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At least 415 records · Page 23

Digital flight control for the NASA 737 airplane

A brief description of the hardware and software for the digital flight control computers for the NASA 737 airplane is given. Software modules include the basic executive, scheduler, redundancy management, software signal selection, system test, mode logic, pitch axis flight control program and the lateral axis flight control program. A more detailed description of the software development effort is given for the digital flight control software. The software development tasks discussed are: software requirements, development, documentation, control, lab evaluation and formal lab tests. The software development costs are identified and conclusions are drawn concerning the software development effort required to support digital flight control for commercial jet transport applications.

Malcom, L. G.↗

Microbiology studies in the Space Shuttle

Past space microbiology studies have evaluated three general areas: microbe detection in extraterrestrial materials; monitoring of autoflora and medically important species on crewmembers, equipment, and cabin air; and in vitro evaluations of isolated terrestrial species carried on manned and unmanned spaceflights. These areas are briefly reviewed to establish a basis for presenting probable experiment subjects applicable to the Space Shuttle era. Most extraterrestrial life detection studies involve visitations to other heavenly bodies. Although this is not applicable to the first series of Shuttle flights, attempts to capture meteors and spores in space could be important. Human pathogen and autoflora monitoring will become more important with increased variety among crewmembers. Inclusion of contaminated animal and plant specimens in the space lab will necessitate inflight evaluation of cross-contamination and infection potentials. The majority of Shuttle microbiology studies will doubtless fall into the third study area. Presence of a space lab will permit a whole range of experimentation under conditions similar to these experienced in earth-based laboratories. The recommendations of various study groups are analyzed, and probable inflight microbiological experiment areas are identified for the Life Sciences Shuttle Laboratory.

Taylor, G. R.↗

A comparison of synthetic and measured solar continuum intensities and limb darkening coefficients

The paper compares recent center-limb studies of optical and IR continuum intensities (over the wavelength range 0.3-2.4 microns, with the data tabulated in the form of second- and fifth-order polynomial fits to empirical limb darkening curves) by Pierce and Slaughter (1977) and by Pierce et al. (1977) with predictions based on several current photospheric thermal structure models, using calibrated specific intensity measurements by Labs and Neckel (1968, 1970) to set an absolute temperature scale. The thermal structure in best quantitative agreement with the measurements of Pierce and Slaughter and Pierce et al. is the semiempirical model of Vernazza, Avrett and Loeser (1976). The temperatures in this model must be scaled upward, however, by a factor of 1.015 plus or minus 0.0005 to be consistent with the Labs and Neckel absolute calibration of continuum high points in the 0.40-0.65 micron region.

Ayres, T. R.↗

Heave-pitch-roll analysis and testing of air cushion landing systems

The analytical tools (analysis and computer simulation) needed to explain and predict the dynamic operation of air cushion landing systems (ACLS) is described. The following tasks were performed: the development of improved analytical models for the fan and the trunk; formulation of a heave pitch roll analysis for the complete ACLS; development of a general purpose computer simulation to evaluate landing and taxi performance of an ACLS equipped aircraft; and the verification and refinement of the analysis by comparison with test data obtained through lab testing of a prototype cushion. Demonstration of simulation capabilities through typical landing and taxi simulation of an ACLS aircraft are given. Initial results show that fan dynamics have a major effect on system performance. Comparison with lab test data (zero forward speed) indicates that the analysis can predict most of the key static and dynamic parameters (pressure, deflection, acceleration, etc.) within a margin of a 10 to 25 percent.

Boghani, A. B.↗

A VLF transmitter on the Space Shuttle

The use of space-borne transmitters for the study of interactions of energetic radiation belt particles and coherent plasma waves in the earth's magnetosphere has been considered. The proposed Space Shuttle/Space Lab system would provide a useful VLF transmitter platform since it can lift the required large payloads into orbit, erect long antennas, supply the electrical power required, and provide real-time control. A study is conducted of the power budget of such a VLF transmitter in an attempt to assess the feasibility of the experiment. It is found that a 1-10 kW transmitter placed on the Space Shuttle/Space Lab system can inject from one watt to up to a few kilowatts of wave power into the whistler mode. Recent results of ground-based VLF wave-injection experiments show that such power levels would be more than enough for initiating nonlinear wave growth and amplification and emission triggering in the magnetosphere.

Inan, U. S.↗

Langley test highlights, 1982

A 20 ft vertical spin tunnel, a 30 by 60 ft tunnel, a 7 by 10 ft high speed tunnel, a 4 by 7 meter tunnel, an 8 ft transonic pressure tunnel, a transonic dynamics tunnel, a 16 ft transonic tunnel, a national transonic facility, a 0.3 meter transonic cryogenic tunnel, a unitary plan wind tunnel, a hypersonic facilities complex, an 8 ft high temperature tunnel, an aircraft noise reduction lab, an avionics integration research lab, a DC9 full workload simulator, a transport simulator, a general aviation simulator, an advanced concepts simulator, a mission oriented terminal area simulation (MOTAS), a differential maneuvering simulator, a visual/motion simulator, a vehicle antenna test facility, an impact dynamics research facility, and a flight research facility are all reviewed.

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The utilization of Spacelab

This paper describes the general characteristics of Spacelab and discusses its past, current, and planned utilization. To date, the major emphasis has focused on the development of the Spacelab hardware and on the first two flights. The experience gained from planning these early flights has shown that mixing disciplines with conflicting requirements on the same flight significantly compounds the complexity of the mission and leads to an inefficient use of the Spacelab and Shuttle resources. To minimize the complexity and to better utilize the Spacelab and Shuttle capabilities, a new utilization concept is being developed. This new concept, called 'Dedicated Discipline Labs', involves the grouping of scientifically compatible instruments into an appropriate carrier regularly flown at intervals on the order of six months to two years. The long term goal is to evolve many of these labs into low earth orbiting facilities for space stations.

Lester, R. C.↗

Laboratory

Definition of laboratory data; sources of data and data volume, required support documentation for lab data; urgency of building a computerized archieve; software needed for management of lab data; analysis of data; and location and access to the data archive are discussed.

Source record↗

STS science and applications payloads - An evolving perspective

The present investigation is mainly concerned with a reexamination of the Spacelab payload process. The candidate missions are considered in connection with discipline payloads or laboratories. Attention is given to the Space Biomedical Laboratory (SBL), the Space Plasma Lab (SPL), the Astronomy Research Laboratory (Astro), the Shuttle High Energy Astrophysics Laboratory (SHEAL), the Shuttle Infrared Telescope Facility (SIRTF), the Solar Optical Telescope (SOT), the Materials Sciences Laboratory (MLS), the Environmental Observations Mission (EOM), the Shuttle Radar Lab (SRL), the International Microgravity Laboratory (IML), and the Payload of Opportunity Carrier (POOC). The POOC is a low cost means of placing experiments aboard the Shuttle in the cargo bay.

Sander, M. J.↗

Separator plugs for liquid helium

Work performed during Summer 1984 (from June to Sept. 30) in the area of porous media for use in low temperature applications is discussed. Recent applications are in the area of vapor - liquid phase separation, pumping based on the fountain effect and related subsystems. Areas of potential applications of the latter are outlined in supplementary work. Experimental data have been developed. The linear equations of the two-fluid model are inspected critically in the light of forced convection evidence reported recently. It is emphasized that the Darcy permeability is a unique throughput quantity in the porous media application areas whose use will permit meaningful comparisons of data not only in one lab but also within a group of labs doing porous plug studies.

Lee, J. M.↗

Containerless high temperature property measurements by atomic fluorescence

Containerless high temperature processing and material property measurements are discussed. Researchers developed methods for non-contact suspension, heating, and property measurement for materials at temperatures up to 3,680K, the melting point of tungsten. New, scientifically interesting results were obtained in Earth-based research. These results and the demonstration of new methods and techniques form a basis for further advances under the low gravity environment of space where containerless conditions are more easily achieved. Containerless high temperature material property investigations that have been completed in this and our earlier projects include measurements of fluorine LaB sub 6 reaction kinetics at 1,000 to 1,500K; optical property measurements on sapphire (Al2O3) at temperatures up to the melting point (2,327K); and vapor pressure measurements for LaB sub 6 at 2,000 to 2,500K, for molybdenum up to 2,890K and for tungsten up to 3,680K. Gas jet levitation which is applicable to any solid material, and electromagnetic levitation of electrical conductors were used to suspend the materials of interest. Non-contact heating and property measurements were achieved by optical techniques, i.e., laser heating, laser induced fluorescence measurements of vapor concentrations, and optical pyrometry for specimen temperatures.

Nordine, Paul C.↗

The Lewis Strain Gauge Laboratory: Status and plans

An in-house lab was established for developing, testing, and evaluating high-temperature strain gauges and to aid in in-house applications of high-temperature strain instrumentation. The lab is automated to provide computer control of oven temperatures, imposed strain, and data sampling.

Hobart, Howard F.↗

Calibrating AIS images using the surface as a reference

A method of evaluating the initial assumptions and uncertainties of the physical connection between Airborne Imaging Spectrometer (AIS) image data and laboratory/field spectrometer data was tested. The Tuscon AIS-2 image connects to lab reference spectra by an alignment to the image spectral endmembers through a system gain and offset for each band. Images were calibrated to reflectance so as to transform the image into a measure that is independent of the solar radiant flux. This transformation also makes the image spectra directly comparable to data from lab and field spectrometers. A method was tested for calibrating AIS images using the surface as a reference. The surface heterogeneity is defined by lab/field spectral measurements. It was found that the Tuscon AIS-2 image is consistent with each of the initial hypotheses: (1) that the AIS-2 instrument calibration is nearly linear; (2) the spectral variance is caused by sub-pixel mixtures of spectrally distinct materials and shade, and (3) that sub-pixel mixtures can be treated as linear mixtures of pure endmembers. It was also found that the image can be characterized by relatively few endmembers using the AIS-2 spectra.

Smith, M. O.↗

User interface devices for mission control

The Mission Control Center (MCC) at Johnson Space Center (JSC) in Houston, Texas, is being upgraded with new technology engineering/scientific workstations. These workstations will replace the existing consoles and will emulate the present hardware input and display media. The workstations will be using new and different input devices for the flight controller to interact with the workstation and mainframes. This paper presents the results of the User Interface survey conducted by the Workstation Prototype Lab (WPL). The WPL offered the opportunity for users to do hands-on evaluations of a number of user interface options prototyped by lab personnel.

Boatman, Wayne↗

Formulation of a General Technique for Predicting Pneumatic Attenuation Errors in Airborne Pressure Sensing Devices

Presented is a mathematical model derived from the Navier-Stokes equations of momentum and continuity, which may be accurately used to predict the behavior of conventionally mounted pneumatic sensing systems subject to arbitrary pressure inputs. Numerical techniques for solving the general model are developed. Both step and frequency response lab tests were performed. These data are compared with solutions of the mathematical model and show excellent agreement. The procedures used to obtain the lab data are described. In-flight step and frequency response data were obtained. Comparisons with numerical solutions of the math model show good agreement. Procedures used to obtain the flight data are described. Difficulties encountered with obtaining the flight data are discussed.

Whitmore, Stephen A.↗

Meteorological and Environmental Inputs to Aviation Systems

Reports on aviation meteorology, most of them informal, are presented by representatives of the National Weather Service, the Bracknell (England) Meteorological Office, the NOAA Wave Propagation Lab., the Fleet Numerical Oceanography Center, and the Aircraft Owners and Pilots Association. Additional presentations are included on aircraft/lidar turbulence comparison, lightning detection and locating systems, objective detection and forecasting of clear air turbulence, comparative verification between the Generalized Exponential Markov (GEM) Model and official aviation terminal forecasts, the evaluation of the Prototype Regional Observation and Forecast System (PROFS) mesoscale weather products, and the FAA/MIT Lincoln Lab. Doppler Weather Radar Program.

Camp, Dennis W.↗

Magellan attitude and articulation control subsystem closed loop testing

In the spring of 1989, the Magellan spacecraft will embark on a two-year mission to map the surface of the planet Venus. Guiding it there will be the Attitude and Articulation Control Subsystem (AACS). To ensure reliable operations the AACS is being put through a rigorous test program at Martin Marietta Denver Aerospace. Before Magellan ever leaves the Space Shuttle bay from which it is to be launched, its components will have flown a simulated spaceflight in a ground-based lab. The primary objectives of the test program are to verify form, fit, and function of the AACS, particularly subsystem external interfaces and functional operation of the flight software. This paper discusses the Magellan Closed Loop Test Systems which makes realistic tests possible by simulating the dynamic and 'visual' flight environment for AACS components in the lab.

Olschansky, David G.↗