.007 to 300 gpm) with the uncertainty in volume flow rate not exceeding plus or minus 0.25 percent over the range 0.06 to 19 1/s and not exceeding plus or minus 0.5 percent over the range 0.0004 to 0.06 1/s. Data reduction and plotting of results are by computer.
Results are reported for analysis of the uranium in multiple samples of each of six igneous-rock standards (dunite, granite, lujavrite, norite, pyroxenite, and syenite) prepared as geochemical reference standards for elemental and isotopic compositions. Powdered rock samples were examined by measuring delayed neutron emission after irradiation with a flux of the order of 10 to the 13th power neutrons/sq cm per sec in a nuclear reactor. The measurements are shown to compare quite favorably with previous uranium determinations for other standard rock samples.
This paper deals with the efforts of the National Aeronautics and Space Administration to take advantage of the economies made possible by the Space Shuttle by reducing the costs of acquiring and flying payloads for the Shuttle. Specifically, the paper addresses the route that NASA's Low Cost Systems Office is following in order to reduce the cost of auxiliary propulsion systems. This approach emphasizes the establishment of standard hardware items, which will be used on as many spacecraft as possible. The method by which a standard is selected and how it is maintained as a standard are discussed. The process by which the 5 Newton hydrazine thruster was adopted is described, as a typical example.
Emissions of air pollutants from aircraft were investigated in order to determine: (1) the extent to which such emissions affect air quality in air quality control regions throughout the United States; and (2) the technological feasibility of controlling such emissions. The basic information supporting the need for aircraft emissions standards is summarized. The EPA ambient air quality standards are presented. Only the primary (health related) standards are shown. Of the six pollutants, only the first three, carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides, are influenced significantly by aircraft.
The most direct way to determine the deceleration parameter, q(0), of the universe is through the study of the redshift-magnitude relation of extragalactic sources. Progress has been slow because the necessary sources for this study must be standard candles, which have identical absolute total luminosity (balometric or monochromatic). The present paper shows, first of all, that, although necessary, this is not a sufficient condition for nonpoint-like (or resolved) sources. A modification of the redshift-magnitude relation is then described for a certain class of nonstandard candles using measurements of isophotal surface brightness. It is noted that such measurements can be used to standardize the central surface brightness of galaxies, but the standardization of the scale parameter remains beyond observations.
Relatively-simple microwave integrated circuit comprising two resonators linked by Josephson junction could be set up to generate standard Josephson volt in any industrial laboratory. Standard cells and electronic equipment could be readily compared and calibrated to this standard.
The Standard Telemetry and Command Components (STACC) were conceived by NASA for use on the Multimission Modular Spacecraft. The components have wider application, however, and already are being considered for many other spacecraft. A programmable Central Unit controls Remote Interface Units via a full duplex data bus, providing data acquisition and command distribution capability throughout the spacecraft. The Central Unit can meet any uplink, time code, and format requirements without hardware changes. Each remote unit can acquire any type of data (serial digital, bi-level, analog, or passive analog) on any channel. A third type of unit is an optional interface providing I/O capability to an on-board computer. The protocols used on the 1Mbps data bus are compatible with MSFC's 'Standard Interfaces for Digital Data, Multiplex Serial Data Acquisition and Distribution Systems (SIDD/MSDADS Standard)'. The bus design saves significant harness weight and simplifies the single point ground and isolation approaches.
Packetized telemetry-handling offers an opportunity to standardize major portions of the spacecraft-to-ground interface for future NASA missions. An end-to-end packet transport protocol is proposed which enables delivery of telemetry data from a remote space sensor to a ground-based user with virtually no project-unique intermediate processing. This paper reviews the possibility of creating a single telemetry format standard for both deep-space and near-earth missions. The proposed standard addresses the greatest NASA problem of the coming decade - cost - by allowing telemetry streams from many inflight spacecraft to be handled on the ground by common, simple, multimission processing elements.
Standard round specimen fracture test results compared satisfactorily with results from standard rectangular compact specimens machined from the same material. The location of the loading pin holes was found to provide adequate strength in the load bearing region for plane strain fracture toughness testing. Excellent agreement was found between the stress intensity coefficient values obtained from compliance measurements and the analytic solution proposed for inclusion in the standard test method. Load displacement measurements were made using long armed displacement gages and hollow loading cylinders. Gage points registered on the loading hole surfaces through small holes in the walls of the loading cylinders.