ALBERT

Description: The primary objective of the University of Colorado Advanced Mission Design Program is to define the characteristics and evolution of a near-Earth space infrastructure. The envisioned foundation includes a permanently manned, self-sustaining base on the lunar surface, an L1 space station, and a transportation system that anchors these elements to a low Earth orbit (LEO) station. The motivation of this project was based on the idea that a near-Earth space infrastructure is not an end but an important step in a larger plan to expand man's capabilities in space science and technology. The presence of a cislunar space infrastructure would greatly facilitate the staging of future planetary missions, as well as facilitating the full exploration of the potential for science and industry on the lunar surface. This paper will provide a sound rationale and a detailed scenario in support of the cislunar infrastructure design.

Description: The principles involved in various applications of space tethers are discussed, with emphasis placed on tethers approved for flight on the US Shuttle. Special consideration is given to the NASA-Italy Tethered Satellite System (TSS) experiment, which will consist of three missions. The purposes of these missions and the types of experiments planned for the TSS are described. Other scientific applications of thether use in the fields of aeronomy and aerodynamics, geodynamics and remote sensing, electrodynamics, physics, astronomy, and life sciences are discussed together with particulars inolved in the measurements.

Description: The damage to spacecraft caused by debris and design of the Space Station to minimize damage from debris are discussed. Although current estimates of the debris environment show that fragments bigger than 2 cm are not likely to hit the Space Station, orbital debris from about 0.5 mm to 2 cm will pose a hazard, especially on brittle surfaces, such as glass. Spacesuits are being designed to reduce debris caused dangers to astronauts during EVA. About 5 cm of high-strength aluminum are needed to prevent penetration by a 1 cm piece of aluminum with a mass near 1.5 g colliding at 10 km/sec. Because aluminum bumpers have the drawback of metallic debris ejected outward after a hypervelocity collision, the use of nonmetallic materials for bumpers is being studied. Methods of reducing the weight and volume of the shield for the Space Station are also being researched. A space station habitation module using bumpers has a 99.6 percent chance of avoiding penetration during its lifetime.

Description: The probable amount, sizes, and relative velocities of debris are discussed, giving examples of the damage caused by debris, and focusing on the use of mathematical models to forecast the debris environment and solar activity now and in the future. Most debris are within 2,000 km of the earth's surface. The average velocity of spacecraft-debris collisions varies from 9 km/sec at 30 degrees of inclination to 13 km/sec near polar orbits. Mathematical models predict a 5 percent per year increase in the large-fragment population, producing a small-fragment population increase of 10 percent per year until the year 2060, the time of critical density. A 10 percent increase in the large population would cause the critical density to be reached around 2025.

Description: A problem of considerable interest in orbital debris research is the determination of the cause of the fragmentation of a satellite from the observed radar cross section and orbital element data. In this paper, analytic representations of the observed distribution functions of the radar cross section and the orbital plane change angle are derived. This then allows for the extraction of a small number of features that describe the observed data. Based on the known cause of fragmentation of a subset of satellites, a linear classifier is trained on these derived features. The discriminant function derived from this training is used to determine the previously unknown cause of the satellite breakup. the technique developed is objective and has been applied to the study of the cause of a number of unknown satellite breakup events.

Description: The Space Station is expected to be equipped with intelligent, autonomous capabilities; to achieve and incorporate these capabilities, the required technologies need to be identitifed, developed and validated within realistic application scenarios. The critical technologies for the development of intelligent, autonomous systems are discussed in the context of a generalized functional architecture. The present state of this technology implies that it be introduced and applied in an evolutionary process which must start during the Space Station design phase. An approach is proposed to accomplish design information acquisition and management for knowledge-base development.

Description: The scientific results of the Seasat mission are reviewed, including altimeter, scatterometer, microwave radiometer, and imaging radar studies. The analyses of Seasat data showed that global calibrations of satellite observations are much more accurate than measurements made at points on the ocean. It is found that the accuracy of satellite measurements of a particular variable are improved if the variable is measured by different instruments on the same satellite. The results suggest that important oceanographic variables can be mapped from space with accuracies required by climatological and scientific studies.

Description: A computational procedure is presented to simulate transonic unsteady flows and corresponding aeroelasticity of wings at low-supersonic freestreams. The flow is modeled by using the transonic small-perturbation theory. The structural equations of motions are modeled using modal equations of motion directly coupled with aerodynamics. Supersonic freestreams are simulated by properly accounting for the boundary conditions based on pressure waves along the flow characteristics in streamwise planes. The flow equations are solved using the time-accurate, alternating-direction implicit finite-difference scheme. The coupled aeroelastic equations of motion are solved by an integration procedure based on the time-accurate, linear-acceleration method. The flow modeling is verified by comparing calculations with experiments for both steady and unsteady flows at supersonic freestreams. The unsteady computations are made for oscillating wings. Comparisons of computed results with experiments show good agreement. Aeroelastic responses are computed for a rectangular wing at Mach numbers ranging from subtransonic to upper-transonic (supersonic) freestreams. The extension of the transonic dip into the upper transonic regime is illustrated.

Description: The effect of a simulated glaze-ice accretion on the aerodynamic performance of a NACA 0012 airfoil was studied experimentally. Two ice shapes were tested: one from an experimentally measured accretion, and one from an accretion predicted using a computer model given the same icing conditions. Lift, drag, and pitching moment were measured for the airfoil with both smooth and rough ice shapes. The ice shapes caused large lift and drag penalties, primarily due to large separation bubbles. Surface pressure distributions clearly showed the regions of separated flow. The aerodynamic performance of the two shapes compared well at positive, but not negative, angles of attack.

Description: The drag of airfoils in transonic flow can be reduced through the use of a passive venting system that employs a porous plate for part of the airfoil upper surface with a vent chamber underneath the porous plate Attention is given to the results obtained with a wind tunnel model employing such a porous floor system. This passive venting system has been used to extend the length/height value before the onset of high drag-producing closed cavity flow at supersonic speeds.

Description: The wakes of highly loaded compressor blades are generally considered to be turbulent flows. Recent work has suggested that the blade wakes are dominated by a vortex streetlike structure. The experimental evidence supporting the wake vortex structure is reviewed. This structure is shown to redistribute thermal energy within the flowfield. The effect of the wake structure on conventional aerodynamic measurements of compressor performance is noted. A two-dimensional, time-accurate, viscous numerical simulation of the flow exhibits both vortex shedding in the wake and a lower-frequency flow instability that modulates the shedding. The numerical results are shown to agree quite well with the measurement from transonic compressor rotors.

Description: To achieve a nanogravity environment on the Space Shuttle Orbiter or Space Station a floating table is proposed. With precise control of the initial release conditions, float times of many minutes can be expected before touching a wall. The use of small thrusters available on the spacecraft to fly the station around the floating table would allow experiment times of many hours.

Description: The effects of mean-flow incidence, airfoil camber, and airfoil thickness on the incompressible aerodynamics of an oscillating airfoil are investigated theoretically, developing and applying a first-order FEM based on locally analytical solutions (LASs). Laplace equations are used to describe the steady and unsteady harmonic velocity potentials; a body-fitted computational grid is employed; grid-element solutions for both potentials are determined using a numerical LAS method; and the LASs are then assembled to obtain a complete solution. Results for a series of flat-plate and Joukowski airfoils are presented in extensive graphs and discussed in detail.

Description: The problem of building an infrastructure on the moon is discussed, assuming that earth-to-moon and moon-to-earth transport will be available. The sequence of events which would occur in the process of building an infrastructure is examined. The human needs which must be met on a lunar base are discussed, including minimal life support, quality of life, and growth stages. The technology available to meet these needs is reviewed and further research in fields related to a lunar base, such as the study of the moon's polar regions and the limits of lunar agriculture, is recommended.

Description: The Dynamics Explorer (DE) program summarizes its accomplishments during the first 5 years since the launch of the two DE satellites. This introduction to six review articles provides background information and a brief history of the program, especially citing the contributions of many people to its development. The principal investigators who had primary responsibility to implement the program are listed, together with the instruments they provided. Orbital information and approaches and constraints to data acquisition are explained. The brief description of the ground data processing and analysis system provides information on access to data catalogs and data sets. Each review article is then placed in the context of the categories of scientific objectives of the program.

Description: The current status and potential scientific applications of intelligent 1-5-kg projectiles being developed by SDIO and DARPA for military missions are discussed. The importance of advanced microelectronics for such small spacecraft is stressed, and it is pointed out that both chemical rockets and EM launchers are currently under consideration for these lightweight exoatmospheric projectiles (LEAPs). Long-duration power supply is identified as the primary technological change required if LEAPs are to be used for interplanetary scientific missions, and the design concept of a solar-powered space-based railgun to accelerate LEAPs on such missions is considered.

Description: The complexity and variety of objects in the infrared universe have been revealed by the Infrared Astronomical Satellite (IRAS). Further exploration of this universe will be possible with the Space Infrared Telescope Facility (SIRTF), which offers vast improvements in sensitivity and resolution over IRAS. SIRTF's planned capabilities and current status are briefly reviewed.

Description: A complete mathematical model is formulated to analyze the effects of mean-flow incidence angle on the unsteady aerodynamics of an oscillating airfoil in an incompressible flow field. A velocity potential formulation is utilized. The steady flow is independent of the unsteady flow field but coupled to it through the boundary conditions on the oscillating airfoil. The numerical solution technique for both the steady and unsteady flow fields is based on a locally analytical method. The flow model and solution method are then verified through the excellent correlation obtained with the Theodorsen oscillating-flat-plate and Sears transverse-gust classical solutions. The effects of mean flow incidence on the steady and oscillating airfoil aerodynamics are then investigated.

Description: Computational results are presented for the transitional or turbulent flow about a prolate spheroid, at alpha = 10 deg or 30 deg, correspondingly, using an implicit, approximately factored, partially flux-split algorithm, based on the thin-layer equations. The computed flow field is in good agreement with available experimental data.

Description: Thin-element riblets for aircraft aerodynamic surface turbulent viscous drag reduction are presently found to be as effective as symmetric V-grooves in this role, while possessing a greater range of admissible spacings. The thin-element geometry shows the qualitatively predictable influence of independent riblet height and spacing variations. The evidence for more than one drag-reduction mechanism in thin-element riblets is found to be inconclusive.

Description: This paper briefly reviews some national studies and new programs concerning hypersonic flight. The flight environment that will be encountered by this new class of hypersonic vehicles is described, and the fluid-dynamic and chemical phenomena that occur in hypersonic flight are examined. Ground-based facilities are briefly described, and their use in helping to validate the codes is examined.

Description: Different models for inviscid transonic flows are examined. The common assumptions that the flow is isentropic and irrotational are critically evaluated. Entropy and vorticity correction procedures for potential and stream function formulations are presented, together with the details of the treatment of shocks and wakes, and drag and lift calculations. The non-uniqueness problem of the potential formulation is studied using different artificial viscosity forms. Numerical results are compared with Euler solutions.

Description: Low-speed wind tunnel drag force measurements were taken on a laminar flow body of revolution free of support interference. This body was tested at zero incidence in the NASA Langley 13 inch Magnetic Suspension and Balance System (MSBS). The primary objective of these tests was to substantiate the drag force measuring capabilities of the 13 inch MSBS. A secondary objective was to obtain support interference free drag measurements on an axisymmetric body of interest. Both objectives were met. The drag force calibrations and wind-on repeatability data provide a means of assessing the drag force measuring capabilities of the 13 inch MSBS. The measured drag coefficients for this body are of interest to researchers actively involved in designing minimum drag fuselage shapes. Additional investigations included: the effects of fixing transition; the effects of fins installed in the tail; surface flow visualizations using both liquid crystals and oil flow; and base pressure measurements using a one-channel telemetry system. Two drag prediction codes were used to assess their usefulness in estimating overall body drag. These theoretical results did not compare well with the measured values because of the following: incorrect or non-existent modeling of a laminar separation bubble on the body and incorrect of non-existent estimates of base pressure drag.

Description: It is observed that the center of pressure on a wing shifts as the Mach number is changed. Such shifts are in general undesirable and are sometimes compensated for by actively shifting the center of gravity of the aircraft or by using active stability controls. To avoid this complication, it is desirable to design the wings of a high speed aircraft so as to minimize the extent of the center-of-pressure shifts. This, together with a desire to minimize the center-of-pressure shifts in missile control surfaces, provides the motivation for this project. There are many design parameters which affect center-of-pressure shifts, but it is expected that the largest effects are due to the wing planform. Thus, for the sake of simplicity, this study is confined to an investigation of thin, flat, (i.e., no camber or twist), relatively slender, pointed wings flying at a small angle of attack. Once the dependence of the center of pressure on planform and Mach number is understood, we can expect to investigate the sensitivity of the center-of-pressure shifts to various other parameters.

Description: Information is given in viewgraph form on the Aeroassist Flight Experiment (AFE), an experiment with the objective of investigating critical vehicle design and environmental technologies applicable to the design of aeroassisted space transfer vehicles. Information is given on design, simulation, flight regime, mission requirements and objectives, instrumentation, and the project schedule.

Description: Information on sensors research and technology is given in viewgraph form. Information is given on sensing techniques for space science, passive remote sensing techniques and applications, submillimeter coherent sensing, submillimeter mixers and local oscillator sources, non-coherent sensors, active remote sensing, solid state laser development, a low vibration cooler, separation of liquid helium and vapor phase in zero gravity, and future plans.

Description: Information on systems autonomy is given in viewgraph form. Information is given on space systems integration, intelligent autonomous systems, automated systems for in-flight mission operations, the Systems Autonomy Demonstration Project on the Space Station Thermal Control System, the architecture of an autonomous intelligent system, artificial intelligence research issues, machine learning, and real-time image processing.

Description: Within the last two decades, there has been increasing emphasis on developing more sophisticated computational fluid dynamics (CFD) methods to handle a wide range of problems of interest to the aerospace community. The comprehensive picture of the status of CFD development and capability as well as an assessment of requirements and future directions are given. An independent review and assessment was also carried out by the author as part of the current assignment and the results are outlined herein.

Description: The purpose of Space Experiments with Particle Accelerators (SEPAC) on the Atmospheric Laboratory for Applications and Science (ATLAS 1) mission, is to carry out active and interactive experiments on and in the earth's ionosphere, atmosphere, and magnetosphere. The instruments to be used are an electron beam accelerator (EBA), plasma contactor, and associated instruments the purpose of which is to perform diagnostic, monitoring, and general data taking functions. Four major classes of investigations are to be performed by SEPAC. They are: beam plasma physics, beam-atmosphere interactions, the use of modulated electron beams as transmitting antennas, and the use of electron beams for remote sensing of electric and magnetic fields. The first class consists mainly of onboard plasma physics experiments to measure the effects of phenomena in the vicinity of the shuttle. The last three are concerned with remote effects and are supported by other ATLAS 1 investigations as well as by ground-based observations.

Description: The Grille spectrometer was designed and flown on Spaceklab 1 by two organizations: The Office National d'Etudes et de Recherches Aerospatiales in France and the Belgian Institute for Space Aeronomy in Belgium. Its purpose is to study, on a global scale, atmospheric parameters between 15 and 150 km altitude. The investigation uses high-resolution (better than 0.1/cm) spectroscopic observations of the earth's limb in the wavelength range characteristic of the vibrational-rotational lines of the relevant atmospheric constituents. Characteristics and proposed modifications of the grille spectrometer are described. This instrument will be part of the atmospheric science research payload flown on the Atmospheric Laboratory for Applications and Science (ATLAS 1) NASA mission planned for late 1990.

Description: Space plasma physics will be studied on the Atmospheric Laboratory for Applications and Science (ATLAS 1) NASA mission during the Atmospheric Emissions Photometric Imaging (AEPI) experiment. The basic scientific objective of the AEPI is the investigation of the upper atmosphere-ionosphere and the space shuttle environment. The experiment areas of the AEPI include: (1) the investigation of ionospheric transport processes by observing Mg(+) ions; (2) studies of optical properties of artificially induced electron beams; (3) measurement of electron cross sections for selected atmospheric species; (4) studies of natural airglow; and (5) studies of natural auroras. On ATLAS 1, optical emissions generated by the shuttle (shuttle ram glow) will also be investigated.

Description: Measurement of the Solar Constant (SOLCON) is a solar physics experiment of the Atmospheric Laboratory for Applications and Science (ATLAS 1) NASA mission scheduled for late 1990. The objectives of this investigation are: (1) to measure the absolute value of the solar constant with improved accuracy, and (2) to detect and measure long-term variations that may exist in the absolute value of the solar constant. The solar constant is the total irradiance of the sun at a distance of one astronomical unit. This will be measured directly in space by an absolute self-calibrating radiometer with an absolute accuracy estimated to be of the order of + or - 0.1 percent and a sensitivity better than 0.05 percent. Features of this radiometer are given.

Description: The SOLSPEC experiment, planned for the Atmospheric Laboratory for Applications and Science (ATLAS 1) NASA mission, is described. The purpose of this experiment is the measurement of the absolute solar irradiances in the wavelength range from 180 to 3000 nm and the variabilities of the solar irradiances in this wavelength range. Measurements of the irradiances and variabilities are used in: (1) solar-terrestrial/planetary relationships, in particular aeronomy of the stratosphere and mesosphere; (2) climatoglogy; and (3) solar physics.

Description: Two dimensional problems are solved using numerical techniques. Navier-Stokes equations are studied both in the vorticity-stream function formulation which appears to be the optimal choice for two dimensional problems, using a storage approach, and in the velocity pressure formulation which minimizes the number of unknowns in three dimensional problems. Analysis shows that compact centered conservative second order schemes for the vorticity equation are the most robust for high Reynolds number flows. Serious difficulties remain in the choice of turbulent models, to keep reasonable CPU efficiency.

Description: Supersonic external compression inlets are introduced, and the computational fluid dynamics (CFD) codes and tests needed to study flow associated with these inlets are outlined. Normal shock wave turbulent boundary layer interaction is discussed. Boundary layer control is considered. Glancing sidewall shock interaction is treated. The CFD validation of hypersonic inlet configurations is explained. Scramjet inlet modules are shown.

Description: The fluid dynamics of curved diffuser duct flows of military aircraft is discussed. Three-dimensional parabolized Navier-Stokes analysis, and experiment techniques are reviewed. Flow measurements and pressure distributions are shown. Velocity vectors, and the effects of vortex generators are considered.

Description: Fundamental equations encountered in computational fluid dynamics (CFD), and analyses used for internal flow are introduced. Irrotational flow; Euler equations; boundary layers; parabolized Navier-Stokes equations; and time averaged Navier-Stokes equations are treated. Assumptions made and solution methods are outlined, with examples. The overall status of CFD in propulsion is indicated.

Description: Information on space propulsion and technology and the cryogenic fluid depot is given in viewgraph form. Information is given on orbit transfer, electric propulsion, spacecraft propulsion, and program objectives.

Description: The Vertical Horizons experiment represents an initial investigation into the transportation of fine arts materials aboard a space shuttle. Within the confines of a GAS canister, artist quality fine arts materials were packaged and exposed to the rigors of space flight in an attempt to identify adverse effects.

Description: Acceleration ground tests were conducted on the Get Away Special (GAS) payload 559 to verify the structural integrity of the structure/support avionics and two of the planned three flight experiments. The ITA (Integrated Test Area) Standardized Experiment Module (ISEM) structure was modified to accommodate the experiments for payload 559. The ISEM avionics consisted of a heavy duty sliver zinc power supply, three orthogonal-mounted low range microgravity accelerometers, a tri-axis high range accelerometer, a solid state recorder/programmer sequencer, and pressure and temperature sensors. The tests were conducted using the Gravitational Plant Physiology Laboratory Centrifuge of the University City Science Center in Philadelphia, PA. The launch-powered flight steady state acceleration profile of the shuttle was simulated from lift-off through jettison of the External Tank (3.0 g's). Additional tests were conducted at twice the nominal powered flight acceleration levels (6 g's) and an over-test condition of four times the powered flight loads to 12.6 g's. The present test program has demonstrated the value of conducting ground tests to verify GAS payload experiment integrity and operation before flying on the shuttle.

Description: Information is given in viewgraph form on space power technologies. Energy conversion, the role of nuclear power in space, lunar and Mars bases, and the Pathfinder program are covered.

Description: Information is given in viewgraph form on Earth-to-orbit propulsion research and technology, space transportation systems, spacecraft configurations, booster technology and hybrid propellant rocket engines.

Description: Information on physical/chemical closed-loop life support systems are given in viewgraph form. Information is given on program objectives, the elements of a life support system, and Pathfinder program elements.

Description: The Get Away Special payload to investigate the formation of inorganic precipitates (G-405) utilizes six transparent chemical reaction chambers to actively mix a dry powder with a liquid solution. At predetermined intervals the progress of the precipitate formation is photographed and stored as data. The precipitate particles will also be subject to post-flight analysis. The various tasks performed during the 14 hour duration of the experiment are initiated and monitored by a custom-built digital controller. The payload is currently scheduled as a backup payload for STS-29 with a possible launch date of January, 1989.

Description: The feasibility of using welding for the construction, expansion and emergency repair of space based structures is discussed and the advantages of gas tungsten arc welding (GTAW) over other welding techniques are briefly examined. The objective and design concept for the G-169 Get Away Special payload are described. The G-169 experiment will allow the comparison of a space GTA welded joint with a terrestrial GTA welded joint with all parameters held constant except for gravitational forces. Specifically, a bead-on-plate weld around the perimeter of a 2 inch diameter stainless steel pipe section will be performed. The use of Learjet microgravity simulation for the G-169 and other Get Away Special experiments is also addressed.

Description: The Purdue University Get Away Special Project (PUGAS) is a student-run organization dedicated to preparing payloads for flight on NASA's space shuttle. The first such payload (PUGAS I) flew on Challenger in 1983. The second payload (PUGAS II) should be ready by the end of 1988 and will include three experiments. The first experiment will involve the production of tin metal foam under microgravity conditions. The second experiment will focus on the desorption of water from carbon-epoxy composite materials. The third experiment will use a solid polymeric material to detect radiation in space.

Description: The computer subsystem of the Villanova University GAS (Get Away Special) experiment apparatus is discussed. The function of the computer subsystem is to provide data acquisition and control system support to the experiments. The computer subsystem will provide high availability, low power consumption and highly reliable data retention. The general layout of the subsystem provides for redundant processing units, control modules, and multiple data acquisition modules. Each of the two redundant processing units will be composed of a microprocessor, control logic, PROM, RAM, non-volitile memory, timers, self-check logic and data ports to the data acquisition and control modules. One unit will control the experiment while the other shadows the primary unit operation. The data acquisition module gathers data from the experiment. The data is transfered to the processing unit in digital form. The control module validates the data, decodes it and executes the command.

Description: A carrier system has been developed for economical and quick response flight of small attached payloads on the space shuttle. Hitchhiker can accommodate up to 750 lb of customer payloads in canisters or mounted to an exposed side-mount plate, or up to 1200 lb mounted on a cross-bay structure. The carrier connects to the orbiter's electrical systems and provides up to six customers with standard electrical services including power, real time telemetry and commands. A transparent data and command system concept is employed to allow the customer to easily use his own ground support equipment and personnel to control his payload during integration and flight operations. A general description of the Hitchhiker program and the Shuttle Payload of Opportunity Carrier (SPOC) is given and future enhancements are outlined.

Description: Experiments conducted to investigate possible hardware configurations and methodologies for a Get Away Special payload designated G-652 are discussed. Test data collected from the operation of a free electron laser wiggler using simulated ram glow phenomenon are described. Results of an experiment to synthesize organic compounds within a primordial atmosphere using a laser induced plasma are discussed. An experiment is described which utilized neutron bombardment to assess the risk of genetic alterations in embyros in space.

Description: The safety approval process established by the National Aeronautics and Space Administration for Get Away Special (GAS) payloads is described. Although the designing organization is ultimately responsible for the safe operation of its payload, the Get Away Special team at the Goddard Space Flight Center will act as advisors while iterative safety analyses are performed and the Safety Data Package inputs are submitted. This four phase communications process will ultimately give NASA confidence that the GAS payload is safe, and successful completion of the Phase 3 package and review will clear the way for flight aboard the Space Transportation System orbiter.

Description: The Get Away Special (GAS) program has instituted a new project called Complex Self Contained Payloads (CSCP) designed to support GAS type payloads that are beyond the scope of the GAS program. These payloads may be supported by GAS personnel and hardware and will fly as primary or secondary shuttle payloads. The definition, requirements and basic support package for CSCP's are discussed.

Description: As part of the Space Experiment Program of the Society of Japanese Aerospace Companies, three experimental systems (G452, G453, G454) have been developed for materials science studies under microgravity by the NEC Corporation. These systems are to be flown as Get Away Special payloads for studying the feasibility of producing new materials. Together with the experimental modules carrying the hardware specific to the experiment, the three systems all comprise standard subsystems consisting of a power supply, sequence controller, temperature controller, data recorder, and video recorder.

Description: The experiment is designed to measure the heavy ion environment at low altitude (HIEN-LO) in the energy range 0.3 to 100 MeV/nucleon. In order to cover this wide energy range a complement of three sensors is used. A large area ion drift chamber and a time-of-flight telescope are used to determine the mass and energy of the incoming cosmic rays. A third omnidirectional counter serves as a proton monitor. The analysis of mass, energy and incoming direction in combination with the directional geomagnetic cut-off allows the determination of the ionic charge of the cosmic rays. The ionic charge in this energy range is of particular interest because it provides clues to the origin of these particles and to the plasma conditions at the acceleration site. The experiment is expected to be flown in 1988/1989.

Description: The German MAUS project (materials science autonomous experiments in weightlessness) was initiated in 1979 for optimum utilization of NASA's Get Away Special (GAS) program. The standard MAUS system was developed to meet GAS requirements and can accommodate a wide variety of GAS-type experiments. The system offers a range of services to experimenters within the framework of standardized interfaces. Four MAUS payloads being prepared for future space shuttle flight opportunities are described. The experiments include critical Marangoni convection, oscillatory Marangoni convection, pool boiling, and gas bubbles in glass melts. Scientific objectives as well as equipment hardware are presented together with recent improvements to the MAUS standard system, e.g., a new experiment control and data management unit and a semiconductor memory. A promising means of increasing resources in the field of GAS experiments is the interconnection of GAS containers. This important feature has been studied to meet the challenge of future advanced payloads. In the TWIN-MAUS configuration, electrical power and data will be transferred between two containers mounted adjacent to each other.

Description: TUBSAT-1 (Technical University of Berlin Satellite) is an experimental low-cost satellite within the NASA Get Away Special (GAS) program. This project is being financed by the German BMFT (Federal Ministry for Research and Technology), mainly for student education. The dimensions and weight are determined by GAS requirements and the satellite will be ejected from the space shuttle into an approximately 300-km circular orbit. It is a sun/star oriented satellite with an additional spin stabilization mode. The first planned payload is to be used for observing flight paths of migratory birds from northern Europe to southern Africa and back.

Description: The first Chinese Getaway Special program is described. Program organization, the student proposal evaluation procedure, and the objectives of some of the finalist's experiments are covered. The two experiments selected for eventual flight on the space shuttle are described in detail. These include: (1) the control of debris in the cabin of the space shuttle; and (2) the solidification of two immiscible liquids in space.

Description: Four experiment systems which have fundamental significance in the field of biotechnology are developed for the Get Away Special (GAS). Unique considerations were necessary to develop the systems which carry out biotechnological experiments under GAS's restricted conditions: delicate thermal control, fluid handling and protection from contamination. All experimental processes are controlled by internal sequencers and results of the experiments are recorded as images and numerical data within the systems. The systems are standardized in order to enable repeated use with a variety of experiments by replacement of the experiment modules and modification of experiment sequencing programs.

Description: One of the flows inherent in VSTOL operations, the jet in ground effect with a crossflow, is studied using the Fortified Navier-Stokes (FNS) scheme. Through comparison of the simulation results and the experimental data, and through the variation of the flow parameters (in the simulation) a number of interesting characteristics of the flow have been observed. For example, it appears that the forward penetration of the ground vortex is a strong inverse function of the level of mixing in the ground vortex. Also, an effort has been made to isolate issues which require additional work in order to improve the numerical simulation of the jet in ground effect flow. The FNS approach simplifies the simulation of a single jet in ground effect, but it will be even more effective in applications to more complex topologies.

Description: Key results from low speed wind tunnel testing of the F-15 STOL and Maneuver Technology Demonstrator (SMDT) with thrust reversers are presented. Longitudinally, the largest induced increments in the stability and control occur at landing gear height. These generally reflect an induced lift loss and a nose-up pitching moment, and vary with sideslip. Directional stability is reduced at landing gear height with full reverse thrust. Nonlinearities in the horizontal tail effectiveness are found in free air and at landing gear height.

Description: A new testing technique was developed wherein the rate of descent can be included as a parameter in ground effects investigations. This technique simulates the rate of descent by horizontal motion of a model over an inclined ground board in the Langley Vortex Research Facility (VRF) During initial evaluations of the technique, dynamic ground effects data were obtained over the inclined ground board, steady state ground effects data were obtained over a flat portion of the ground board, and the results were compared to conventional static wind tunnel ground effect data both with and without a moving belt ground plane simulation. Initial testing and analysis led to the following conclusions: the moving belt ground plane had little effect on static ground effects for the configurations tested unless thrust reversers were employed; in general, rate-of-descent reduced ground effects to the point that for reversed thrust cases an expected loss of lift due to ground effects was eliminated at approach conditions; and, in general, the steady state results from the VRF matched static results obtained from the wind tunnel once the flow field stabilized over the flat portion of the ground board.

Description: The results of an experimental investigation into the position and characteristics of the ground vortex are summarized. A 48-inch wind tunnel was modified to create a testing environment suitable for the ground vortex study. Flow visualization was used to document the jet-crossflow interaction and a two-component Laser Doppler Velocimeter (LDV) was used to survey the flowfield in detail. Measurements of the ground vortex characteristics and location as a function of freestream-to-jet velocity ratio, jet height, pressure gradient and upstream boundary layer thickness were obtained.

Description: Flow field investigations were conducted at the NASA Ames-Dryden Flow Visualization Facility (water tunnel) to investigate the ground effect produced by the impingement of jets from aircraft nozzles on a ground board in a STOL operation. Effects on the overall flow field with both a stationary and a moving ground board were photographed and compared with similar data found in other references. Nozzle jet impingement angles, nozzle and inlet interaction, side-by-side nozzles, nozzles in tandem, and nozzles and inlets mounted on a flat plate model were investigated. Results show that the wall jet that generates the ground effect is unsteady and the boundary between the ground vortex flow field and the free-stream flow is unsteady. Additionally, the forward projection of the ground vortex flow field with a moving ground board is one-third less than that measured over a fixed ground board. Results also showed that inlets did not alter the ground vortex flow field.

Description: The interaction of the free stream velocity on the wall jet formed by the impingement of deflected engine thrust results in a rolled up vortex which exerts sizable forces on a short takeoff (STOL) airplane configuration. Some data suggest that the boundary layer under the free stream ahead of the configuration may be important in determining the extent of the travel of the wall jet into the oncoming stream. Here, early studies of the ground vortex are examined, and those results are compared to some later data obtained with moving a model over a fixed ground board. The effect of the ground vortex on the aerodynamic characteristics are discussed.

Description: Guidance in preparing and updating an integrated logistics support plan (ILSP) is given. Clear, concise, and detailed instructions are provided on the preparation and content of an ILSP in order to ensure a quality document that reflects total program requirements.

Description: A mission designed to collect and return samples from Mars will provide information regarding its composition, history, and evolution. At the same time, a sample return mission generates a technical challenge. Sophisticated, semi-autonomous, robotic spacecraft systems must be developed in order to carry out complex operations at the surface of a very distant planet. An interdisciplinary effort was conducted to consider how much a Mars mission can be realistically structured to maximize the planetary science return. The focus was to concentrate on a particular set of scientific objectives (exobiology), to determine the instrumentation and analyses required to search for biological signatures, and to evaluate what analyses and decision making can be effectively performed by the rover in order to minimize the overhead of constant communication between Mars and the Earth. Investigations were also begun in the area of machine vision to determine whether layered sedimentary structures can be recognized autonomously, and preliminary results are encouraging.

Description: The complexity of the U.S. Sample Return Mission is ultimately dependent on current mission funding and the projected direction of the U.S. space program. Despite these uncertainties, it is important to examine mission scenarios to address desired scientific objectives that can be summarized in the following list: (1) determine existence of climatic records in geologic records; (2) does Mars have a subpermafrost groundwater system; (3) fundamental questions on the existence of Mars biology; (4) what is the internal structure of Mars; (5) determine the systems for regolith formation; and (6) what is the contribution of meteorites to Martian geology and climate are presented. To address these objectives, the sample size, quantity and location must be established and whether this should be the only data searched for on the Martian surface. With this in mind, three mission scenarios are briefly discussed, in order of increasing complexity.

Description: The Far Ultraviolet Space Telescope is a compact, wide field-of-view, far ultraviolet instrument designed for observations of extended and point sources of astronomical interest. It was originally used in sounding rocket work by both French and American investigators. The instrument was modified for flight on the space shuttle and flew on the Spacelab 1 mission as a joint effort between the Laboratoire d'Astronomie Spatiale and the University of California, Berkeley. The prime experiment objective of this telescope on the Atmospheric Laboratory Applications and Science (ATLAS 1) NASA mission is to observe faint astronomical sources in the far ultraviolet with sensitivities far higher than previously available. The experiment will cover the 1300 to 1800 A band, which is inaccessible to observers on earth. The observing program during the mission consists of obtaining deep sky images during spacecraft nighttime. The targets will include hot stars and nebulae in our own galaxy, faint diffuse galactic features similar to the cirrus clouds seen by the Infrared Astronomical Satellite (IRAS), large nearby galaxies, nearby clusters of galaxies, and objects of cosmological interest such as quasars and the diffuse far ultraviolet background.

Description: The Energetic Neutral Atom Precipitation experiment is scheduled to be flown on the Atmospheric Laboratory for Applications and Science (ATLAS 1) NASA mission. The objective of this experiment is to measure very faint emissions at nighttime arising from fluxes of energetic neutral atoms in the thermosphere. These energetic atoms have energies ranging up to about 50 keV, and arise from ions of hydrogen, helium, and oxygen trapped in the inner magnetosphere. Some of these ions become neutralized in charge exchange reactions with neutral hydrogen in the hydrogen geocorona that extends through the region. The ions are trapped on magnetic field lines which cross the equatorial plane at 2 to 6 earth radii distance, and they mirror at a range of heights on these field lines, extending down to the thermosphere at 500 km altitude. The ATLAS 1 measurements will not be of the neutral atoms themselves but of the optical emission produced by those on trajectories that intersect the thermosphere. The ENAP measurements are to be made using the Imaging Spectrometric Observatory (ISO) which is being flown on the ATLAS mission primarily for daytime spectral observations, and the ENAP measurements will all be nighttime measurements because of the faintness of the emissions and the relatively low level of magnetic activity expected.

Description: The Atmospheric Lyman-Alpha Emissions (ALAE) experiment which is designed to measure atomic hydrogen and deuterium in the terrestrial atmosphere is described. The development of the instrument is a joint effort of the Service d'Aeronomie du CNRS in France and the Institut d'Aeronomie Spatiale in Belgium. This experiment will be part of the atmospheric science research payload flown on the Atmospheric Laboratory for Applications and Science (ATLAS 1) NASA mission planned for late 1990.

Description: The Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment is a space-borne investigation designed to obtain fundamental information related to the chemistry and physics of the earth's upper atmosphere (20 to 120 km altitude). The instrument, a high resolution (0.01/cm) interferometric spectrometer, measures the atmospheric absorption of solar radiation over the wavelength range from 2 to 16 micrometers, a spectral band which encompasses active transitions of all of the molecular species of current importance in upper atmospheric studies. There are two major aspects to the experiment: (1) the determination of the detailed compositional structure of the stratosphere and mesosphere, and its global, seasonal, and long-term variability; and (2) the study of the partitioning of absorbed solar energy at levels in the atmosphere characterized by dissociation of many of the constituents and by the breakdown of thermodynamic equilibrium. Characteristics of ATMOS are given. This experiment will be part of the atmospheric science research payload flown on the Atmospheric Laboratory for Applications and Science (ATLAS 1) NASA mission planned for late 1990.

Description: MAS is a remote sensing instrument for passive sounding (limb sounding) of the earth's atmosphere from the Space Shuttle. The main objective of the MAS is to study the composition and dynamic structure of the stratosphere, mesosphere, and lower thermosphere in the height range 20 to 100 km, the region known as the middle atmosphere. The MAS will be flown on the Atmospheric Laboratory for Applications and Science (ATLAS 1) NASA mission scheduled for late 1990. The Millimeter-Wave Atmospheric Sounder will provide, for the first time, information obtained simultaneously on the temperature and on ozone concentrations in the 20 to 90 km altitude region. The information will cover a large area of the globe, will have high accuracy and high vertical resolution, and will cover both day and night times. Additionally, data on the two important molecules, H2O and ClO, will also be provided.

Description: The objective of the Active Cavity Radiometer (ACR) experiment on the Atmospheric Laboratory for Applications and Science (ATLAS) mission is the measurement of the total solar irradiance with state-of-the-art accuracy and precision. This experiment is part of an ongoing program of space flight observations to study short- and long-term variations in the total solar output of optical energy. Precise observations of solar total irradiance provide information on the solar cycle and other long-term trends in solar output that are of climatological significance as well as short-term solar physics phenomena such as radiation anisotropy, active region structure, missing flux due to sunsports, bolometry of solar flares, global oscillations, coronal holes, and large-scale convective flows. The principal role of the ATLAS ACR observations will be in support of extended solar irradiance experiments on free-flying satellites. Annual in-flight comparison of observations by both ATLAS and free-flying experiments is an important part of sustaining the long-term precision of the climatological solar irradiance data base at the required + or - 0.1 percent level. Another role for ATLAS solar irradiance measurements will be establishment of the radiation scale at the solar total flux level in the International System of Units (SI). Two types of pyrheliometers, the ACR and SOLCON, will be directly intercompared during the ATLAS 1 mission. Addition of other sensors is planned for future reflights. Comparisons of solar observations by different pyrheliometers in the shuttle space environment will provide the most definitive experiment for determining their accuracy in defining the radiation scale at the solar total flux level.

Description: The Imaging Spectrometric Observatory (ISO) is designed for low light level spectroscopy of both the day and night side of the earth. The instrument is composed of five spectrometers, each of which covers part of the total wavelength range of 30 to 1300 nm spanned by the instrument. Wavelength resolution varies between 0.2 and 0.6 nm over the spectral range. The five spectrometers are each optimized for a portion of the spectrum by the choice of mirror reflective coatings and detector photocathode materials. The full spectral range for each spectrometer is covered in a total of 11 grating steps. The Imaging Spectrometric Observatory was flown for the first time on the Spacelab 1 mission during which it acquired almost 40 hr of observations. The ISO investigation to be flown on the Atmospheric Laboratory for Applications and Science (ATLAS 1) mission will draw on the experience gained from the data gathered on Spacelab 1. The detector system in each spectrometer was upgraded to provide both higher sensitivity at low light levels and simultaneous imaging over larger spectral segments than was achieved on Spacelab 1. In addition, the instrument and the observing sequences were modified to allow observation of the sun in the extreme ultraviolet. A summary of ISO parameters for ATLAS 1 (scheduled for late 1990) is given.

Description: The first Atmospheric Laboratory for Applications and Science (ATLAS 1) is a NASA mission with an international payload, with the European Space Agency providing operational support for the European investigations. The ATLAS 1 represents the first of a series of shuttle-borne payloads which are intended to study the composition of the middle atmosphere and its possible variations due to solar changes over the course of an 11-year solar cycle. One of the ATLAS missions will coincide with NASA's Upper Atmospheric Research Satellite (UARS) mission and will provide crucial parameters not measured by the instrument complement on the satellite. A first in this evolutionary program, the ATLAS 1 will carry a payload of instruments originally flown on the Spacelab 1 and Spacelab 3 missions. The ATLAS mission therefore exploits the shuttle capability to return sophisticated instruments to the ground for refurbishment and updating, and the multi-mission reflight of the instruments at intervals required by the scientific goals. In addition to the investigations specific to the ATLAS objectives, the first mission payload includes others that are intended to study or use the near earth environment.

Description: Some of the single rotation propfan model wind tunnel aeroelastic findings from the experimental part of this research program are described. These findings include results for unstalled or classical flutter, blade response from separated flow excitations, and blade response from aerodynamic excitations at angled inflow conditions.

Description: The development of G-325, the first high school student-run space flight project, is updated. An overview is presented of a new international program, which involves students from space station countries who will be utilizing Get Away Special technology to cooperatively develop a prototype experiment for controlling a space station research module environment.

Description: The ability of existing data reduction techniques to determine frequency and damping from transient time-history records was evaluated. Analog data records representative of small-scale helicopter aeroelastic stability tests were analyzed. The data records were selected to provide information on the accuracy of reduced frequency and decay coefficients as a function of modal damping level, modal frequency, number of modes present in the time history record, proximity to other modes with different frequencies, steady offset in time history, and signal-to-noise ratio. The study utilized the results from each of the major U.S. helicopter manufacturers, the U.S. Army Aeroflightdynamics Directorate, and NASA Ames Research Center using their inhouse data reduction and analysis techniques. Consequently, the accuracy of different data analysis techniques and the manner in which they were implemented were also evaluated. It was found that modal frequencies can be accurately determined even in the presence of significant random and periodic noise. Identified decay coefficients do, however, show considerable variation, particularly for highly damped modes. The manner in which the data are reduced and the role of the data analyst was shown to be important. Although several different damping determination methods were used, no clear trends were evident for the observed differences between the individual analysis techniques. It is concluded that the data reduction of modal-damping characteristics from transient time histories results in a range of damping values.

Description: In response to a systematic methodology assessment program directed to the aeroelastic stability of hingeless helicopter rotor blades, improved basic aeroelastic reformulations and new formulations relating to structural sweep were achieved. Correlational results are presented showing the substantially improved performance of the G400 aeroelastic analysis incorporating these new formulations. The formulations pertain partly to sundry solutions to classic problem areas, relating to dynamic inflow with vortex-ring state operation and basic blade kinematics, but mostly to improved physical modeling of elastic axis offset (structural sweep) in the presence of nonlinear structural twist. Specific issues addressed are an alternate modeling of the delta EI torsional excitation due to compound bending using a force integration approach, and the detailed kinematic representation of an elastically deflected point mass of a beam with both structural sweep and nonlinear twist.

Description: Supportability issues for the 1.8 meter centrifuge in the Life Science Research Facility are addressed. The analysis focuses on reliability and maintainability and the potential impact on supportability and affordability. Standard logistics engineering methodologies that will be applied to all Office of Space Science and Applications' (OSSA) payload programs are outlined. These methodologies are applied to the 1.8 meter centrifuge.

Description: The purpose is to outline an Office of Space Science and Applications (OSSA) integrated logistics support strategy that will ensure effective logistics support of OSSA payloads at an affordable life-cycle cost. Program objectives, organizational relationships, and implementation of the logistics strategy are discussed.