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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 1,639 records · Page 91
All sourcesNASA NTRSDOE OSTI
NASA NTRS2017

Expansion of Microbial Monitoring Capabilities on the International Space Station (ISS)

Microbial monitoring is one of the tools that the National Aeronautics and Space Administration (NASA) uses on the International Space Station (ISS) to help maintain crew health and safety. In combination with regular housekeeping and disinfection when needed, microbial monitoring provides important information to the crew about the quality of the environment. Rotation of astronauts, equipment, and cargo on the ISS can affect the microbial load in the air, surfaces, and water. The current ISS microbial monitoring methods are focused on culture-based enumeration during flight and require a significant amount of crew time as well as long incubation periods of up to 5 days there by proliferating potential pathogens. In addition, the samples require return to Earth for complete identification of the microorganisms cultivated. Although the current approach assess the quality of the ISS environment, molecular technology offers faster turn-around of information particularly beneficial in an off-nominal situation. In 2011, subject matter experts from industry and academia recommended implementation of molecular-based technologies such as quantitative real-time polymerase chain reaction (qPCR) for evaluation to replace current, culture-based technologies. The RAZOR EX (BioFire Defense, Inc, Salt Lake City, UT) a ruggedized, compact, COTS (commercial off the shelf) qPCR instrument was tested, evaluated and selected in the 2 X 2015 JSC rapid flight hardware demonstration initiative as part of the Water Monitoring Suite. RAZOR EX was launched to ISS on SpaceX-9 in July 2016 to evaluate the precision and accuracy of the hardware by testing various concentrations of DNA in microgravity compared to ground controls. Flight testing was completed between September 2016 and March 2017. Data presented will detail the hardware performance of flight testing results compared to ground controls. Future goals include additional operational ground-based testing and assay development to determine if this technology can meet spaceflight microbial monitoring requirements.

Khodadad, Christina L.↗
NASA NTRS1988

Aircraft flight test trajectory control

Two control law design techniques are compared and the performance of the resulting controllers evaluated. The design requirement is for a flight test trajectory controller (FTTC) capable of closed-loop, outer-loop control of an F-15 aircraft performing high-quality research flight test maneuvers. The maneuver modeling, linearization, and design methodologies utilized in this research, are detailed. The results of applying these FTTCs to a nonlinear F-15 simulation are presented.

Menon, P. K. A.↗
NASA NTRS2011

High-Payoff Space Transportation Design Approach with a Technology Integration Strategy

A general architectural design sequence is described to create a highly efficient, operable, and supportable design that achieves an affordable, repeatable, and sustainable transportation function. The paper covers the following aspects of this approach in more detail: (1) vehicle architectural concept considerations (including important strategies for greater reusability); (2) vehicle element propulsion system packaging considerations; (3) vehicle element functional definition; (4) external ground servicing and access considerations; and, (5) simplified guidance, navigation, flight control and avionics communications considerations. Additionally, a technology integration strategy is forwarded that includes: (a) ground and flight test prior to production commitments; (b) parallel stage propellant storage, such as concentric-nested tanks; (c) high thrust, LOX-rich, LOX-cooled first stage earth-to-orbit main engine; (d) non-toxic, day-of-launch-loaded propellants for upper stages and in-space propulsion; (e) electric propulsion and aero stage control.

McCleskey, C. M.↗
NASA NTRS1972

Automated design and optimization of flexible booster autopilots via linear programming, volume 1

A nonlinear programming technique was developed for the automated design and optimization of autopilots for large flexible launch vehicles. This technique, which resulted in the COEBRA program, uses the iterative application of linear programming. The method deals directly with the three main requirements of booster autopilot design: to provide (1) good response to guidance commands; (2) response to external disturbances (e.g. wind) to minimize structural bending moment loads and trajectory dispersions; and (3) stability with specified tolerances on the vehicle and flight control system parameters. The method is applicable to very high order systems (30th and greater per flight condition). Examples are provided that demonstrate the successful application of the employed algorithm to the design of autopilots for both single and multiple flight conditions.

Hauser, F. D.↗
NASA NTRS1974

Configuration management during transition for a powered lift STOL aircraft

Presented in this paper are the analytical and moving-base simulation results of a study to improve flight safety and operations of V/STOL type aircraft. One of the more significant and novel aspects of the work accomplished has been the concept and implementation of a configuration management flight control system designed to take the guesswork out of, and improve the operational safety of, transition flight in the region from cruise to STOL.

Johnson, W. A.↗
NASA NTRS1977

Maintenance cost study of rotary wing aircraft

The feasibility was studied of predicting rotary wing operation maintenance costs by using several aircraft design factors for the aircraft dynamic systems. The dynamic systems considered were engines, drives and transmissions, rotors, and flight controls. Multiple regression analysis was used to correlate aircraft design and operational factors with manhours per flight hour, and equations for each dynamic system were developed. Results of labor predictions using the equations compare favorably with actual values.

Source record↗
NASA NTRS1981

Measurement of characteristics of lightning at high altitudes

New development in aeronautical technology -- the use of composite materials, new electronic components, electric flight controls -- have made aircraft potentially more and more vulnerable to the effects of lightning. In-flight tests were conducted to evaluate the current in a bolt of lightning, to measure voltage surge in the onboard circuitry and in certain pieces of equipment, and to document the relationship lightning bolt current and the voltage surge so as to develop a theoretical model and thuds to become acquainted with the significant

Coquelet, M.↗
NASA NTRS1979

Development of a low risk augmentation system for an energy efficient transport having relaxed static stability

An augmentation system for a 230 passenger, twin engine aircraft designed with a relaxation of conventional longitudinal static stability was developed. The design criteria are established and candidate augmentation system control laws and hardware architectures are formulated and evaluated with respect to reliability, flying qualities, and flight path tracking performance. The selected systems are shown to satisfy the interpreted regulatory safety and reliability requirements while maintaining the present DC 10 (study baseline) level of maintainability and reliability for the total flight control system. The impact of certification of the relaxed static stability augmentation concept is also estimated with regard to affected federal regulations, system validation plan, and typical development/installation costs.

Sizlo, T. R.↗
NASA NTRS1983

Restructurable controls for aircraft

Future aircraft with highly sophisticated controls are likely to have multiple interdependent failure modes which will be difficult for the pilot to recognize. Such failures may lead to unanticipated sequences of events from which the pilot cannot intuitively recover. Advances in the state-of-the-art in failure detection, failure identification, and control system technology suggest it may be feasible to detect and identify potentially catastrophic failures in flight controls and to restructure the controls in real time to execute a safe landing. Two accidents are reviewed, one in which the pilot successfully restructured the controls and one in which he did not, but for which a solution existed. The problem requirements and potential theoretical techniques which apply are also discussed.

Howell, W. E.↗
NASA NTRS1984

Allowable response delay for large aircraft

The degree of permissible time delay in an airliner flight control system is presently sought by means of a pilot-in-the-loop moving base flight simulator, assuming the characteristics of an advanced L-1011 aircraft variant. Test pilots and engineers from the U.S. Navy, the airliner manufacturer, and NASA Langley were used in a task which encompassed approach and landing after recovery from offsets in localizer and glide slope, during calm, turbulent, and cross-wind conditions. The data obtained in the course of 279 runs included statistics on pilot workload and performance as well as pilot opinion. Preliminary results indicate that requirements for a 0.1-sec maximum delay in aircraft response are excessively conservative for large aircraft, where an offset landing maneuver is the critical design task. Lateral axis delays appear to be more critical than longitudinal ones.

Meyer, R. T.↗
NASA NTRS1984

Six Degrees of Freedom Control with Each Hand?

For some time man has made six degree of freedom inputs to a pair of dextrous manipulators using both hands simultaneously by the use of the master/slave concept. The advent of the microprocessor has the potential to make the master/slave concept redundant by replacing the master with a mathematical model. All spacecraft to date, including the space shuttle, that were flown in six degrees of freedom were controlled by using both hands, the left hand controlling translation and the right rotation. Almost inevitably the same principle was applied to the CANADARM. At the instigation of NASA the development of a device whereby both translation and rotation could be combined allowing full control with one hand was developed. The development and testing of the device, and the extension of its application into spaceflight control are described. Also the concept of an adaptable workstation for multi-maniipulator and spacecraft flight control is discussed.

King, M. L.↗
NASA NTRS1991

Neural network application to aircraft control system design

The feasibility of using artificial neural networks as control systems for modern, complex aerospace vehicles is investigated via an example aircraft control design study. The problem considered is that of designing a controller for an integrated airframe/propulsion longitudinal dynamics model of a modern fighter aircraft to provide independent control of pitch rate and airspeed responses to pilot command inputs. An explicit model following controller using H infinity control design techniques is first designed to gain insight into the control problem as well as to provide a baseline for evaluation of the neurocontroller. Using the model of the desired dynamics as a command generator, a multilayer feedforward neural network is trained to control the vehicle model within the physical limitations of the actuator dynamics. This is achieved by minimizing an objective function which is a weighted sum of tracking errors and control input commands and rates. To gain insight in the neurocontrol, linearized representations of the nonlinear neurocontroller are analyzed along a commanded trajectory. Linear robustness analysis tools are then applied to the linearized neurocontroller models and to the baseline H infinity based controller. Future areas of research are identified to enhance the practical applicability of neural networks to flight control design.

Troudet, Terry↗
NASA NTRS2002

Search and Rescue Operations of Aircraft in Africa: Some Compelling Issues

The world aviation community has felt the compelling need for a well-coordinated global programme for search and rescue operations of aircraft ever since commercial aviation was regulated in 1944. Guidelines and plans of action for search and rescue have therefore been considered critical in the event of an aircraft accident. This fact is eminently brought to bear in the continental regions of Africa and South America in particular, where vast expanses of land are still uninhabited or sparsely populated and controlled flight into terrain (CFIT-where an aircraft may crash on land while still under the control of technical crew) is a common occurrence. There are numerous guidelines that have been adopted under the umbrella of the International Civil Aviation Organization which are already in place for the provision of search and rescue operations pertaining to aircraft. However, when an accident occurs in the territory of a State, there are sensitivities involving the State in which the aircraft concerned was registered and issues of sovereignty which have to be considered. Additionally. issues such as the voluntary nature of the search and rescue services offered. confidentiality, timeliness of such operations, fairness and uniformity all play a critical role. This article addresses the issue of search and rescue operations in Africa and examines in some detail where the world aviation community is right now and where it is headed in this important field of human endeavour.

Abeyratne, Ruwantissa I. R.↗
NASA NTRS2002

STS 110 Mission Highlights Resource Tape

A continuation of 'STS 110 Mission Highlights Resource Tape'. This video, Part 4 of 4, shows footage from flight days 10 through 12 of STS-110. The spacecrew includes Michael J. Bloomfield, Commander; Stephen N. Frick, Pilot; Jerry L. Ross, Mission Specialist; Steven L. Smith, Mission Specialist; Ellen Ochoa, Mission Specialist; Lee M.E. Morin, Mission Specialist; Rex J. Walheim, Mission Specialist. Flight day 10 includes an exchange of farewells with the Expedition 4 crew (Yury I. Onufrienko, Commander; Daniel W. Bursch, Flight Engineer; Carl E. Walz, Flight Engineer) of the International Space Station (ISS), and undocking. The video includes many views of the ISS as Atlantis departs, including cloud cover and the Earth's limb as backgrounds. There is also a view of Atlantis with its payload bay open. On flight day 11, in preparation for landing, the crew conducts a checkout of flight controls and a test firing. A spaceborne wheat plant experiment onboard the ISS is briefly shown. Flight day 12 includes closing the payload bay, suit-up, and landing. Kennedy Space Center is seen from the air, and the video shows landing replays, as well as a heads-up display view of the landing. Earth views include clear views of Western Sahara, Morocco, Mauritania, and Algeria, with the Atlantic Ocean, a cloud obstructed view of Newfoundland and the Atlantic, Pacific Ocean sun glint, and an excellent view of the Chicago area and Lake Michigan at night. The activities from other flights days can be seen on "STS 110 Mission Highlights Resource Tape" Part 1 of 4 (internal ID 2002137575), "STS 110 Mission Highlights Resource Tape" Part 2 of 4 (internal ID 2002137573), and "STS 110 Mission Highlights Resource Tape" Part 3 of 4 (internal ID 2002137574).

Source record↗
NASA NTRSDate not supplied

Closed-Loop Simulations of Human-Scale Mars Lander Descent Trajectories on Frontier

A computational campaign was performed to run high-fidelity, free-flight simulations of a human-scale Mars lander concept vehicle decelerating under retropropulsion through the Martian atmosphere with closed-loop flight control. A novel approach is used to couple computational fluid dynamics (CFD) software with a mature flight mechanics package, where the two applications communicate in real-time across two geographically-dispersed computational facilities. The CFD is performed on the Frontier exascale system located at Oak Ridge National Laboratory, and the flight mechanics are executed on a system located at NASA Langley Research Center. In the current campaign, CFD is performed using finite-rate chemistry to account for the interactions between the LOXCH 4 engines and the CO 2 Martian atmosphere. A simulation of a closed-loop main engine throttling and RCS actuation is presented, demonstrating that the vehicle and model are able to maintain stability in a long-duration CFD-in-the-loop flight simulation. Comparisons are made to a reduced order model ignoring aero-propulsive interactions.

CFD↗
NASA NTRS2011

NASA Flight Planning Branch Space Shuttle Lessons Learned

Planning products and procedures that allowed the mission Flight Control Teams and the Astronaut crews to plan, train and fly every Space Shuttle mission were developed by the Flight Planning Branch at the NASA Johnson Space Center in Houston, Texas. As the Space Shuttle Program came to a close, lessons learned were collected from each phase of the successful execution of these Space Shuttle missions. Specific examples of how roles and responsibilities of console positions that develop the crew and vehicle attitude timelines have been analyzed and will be discussed. Additionally, the relationships and procedural hurdles experienced through international collaboration have molded operations. These facets will be explored and related to current and future operations with the International Space Station and future vehicles. Along with these important aspects, the evolution of technology and continual improvement of data transfer tools between the Space Shuttle and ground team has also defined specific lessons used in improving the control team s effectiveness. Methodologies to communicate and transmit messages, images, and files from the Mission Control Center to the Orbiter evolved over several years. These lessons were vital in shaping the effectiveness of safe and successful mission planning and have been applied to current mission planning work in addition to being incorporated into future space flight planning. The critical lessons from all aspects of previous plan, train, and fly phases of Space Shuttle flight missions are not only documented in this paper, but are also discussed regarding how they pertain to changes in process and consideration for future space flight planning.

Clevenger, Jennifer D.↗
NASA NTRS2017

Optimal Control Allocation with Load Sensor Feedback for Active Load Suppression

These slide sets describe the OCLA formulation and associated algorithms as a set of new technologies in the first practical application of load limiting flight control utilizing load feedback as a primary control measurement. Slide set one describes Experiment Development and slide set two describes Flight-Test Performance.

Miller, Christopher↗
NASA NTRS2017

Optimal Control Allocation with Load Sensor Feedback for Active Load Suppression

These slide sets describe the OCLA formulation and associated algorithms as a set of new technologies in the first practical application of load limiting flight control utilizing load feedback as a primary control measurement. Slide set one describes Experiment Development and slide set two describes Flight-Test Performance.

Miller, Christopher↗