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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,675 records · Page 93
All sourcesNASA NTRSDOE OSTI
NASA NTRS2008

Constellation Training Facility Support

The National Aeronautics and Space Administration is developing the next set of vehicles that will take men back to the moon under the Constellation Program. The Constellation Training Facility (CxTF) is a project in development that will be used to train astronauts, instructors, and flight controllers on the operation of Constellation Program vehicles. It will also be used for procedure verification and validation of flight software and console tools. The CxTF will have simulations for the Crew Exploration Vehicle (CEV), Crew Module (CM), CEV Service Module (SM), Launch Abort System (LAS), Spacecraft Adapter (SA), Crew Launch Vehicle (CLV), Pressurized Cargo Variant CM, Pressurized Cargo Variant SM, Cargo Launch Vehicle, Earth Departure Stage (EDS), and the Lunar Surface Access Module (LSAM). The Facility will consist of part-task and full-task trainers, each with a specific set of mission training capabilities. Part task trainers will be used for focused training on a single vehicle system or set of related systems. Full task trainers will be used for training on complete vehicles and all of its subsystems. Support was provided in both software development and project planning areas of the CxTF project. Simulation software was developed for the hydraulic system of the Thrust Vector Control (TVC) of the ARES I launch vehicle. The TVC system is in charge of the actuation of the nozzle gimbals for navigation control of the upper stage of the ARES I rocket. Also, software was developed using C standards to send and receive data to and from hand controllers to be used in CxTF cockpit simulations. The hand controllers provided movement in all six rotational and translational axes. Under Project Planning & Control, support was provided to the development and maintenance of integrated schedules for both the Constellation Training Facility and Missions Operations Facilities Division. These schedules maintain communication between projects in different levels. The CxTF support provided is one that requires continuous maintenance since the project is still on initial development phases.

Flores, Jose M.↗
NASA NTRS2000

Flying Quality Analysis of a JAS 39 Gripen Ministick Controller in an F/A-18 Aircraft

NASA Dryden conducted a handling qualities experiment using a small displacement centerstick controller that Saab-Scania developed for the JAS 39 Gripen aircraft. The centerstick, or ministick, was mounted in the rear cockpit of an F/A-18 aircraft. Production support flight control computers (PSFCC) provided a pilot-selectable research control system. The objectives for this experiment included determining whether the mechanical characteristics of the centerstick controller had any significant effect on the handling qualities of the F/A-18, and determining the usefulness of the PSFCCs for this kind of experiment. Five pilots evaluated closed-loop tracking tasks, including echelon and column formation flight and target following. Cooper-Harper ratings and pilot comments were collected for each maneuver. This paper describes the test system, including the PSFCCs, the Gripen centerstick, and the flight test experiment. The paper presents results of longitudinal handling qualities maneuvers, including low order equivalent systems, Neal-Smith, and controls anticipation parameter analyses. The experiment showed that, while the centerstick controller provided a different aircraft feel, few handling qualities deficiencies resulted. It also demonstrated that the PSFCCs were useful for this kind of investigation.

Carter, John F.↗
NASA NTRS1988

Effect of manipulator and feel system characteristics on pilot performance in roll tracking

The control system features of force vs displacement stick command, feel/force displacement gradient, 'feel' system vs command prefilter dynamic lag, and flight control system effective time delay, have been investigated by a fixed-base simulation employing both joysticks and side-sticks in order to ascertain their effect on pilot opinion, pilot performance, and their hand/arm neuromuscular subsystem interaction. The results obtained indicate that the use of displacement sensing added the feel system dynamic lag to the command path and increased effective system flight delay, thereby lowering pilot opinion and performance but reducing the possibility of roll instability; the use of force sensing as stick command to exclude feel system dynamic lag had the obverse effect.

Aponso, Bimal L.↗
NASA NTRS1979

Hydrazine monopropellant reciprocating engine development

A hydrazine-fueled piston-type engine for providing 11.2 kW (15 hp) has been developed to satisfy the need for an efficient power supply in the range from 3.7 to 74.6 kW (5 to 100 hp) where existing nonair-breathing power supplies such as fuel cells or turbines are inappropriate. The engine was developed for an aircraft to fly to 21.3 km (70,000 ft) and above and cruise for extended periods. The NASA Hugh L. Dryden Flight Research Center developed a remotely piloted aircraft and the associated flight control techniques for this application. About 20 hr of run time have demonstrated good efficiency and adequate life. One flight test to 6.1 km (20,000 ft) has been made using the engine with a small fixed-pitch four-bladed propeller. The test was successful in demonstrating operational characteristics and future potential.

Akkerman, J. W.↗
NASA NTRS1982

Shuttle navigation overview

Space Shuttle onboard navigation system tasks are related to position and velocity determination, attitude determination, sensor management, sensor Redundancy Management (RM), and navigation-related functions such as transformations, timing system utilization, and user processing for displays, guidance, and flight control. It is pointed out that Shuttle navigation is different in at least two areas from previous manned space flight navigation. The differences are related to the use of multiple units to provide protection from increased risk of failure of off-the-shelf-type equipment used for more than one flight, and the need to land at a runway. Attention is given to the navigation sensor system, the Shuttle Inertial Measurement Units, the Shuttle Star Tracker, the Crew Optical Alinement Sight, the Shuttle Tacan, the Air Data Subsystem, and aspects of navigation system mechanization.

Savely, R. T.↗
NASA NTRS1982

Effect of space flight on bone strength

To test the possibility that spaceflight has a deleterious effect on bone mechanical properties, femur breaking strength by torsional loading in rats that had been flown for 19 days aboard Cosmos 936 was determined. The results showed that femurs from flight rats were less stiff than the flight controls, and failed under torsion at a lower torque and energy of absorption. The defect was corrected following space flight and could be prevented during space flight by centrifuging the rats at 1 x g. Altered bone geometry due to inhibition of bone formation at the periosteal surface provides the most likely explanation for the decrease in bone strength during spaceflight.

Spengler, D. M.↗
NASA NTRS1991

Issues associated with establishing control zones for international space operations

Cooperative missions in Earth orbit can be facilitated by developing a strategy to regulate the manner in which vehicles interact in orbit. One means of implementing such a strategy is to utilize a control zones technique that assigns different types of orbital operations to specific regions of space surrounding a vehicle. Considered here are issues associated with developing a control zones technique to regulate the interactions of spacecraft in proximity to a manned vehicle. Technical and planning issues, flight hardware and software issues, mission management parameter, and other constraints are discussed. Also covered are manned and unmanned vehicle operations, and manual versus automated flight control. A review of the strategies utilized by the Apollo Soyuz Test Project and the Space Station Freedom Program is also presented.

Nader, Blair A.↗
NASA NTRS1992

Issues in developing control zones for international space operations

Cooperative missions in earth orbit can be facilitated by developing a strategy to regulate the manner in which vehicles interact in orbit. One means of implementing such a strategy is to utilize a control zones technique that assigns different types of orbital operations to specific regions of space surrounding a vehicle. Considered here are issues associated with developing a control zones technique to regulate the interactions of spacecraft in proximity to a manned vehicle. Technical and planning issues, flight hardware and software issues, mission management parameter, and other constraints are discussed. Also covered are manned and unmanned vehicle operations, and manual versus automated flight control. A review of the strategies utilized by the Apollo Soyuz Test Project and the Space Station Freedom Program is also presented.

Nader, Blair A.↗
NASA NTRS2014

Range Safety Flight Elevation Limit Calculation Software

This program was developed to fill a need within the Wallops Flight Facility workflow for automation of the development of vertical plan limit lines used by flight safety officers during the conduct of expendable launch vehicle missions. Vertical plane present-position-based destruct lines have been used by range safety organizations at numerous launch ranges to mitigate launch vehicle risks during the early phase of flight. Various ranges have implemented data submittal and processing workflows to develop these destruct lines. As such, there is significant prior art in this field. The ElLimits program was developed at NASA's Wallops Flight Facility to automate the process for developing vertical plane limit lines using current computing technologies. The ElLimits program is used to configure launch-phase range safety flight control lines for guided missiles. The name of the program derives itself from the fundamental quantity that is computed - flight elevation limits. The user specifies the extent and resolution of a grid in the vertical plane oriented along the launch azimuth. At each grid point, the program computes the maximum velocity vector flight elevation that can be permitted without endangering a specified back-range location. Vertical plane x-y limit lines that can be utilized on a present position display are derived from the flight elevation limit data by numerically propagating 'streamlines' through the grid. The failure turn and debris propagation simulation technique used by the application is common to all of its analysis options. A simulation is initialized at a vertical plane grid point chosen by the program. A powered flight failure turn is then propagated in the plane for the duration of the so-called RSO reaction time. At the end of the turn, a delta-velocity is imparted, and a ballistic trajectory is propagated to impact. While the program possesses capability for powered flight failure turn modeling, it does not require extensive user inputs of vehicle characteristics (e.g., thrust and aerodynamic data), nor does it require reams of turn data after the traditional fashion of the Air Force ranges. The program requires a nominal trajectory table (time, altitude, range, velocity, and flight elevation) and makes heavy use of it to initialize and model a failure turn.

Lanzi, Raymond J↗
NASA NTRS2014

IRIS Mission Operations Director's Colloquium

Pursuing the Mysteries of the Sun: The Interface Region Imaging Spectrograph (IRIS) Mission. Flight controllers from the IRIS mission will present their individual experiences on IRIS from development through the first year of flight. This will begin with a discussion of the unique nature of IRISs mission and science, and how it fits into NASA's fleet of solar observatories. Next will be a discussion of the critical roles Ames contributed in the mission including spacecraft and flight software development, ground system development, and training for launch. This will be followed by experiences from launch, early operations, ongoing operations, and unusual operations experiences. The presentation will close with IRIS science imagery and questions.

Mission Operations↗
NASA NTRS2018

Tonal Noise Prediction of a Distributed Propulsion Unmanned Aerial Vehicle

Noise is expected to be a major barrier of unmanned aerial vehicles (UAVs) to public acceptance. A noise prediction scheme is introduced in this paper and applied to a specific vehicle configuration, namely, the Greased Lightning-10. Results herein will be used to demonstrate the feasibility of incorporating a noise constraint within the flight control system of a distributed electric propulsion vehicle by modifying commands for low-noise operation over sensitive areas, e.g., communities, schools, etc. Steady loading and thickness noise signatures of single propellers are computed using the Propeller Analysis System of the NASA Aircraft NOise Prediction Program. The individual signatures are then superposed at far field observers after applying corrections for spherical spreading and phase delays based on straight ray propagation. Two-propeller source fields are verified using analytical directivity patterns of monopoles. Notional effects of rotation rate, rotation direction, and relative propeller phase are given. Under ideal circumstances and equivalent RPM, random phasing, which occurs in most small UAVs, can produce up to 20 decibels uncertainty in the tonal sound pressure level at a given ground observer. Additionally, directivity modification via relative propeller phase control is shown to have great potential as a noise reduction technique. This paper will focus on the forward flight mode but will also briefly discuss the vertical flight mode.

Pascioni, Kyle A.↗
NASA NTRS1983

Flight test trajectory control analysis

Recent extensions to optimal control theory applied to meaningful linear models with sufficiently flexible software tools provide powerful techniques for designing flight test trajectory controllers (FTTCs). This report describes the principal steps for systematic development of flight trajectory controllers, which can be summarized as planning, modeling, designing, and validating a trajectory controller. The techniques have been kept as general as possible and should apply to a wide range of problems where quantities must be computed and displayed to a pilot to improve pilot effectiveness and to reduce workload and fatigue. To illustrate the approach, a detailed trajectory guidance law is developed and demonstrated for the F-15 aircraft flying the zoom-and-pushover maneuver.

Walker, R.↗
NASA NTRS1992

Collaborative research on V/STOL control system/cockpit display tradeoffs under the NASA/MOD joint aeronautical program

Summarized here are activities that have taken place from 1979 to the present in a collaborative program between NASA Ames Research Center and the Royal Aerospace Establishment (now Defence Research Agency), Bedford on flight control system and cockpit display tradeoffs for low-speed and hover operations of future V/STOL aircraft. This program was created as Task 8A of the Joint Aeronautical Program between NASA in the United States and the Ministry of Defence (Procurement Executive) in the United Kingdom. The program was initiated based on a recognition by both parties of the strengths of the efforts of their counterparts and a desire to participate jointly in future simulation and flight experiments. In the ensuing years, teams of NASA and RAE engineers and pilots have participated in each other's simulation experiments to evaluate control and display concepts and define design requirements for research aircraft. Both organizations possess Harrier airframes that have undergone extensive modification to provide in-flight research capabilities in the subject areas. Both NASA and RAE have profited by exchanges of control/display concepts, design criteria, fabrication techniques, software development and validation, installation details, and ground and flight clearance techniques for their respective aircraft. This collaboration has permitted the two organizations to achieve jointly substantially more during the period than if they had worked independently. The two organizations are now entering the phase of flight research for the collaborative program as currently defined.

Franklin, J. A.↗
NASA NTRS1961

Stability and Control Characteristics of a Model of an Aerial Vehicle Supported by Four Ducted Fans

The stability and control characteristics of a simple, lightly loaded model approximately one-third the size of a full-scale vehicle have been investigated by a series of free-flight tests. The model is representative of a type of vertically rising aircraft which would utilize four ducted fans as its sole source of lift and propulsion. The ducts were arranged in a rectangular pattern and were fixed to the airframe so that their axes of revolution were vertical for hovering flight. Control moments were provided by remotely controlled compressed-air jets at the sides and ends of the model. In hovering, the model in its original configuration exhibited divergent oscillations about both the roll and pitch axes. Because these oscillations were of a rather short period., the model was very difficult to control by the use of remote controls only. The model could be completely stabilized by the addition of a sufficient amount of artificial damping. The pitching oscillation was made easier to control by increasing the distance between the forward and rearward pairs of ducts. In forward flight, with the model in its original configuration, the top speed was limited by the development of an uncontrollable pitch-up. Large forward tilt angles were required for trim at the highest speeds attained. With the model rotated so that the shorter axis became the longitudinal axis, the pitch trim problem was found to be less than with the longer axis as the longitudinal axis. The installation of a system of vanes in the slipstream of the forward ducts reduced the tilt angle but increased the power required.

Parlett, Lysle P.↗
NASA NTRS1983

Aircraft Controls

CARSRA, a computer program supplied by COSMIC (Computer Software Management and Information Center), enables Hamilton Standard to predict the reliability of electronic systems for jet engines. The flight control is fully automatic. With CARSRA, engineers can study a proposed design, predict its operation, and make necessary design modifications. The program is accurate and flexible, and Hamilton Standard has developed a more advanced program based on the COSMIC software.

Source record↗
NASA NTRS1980

AD-1 oblique wing aircraft program

The oblique wing concept for super- and subsonic transport was assessed by analysis and wind tunnel radio control model and remotely piloted vehicle testing. A one-sixth scale wind tunnel model and a low speed manned oblique wing research airplane (AD-1) were developed. Model wind tunnel test data on dynamic structural response characteristics were used in a simulator to develop the control system. The airplane is of simple design with fiber glass skin, weight of approximately 2100 lbs and speeds of up to 175 knots at altitudes up to 15,000 ft. Flight testing will investigate handling and flying qualities, oblique wing flight control characteristics, aeroelastic wing design and will compare actual with predicted aerodynamic characteristics. Nineteen flights were made at 12,000 to 13,000 feet with speeds of 100-160 knots. Flutter clearance as a function of wing sweep angle is now under investigation.

Andrews, W. H.↗