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1

Technical Seminar: Oil-Free Turbomachinery for Rotorcraft  

NASA Video Gallery

Rotorcraft engines are among the most demanding applications for conventional oil-lubricated bearings because they must operate with extreme reliability and the highest possible power density. Recent breakthroughs in gas-lubricated oil bearings, high temperature solid lubricants and computer based modeling enable the deployment of revolutionary oil-free turbomachinery systems that weigh less and cost less to operate and maintain. Presented November 4, 2008.

Christopher O

2010-11-15

2

Recent developments in the simulation of steady and transient transverse jet interactions for missile, rotorcraft, and propulsive applications  

Microsoft Academic Search

A review of recent activities focused on the simulation of transverse jet interaction problems using advanced time-asymptotic and time-accurate Navier-Stokes methodology is presented. Missile work has involved the simulation of short-duration control jets issued from solid rocket motor nozzles. For the simulation of time-accurate particle-laden flows, a new Eulerian-based upwind\\/implicit particle-solver was developed and coupled with the gas-phase solver. Rotorcraft

S. M. Dash; B. J. York; N. Sinha; R. A. Lee; A. Hosangadi; D. C. Kenzakowski

1993-01-01

3

Rotorcraft Conceptual Design Environment.  

National Technical Information Service (NTIS)

Requirements for a rotorcraft conceptual design environment are discussed, from the perspective of a government laboratory. Rotorcraft design work in a government laboratory must support research, by producing technology impact assessments and defining th...

J. Sinsay W. Johnson

2009-01-01

4

Propulsion  

ERIC Educational Resources Information Center

|An introductory discussion of aircraft propulsion is included along with diagrams and pictures of piston, turbojet, turboprop, turbofan, and jet engines. Also, a table on chemical propulsion is included. (MDR)|

Air and Space, 1978

1978-01-01

5

New Concepts and Perspectives on Micro-Rotorcraft and Small Autonomous Rotary-Wing Vehicles.  

National Technical Information Service (NTIS)

This paper summarizes ongoing work concerning micro-rotorcraft (MRC)- -i.e., rotary-wing micro air vehicles (MAV)-- research and development. Technology trends involving microelectronic miniaturization, vehicle autonomy systems, electric propulsion and po...

E. W. Aiken J. Andrews J. L. Johnson L. A. Young R. Demblewski

2002-01-01

6

Rotorcraft Flight-Propulsion Control Integration.  

National Technical Information Service (NTIS)

The NASA Ames and Lewis Research Centers, in conjunction with the Army Research and Technology Laboratories have initiated and completed, in part, a joint research program focused on improving the performance, maneuverability, and operating characteristic...

J. R. Mihaloew M. G. Ballin D. G. C. Ruttledge

1988-01-01

7

Center of Excellence in Rotorcraft Technology.  

National Technical Information Service (NTIS)

Georgia Tech's research investigations during the reporting period focused on several analytical and experimental tasks in rotorcraft technology. In the area of Rotorcraft Aerodynamics, work continued on the development of numerical formulations for predi...

D. P. Schrage E. A. Armanios V. L. Berdichevsky A. J. Calise S. V. Hanagud

1995-01-01

8

Nonlinear Rotorcraft Analysis-Experimental and Analytical.  

National Technical Information Service (NTIS)

A parallel effort involving both analytical and experimental work was performed to allow a deeper understanding of the limit cycle behavior of rotorcraft and of the implication of this behavior for the safe operation of such rotorcraft. The theoretical de...

B. H. Tongue

1988-01-01

9

Applications of Smart Antennas to Rotorcrafts  

Microsoft Academic Search

Amin, M., Zhang, Y., Mancuso, V., and Hoorfar, A., Applications of Smart Antennas to Rotorcrafts, Digital Signal Processing 12 (2002) 159-174. Transmitted and received signals involving rotorcrafts are subject to intermodulations caused by the rotor blades. In this paper, the statistical characteristics of the wireless communication link between a rotorcraft transmitter and a receiver on the ground are developed. Both

Moeness G. Amin; Yimin Zhang; Vincent Mancuso; Ahmad Hoorfar

2002-01-01

10

NASA Heavy Lift Rotorcraft Systems Investigation  

Microsoft Academic Search

The NASA Heavy Lift Rotorcraft Systems Investigation examined in depth several rotorcraft configurations for large civil transport, designed to meet the technology goals of the NASA Vehicle Systems Program. The investigation identified the Large Civil Tiltrotor as the configuration with the best potential to meet the technology goals. The design presented was economically competitive, with the potential for substantial impact

Wayne Johnson; Gloria K. Yamauchi; Michael E. Watts

11

In-Flight Rotorcraft Acoustics Program.  

National Technical Information Service (NTIS)

A key part of NASA's aeronautics research is reducing noise to make helicopters and tiltrotors more acceptable to the public. The objective of the In-Flight Rotorcraft Acoustics Program (IRAP) is to acquire rotorcraft noise data in flight for comparison t...

R. L. Peterson

1996-01-01

12

Rotorcraft noise: Status and recent developments  

Microsoft Academic Search

This paper briefly reviews rotorcraft noise mechanisms and their approximate importance for different types of rotorcraft in different flight regimes. Discrete noise is due to periodic flow disturbances and includes impulsive noise produced by phenomena which occur during a limited segment of a blade's rotation. Broadband noise results when rotors interact with random disturbances, such as turbulence, which can originate

Albert R. George; Ben Wel-C. Sim; David R. Polak

1993-01-01

13

General Rotorcraft Aeromechanical Stability Program (GRASP): Theory Manual.  

National Technical Information Service (NTIS)

The general rotorcraft aeromechanical stability program (GRASP) was developed to calculate aeroelastic stability for rotorcraft in hovering flight, vertical flight, and ground contact conditions. GRASP is described in terms of its capabilities and its phi...

D. H. Hodges A. S. Hopkins D. L. Kunz H. E. Hinnant

1990-01-01

14

Shipboard/rotorcraft simulation and analysis  

NASA Astrophysics Data System (ADS)

This research has simulated the rotorcraft on-deck dynamic interface for defining safe operational conditions and for the first time, compared the results of studies with measured performance stability data. A comprehensive interface simulation and analysis of rotorcraft shipboard on-deck operational envelopes were developed in FLIGHTLAB (a software tool for rapid prototyping and interactive evaluation of simulation models). The helicopter was modeled using a blade element model and the ship airwake was simulated using Computational Fluid Dynamics (CFD) data. Investigations showed that the ship speed, the ship heading, the rotor speed, and sea conditions significantly influence rotorcraft on-deck handling. Dynamic interface studies used the FLIGHTLAB to simulate the SH-60B Helicopter operating from an LHA class ship to properly quantify shipboard rotorcraft operational capabilities under various conditions. Hazardous flight conditions such as high winds, low visibility, a moving-landing platform and unusual airflows around ships can have significant effect on pilot workload and crew safety. The dynamic interface problem involved the determination of shipboard rotorcraft operational performance and envelope. The unique problem areas for current simulation studies include ship airwake, turbulence modeling and rotorcraft/ship aerodynamics. The rotorcraft/ship interaction is a problem of two-way interference. On the one side, the ship's induced airwake affects the rotors and airframe aerodynamics due to changes in their angles of attack and dynamic pressure variations. On the other side, the rotors or airframe induced wake impacts the ship's deck/structure to alter the airwake distribution. Encouragingly, results from research have shown good correlation with measured data.

Akinyanju, Ted A.

15

Computational Procedures for the Aeroelastic Simulation of Maneuvering Rotorcraft Vehicles  

Microsoft Academic Search

We propose a methodology for extending the applicability of comprehensive analysis rotorcraft codes to the ma- neuvering ight regime. Our approach can be interpreted as a generalization of the classical steady ight trim procedures, implemented in all rotorcraft codes, to the problem of time dependent trim in unsteady ight. Rotorcraft maneuvers are here mathematically described in a concise yet completely

Carlo L. Bottassoá; Daniel Guggenheim

16

Robust flight control of rotorcraft  

NASA Astrophysics Data System (ADS)

With recent design improvement in fixed wing aircraft, there has been a considerable interest in the design of robust flight control systems to compensate for the inherent instability necessary to achieve desired performance. Such systems are designed for maximum available retention of stability and performance in the presence of significant vehicle damage or system failure. The rotorcraft industry has shown similar interest in adopting these reconfigurable flight control schemes specifically because of their ability to reject disturbance inputs and provide a significant amount of robustness for all but the most catastrophic of situations. The research summarized herein focuses on the extension of the pseudo-sliding mode control design procedure interpreted in the frequency domain. Application of the technique is employed and simulated on two well known helicopters, a simplified model of a hovering Sikorsky S-61 and the military's Black Hawk UH-60A also produced by Sikorsky. The Sikorsky helicopter model details are readily available and was chosen because it can be limited to pitch and roll motion reducing the number of degrees of freedom and yet contains two degrees of freedom, which is the minimum requirement in proving the validity of the pseudo-sliding control technique. The full order model of a hovering Black Hawk system was included both as a comparison to the S-61 helicopter design system and as a means to demonstrate the scaleability and effectiveness of the control technique on sophisticated systems where design robustness is of critical concern.

Pechner, Adam Daniel

17

Rotorcraft Flight-Propulsion Control Integration: An Eclectic Design Concept.  

National Technical Information Service (NTIS)

The NASA Ames and Lewis Research Centers, in conjunction with the Army Research and Technology Laboratories, have initiated and partially completed a joint research program focused on improving the performance, maneuverability, and operating characteristi...

J. R. Mihaloew M. G. Ballin D. C. G. Ruttledge

1988-01-01

18

Influence of Lift Offset on Rotorcraft Performance  

Microsoft Academic Search

The influence of lift offset on the performance of several rotorcraft configurations is explored. A lift- offset rotor, or advancing blade concept, is a hingeless rotor that can attain good efficiency at high speed, by operating with more lift on the advancing side than on the retreating side of the rotor disk. The calculated performance capability of modern-technology coaxial rotors

Wayne Johnson

19

ROTORCRAFT AEROMECHANICS APPLICATIONS OF A COMPREHENSIVE ANALYSIS  

Microsoft Academic Search

Results from the comprehensive analysis CAMRAD II are presented, illustrating recent developments in the aerodynamics and dynamics models, and demonstrating the technology that is needed for an adequate calculation of rotorcraft behavior. Calculations of rotor performance, airloads, structural loads, and stability are presented, including comparisons with experimental data.

Wayne Johnson; Johnson Aeronautics

1998-01-01

20

Rotorcraft research in India: recent developments  

Microsoft Academic Search

Purpose – The purpose of this paper is to discuss published research in rotorcraft which has taken place in India during the last ten years. The helicopter research is divided into the following parts: health monitoring, smart rotor, design optimization, control, helicopter rotor dynamics, active control of structural response (ACSR) and helicopter design and development. Aspects of health monitoring and

Ranjan Ganguli

2010-01-01

21

14 CFR 29.519 - Hull type rotorcraft: Water-based and amphibian.  

Code of Federal Regulations, 2010 CFR

...false Hull type rotorcraft: Water-based and amphibian. 29...AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Water Loads § 29.519 Hull type rotorcraft: Water-based and amphibian....

2009-01-01

22

14 CFR 29.519 - Hull type rotorcraft: Water-based and amphibian.  

Code of Federal Regulations, 2010 CFR

...false Hull type rotorcraft: Water-based and amphibian. 29...AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Water Loads § 29.519 Hull type rotorcraft: Water-based and amphibian....

2010-01-01

23

Hierarchical control of future generation rotorcraft  

Microsoft Academic Search

A two-tier architecture of hierarchical control is proposed for future generation rotorcraft that demand enhanced performance and reliability. The continuously-varying controller at the lower tier is designed using probabilistic robust control approaches. The discrete-event supervisory controller at the upper tier is built upon the concepts of time-frequency analysis, symbolic dynamics, and automata theory. Results of simulation experiments based on the

Devendra K Tolani; J. F. Horn; A. Ray; Jialing Chen

2004-01-01

24

Sikorsky Aircraft Advanced Rotorcraft Transmission (ART) program  

Microsoft Academic Search

The objectives of the Advanced Rotorcraft Transmission program were to achieve a 25 percent weight reduction, a 10 dB noise reduction, and a 5,000 hour mean time between removals (MTBR). A three engine Army Cargo Aircraft (ACA) of 85,000 pounds gross weight was used as the baseline. Preliminary designs were conducted of split path and split torque transmissions to evaluate

Jules G. Kish

1993-01-01

25

Rotorcraft parameter estimation using radial basis function neural network  

Microsoft Academic Search

Increased emphasis on rotorcraft performance and operational capabilities has resulted in accurate computation of aerodynamic stability and control parameters. System identification is one such tool in which the model structure and parameters such as aerodynamic stability and control derivatives are derived. In the present work, the rotorcraft aerodynamic parameters are computed using radial basis function neural networks (RBFN) in the

Rajan Kumar; Ranjan Ganguli; S. N. Omkar

2010-01-01

26

Development and implementation of rotorcraft preliminary design methodology using multidisciplinary design optimization  

NASA Astrophysics Data System (ADS)

Rotorcraft's evolution has lagged behind that of fixed-wing aircraft. One of the reasons for this gap is the absence of a formal methodology to accomplish a complete conceptual and preliminary design. Traditional rotorcraft methodologies are not only time consuming and expensive but also yield sub-optimal designs. Rotorcraft design is an excellent example of a multidisciplinary complex environment where several interdependent disciplines are involved. A formal framework is developed and implemented in this research for preliminary rotorcraft design using IPPD methodology. The design methodology consists of the product and process development cycles. In the product development loop, all the technical aspects of design are considered including the vehicle engineering, dynamic analysis, stability and control, aerodynamic performance, propulsion, transmission design, weight and balance, noise analysis and economic analysis. The design loop starts with a detailed analysis of requirements. A baseline is selected and upgrade targets are identified depending on the mission requirements. An Overall Evaluation Criterion (OEC) is developed that is used to measure the goodness of the design or to compare the design with competitors. The requirements analysis and baseline upgrade targets lead to the initial sizing and performance estimation of the new design. The digital information is then passed to disciplinary experts. This is where the detailed disciplinary analyses are performed. Information is transferred from one discipline to another as the design loop is iterated. To coordinate all the disciplines in the product development cycle, Multidisciplinary Design Optimization (MDO) techniques e.g. All At Once (AAO) and Collaborative Optimization (CO) are suggested. The methodology is implemented on a Light Turbine Training Helicopter (LTTH) design. Detailed disciplinary analyses are integrated through a common platform for efficient and centralized transfer of design information from one discipline to another in a collaborative manner. Several disciplinary and system level optimization problems are solved. After all the constraints of a multidisciplinary problem have been satisfied and an optimal design has been obtained, it is compared with the initial baseline, using the earlier developed OEC, to measure the level of improvement achieved. Finally a digital preliminary design is proposed. The proposed design methodology provides an automated design framework, facilitates parallel design by removing disciplinary interdependency, current and updated information is made available to all disciplines at all times of the design through a central collaborative repository, overall design time is reduced and an optimized design is achieved.

Khalid, Adeel Syed

27

Rotorcraft Low Altitude IFR Benefit/Cost Analysis: Operations Analysis.  

National Technical Information Service (NTIS)

The Rotorcraft Master Plan advocates the establishment of additional communications, navigation, and surveillance (CNS) facilities, as well as the analysis and development of systems to satisfy the increasing demand for widespread instrument flight rules ...

L. D. Dzamba L. J. Labelle R. B. Newman R. K. Anoll R. N. Lindgren

1991-01-01

28

Fundamental Rotorcraft Acoustic Modeling from Experiments (FRAME)  

NASA Astrophysics Data System (ADS)

A new methodology is developed for the construction of helicopter source noise models for use in mission planning tools from experimental measurements of helicopter external noise radiation. The models are constructed by employing a parameter identification method to an assumed analytical model of the rotor harmonic noise sources. This new method allows for the identification of individual rotor harmonic noise sources and allows them to be characterized in terms of their individual non-dimensional governing parameters. The method is applied to both wind tunnel measurements and ground noise measurements of two-bladed rotors. The method is shown to match the parametric trends of main rotor harmonic noise, allowing accurate estimates of the dominant rotorcraft noise sources to be made for operating conditions based on a small number of measurements taken at different operating conditions. The ability of this method to estimate changes in noise radiation due to changes in ambient conditions is also demonstrated.

Greenwood, Eric, II

29

14 CFR 133.47 - Rotorcraft-load combination flight manual.  

Code of Federal Regulations, 2013 CFR

...peculiarities discovered when operating particular rotorcraft-load combinations; (2) Precautionary advice regarding static electricity discharges for Class B, Class C, and Class D rotorcraft-load combinations; and (3) Any other...

2013-01-01

30

Development and implementation of rotorcraft preliminary design methodology using multidisciplinary design optimization  

Microsoft Academic Search

Rotorcraft's evolution has lagged behind that of fixed-wing aircraft. One of the reasons for this gap is the absence of a formal methodology to accomplish a complete conceptual and preliminary design. Traditional rotorcraft methodologies are not only time consuming and expensive but also yield sub-optimal designs. Rotorcraft design is an excellent example of a multidisciplinary complex environment where several interdependent

Adeel Syed Khalid

2006-01-01

31

Rotorcraft acoustic radiation prediction based on a refined blade-vortex interaction model  

Microsoft Academic Search

The analysis of rotorcraft aerodynamics and acoustics is a challenging problem, primarily due to the fact that a rotorcraft continually flies through its own wake. The generation mechanism for a rotorcraft wake, which is dominated by strong, concentrated blade-tip trailing vortices, is similar to that in fixed wing aerodynamics. However, following blades encounter shed vortices from previous blades before they

John Allen Rule

1997-01-01

32

Synthetic vision for rotorcraft: low level flight  

NASA Astrophysics Data System (ADS)

Two topics are discussed in this paper. The first is the Integrated Multi-sensor Synthetic Imagery System (IMSIS), being developed under an Army SBIR contract. The system updates on-board, pre-stored, terrain elevation data with 3D terrain elevation sensor data (such as radar). The system also merges 2D image contrast sensor data (such as infrared imagery) with the updated 3D terrain elevation data to render a synthetic image of the terrain on the rotorcraft pilot's display. The second topic is the testing of a new flight path marker, to show the pilot the predicted location of the aircraft with respect to the synthetic terrain (at 100m distance), as well as the predicted height above the terrain, the desired height above the terrain, and the point on the terrain the aircraft is expected to fly over. The Altitude and ground Track Predicting Flight Path Marker (ATP-FPM) symbol takes advantage of knowledge of terrain elevations ahead of the aircraft from a synthetic vision system, such as IMSIS. In simulation, the maximum low altitude error and maximum ground track error were both reduced by a factor of 2 with the ATP-FPM compared to the traditional instantaneous flight path marker. Pilot-to-pilot variations in performance were reduced and workload decreased with the ATP-FPM.

Szoboszlay, Zoltan; Jennings, Chad; Tiana, Carlo

2006-06-01

33

Electric propulsion  

NASA Astrophysics Data System (ADS)

Electric propulsion (EP) is an attractive option for unmanned orbital transfer vehicles (OTV's). Vehicles with solar electric propulsion (SEP) could be used routinely to transport cargo between nodes in Earth, lunar, and Mars orbit. Electric propulsion systems are low-thrust, high-specific-impulse systems with fuel efficiencies 2 to 10 times the efficiencies of systems using chemical propellants. The payoff for this performance can be high, since a principal cost for a space transportation system is that of launching to low Earth orbit (LEO) the propellant required for operations between LEO and other nodes. Several aspects of electric propulsion, including candidate systems and the impact of using nonterrestrial materials, are discussed.

Garrison, Philip W.

34

Low-Altitude Operation of Unmanned Rotorcraft  

NASA Astrophysics Data System (ADS)

Currently deployed unmanned rotorcraft rely on preplanned missions or teleoperation and do not actively incorporate information about obstacles, landing sites, wind, position uncertainty, and other aerial vehicles during online motion planning. Prior work has successfully addressed some tasks such as obstacle avoidance at slow speeds, or landing at known to be good locations. However, to enable autonomous missions in cluttered environments, the vehicle has to react quickly to previously unknown obstacles, respond to changing environmental conditions, and find unknown landing sites. We consider the problem of enabling autonomous operation at low-altitude with contributions to four problems. First we address the problem of fast obstacle avoidance for a small aerial vehicle and present results from over a 1000 rims at speeds up to 10 m/s. Fast response is achieved through a reactive algorithm whose response is learned based on observing a pilot. Second, we show an algorithm to update the obstacle cost expansion for path planning quickly and demonstrate it on a micro aerial vehicle, and an autonomous helicopter avoiding obstacles. Next, we examine the mission of finding a place to land near a ground goal. Good landing sites need to be detected and found and the final touch down goal is unknown. To detect the landing sites we convey a model based algorithm for landing sites that incorporates many helicopter relevant constraints such as landing sites, approach, abort, and ground paths in 3D range data. The landing site evaluation algorithm uses a patch-based coarse evaluation for slope and roughness, and a fine evaluation that fits a 3D model of the helicopter and landing gear to calculate a goodness measure. The data are evaluated in real-time to enable the helicopter to decide on a place to land. We show results from urban, vegetated, and desert environments, and demonstrate the first autonomous helicopter that selects its own landing sites. We present a generalized planning framework that enables reaching a goal point, searching for unknown landing sites, and approaching a landing zone. In the framework, sub-objective functions, constraints, and a state machine define the mission and behavior of an UAV. As the vehicle gathers information by moving through the environment, the objective functions account for this new information. The operator in this framework can directly specify his intent as an objective function that defines the mission rather than giving a sequence of pre-specified goal points. This allows the robot to react to new information received and adjust its path accordingly. The objective is used in a combined coarse planning and trajectory optimization algorithm to determine the best patch the robot should take. We show simulated results for several different missions and in particular focus on active landing zone search. We presented several effective approaches for perception and action for low-altitude flight and demonstrated their effectiveness in field experiments on three autonomous aerial vehicles: a 1m quadrocopter, a 36m helicopter, and a hill-size helicopter. These techniques permit rotorcraft to operate where they have their greatest advantage: In unstructured, unknown environments at low-altitude.

Scherer, Sebastian

35

Improving rotorcraft survivability to RPG attack using inverse methods  

Microsoft Academic Search

This paper presents the results of a preliminary investigation of optimal threat evasion strategies for improving the survivability of rotorcraft under attack by rocket propelled grenades (RPGs). The basis of this approach is the application of inverse simulation techniques pioneered for simulation of aggressive helicopter manoeuvres to the RPG engagement problem. In this research, improvements in survivability are achieved by

D. Anderson; D. G. Thomson

2009-01-01

36

Topological optimization of rotorcraft subfloor structures for crashworthiness considerations  

Microsoft Academic Search

The present paper discusses significant design issues in the sizing of rotorcraft structures for requirements of enhanced crash performance. The focus of the study is on topological design of the subfloor structure, defined as a crush zone under a more rigid floor structure. The topological design problem includes both an appropriate selection of an energy absorbing material (tailored load-deflection curve),

P. Hajela; E. Lee

1997-01-01

37

Rotorcraft flight test automation-the saga continues  

Microsoft Academic Search

The cost associated with the next generation rotorcraft testing, training, and support, using current techniques, promises to escalate in a predicted hostile fiscal environment. Aircraft testing, and the associated training and support, place large demands on flight vehicles, avionics, weapons systems, test teams and scarce fiscal resources. Innovative technology options in the form of case based reasoning, automatic test plan

Dean Carico

1998-01-01

38

Towards an advanced nonlinear rotorcraft flight control system design  

Microsoft Academic Search

Traditional rotorcraft flight control designs rely heavily on plant models which have been linearized about various operating set points. These designs are only valid for operating conditions close to the original trim points and suffer performance degradations for significant deviations. Consequently, several linear controllers are designed and scheduled to cover the operational flight envelope. An alternate approach that uses the

Chima E. Njaka; P. K. Menon; V. H. L. Cheng

1994-01-01

39

Computer vision techniques for rotorcraft low-altitude flight  

Microsoft Academic Search

A description is given of research that applies techniques from computer vision to automation of rotorcraft navigation, especially when flying low to avoid detection by an enemy. The effort emphasizes the development of a methodology for detecting the ranges to obstacles in the region of interest based on the maximum utilization of passive sensors. The range map derived from the

Banavar Sridhar; Victor H. L. Cheng

1988-01-01

40

INNOVATIVE ENERGY ABSORBING MOUNTING SYSTEMS FOR HIGH MASS ROTORCRAFT PAYLOADS  

Microsoft Academic Search

This paper presents recent developments on two innovative types of crashworthy cargo restraints for high mass rotorcraft payloads: textile-based devices and flexible matrix composite devices. Each type of device employs energy dissipation mechanisms to arrest the motion of payloads and limit the maximum load transmitted to tie-down points, thereby maintaining control over payload motion and improving crew survivability in the

William Kong; Chandrashekhar Tiwari; Matthew J. Hagon; Charles E. Bakis; Edward C. Smith; Michael A. Yukish

41

Envelope protection systems for piloted and unmanned rotorcraft  

Microsoft Academic Search

Performance and agility of rotorcraft can be improved using envelope protection systems (or carefree maneuvering systems), which allow the aircraft to use the full flight envelope without risk of exceeding structural or controllability limits. Implementation of such a system can be divided into two necessary parts: \\

Nilesh A. Sahani

2005-01-01

42

Adverse rotorcraft pilot couplings—Past, present and future challenges  

NASA Astrophysics Data System (ADS)

Fixed and rotary wing pilots alike are familiar with potential instabilities or with annoying limit cycle oscillations that arise from the effort of controlling aircraft with high response actuation systems. Understanding, predicting and suppressing these inadvertent and sustained aircraft oscillations, known as aircraft (rotorcraft)-pilot couplings (A/RPCs) is a challenging problem for the designers. The goal of the present paper is to give an overview on the state-of-the-art in RPC problem, underlining the future challenges in this field. It is shown that, exactly as in the case of fixed wing APCs, RPCs existed from the beginning of rotorcraft development and that the problem of eliminating them is not yet solved: the current rotorcraft modelling for RPC analysis is rather limited to the particular case analysed and there is a lack of quantitative pilot behavioural models to analyse RPCs. The paper underlines the importance of involuntary pilot control actions, generally attributed to biodynamic couplings in predicting RPCs in rotorcraft. It is also shown that recent experiences demonstrate that modern rotorcraft seem to embed tendencies predisposing the flight control system FCS system towards dangerous RPCs. As the level of automation is likely to increase in future designs, extending to smaller aircraft and to different kinds of operation, the consequences of the pilot 'fighting' the FCS system and inducing A/RPCs needs to be eradicated. In Europe, the ARISTOTEL project (2010-2013) has been launched with the aim of understanding and predicting modern aircraft's susceptibility to A/RPC. The present paper gives an overview of future challenges to be solved for RPC-free design and some new solutions herein.

Pavel, Marilena D.; Jump, Michael; Dang-Vu, Binh; Masarati, Pierangelo; Gennaretti, Massimo; Ionita, Achim; Zaichik, Larisa; Smaili, Hafid; Quaranta, Giuseppe; Yilmaz, Deniz; Jones, Michael; Serafini, Jacopo; Malecki, Jacek

2013-10-01

43

Focused Technology: Nuclear Propulsion.  

National Technical Information Service (NTIS)

Five viewgraphs are presented that outline the objectives and elements of the Nuclear Propulsion Program, mission considerations, propulsion technologies, and the logic flow path for nuclear propulsion development.

T. J. Miller

1993-01-01

44

Impact of pilots' biodynamic feedthrough on rotorcraft by robust stability  

NASA Astrophysics Data System (ADS)

The coupling of rotorcraft dynamics with the dynamics of one of the main systems devoted to its control, the pilot, may lead to several peculiar phenomena, known as Rotorcraft–Pilot Couplings (RPCs), all characterized by an abnormal behavior that may jeopardize flight safety. Among these phenomena, there is a special class of couplings which is dominated by the biodynamic behavior of the pilot's limbs that close the loop between the vibrations and the control inceptors in the cockpit. Leveraging robust stability analysis, the inherently uncertain pilot biodynamics can be treated as the uncertain portion of a feedback system, making analytical, numerical or graphical determination of proneness to RPC possible by comparing robust stability margins of helicopter models with experimental Biodynamic Feedthrough (BDFT) data. The application of the proposed approach to collective bounce is exemplified using simple analytical helicopter and pilot models. The approach is also applied to detailed helicopter models and experimental BDFT measurement data.

Quaranta, Giuseppe; Masarati, Pierangelo; Venrooij, Joost

2013-09-01

45

A new oil-free mechanical vacuum pump  

Microsoft Academic Search

A number of entirely oil-free, four-stage reciprocating-piston vacuum pumps which produce an ultimate pressure of approximately 15 mTorr have been in operation for periods approaching two years. These pumps have been used for pre-evacuation of high and ultra-high vacuum chambers and devices, backing of turbomolecular pumps, molecular drag pumps and Roots-type blowers, regeneration of cryo-pumps, pumping of vacuum furnances and

E. Bez; D. Guarnaccia; M. Hablanian

1988-01-01

46

Performance of GM Cryocooler with Oil-Free Linear Compressor  

Microsoft Academic Search

A completely oil-free compressor for use with GM cryocoolers has been designed, built, and tested. The compressor uses two, fully-balanced, STAR linear motors together with friction-free reed valves. This arrangement eliminates all possibility of oil contamination in the helium working fluid, and therefore also eliminates the regular servicing that is required by conventional GM compressors. The compressor delivers high-pressure flows

J. R. Maddocks; A. Kashani; B. P. M. Helvensteijn; D. W. Hoch; G. F. Nellis; J. A. Corey; E. L. James; G. L. Rhoads

2006-01-01

47

Envelope protection systems for piloted and unmanned rotorcraft  

NASA Astrophysics Data System (ADS)

Performance and agility of rotorcraft can be improved using envelope protection systems (or carefree maneuvering systems), which allow the aircraft to use the full flight envelope without risk of exceeding structural or controllability limits. Implementation of such a system can be divided into two necessary parts: "Limit Prediction" which detects the impending violation of the limit parameter, and "Limit Avoidance" where a preventive action is taken in the form of pilot cueing or autonomous limiting. Depending upon the underlying flight control system, implementation of the envelope limiting system was categorized into two different structures: "Inceptor Constraint Architecture" and "Command Limiting Architecture". The Inceptor Constraint Architecture is applicable to existing rotorcraft with conventional flight control system where control input proportionally affects control surfaces. The relationship between control input and limit parameter is complex which requires advanced algorithms for predicting impending limit violations. This research focuses on limits that exceed in transient response. A new algorithm was developed for predicting transient response using non-linear functions of measured aircraft states. The functions were generated off-line using simulation data from a non-real-time simulation, model to demonstrate the procedure for extracting them from flight test data. Modern rotorcraft flight control systems are designed to accurately track certain aircraft states like roll and pitch attitudes which are either specified as command inputs in unmanned rotorcraft or mapped to control stick in piloted aircrafts. In the Command Limiting Architecture applicable to these systems, performance constraints were generated on the command input corresponding to the envelope limit. To simulate this flight control system, an adaptive model inversion controller was applied to a non-linear, blade element simulation model of a helicopter. The controller generated fully-coupled lateral, longitudinal, vertical and yaw axis control inputs using a single design point linear model. (Abstract shortened by UMI.)

Sahani, Nilesh A.

48

IDT sensors for detection of ice on rotorcraft  

NASA Astrophysics Data System (ADS)

IDT (Interdigital Transducers) offer significant potential for detecting ice formation on rotorcraft applications. Sensing of flex beam deflection and acceleration, ice formation and deicing are major candidate areas where smart conformal IDT and MEMS based sensors can be exploited by the rotorcraft community. The major technical barrier of the present day smart structures technology is the need for wired communication between sensors and actuators in the rotating system and controllers, data storage units, and cockpit avionics. Many proposed sensors and actuators are commonly distributed either along the blade length or, in the active flap devices, out near the 75% blade radial station. Also they are not conformal to the airfoil shape of the rotor blades. The communication between rotating and fixed systems is typically accomplished using complex slip ring assemblies transferring electronic information down through the rotor shaft. Although advances have been made in wired communication, these complex assemblies are essentially similar to test hardware and present numerous reliability and maintainability limitations when implemented on a production scale. Considering these limitations, development of a wireless means of communication through a new generation of conformal sensors with built-in antenna, akin to telemetry, could have a dramatic beneficial payoff for rotorcraft applications. In this paper, an integration of IDT microsensors and MEMS sensors is presented.

Varadan, Vasundara V.; Varadan, Vijay K.; Bao, Xiao-Qi

1998-07-01

49

MEMS for measuring deflection, acceleration, and ice sensing on rotorcraft  

NASA Astrophysics Data System (ADS)

Smart MEMS (MicroElectroMechanical Systems) in the form of integrated sensors and actuators offer significant potential for many rotorcraft applications. Sensing of flex beam deflection and acceleration, ice formation and deicing are major candidate areas where smart conformal MEMS based sensors can be exploited by the rotorcraft community. The major technical barrier of the present day smart structures technology is the need for wired communication between sensors and actuators in the rotating system and controllers, data storage units, and cockpit avionics. Many proposed sensors and actuators are commonly distributed either along the blade length or, in the active flap devices, out near the 75% blade radial station. Also they are not conformal to the airfoil shape of the rotor blades. The communication between rotating and fixed systems is typically accomplished using complex slip ring assemblies transferring electronic information down through the rotor shaft. Although advances have been made in wired communication, these complex assemblies are essentially similar to test hardware and present numerous reliability and maintainability limitations when implemented on a production scale. Considering these limitations, development of a wireless means of communication through a new generation of conformal sensors with built-in antenna, akin to telemetry, could have a dramatic beneficial payoff for rotorcraft applications. In this paper, an integration of IDT (inter digital transducer) microsensors and MEMS sensors is presented.

Varadan, Vijay K.; Varadan, Vasundara V.

1998-04-01

50

Propulsion System.  

National Technical Information Service (NTIS)

The closed cycle propulsion system for a torpedo uses aluminum as a source of hydrogen. The system includes a fuel generator, a store of oxidizer, a combustion chamber, a steam-driven prime mover, a condenser and three displacement pumps driven by a commo...

N. Fatica

1966-01-01

51

Marine Propulsion Load Emulation.  

National Technical Information Service (NTIS)

Improved propulsion plant control schemes for gas turbine ships can provide both economic and tactical benefits to the fleet. One way to develop improved propulsion controllers is to use a marine propulsion emulator as an implementation test bed for propo...

P. N. Johnson

1985-01-01

52

Hermes Propulsion System.  

National Technical Information Service (NTIS)

The initial baseline concept of the storable bipropellant propulsion system of the Hermes spaceplane is discussed. The general architecture of the propulsion system is shown. The design features of the engines of the main propulsion system and of the thru...

H. Immich H. Hopmann T. Caussin

1987-01-01

53

Feasibility of data fusion techniques applied to rotorcraft transmission diagnostics  

NASA Astrophysics Data System (ADS)

This paper addresses the feasibility of applying data fusion techniques to resolve the sensitivity versus false alarm dilemma of rotorcraft transmission diagnostics. Traditionally, data fusion techniques have been applied almost exclusively to automatic target recognition problems, but the processing concepts are well-suited to address complex machine diagnostics and prognostics. Processing methods such as data alignment and association, hierarchical inferencing, situation assessment, threat assessment, time predictions, sensor management, and human-computer interface are common to both automatic target recognition and transmission diagnostics. The benefits of this approach include: (1) improved decision support, (2) reduced false alarm rates, (3) improved mission effectiveness, and (4) enhanced safety.

DuBois, Thomas A.; Pruyn, Richard R.

1993-09-01

54

Future of space propulsion  

SciTech Connect

A development status-and-prospects evaluation is presented for the range of spacecraft propulsion alternatives under consideration by the USAF's Phillips Laboratory, encompassing technologies broadly characterizable as 'conventional' (solid, storable liquid, cryogenic) and 'nonconventional'. Nonconventional spacecraft propulsion system types include arcjets, magnetoplasmadynamic thrusters, solar thermal propulsion, and nuclear propulsion. The prospects for high energy density materials' application to more coventional propulsion concepts are noted.

Weiss, R.R.; Mackay, D.S. (USAF, Phillips Laboratory, Edwards AFB, CA (United States))

1992-03-01

55

Active vibration and noise alleviation in rotorcraft using microflaps  

NASA Astrophysics Data System (ADS)

This work presents a comprehensive analysis of active Gurney flaps, or microflaps, for on blade control of noise and vibration in rotorcraft. The initial portion of the work considered the two-dimensional unsteady aerodynamic characteristics of three different oscillating microflap configurations using a compressible computational fluid dynamics (CFD) flow solver. Among these the configuration most suitable for rotorcraft applications was chosen. An unsteady reduced order aerodynamic model (ROM) was developed for the microflap using the Rational Function Approximation approach and CFD based oscillatory aerodynamic load data. The resulting ROM is a state-space, time-domain model that accounts for unsteadiness, compressibility and time-varying freestream effects. The ROM was validated against direct CFD calculations for a wide range of flow conditions showing excellent agreement. Subsequently, the ROM was then incorporated into a comprehensive rotorcraft simulation code featuring a free-wake model, an acoustic prediction tool, and fully coupled flap-lag-torsional blade dynamics. The higher harmonic control (HHC) algorithm was used to simulate closed-loop active control with a 1.5% chord microflap on a hingeless rotor configuration resembling the MBB BO-105. Three span-wise configurations, single, dual, and a five-microflap configuration were considered. Results indicate that the microflap can achieve reductions ranging from 3-6 dB in the blade-vortex interaction (BVI) noise. Vibration reduction ranging from 70-90% was also demonstrated at both low-speed and high-speed flight conditions. It was also found that reduction in BVI noise results in an increase in vibrations and vice versa, a trend also noted in previous active control studies employing HHC and conventional partial span trailing-edge flaps. Next, simultaneous BVI noise and vibration reduction was studied. A reduction of 2-3 dB in the advancing and retreating side noise combined with a 55% reduction in the vibratory loads was achieved using the five-microflap configuration. The 1.5% chord microflap was also compared to a 20% chord plain trailing-edge flap showing similar effectiveness in reducing vibration and noise. Finally, a new approach for dealing with actuator saturation in the HHC algorithm was developed using nonlinear constrained optimization techniques. The optimization approach takes less computational time compared to the previous approaches while yielding better performance in the case of multiple control surfaces.

Padthe, Ashwani Kumar

56

H?Hover-to-Cruise Conversion for a Tilt-Wing Rotorcraft  

Microsoft Academic Search

This paper describes the development of robust, multi-variable H? control systems for the conversion of the High-Speed Autonomous Rotorcraft Vehicle (HARVee), an experimental tilt-wing aircraft. Tilt-wing rotorcraft combine the high-speed cruise capabilities of a conventional airplane with the hovering capabilities of a helicopter by rotating their wings at the fuselage. Changing between cruise and hover flight modes in mid-air is

Jeffrey J. Dickeson; David R. Mix; John S. Koenig; Karen M. Linda; Oguzhan Cifdaloz; Valana L. Wells; Armando A. Rodriguez

2005-01-01

57

Space propulsion  

NASA Astrophysics Data System (ADS)

Lewis Research Center is developing broad-based new technologies for space chemical engines to satisfy long-term needs of ETO launch vehicles and other vehicles operating in and beyond Earth orbit. Specific objectives are focused on high performance LO2/LH2 engines providing moderate thrusts of 7,5-200 klb. This effort encompasses research related to design analysis and manufacturing processes needed to apply advanced materials to subcomponents, components, and subsystems of space-based systems and related ground-support equipment. High-performance space-based chemical engines face a number of technical challenges. Liquid hydrogen turbopump impellers are often so large that they cannot be machined from a single piece, yet high stress at the vane/shroud interface makes bonding extremely difficult. Tolerances on fillets are critical on large impellers. Advanced materials and fabricating techniques are needed to address these and other issues of interest. Turbopump bearings are needed which can provide reliable, long life operation at high speed and high load with low friction losses. Hydrostatic bearings provide good performance, but transients during pump starts and stops may be an issue because no pressurized fluid is available unless a separate bearing pressurization system is included. Durable materials and/or coatings are needed that can demonstrate low wear in the harsh LO2/LH2 environment. Advanced materials are also needed to improve the lifetime, reliability and performance of other propulsion system elements such as seals and chambers.

Kazaroff, John M.

1993-02-01

58

Electric Propulsion Orbital Platform.  

National Technical Information Service (NTIS)

This paper describes the Electric Propulsion Orbital Platform (EPOP), of which the primary objective is to provide an instrumented platform for testing electric propulsion devices in space. It is anticipated that the first flight, EPOP-1, will take place ...

1993-01-01

59

Advanced Chemical Propulsion Study.  

National Technical Information Service (NTIS)

A study was performed of advanced chemical propulsion technology application to space science (Code S) missions. The purpose was to begin the process of selecting chemical propulsion technology advancement activities that would provide greatest benefits t...

G. Woodcock D. Byers L. A. Alexander A. Krebsbach

2004-01-01

60

Advanced space propulsion  

Microsoft Academic Search

An evaluation is made of the conceptual development status and prospective performance gains anticipated from fully developed spacecraft propulsion systems of radically innovative character. Candidate systems encompass such widely different technologies as solar sails, tethers, laser-sustained ablative propellant evaporation, nuclear propulsion, solar-thermal propulsion, and such ultrahigh energy exotic fuels as metallic hydrogen, which has been calculated to be capable of

1990-01-01

61

Future Issues and Approaches to Health Monitoring and Failure Prevention for Oil-Free Gas Turbines.  

National Technical Information Service (NTIS)

Recent technology advances in foil air bearings, high temperature solid lubricants and computer based modeling has enabled the development of small Oil-Free gas turbines. These turbomachines are currently commercialized as small (<100 kW) microturbine ...

C. DellaCorte

2004-01-01

62

Remaining Technical Challenges and Future Plans for Oil-Free Turbomachinery.  

National Technical Information Service (NTIS)

The application of Oil-Free technologies (foil gas bearings, solid lubricants and advanced analysis and predictive modeling tools) to advanced turbomachinery has been underway for several decades. During that time, full commercialization has occurred in a...

C. DellaCorte R. J. Bruckner

2010-01-01

63

A Tool for Low Noise Procedures Design and Community Noise Impact Assessment: The Rotorcraft Noise Model (RNM)  

Microsoft Academic Search

To improve aircraft noise impact modeling capabilities and to provide a tool to aid in the development of low noise terminal area operations for rotorcraft and tiltrotors, the Rotorcraft Noise Model (RNM) was developed by the NASA Langley Research Center and Wyle Laboratories. RNM is a simulation program that predicts how sound will propagate through the atmosphere and accumulate at

David A. Conner

2002-01-01

64

Advanced Transportation System Studies. Alternate Propulsion Subsystem Concepts: Propulsion Database.  

National Technical Information Service (NTIS)

The Advanced Transportation System Studies alternate propulsion subsystem concepts propulsion database interim report is presented. The objective of the database development task is to produce a propulsion database which is easy to use and modify while al...

D. Levack

1993-01-01

65

Analysis of computational modeling techniques for complete rotorcraft configurations  

NASA Astrophysics Data System (ADS)

Computational fluid dynamics (CFD) provides the helicopter designer with a powerful tool for identifying problematic aerodynamics. Through the use of CFD, design concepts can be analyzed in a virtual wind tunnel long before a physical model is ever created. Traditional CFD analysis tends to be a time consuming process, where much of the effort is spent generating a high quality computational grid. Recent increases in computing power and memory have created renewed interest in alternative grid schemes such as unstructured grids, which facilitate rapid grid generation by relaxing restrictions on grid structure. Three rotor models have been incorporated into a popular fixed-wing unstructured CFD solver to increase its capability and facilitate availability to the rotorcraft community. The benefit of unstructured grid methods is demonstrated through rapid generation of high fidelity configuration models. The simplest rotor model is the steady state actuator disk approximation. By transforming the unsteady rotor problem into a steady state one, the actuator disk can provide rapid predictions of performance parameters such as lift and drag. The actuator blade and overset blade models provide a depiction of the unsteady rotor wake, but incur a larger computational cost than the actuator disk. The actuator blade model is convenient when the unsteady aerodynamic behavior needs to be investigated, but the computational cost of the overset approach is too large. The overset or chimera method allows the blades loads to be computed from first-principles and therefore provides the most accurate prediction of the rotor wake for the models investigated. The physics of the flow fields generated by these models for rotor/fuselage interactions are explored, along with efficiencies and limitations of each method.

O'Brien, David M., Jr.

66

Advanced space propulsion  

SciTech Connect

An evaluation is made of the conceptual development status and prospective performance gains anticipated from fully developed spacecraft propulsion systems of radically innovative character. Candidate systems encompass such widely different technologies as solar sails, tethers, laser-sustained ablative propellant evaporation, nuclear propulsion, solar-thermal propulsion, and such ultrahigh energy exotic fuels as metallic hydrogen, which has been calculated to be capable of yielding a specific impulse of 1700 sec; the most energetic current rockets, operating on LH2/LOX, yield 500 sec. The performance levels of these exotic propulsion systems are considered essential for the efficient exploration of Mars.

Forward, R.L. (Forward Unlimited, Malibu, CA (USA))

1990-07-01

67

NASA Breakthrough Propulsion Physics Program.  

National Technical Information Service (NTIS)

In 1996, NASA established the Breakthrough Propulsion Physics program to seek the ultimate breakthroughs in space transportation: propulsion that requires no propellant mass, propulsion that attains the maximum transit speeds physically possible, and brea...

M. G. Millis

1998-01-01

68

Prediction of acoustic scattering in the time domain and its applications to rotorcraft noise  

Microsoft Academic Search

This work aims at the development of a numerical method for the analysis of acoustic scattering in the time domain and its applications to rotorcraft noise. This purpose is achieved by developing two independent methods: (1) an analytical formulation of the pressure gradient for an arbitrary moving source and (2) a time-domain moving equivalent source method. First, the analytical formulation

Seongkyu Lee

2009-01-01

69

A Linear Domain System Identification for Small Unmanned Aerial Rotorcraft Based on Adaptive Genetic Algorithm  

Microsoft Academic Search

This paper proposes a new adaptive linear domain system identification method for small unmanned aerial rotorcraft. By using the flash memory integrated into the micro guide navigation control module, system records the data sequences of flight tests as inputs (control signals for servos) and outputs (aircraft's attitude and velocity information). After data preprocessing, the system constructs the horizontal and vertical

Xusheng Lei; Yuhu Du

2010-01-01

70

Analytical Assessment of Performance, Handling Qualities, and Added Dynamics in Rotorcraft Flight Control  

Microsoft Academic Search

Data from a recent experimental study aimed at investigating the allowable errors in vehicle models for use in rotorcraft flight simulators are employed in the exercise of a pilot\\/vehicle analysis tool. It is demonstrated that a simplified multiaxis pilot model emulating pursuit tracking behavior can provide estimates of tracking performance and handling qualities. In an approximate manner, this model can

Ronald A. Hess

2009-01-01

71

Rotorcraft Research Testing in the National Full-Scale Aerodynamics Complex at NASA Ames Research Center.  

National Technical Information Service (NTIS)

The unique capabilities of the National Full-Scale Aerodynamics Complex (NFAC) for testing rotorcraft systems are described. The test facilities include the 40- by 80-Foot Wind Tunnel, the 80- by 120-Foot Wind Tunnel, and the Outdoor Aerodynamic Research ...

W. Warmbrodt C. A. Smith W. Johnson

1985-01-01

72

Evaluation of innovative concepts for semi-active and active rotorcraft control  

NASA Astrophysics Data System (ADS)

Lead-lag dampers are present in most rotor systems to provide the desired level of damping for all flight conditions. These dampers are critical components of the rotor system, and the performance of semi-active Coulomb friction-based lead-lag dampers is examined for the UH-60 aircraft. The concept of adaptive damping, or "damping on demand," is discussed for both ground resonance and forward flight. The concept of selective damping is also assessed, and shown to face many challenges. In rotorcraft flight dynamics, optimized warping twist change is a potentially enabling technology to improve overall rotorcraft performance. Research efforts in recent years have led to the application of active materials for rotorcraft blade actuation. An innovative concept is proposed wherein the typically closed section blade is cut open to create a torsionally compliant structure that acts as its own amplification device; deformation of the blade is dynamically controlled by out-of-plane warping. Full-blade warping is shown to have the potential for great design flexibility. Recent advances in rotorcraft blade design have also focused on variable-camber airfoils, particularly concepts involving "truss-core" configurations. One promising concept is the use of hexagonal chiral lattice structures in continuously deformable helicopter blades. The static behavior of passive and active chiral networks using piezoelectric actuation strategies is investigated, including under typical aerodynamic load levels. The analysis is then extended to the dynamic response of active chiral networks in unsteady aerodynamic environments.

Van Weddingen, Yannick

73

Robotic rotorcraft and perch-and-stare: sensing landing zones and handling obscurants  

Microsoft Academic Search

Perch and stare is a maneuver where a vehicle flies to an overhead vantage point to provide a user with improved tactical information. This may include landing on rooftops, flying from rooftop to rooftop, or to windowsills all while carrying cameras or other intelligence gathering sensors. Miniature rotorcraft are ideal surveillance platforms, especially for perch and stare maneuvers because of

Todd W. Danko; Andreas Kellas; Paul Y. Oh

2005-01-01

74

Deuterium microbomb rocket propulsion  

Microsoft Academic Search

Large scale manned space flight within the solar system is still confronted with the solution of two problems: 1. A propulsion system to transport large payloads with short transit times between different planetary orbits. 2. A cost effective lifting of large payloads into earth orbit. For the solution of the first problem a deuterium fusion bomb propulsion system is proposed

Friedwardt Winterberg

2008-01-01

75

Deuterium microbomb rocket propulsion  

Microsoft Academic Search

Large scale manned space flight within the solar system is still confronted with the solution of two problems: (1) A propulsion system to transport large payloads with short transit times between different planetary orbits. (2) A cost effective lifting of large payloads into earth orbit. For the solution of the first problem a deuterium fusion bomb propulsion system is proposed

Friedwardt Winterberg

2010-01-01

76

Rarefaction wave gun propulsion  

Microsoft Academic Search

A new species of gun propulsion that dramatically reduces recoil momentum imparted to the gun is presented. First conceived by the author on 18 March 1999, the propulsion concept is explained, a methodology for the design of a reasonable apparatus for experimental validation using NATO standard 35mm TP anti-aircraft ammunition is developed, and the experimental results are presented. The firing

Eric Lee Kathe

2002-01-01

77

Nuclear Pulse Propulsion  

Microsoft Academic Search

A general technical description and programmatic review of nuclear pulse propulsion activities over the last decade is presented. Major problem areas are reviewed together with the status of current research efforts. Sufficient technical information is now available to predict achievable propulsion systems performance with a rather high degree of confidence based on current materials and nuclear technology. Expected performance is

J. C. Nance

1965-01-01

78

Electric propulsion system technology  

Microsoft Academic Search

The work performed on the Ion Propulsion System Technology Task in FY90 is described. The objectives of this work fall under two broad categories. The first of these deals with issues associated with the application of xenon ion thrusters for primary propulsion of planetary spacecraft, and the second with the investigation of technologies which will facilitate the development of larger,

John R. Brophy; Charles E. Garner; Keith D. Goodfellow

1991-01-01

79

Flagellar propulsion near walls  

Microsoft Academic Search

Confinement and wall effects are known to affect the kinematics and propulsive characteristics of swimming microorganisms. When a solid body is dragged through a viscous fluid at constant velocity, the presence of a wall increases fluid drag, and thus the net force required to maintain speed has to increase. In contrast, recent optical trapping experiments have revealed that the propulsive

Arthur Evans; Eric Lauga

2010-01-01

80

Conceptual Design and Feasibility of Foil Bearings for Rotorcraft Engines: Hot Core Bearings.  

National Technical Information Service (NTIS)

Recent developments in gas foil bearing technology have led to numerous advanced high-speed rotating system concepts, many of which have become either commercial products or experimental test articles. Examples include oil-free microturbines, motors, gene...

S. A. Howard

2007-01-01

81

Finite element analysis of gas bearings for oil-free turbomachinery  

Microsoft Academic Search

Further advancements in high performance turbomachinery operating at extreme temperatures mandate the development of gas film bearing technology to procure compact units with improved efficiency in an oil-free environment. A novel finite element (FE) procedure to model thin film gas bearings follows. The FE model incorporates a novel class of high order shape functions ensuring computational efficiency and numerical stability

Luis San Andrés; Deborah Wilde

2001-01-01

82

The USAF Electric Propulsion Program  

NASA Astrophysics Data System (ADS)

An overview of the current state of electric propulsion technology development efforts within the United States Air Force is presented. Air Force Mission Needs Statements which call for electric propulsion are likewise discussed. Two groups within the Air Force Research Laboratory contribute to the electric propulsion program: Propulsion Directorate and Air Force Office of Scientific Research (AFOSR). The Propulsion Directorate is conducting electric propulsion efforts in basic research. engineering development as well as an Advanced Technology Development effort that will result in a space flight experiment of a 30 kilowatt arcjet system. AFOSR funds basic research in electric propulsion throughout the country in both academia and industry.

Spores, R. A.; Birkan, M.

1998-07-01

83

CFD for Hypersonic Propulsion.  

National Technical Information Service (NTIS)

An overview is given of research activity on the application of computational fluid dynamics (CDF) for hypersonic propulsion systems. After the initial consideration of the highly integrated nature of air-breathing hypersonic engines and airframe, attenti...

L. A. Povinelli

1990-01-01

84

NASA - Space Propulsion  

NASA Website

Along with new chemical engines, Glenn is also developing new concepts, like electric propulsion and ion thrusters, that could provide safe, reliable, and affordable trips beyond low Earth orbit and beyond.

85

Flagellar propulsion near walls  

NASA Astrophysics Data System (ADS)

Confinement and wall effects are known to affect the kinematics and propulsive characteristics of swimming microorganisms. When a solid body is dragged through a viscous fluid at constant velocity, the presence of a wall increases fluid drag, and thus the net force required to maintain speed has to increase. In contrast, recent optical trapping experiments have revealed that the propulsive force generated by human spermatozoa is decreased by the presence of boundaries. Here we use simple models to analytically elucidate the propulsive effects of a solid boundary on passively actuated filaments and model eukaryotic flagella. We show that in some cases, the increase in fluid friction induced by the wall can lead to a change in the waveform expressed by the flagella which results in a decrease of their propulsive force near a no-slip wall.

Evans, Arthur; Lauga, Eric

2010-11-01

86

Robust H? Gain-Scheduled Conversion for a Tilt-Wing Rotorcraft  

Microsoft Academic Search

This paper describes the development an analysis of robust, multi-variable H? control systems for the conversion of the high-speed autonomous rotorcraft vehicle (HARVee), an experimental tilt-wing aircraft. Tilt-wing aircraft combine the high-speed cruise capabilities of a conventional airplane with the vertical takeoff and station keeping abilities of a helicopter by rotating their wings at the fuselage. Changing between cruise and

Jeffrey J. Dickeson; Oguzhan Cifdaloz; David W. Miles; Paul M. Koziol; Valana L. Wells; Armando A. Rodriguez

2006-01-01

87

MultiSensor Track Classification in Rotorcraft Pilot's Associate Data Fusion  

Microsoft Academic Search

The objective of the Rotorcraft Pilot's Associate (RPA) Advanced Technology Demonstration (ATD) is to apply artificial intelligence and state-of-the-art computing tech- nologies to manage and integrate next generation mission equipment and battlefield information in order to enhance the lethality, survivability, and mission effectiveness of combat helicopters. Lockheed Martin Advanced Technol- ogy Laboratories is responsible for the real-time, compute- intensive Data

Martin O. Hofmann

1997-01-01

88

Comparative Results on Stabilization of the Quad-rotor Rotorcraft Using Bounded Feedback Controllers  

Microsoft Academic Search

In the recent years autonomous flying vehicles are being increasingly used in both civil and military areas. With the advancement\\u000a of the technology it has become possible to test efficiently and cost-effectively different autonomous flight control concepts\\u000a and design variations using small-scale aerial vehicles. In this paper the stabilization problem of the quad-rotor rotorcraft\\u000a using bounded feedback controllers is investigated.

Nikola Georgiev Shakev; Andon Venelinov Topalov; Okyay Kaynak; Kostadin Borisov Shiev

89

A Multi-Disciplinary Rotorcraft Simulation Facility Composed of Commodity Components and Open Source Software  

Microsoft Academic Search

Abstract Alow-cost rotorcraft simulation facility was developed ,for university-based multi-disciplinary research programs. The objective was to develop ,a flexible and effective research facility with minimal ,initial costs and little to no recurring costs. The simulation facility was constructed entirely from commercially,available commodity,hardware components. Several PC computers ,are linked together via a local network to form ,a “graphical cluster”. The arrangement

Joseph F. Horn; Derek O. Bridges Charu Sharma; Leonard V. Lopes; Kenneth S. Brentner

90

Flow control strategies for improved aerodynamic efficiency of micro-rotorcraft  

Microsoft Academic Search

This thesis is aimed at demonstrating substantial improvements in aerodynamic efficiency of micro-rotorcraft. The work investigates the effect of airfoil surface temperature and heat transfer, and unsteady blade pitching motion on the performance of micro-scale rotors. Prior to testing of new strategies to enhance performance, the baseline aerodynamic performance of the micro-rotor system was quantified. This study indicated that the

Jongmin Kim

2004-01-01

91

Laser space propulsion overview  

NASA Astrophysics Data System (ADS)

In this paper, we review the history of laser space propulsion from its earliest theoretical conceptions to modern practical applicatons. Applications begin with the "Lightcraft" flights of Myrabo and include practical thrusters for satellites now completing development as well as proposals for space debris removal and direct launch of payloads into orbit. We consider laser space propulsion in the most general sense, in which laser radiation is used to propel a vehicle in space. In this sense, the topic includes early proposals for pure photon propulsion, laser ablation propulsion, as well as propulsion using lasers to detonate a gas, expel a liquid, heat and expel a gas, or even to propagate power to a remote conventional electric thruster. We also discuss the most recent advances in LSP. For the first time, it is possible to consider space propulsion engines which exhibit thrust of one to several newtons while simultaneously delivering 3,000 seconds, or greater, specific impulse. No other engine concept can do both in a compact format. These willl use onboard, rather than remote, lasers. We will review the concept of chemically augmented electric propulsion, which can provide overall thrust efficiency greater than unity while maintaining very low mass to power ratio, high mean time to failure and broad operating range. The main advantage of LSP is exhaust velocity which can be instantaneously varied from 2km/s to 30km/s, simply by varying laser pulsewidth and focal spot size on target. The laser element will probably be a diode-pumped, fiber master-oscillator-power-amplifier (MOPA) system. Liquid fuels are necessary for volumetric efficiency and reliable performance at the multi-kW optical power levels required for multi-N thrust.

Phipps, Claude; Luke, James; Helgeson, Wesley

2007-04-01

92

Laser Propulsion Standardization Issues  

SciTech Connect

It is a relevant issue in the research on laser propulsion that experimental results are treated seriously and that meaningful scientific comparison is possible between groups using different equipment and measurement techniques. However, critical aspects of experimental measurements are sparsely addressed in the literature. In addition, few studies so far have the benefit of independent confirmation by other laser propulsion groups. In this paper, we recommend several approaches towards standardization of published laser propulsion experiments. Such standards are particularly important for the measurement of laser ablation pulse energy, laser spot area, imparted impulse or thrust, and mass removal during ablation. Related examples are presented from experiences of an actual scientific cooperation between NU and DLR. On the basis of a given standardization, researchers may better understand and contribute their findings more clearly in the future, and compare those findings confidently with those already published in the laser propulsion literature. Relevant ISO standards are analyzed, and revised formats are recommended for application to laser propulsion studies.

Scharring, Stefan; Eckel, Hans-Albert [Institute of Technical Physics, German Aerospace Center (DLR), D-70569 Stuttgart, Pfaffenwaldring 38-40 (Germany); Roeser, Hans-Peter [Institute of Space Systems, University of Stuttgart, D-70569 Stuttgart, Pfaffenwaldring 31 (Germany); Sinko, John E. [Micro-Nano Global Center of Excellence, Nagoya University (Niue), Nagoya, Aichi, 464-8603 (Japan); Sasoh, Akihiro [Department of Aerospace Engineering, Nagoya University, Nagoya, Aichi, 464-8603 (Japan)

2010-10-08

93

In-Space Propulsion Electric Propulsion Technologies Mission Benefits  

Microsoft Academic Search

The primary source of electric propulsion development within NASA is the In-Space Propulsion Technology (ISPT) Project at the NASA Glenn Research Center under the management of the Science Mission Directorate. The electric propulsion (EP) technology area's objective is to develop near and mid-term EP technology that enhances or enables mission capture while minimizing risk and cost to the end user.

John W. Dankanich

2008-01-01

94

Rotorcraft acoustic radiation prediction based on a refined blade-vortex interaction model  

NASA Astrophysics Data System (ADS)

The analysis of rotorcraft aerodynamics and acoustics is a challenging problem, primarily due to the fact that a rotorcraft continually flies through its own wake. The generation mechanism for a rotorcraft wake, which is dominated by strong, concentrated blade-tip trailing vortices, is similar to that in fixed wing aerodynamics. However, following blades encounter shed vortices from previous blades before they are swept downstream, resulting in sharp, impulsive loading on the blades. The blade/wake encounter, known as Blade-Vortex Interaction, or BVI, is responsible for a significant amount of vibratory loading and the characteristic rotorcraft acoustic signature in certain flight regimes. The present work addressed three different aspects of this interaction at a fundamental level. First, an analytical model for the prediction of trailing vortex structure is discussed. The model as presented is the culmination of a lengthy research effort to isolate the key physical mechanisms which govern vortex sheet rollup. Based on the Betz model, properties of the flow such as mass flux, axial momentum flux, and axial flux of angular momentum are conserved on either a differential or integral basis during the rollup process. The formation of a viscous central core was facilitated by the assumption of a turbulent mixing process with final vortex velocity profiles chosen to be consistent with a rotational flow mixing model and experimental observation. A general derivation of the method is outlined, followed by a comparison of model predictions with experimental vortex measurements, and finally a viscous blade drag model to account for additional effects of aerodynamic drag on vortex structure. The second phase of this program involved the development of a new formulation of lifting surface theory with the ultimate goal of an accurate, reduced order hybrid analytical/numerical model for fast rotorcraft load calculations. Currently, accurate rotorcraft airload analyses are limited by the massive computational power required to capture the small time scale events associated with BVI. This problem has two primary facets: accurate knowledge of the wake geometry, and accurate resolution of the impulsive loading imposed by a tip vortex on a blade. The present work addressed the second facet, providing a mathematical framework for solving the impulsive loading problem analytically, then asymptotically matching this solution to a low-resolution numerical calculation. A method was developed which uses continuous sheets of integrated boundary elements to model the lifting surface and wake. Special elements were developed to capture local behavior in high-gradient regions of the flow, thereby reducing the burden placed on the surrounding numerical method. Unsteady calculations for several classical cases were made in both frequency and time domain to demonstrate the performance of the method. Finally, a new unsteady, compressible boundary element method was applied to the problem of BVI acoustic radiation prediction. This numerical method, combined with the viscous core trailing vortex model, was used to duplicate the geometry and flight configuration of a detailed experimental BVI study carried out at NASA Ames Research Center. Blade surface pressure and near- and far-field acoustic radiation calculations were made. All calculations were shown to compare favorably with experimentally measured values. The linear boundary element method with non-linear corrections proved sufficient over most of the rotor azimuth, and particular in the region of the blade vortex interaction, suggesting that full non-linear CFD schemes are not necessary for rotorcraft noise prediction.

Rule, John Allen

1997-08-01

95

Electrolysis Propulsion for Spacecraft Applications.  

National Technical Information Service (NTIS)

Electrolysis propulsion has been recognized over the last several decades as a viable option to meet many satellite and spacecraft propulsion requirements. This technology, however, was never used for in-space missions. In the same time frame, water based...

W. A. deGroot L. A. Arrington J. F. McElroy F. Mitlitsky A. H. Weisberg P. H. Carter B. Myers B. D. Reed

1997-01-01

96

Main Propulsion Test Article (MPTA).  

National Technical Information Service (NTIS)

Scope: The Main Propulsion Test Article integrated the main propulsion subsystem with the clustered Space Shuttle Main Engines, the External Tank and associated GSE. The test program consisted of cryogenic tanking tests and short- and long duration static...

C. Snoddy

2010-01-01

97

Space flights with electric propulsion  

NASA Astrophysics Data System (ADS)

Electric propulsion systems are not always favoured because of their low-thrust performance. However they can significantly reduce the weight of the propulsion system and improve its effectiveness in comparison with conventional, i.e. chemical, propulsion systems. In the future electric propulsion will be widely used for spacecraft operations, both in near-earth and deep-space missions. The paper describes the global history of electric propulsion development. With respect to the way the working fluid is accelerated, electrothermal, electrostatic and electromagnetic propulsion are considered. Various types of space power plants, like chemical sources, solar arrays, radioisotope batteries and nuclear reactors are compared in regard with their application in different space missions. The paper presents some computations for flight trajectories of spacecraft with electric propulsion. A comparative analysis with identical missions carried out by conventional propulsion, is also included.

Simons, Wim J. F.; Simon, Kirill I.

98

Nuclear electric propulsion  

NASA Astrophysics Data System (ADS)

The feasibility is investigated of using nuclear electric propulsion (NEP) for slow freighter ships traveling from a 500 km low Earth orbit (LEO) to the Moon's orbit about the Earth, and on to Mars. NEP is also shown to be feasible for transporting people to Mars on long conjunction-class missions lasting about nine months one way, and on short sprint missions lasting four months one way. Generally, it was not attempted to optimize ion exhaust velocities, but rather suitable parameters to demonstrate NEP feasibility were chosen. Various combinations of missions are compared with chemical and nuclear thermal propulsion (NTR) systems. Typically, NEP and NTR can accomplish the same lifting task with similar mass in LEO. When compared to chemical propulsion, NEP was found to accomplish the same missions with 40% less mass in LEO. These findings are sufficiently encouraging as to merit further studies with optimum systems.

Keaton, Paul W.; Tubb, David J.

1986-05-01

99

Space flights with electric propulsion  

Microsoft Academic Search

Electric propulsion systems are not always favoured because of their low-thrust performance. However they can significantly reduce the weight of the propulsion system and improve its effectiveness in comparison with conventional, i.e. chemical, propulsion systems. In the future electric propulsion will be widely used for spacecraft operations, both in near-earth and deep-space missions. The paper describes the global history of

Wim J. F. Simons; Kirill I. Simon

1996-01-01

100

Heat transfer in aerospace propulsion  

Microsoft Academic Search

Presented is an overview of heat transfer related research in support of aerospace propulsion, particularly as seen from the perspective of the NASA Lewis Research Center. Aerospace propulsion is defined to cover the full spectrum from conventional aircraft power plants through the Aerospace Plane to space propulsion. The conventional subsonic\\/supersonic aircraft arena, whether commercial or military, relies on the turbine

Robert J. Simoneau; Robert C. Hendricks; Herbert J. Gladden

1988-01-01

101

BREAKTHROUGH PROPULSION PHYSICS RESEARCH PROGRAM  

Microsoft Academic Search

In 1996, a team of government, university and industry researchers proposed a program to seek the ultimate breakthroughs in space transportation: propulsion that requires no propellant mass, propulsion that can approach and, if possible, circumvent light speed, and breakthrough methods of energy production to power such devices. This Breakthrough Propulsion Physics program, managed by Lewis Research Center, is one part

Marc G. Millis

1996-01-01

102

Electric Propulsion Orbital Platform  

NASA Astrophysics Data System (ADS)

This paper describes the Electric Propulsion Orbital Platform (EPOP), of which the primary objective is to provide an instrumented platform for testing electric propulsion devices in space. It is anticipated that the first flight, EPOP-1, will take place on the Shuttle-deployed Wake Shield Facility in 1996, and will be designed around a commercial 1.8 kW arcjet system which will be operated on gaseous hydrogen propellant. Specific subsystems are described, including the arcjet system, the propellant and power systems, and the diagnostics systems.

Friedly, V. J.; Ruyten, Wilhelmus M.; Litchford, R. J.; Garrison, G. W.

1993-01-01

103

Research on oil-free air scroll compressor with high speed in 30 kW fuel cell  

Microsoft Academic Search

To supply the clean compressed air to a fuel cell system, an oil-free compressor is needed. The working process of the oil-free air scroll compressor and its cooling feature are discussed in this paper. A prototype, delivering 100 m3\\/h and having a speed of 5000 rpm, is researched. The water from the fuel cell system is used as the lubricant

Zhao Yuanyang; Li Liansheng; Shen Jiang; Zhang Wei; Shu Pengcheng

2003-01-01

104

Electric propulsion applications  

Microsoft Academic Search

The mission enhancing applications of electric propulsion in the integrated satellite system are presented. Applications considered are orbit transfer, on-orbit maneuvering, and effects on launch vehicle selection. Parametric orbit transfer performance is presented for solar powered arcject, ion, resistojet, and hybrid configured upper stages. Mission specific performance is compared for a DSP class spacecraft. Significant reductions in propellant requirements lead

Jeffrey W. Ramos; D. M. Sutton; M. G. McLain; K. P. Zondervan

1992-01-01

105

CFD for hypersonic propulsion  

Microsoft Academic Search

An overview is given of research activity on the application of computational fluid dynamics (CDF) for hypersonic propulsion systems. After the initial consideration of the highly integrated nature of air-breathing hypersonic engines and airframe, attention is directed toward computations carried out for the components of the engine. A generic inlet configuration is considered in order to demonstrate the highly three

Louis A. Povinelli

1990-01-01

106

Jet Propulsion Laboratory Homepage  

NSDL National Science Digital Library

The Jet Propulsion Laboratory's (JPL) homepage provides links to spacecraft and mission information, imagery, news articles, events, features, and public services. Users can access articles and imagery from the Mars Rover and Cassini missions, images from the Spitzer Space Telescope, and an El Nino/La Nina Watch.

107

Nuclear Merchant Ship Propulsion.  

National Technical Information Service (NTIS)

The operation of about 300 nuclear naval vessels has proven the feasibility of nuclear ship propulsion. Until now six non military ships have been built or are under construction. In the Soviet Union two nuclear icebreakers are in operation, and a third o...

E. Schroeder W. Jager H. G. Schafstall

1977-01-01

108

Personal Propulsion System.  

National Technical Information Service (NTIS)

The report describes a laboratory model of a simple manually controlled, tractor type, personnel propulsion unit for use under zero gravity conditions. The device consists of a pair of hand-mounted thrust nozzles with fore and aft thrust vector control. A...

G. E. Hanff R. H. Moulton R. E. Geller

1965-01-01

109

Turboprop Propulsion Mechanic.  

ERIC Educational Resources Information Center

|This instructional package consists of a plan of instruction, glossary, and student handouts and exercises for use in training Air Force personnel to become turboprop propulsion mechanics. Addressed in the individual lessons of the course are the following: common hand tools, hardware, measuring devices, and safety wiring; aircraft and engine…

Chanute AFB Technical Training Center, IL.

110

Hypersonic missile propulsion system  

Microsoft Academic Search

Pratt and Whitney is developing the technology for hypersonic components and engines. A supersonic combustion ramjet (scramjet) database was developed using hydrogen fueled propulsion systems for space access vehicles and serves as a point of departure for the current development of hydrocarbon scramjets. The Air Force Hypersonic Technology (HyTech) Program has put programs in place to develop the technologies necessary

Kazmar

1998-01-01

111

Advanced Chemical Propulsion  

NASA Astrophysics Data System (ADS)

Improving the performance and reliability characteristics of chemical propulsion systems requires research and testing of higher-performance propellants, higher efficiency thrusters, cryogenics technology, lightweight components and advancements in propulsion system design and assessment. Propellants are being investigated to identify practical combinations with higher efficiencies and better thermal properties to reduce thermal control requirements. This includes combinations with modest increases, such as LOX-hydrazine, as well as a new evaluation of major improvements available from fluorine-bearing oxidizers. Practical ways of implementing cryogenic propulsion to further increase efficiency are also being studied. Some potential advances include small pump-fed engines, and improvements in cryocooler technology and tank pressure control. Gelled propellants will be tested to determine the practicality of letting propellants freeze at low environmental temperatures and thawing them only when required for use. The propellant tank is typically the single highest non-expendable mass in a chemical propulsion system. Lightweight tank designs, materials and methods of fabrication are being investigated. These are projected to offer a 45-50 percent decrease in tank mass, representing the potential inert system mass savings. Mission and systems analyses are being conducted to guide the technology research and set priorities for technology investment, based on estimated gains in payload and mission capabilities. This includes development of advanced assessment tools and analyses of specific missions selected from Science Missions' Directorate. The goal is to mature a suite of reliable advanced propulsion technologies that will promote more cost efficient missions through the reduction of interplanetary trip time, increased scientific payload mass fraction and longer on-station operations. This talk will review the Advanced Chemical technology development roadmap, current funded technology development work, future funding opportunities and results from on-going mission studies.

Alexander, L.

2004-11-01

112

Interfacing comprehensive rotorcraft analysis with advanced aeromechanics and vortex wake models  

NASA Astrophysics Data System (ADS)

This dissertation describes three aspects of the comprehensive rotorcraft analysis. First, a physics-based methodology for the modeling of hydraulic devices within multibody-based comprehensive models of rotorcraft systems is developed. This newly proposed approach can predict the fully nonlinear behavior of hydraulic devices, and pressure levels in the hydraulic chambers are coupled with the dynamic response of the system. The proposed hydraulic device models are implemented in a multibody code and calibrated by comparing their predictions with test bench measurements for the UH-60 helicopter lead-lag damper. Predicted peak damping forces were found to be in good agreement with measurements, while the model did not predict the entire time history of damper force to the same level of accuracy. The proposed model evaluates relevant hydraulic quantities such as chamber pressures, orifice flow rates, and pressure relief valve displacements. This model could be used to design lead-lag dampers with desirable force and damping characteristics. The second part of this research is in the area of computational aeroelasticity, in which an interface between computational fluid dynamics (CFD) and computational structural dynamics (CSD) is established. This interface enables data exchange between CFD and CSD with the goal of achieving accurate airloads predictions. In this work, a loose coupling approach based on the delta-airloads method is developed in a finite-element method based multibody dynamics formulation, DYMORE. To validate this aerodynamic interface, a CFD code, OVERFLOW-2, is loosely coupled with a CSD program, DYMORE, to compute the airloads of different flight conditions for Sikorsky UH-60 aircraft. This loose coupling approach has good convergence characteristics. The predicted airloads are found to be in good agreement with the experimental data, although not for all flight conditions. In addition, the tight coupling interface between the CFD program, OVERFLOW-2, and the CSD program, DYMORE, is also established. The ability to accurately capture the wake structure around a helicopter rotor is crucial for rotorcraft performance analysis. In the third part of this thesis, a new representation of the wake vortex structure based on Non-Uniform Rational B-Spline (NURBS) curves and surfaces is proposed to develop an efficient model for prescribed and free wakes. NURBS curves and surfaces are able to represent complex shapes with remarkably little data. The proposed formulation has the potential to reduce the computational cost associated with the use of Helmholtz's law and the Biot-Savart law when calculating the induced flow field around the rotor. An efficient free-wake analysis will considerably decrease the computational cost of comprehensive rotorcraft analysis, making the approach more attractive to routine use in industrial settings.

Liu, Haiying

113

Semi-active magnetorheological seat suspensions for enhanced crashworthiness and vibration isolation of rotorcraft seats  

NASA Astrophysics Data System (ADS)

This research focuses on the use of magnetorheological (MR) dampers for enhanced occupant protection during harsh vertical landings as well as isolation of the occupant from cockpit vibrations. The capabilities of the current state-of-the-art in helicopter crew seat energy absorption systems are highly limited because they cannot be optimally adapted to each individual crash scenario (i.e. variations in both occupant weight and crash load level). They also present an unnecessarily high risk of injury by not minimizing the load transmitted to the occupant during a crash. Additionally, current rotorcraft seats provide no means of isolating the occupant from harmful cockpit vibrations. The objective of this research was to investigate and demonstrate the feasibility and benefits of an MR-based suspension for rotorcraft seats. As such, this research began with an in-depth investigation into design feasibility. Three MR seat suspension design cases are investigated: (1) for only vibration isolation, (2) for adaptive occupant protection, and (3) for combined adaptive occupant protection and vibration isolation. It is shown that MR-based suspensions are feasible for each of these cases and the performance benefits and tradeoffs are discussed for each case. Next, to further illustrate the occupant protection benefits gained with an MR-based suspension, three control strategies were developed and performance metrics were compared. It was shown that MR dampers can be controlled such that they will automatically adapt to the crash load level as well as occupant weight. By using feedback of sensor signals, MR dampers were adjusted to utilize the full stroke capability of the seat suspension regardless crash level and occupant weight. The peak load transmitted to the occupant and the risk of spinal injury, therefore, was always minimized. Because this control significantly reduced or eliminated injury risk during less severe landings, it is a significant advance over the current state-of-the-art rotorcraft seat suspensions which can provide no better than 20% risk of occupant injury. Finally, an MR-based seat suspension designed solely for the purposes of vibration isolation was designed, analyzed, and experimentally demonstrated. MR dampers were integrated into the current crashworthy SH-60 crew seat with minimal weight impact such that the original crashworthy capabilities were maintained. Then, utilizing semi-active control, experimental vibration testing demonstrated that the system reduced vertical cockpit vibrations transmitted to the occupant by 76%. This is a significant advance over current state-of-the-art rotorcraft seats which provide no attenuation of cockpit vibrations.

Hiemenz, Gregory J.

114

Micro electric propulsion feasibility  

NASA Astrophysics Data System (ADS)

Miniature, 50 kg class, strategic satellites intended for extended deployment in space require an on-board propulsion capability to perform needed attitude control adjustments and drag compensation maneuvers. Even on such very small spacecraft, these orbit maintenance functions can be significant and result in a substantial propellant mass requirement. Development of advanced propulsion technology could reduce this propellant mass significantly, and thereby maximize the payload capability of these spacecraft. In addition, spacecraft maneuverability could be enhanced and/or multi-year mission lifetimes realized. These benefits cut spacecraft replacement costs, and reduce services needed to maintain the launch vehicles. For SDIO brilliant pebble spacecraft, a miniaturized hydrazine propulsion system provides both boost and divert thrust control. This type of propulsion system is highly integrated and is capable of delivering large thrust levels for short time periods. However, orbit maintenance functions such as drag make-up require only very small velocity corrections. Using the boost and/or divert thrusters for these small corrections exposes this highly integrated propulsion system to continuous on/off cycling and thereby increases the risk of system failure. Furthermore, since drag compensation velocity corrections would be orders of magnitude less than these thrusters were designed to deliver, their effective specific impulse would be expected to be lower when operated at very short pulse lengths. The net result of these effects would be a significant depletion of the on-board hydrazine propellant supply throughout the mission, and a reduced propulsion system reliability, both of which would degrade the interceptors usefulness. In addition to SDIO brilliant pebble spacecraft, comparably small spacecraft can be anticipated for other future strategic defense applications such as surveillance and communication. For such spacecraft, high capability and reliability, minimal detectability and low cost are requirements. All these miniature spacecraft share a common characteristic: because of their on-board electronic equipment they have, by design, solar order 50-100 W. In a relative sense, such spacecraft are power rich when compared to other larger spacecraft. This power rich situation is offset by very tight mass budgets, which make reductions in propellant mass requirements a key issue in meeting overall spacecraft minimum mass goals. In principle, power rich and propellant poor brilliant pebbles class spacecraft can benefit from using high specific impulse electric propulsion to reduce chemical propellant mass requirements. However, at power levels of order 50 W, arcjets cannot be made to function, ion thrusters are too complex and heavy and resistojets have too low a specific impulse. Recognizing these capability limitations in existing electric propulsion technology, the SDIO/IST sponsored the Phase I SBIR Micro Electric Propulsion (MEP) thruster study described in this report.

Aston, Graeme; Aston, Martha

1992-11-01

115

Plasmas for space propulsion  

NASA Astrophysics Data System (ADS)

Plasma thrusters are challenging the monopoly of chemical thrusters in space propulsion. The specific energy that can be deposited into a plasma beam is orders of magnitude larger than the specific chemical energy of known fuels. Plasma thrusters constitute a vast family of devices ranging from already commercial thrusters to incipient laboratory prototypes. Figures of merit in plasma propulsion are discussed. Plasma processes and conditions differ widely from one thruster to another, with the pre-eminence of magnetized, weakly collisional plasmas. Energy is imparted to the plasma via either energetic electron injection, biased electrodes or electromagnetic irradiation. Plasma acceleration can be electrothermal, electrostatic or electromagnetic. Plasma-wall interaction affects energy deposition and erosion of thruster elements, and thus is central for thruster efficiency and lifetime. Magnetic confinement and magnetic nozzles are present in several devices. Oscillations and turbulent transport are intrinsic to the performances of some thrusters. Several thrusters are selected in order to discuss these relevant plasma phenomena.

Ahedo, Eduardo

2011-12-01

116

CFD for hypersonic propulsion  

NASA Astrophysics Data System (ADS)

An overview is given of research activity on the application of computational fluid dynamics (CDF) for hypersonic propulsion systems. After the initial consideration of the highly integrated nature of air-breathing hypersonic engines and airframe, attention is directed toward computations carried out for the components of the engine. A generic inlet configuration is considered in order to demonstrate the highly three dimensional viscous flow behavior occurring within rectangular inlets. Reacting flow computations for simple jet injection as well as for more complex combustion chambers are then discussed in order to show the capability of viscous finite rate chemical reaction computer simulations. Finally, the nozzle flow fields are demonstrated, showing the existence of complex shear layers and shock structure in the exhaust plume. The general issues associated with code validation as well as the specific issue associated with the use of CFD for design are discussed. A prognosis for the success of CFD in the design of future propulsion systems is offered.

Povinelli, Louis A.

117

Electromagnetic propulsion for spacecraft  

NASA Astrophysics Data System (ADS)

Three electromagnetic propulsion technologies, solid propellant pulsed plasma thrusters (PPT), magnetoplasmadynamic (MPD) thrusters, and pulsed inductive thrusters (PIT) have been developed for application to auxiliary and primary spacecraft propulsion. Both the PPT and MPD thrusters have been flown in space, though only PPTs have been used on operational satellites. The performance of operational PPTs is quite poor, providing only about 8 percent efficiency at about 1000 sec specific impulse. Laboratory PPTs yielding 34 percent efficiency at 5170 sec specific impulse have been demonstrated. Laboratory MPD thrusters have been demonstrated with up to 70 percent efficiency and 7000 sec specific impulse. Recent PIT performance measurements using ammonia and hydrazine propellants are extremely encouraging, reaching 50 percent efficiency for specific impulses between 4000 and 8000 sec.

Myers, Roger M.

1993-02-01

118

Digital MicroPropulsion  

Microsoft Academic Search

Arrays of “Digital Propulsion” micro-thrusters have been fabricated and tested. A three-layer sandwich is fabricated containing micro-resistors, thrust chambers, and rupture diaphragms. A propellant is loaded into the chambers, which are then sealed. When the resistor is heated sufficiently, the propellant ignites raising the pressure in the chamber and rupturing the diaphragm. An impulse is imparted as the high-pressure fluid

S. W. Janson; R. B. Cohen; E. K. Antonsson

1999-01-01

119

Electric propulsion: An evolutionary technology  

NASA Astrophysics Data System (ADS)

The NASA Lewis Research Center (LeRC) conducts and directs an electric propulsion research and technology program aimed at providing high-performance electric propulsion system options for a broad range of near and far-term missions. This evolutionary program emphasizes the development of propulsion systems for three classes of missions: (1) near term auxiliary propulsion applications such as North-South Stationkeeping for next generation communications satellites and orbit maintainence for orbiting platforms such as Space Station Freedom; (2) advanced solar electric propulsion and SP-100-class nuclear electric propulsion for Earth-space orbit transfer and robotic planetary missions; and (3) very high power systems to support major space missions including the Space Exploration Initiative. To cover widely disparate mission requirements, the LeRC program includes research on electrothermal, electrostatic, and electromagnetic systems. This paper provides an overview of the LeRC program with a focus on recent progress.

Curran, Francis M.; Sovey, James S.; Myers, Roger M.

120

Two-Dimensional Aerodynamic Characteristics of Several Rotorcraft Airfoils at Mach Numbers from 0.35 to 0.90.  

National Technical Information Service (NTIS)

An investigation was conducted in the Langley 6- by 28-inch transonic tunnel and the 6- by 19-inch transonic tunnel to determine the two-dimensional aerodynamic characteristics of several rotorcraft airfoils at Mach numbers from 0.35 to 0.90. The airfoils...

K. W. Noonan G. J. Bingham

1977-01-01

121

A new marine propulsion system  

NASA Astrophysics Data System (ADS)

A new marine propulsion system is proposed. A small liquid sodium cooled reactor acts as prime mover; alkali-metal thermal-to-electric conversion (AMTEC) cells are employed to convert the heat energy to electricity; superconducting magneto-hydrodynamic thruster combined with spray-water thruster works as propulsion. The configuration and characteristics of this system are described. Such a nuclear-powered propulsion system is not only free of noise, but also has high reliability and efficiency. It would be a preferable propulsion system for ships in the future.

Han, Wei-Shi; Liu, Tao

2003-06-01

122

Hybrid Propulsion Systems for Space Exploration Missions.  

National Technical Information Service (NTIS)

Combinations of nuclear thermal propulsion (NTP), nuclear electric propulsion (NEP), and chemical propulsion are discussed. Technical details are given in viewgraph form. The characteristics of each configuration are discussed, particularly thrust charact...

D. K. Darooka

1991-01-01

123

46 CFR 130.120 - Propulsion control.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 2009-10-01 false Propulsion control. 130.120 Section 130...SYSTEMS Vessel Control § 130.120 Propulsion control. (a) Each vessel must haveâ (1) A propulsion-control system operable from the...

2009-10-01

124

46 CFR 130.120 - Propulsion control.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Propulsion control. 130.120 Section 130...SYSTEMS Vessel Control § 130.120 Propulsion control. (a) Each vessel must haveâ (1) A propulsion-control system operable from the...

2010-10-01

125

Liquid rocket propulsion. Theory  

NASA Astrophysics Data System (ADS)

The purpose is to introduce the fundamentals and the basic technology of liquid propellant rockets. Much of the material is derived from other courses on propulsion. The first lecture covers the foundations at the broad brush level. Starting from the functional requirements placed on the device, various types of rocket are examined. The missions for which liquid propellant rockets are the better choice are identified. An ideal gas examination of the essential performance parameters and their variation with basic controllable inputs is presented. The thermodynamics and the fluid mechanics of the reacting flows occurring in rocket combustors and nozzles are considered. The effects of propellant choices and the +/- 5 performance estimates are included.

Martinez-Sanchez, M.

126

Nuclear propulsion systems engineering  

SciTech Connect

The Nuclear Energy for Rocket Vehicle Application (NERVA) program of the 1960`s and early 1970`s was dramatically successful, with no major failures during the entire testing program. This success was due in large part to the successful development of a systems engineering process. Systems engineering, properly implemented, involves all aspects of the system design and operation, and leads to optimization of theentire system: cost, schedule, performance, safety, reliability, function, requirements, etc. The process must be incorporated from the very first and continued to project completion. This paper will discuss major aspects of the NERVA systems engineering effort, and consider the implications for current nuclear propulsion efforts.

Madsen, W.W.; Neuman, J.E.: Van Haaften, D.H.

1992-12-31

127

Nuclear propulsion systems engineering  

SciTech Connect

The Nuclear Energy for Rocket Vehicle Application (NERVA) program of the 1960's and early 1970's was dramatically successful, with no major failures during the entire testing program. This success was due in large part to the successful development of a systems engineering process. Systems engineering, properly implemented, involves all aspects of the system design and operation, and leads to optimization of theentire system: cost, schedule, performance, safety, reliability, function, requirements, etc. The process must be incorporated from the very first and continued to project completion. This paper will discuss major aspects of the NERVA systems engineering effort, and consider the implications for current nuclear propulsion efforts.

Madsen, W.W.; Neuman, J.E.: Van Haaften, D.H.

1992-01-01

128

Induction-drive magnetohydrodynamic propulsion  

SciTech Connect

The use of magnetohydrodynamic propulsion for marine applications is reviewed with emphasis on induction-drive systems such as the [open quotes]ripple[close quotes] motor. Comparisons are made with direct-drive MHD propulsion systems. Application to pumps for hazardous fluids and liquid-metal coolants is also discussed. 13 refs., 8 figs., 2 tabs.

Mitchell, D.L. (Mitchell Associates, Reston, VA (United States)); Gubser, D.U. (Naval Research Lab., Washington, DC (United States))

1993-08-01

129

Breakthrough Propulsion Physics Research Consortium  

Microsoft Academic Search

To assess the prospects for discovering spaceflight breakthroughs from emerging physics - the kind of breakthroughs that might one-day enable interstellar travel - NASA established the Breakthrough Propulsion Physics (BPP) Project in 1996. As the catalyst to steer scientific advances in the direction of this ambition, the Project uses the following three grand challenges: (1) Discover propulsion methods that do

Marc Millis

2003-01-01

130

Water Electrolysis Propulsion System Testing.  

National Technical Information Service (NTIS)

A twenty-four month program was conducted to demonstrate the life capability of a water electrolysis propulsion system and to develop flightweight 5-lbf and 0.1-lbf GO2/GH2 thrusters. A water electrolysis propulsion system was tested for 33 weeks at an ac...

J. G. Campbell R. C. Stechman

1974-01-01

131

Magnetohydrodynamic Propulsion for the Classroom  

Microsoft Academic Search

The cinema industry can sometimes prove to be an ally when searching for material with which to motivate students to learn physics. Consider, for example, the electromagnetic force on a current in the presence of a magnetic field. This phenomenon is at the heart of magnetohydrodynamic (MHD) propulsion systems. A submarine employing this type of propulsion was immortalized in the

Scott C. Dudley

2004-01-01

132

Advanced technologies for nuclear propulsion  

Microsoft Academic Search

The Mission Requirements and Resources Allocation Model is presently used to examine nuclear propulsion alternatives on the basis of projected performance levels. All calculations are based on a complete vehicle design, including habitat subsystem masses, external services, propulsion system component performance, power subsystems, tankage factors, and the allocations for both propellant boiloff volumes and the accumulation of unusable residuals. Attention

Benton Clark; Scott Geels; Brian Sutter; Rohan Zaveri; Robert Zubrin

1992-01-01

133

Advanced Space Fission Propulsion Systems.  

National Technical Information Service (NTIS)

Fission has been considered for in-space propulsion since the 1940s. Nuclear Thermal Propulsion (NTP) systems underwent extensive development from 1955-1973, completing 20 full power ground tests and achieving specific impulses nearly twice that of the be...

M. G. Houts S. K. Borowski

2010-01-01

134

Analyses Of Underwater Magnetohydrodynamic Propulsion  

Microsoft Academic Search

Sea water magnetohydrodynamic (MHD) propulsion for marine vehicles offers many unique features. There is no need for propellers, and therefore no noise associated that. Gear reduction system for the shafts is thus no longer needed. It offers maneuverbility by directional thrusts along with quietness. The theories of MHD pump jet propulsion are discussed in detail in this paper. A so-called

J. B. Gilbertt; T. F. Lint

1990-01-01

135

Restartable nuclear thermal propulsion considerations  

Microsoft Academic Search

Nuclear thermal propulsion (NTP) offers significant improvements in rocket engine specific impulse and, therefore, reduction in vehicle gross weight and\\/or mission duration compared to vehicles employing chemical propulsion. Restarting NTP systems, however, for use in multiple maneuvers, requires tht decay power be removed from the NTP to preserve it for reuse. Open and closed-cycle methods of decay power removal are

Charlton Dunn

1992-01-01

136

PROPULSION SYSTEMS FOR HYPERSONIC FLIGHT  

Microsoft Academic Search

During last twenty years, a large effort has been undertaken in Europe, and particularly in France, to improve knowledge on hypersonic airbreathing propulsion, to acquire a first know-how for components design and to develop needed technologies. On this scientific and technology basis, two families of possible application can be imagined for high- speed airbreathing propulsion : reusable space launcher and

François Falempin

137

Laser Propulsion-Quo Vadis  

NASA Astrophysics Data System (ADS)

First, an introductory overview of the different types of laser propulsion techniques will be given and illustrated by some historical examples. Second, laser devices available for basic experiments will be reviewed ranging from low power lasers sources to inertial confinement laser facilities. Subsequently, a status of work will show the impasse in which the laser propulsion community is currently engaged. Revisiting the basic relations leads to new avenues in ablative and direct laser propulsion for ground based and space based applications. Hereby, special attention will be devoted to the impact of emerging ultra-short pulse lasers on the coupling coefficient and specific impulse. In particular, laser sources and laser propulsion techniques will be tested in microgravity environment. A novel approach to debris removal will be discussed with respect to the Satellite Laser Ranging (SRL) facilities. Finally, some non technical issues will be raised aimed at the future prospects of laser propulsion in the international community.

Bohn, Willy L.

2008-04-01

138

Jet propulsion without inertia  

NASA Astrophysics Data System (ADS)

A body immersed in a highly viscous fluid can locomote by drawing in and expelling fluid through pores at its surface. We consider this mechanism of jet propulsion without inertia in the case of spheroidal bodies and derive both the swimming velocity and the hydrodynamic efficiency. Elementary examples are presented and exact axisymmetric solutions for spherical, prolate spheroidal, and oblate spheroidal body shapes are provided. In each case, entirely and partially porous (i.e., jetting) surfaces are considered and the optimal jetting flow profiles at the surface for maximizing the hydrodynamic efficiency are determined computationally. The maximal efficiency which may be achieved by a sphere using such jet propulsion is 12.5%, a significant improvement upon traditional flagella-based means of locomotion at zero Reynolds number, which corresponds to the potential flow created by a source dipole at the sphere center. Unlike other swimming mechanisms which rely on the presentation of a small cross section in the direction of motion, the efficiency of a jetting body at low Reynolds number increases as the body becomes more oblate and limits to approximately 162% in the case of a flat plate swimming along its axis of symmetry. Our results are discussed in the light of slime extrusion mechanisms occurring in many cyanobacteria.

Spagnolie, Saverio E.; Lauga, Eric

2010-08-01

139

Electromagnetic propulsion for spacecraft  

NASA Astrophysics Data System (ADS)

Three electromagnetic propulsion technologies, solid propellant pulsed plasma thrusters (PPT), magnetoplasmadynamic (MPD) thrusters, and pulsed inductive thrusters (PIT), were developed for application to auxiliary and primary spacecraft propulsion. Both the PPT and MPD thrusters were flown in space, though only PPT's were used on operational satellites. The performance of operational PPT's is quite poor, providing only approximately 8 percent efficiency at approximately 1000 s specific impulse. However, laboratory PPT's yielding 34 percent efficiency at 2000 s specific impulse were extensively tested, and peak performance levels of 53 percent efficiency at 5170 s specific impulse were demonstrated. MPD thrusters were flown as experiments on the Japanese MS-T4 spacecraft and the Space Shuttle and were qualified for a flight in 1994. The flight MPD thrusters were pulsed, with a peak performance of 22 percent efficiency at 2500 s specific impulse using ammonia propellant. Laboratory MPD thrusters were demonstrated with up to 70 percent efficiency and 700 s specific impulse using lithium propellant. While the PIT thruster has never been flown, recent performance measurements using ammonia and hydrazine propellants are extremely encouraging, reaching 50 percent efficiency for specific impulses between 4000 to 8000 s. The fundamental operating principles, performance measurements, and system level design for the three types of electromagnetic thrusters are reviewed, and available data on flight tests are discussed for the PPT and MPD thrusters.

Myers, Roger M.

1993-09-01

140

Ship propulsion system  

SciTech Connect

This patent describes an improved efficiency propulsion system for a ship operated at both deep and shallow water depths, and at variable loaded and ballast waterlines. This propulsion system consists of a number of elements interactive in their operation. The first component of the system detailed is a variable diameter propeller means equipped with a mechanism for varying the diameter of the propeller between a maximum extended diameter and a minimum diameter. The next component of the system depicted in the patent is a propeller shaft mounting which enables the propeller to rotate in the stern portion of the ship. The propeller shaft is characterized as extending parallel to the bottom keel of the ship and having an axis of rotation displaced from the bottom keel a distance less than one-half the maximum diameter of the propeller means but more than one-half of the minimum diameter of the propeller means. As a consequence of the systems design characteristics the ship may obtain maximum propeller efficiency by means of the extension in diameter of the propeller means when it is operated in a fully loaded condition in deep water.

Kimon, P.M.

1986-01-21

141

Advanced transportation system studies. Alternate propulsion subsystem concepts: Propulsion database  

NASA Astrophysics Data System (ADS)

The Advanced Transportation System Studies alternate propulsion subsystem concepts propulsion database interim report is presented. The objective of the database development task is to produce a propulsion database which is easy to use and modify while also being comprehensive in the level of detail available. The database is to be available on the Macintosh computer system. The task is to extend across all three years of the contract. Consequently, a significant fraction of the effort in this first year of the task was devoted to the development of the database structure to ensure a robust base for the following years' efforts. Nonetheless, significant point design propulsion system descriptions and parametric models were also produced. Each of the two propulsion databases, parametric propulsion database and propulsion system database, are described. The descriptions include a user's guide to each code, write-ups for models used, and sample output. The parametric database has models for LOX/H2 and LOX/RP liquid engines, solid rocket boosters using three different propellants, a hybrid rocket booster, and a NERVA derived nuclear thermal rocket engine.

Levack, Daniel

1993-04-01

142

Technique for providing a signal for controlling blade vortex interaction noise of a rotorcraft  

US Patent & Trademark Office Database

A technique for providing a signal representative of blade vortex interaction (BVI) noise for a multi-blade rotorcraft. The fluid (air) pressure at one, two, or more predetermined locations on a rotor blade is measured during at least one predetermined azimuthal segment of blade rotation during operation to provide respective pressure measurements. The pressure measurements are processed to provide a signal for use as a control variable in a control system for the active control of BVI noise. The pressure measurements are made within 10% blade chord length of the blade leading edge and preferably two or more are made between 65% and 95% of blade radial-length. The pressure measurements are filtered and the band of retained frequencies is between 20 and 48 times the rotor rotation frequency. An algorithm operative over a determined blade frequency range optimizes the signal for control use.

Lorber; Peter F. (Coventry, CT)

2001-01-09

143

Nuclear thermal propulsion engine cost trade studies  

Microsoft Academic Search

The NASA transportation strategy for the Mars Exploration architecture includes the use of nuclear thermal propulsion as the primary propulsion system for Mars transits. It is anticipated that the outgrowth of the NERVA\\/ROVER programs will be a nuclear thermal propulsion (NTP) system capable of providing the propulsion for missions to Mars. The specific impulse (Isp) for such a system is

Robert K. Paschall; Rocketdyne Division

1993-01-01

144

Electric propulsion and interstellar flight  

SciTech Connect

Two general classes of interstellar space-flights are defined: endothermic and exothermic. Endothermic methods utilize power sources external to the vehicle and associated technology. Faster exothermic methods utilize on-board propulsive power sources or energy-beam technology. Various proposed endothermic electric propulsion methods are described. These include solar electric rockets, mass drivers, and ramjets. A review of previously suggested exothermic electric propulsion methods is presented. Following this review is a detailed discussion of possible near future application of the beamed-laser ramjet, mainly for ultimate relativistic travel. Electric/magnetic techniques offer an excellent possibility for decelerating an interstellar vehicle, regardless of the acceleration technique. 20 references.

Matloff, G.L.

1987-01-01

145

Nuclear propulsion project workshop summary  

NASA Astrophysics Data System (ADS)

A joint DOE/DOD/NASA Nuclear Propulsion Project is being planned and implemented under the leadership of the NASA Lewis Research Center. The plan includes both Nuclear Electric Propulsion and Nuclear Thermal Propulsion. Two major national workshops were held in the summer of 1990 to provide a data base for and identify technology needs for a wide range of NTP and NEP concepts. A Joint DOE/DOD/NASA steering committee has reviewed the results and recommendations from the workshops and identified the high priority issues for near-term implementation. Efforts will be initiated on these issues in FY91 by an interdepartmental/agency team based on available resources.

Miller, Thomas J.; Clark, John S.; Barnett, John W., Dr.

1991-01-01

146

Pulsed hydrojet propulsion  

SciTech Connect

The pulsed hydrojet is a device in which the water ingested from the free stream is accelerated out of the exhaust pipe to produce thrust. In this report we describe and analyze a way of accelerating the stream of water with pockets of high pressure steam and gas generated inside the stream by an exothermal reaction of suitable propellant injected and dispersed in the water. The velocity increment that must be imparted to the water to produce a substantial thrust need not be very large because the density of the water is comparable to the average density of the accelerated body. Results of the numerical modeling of the proposed jet acceleration mechanism indicate that the hydrojet propulsion device is potentially capable of propelling underwater projectiles at speeds three to five times greater than those currently attainable. Several promising applications of the hydrojet thruster are discussed and evaluated.

Bohachevsky, I.O.; Torrey, M.D.

1985-01-01

147

Permanent magnet propulsion system  

US Patent & Trademark Office Database

A permanent magnet propulsion system wherein a steel ball is propelled up an inclined plane between two rows of permanent bar magnets, said magnets being in spaced relationship with all north seeking poles of one of the said rows facing in substantially the same direction and with all south seeking poles in the other row facing in substantially the same but opposite direction to the first of said rows. The magnetic axes of each of the magnets of the first said row are in staggered relationship to the axes of opposing magnets of the second said row. The magnetic field acting on the ball is configured whereby the ball after reaching the top of the inclined plane is able to drop from the said plane out of the field. A pair of parallel tracks positioned between the spaced rows of magnets guide the ball and a clamping means orient and retain the magnets.

1980-07-29

148

Propulsion system assembly  

SciTech Connect

A propulsion system assembly for a vehicle is described having an engine and a nacelle disposed about the engine which has an exterior which comprises: a shroud disposed circumferentially about the nacelle which is spaced radially from the nacelle leaving an opening there between for cooling air from the exterior of the nacelle; structure which extends radially upstream of the opening to block flow from entering the opening, the structure extending between the shroud and nacelle and having at least one under cut portion forming a passage which diverges in the axial direction and which begins upstream of the opening and is bounded by an axially extending wall on the structure; wherein the passage provides a flow path to duct air from the exterior of the nacelle to a location downstream of the blocked portion of the opening on the interior of the shroud.

Zysmaan, S.H.

1993-06-08

149

Electric propulsion system technology  

NASA Astrophysics Data System (ADS)

The work performed in fiscal year (FY) 1991 under the Propulsion Technology Program RTOP (Research and Technology Objectives and Plans) No. (55) 506-42-31 for Low-Thrust Primary and Auxiliary Propulsion technology development is described. The objectives of this work fall under two broad categories. The first of these deals with the development of ion engines for primary propulsion in support of solar system exploration. The second with the advancement of steady-state magnetoplasmadynamic (MPD) thruster technology at 100 kW to multimegawatt input power levels. The major technology issues for ion propulsion are demonstration of adequate engine life at the 5 to 10 kW power level and scaling ion engines to power levels of tens to hundreds of kilowatts. Tests of a new technique in which the decelerator grid of a three-grid ion accelerator system is biased negative of neutralizer common potential in order to collect facility induced charge-exchange ions are described. These tests indicate that this SAND (Screen, Accelerator, Negative Decelerator) configuration may enable long duration ion engine endurance tests to be performed at vacuum chamber pressures an order of magnitude higher than previously possible. The corresponding reduction in pumping speed requirements enables endurance tests of 10 kW class ion engines to be performed within the resources of existing technology programs. The results of a successful 5,000-hr endurance of a xenon hollow cathode operating at an emission current of 25 A are described, as well as the initial tests of hollow cathodes operating on a mixture of argon and 3 percent nitrogen. Work performed on the development of carbon/carbon grids, a multi-orifice hollow cathode, and discharge chamber erosion reduction through the addition of nitrogen are also described. Critical applied-field MPD thruster technical issues remain to be resolved, including demonstration of reliable steady-state operation at input powers of hundreds to thousands of kilowatts, achievement of thruster efficiency and specific impulse levels required for missions of interest, and demonstration of adequate engine life at these input power, efficiency, and specific impulse levels. To address these issues we have designed, built, and tested a 100 kW class, radiation-cooled applied-field MPD thruster and a unique dual-beam thrust stand that enables separate measurements of the applied- and self-field thrust components. We have also initiated the development of cathode thermal and plasma sheath models that will eventually be used to guide the experimental program. In conjunction with the cathode modeling, a new cathode test facility is being constructed. This facility will support the study of cathode thermal behavior and erosion mechanisms, the diagnosis of the near-cathode plasma and the development and endurance testing of new, high-current cathode designs. To facilitate understanding of electrode surface phenomenon, we have implemented a telephoto technique to obtain photographs of the electrodes during engine operation. In order to reduce the background vacuum tank pressure during steady-state engine operation in order to obtain high fidelity anode thermal data, we have developed and are evaluating a gas-dynamic diffuser. A review of experience with alkali metal propellants for MPD thrusters led to the conclusion that alkali metals, particularly lithium, offer the potential for significant engine performance and lifetime improvements.

Brophy, John R.; Garner, Charles E.; Goodfellow, Keith D.; Pivirotto, Thomas J.; Polk, James E.

1992-11-01

150

Physics of magnetic propulsion  

NASA Astrophysics Data System (ADS)

The flight of a magnetic vehicle is expected at the expense of the electrodynamic lift and thrust force of interaction with the natural magnetic field and with the eddy currents in ground or water at low altitudes. It would present in future an alternative to rocketry and aviation owing to the expected better efficiency, constant mass and pure ecology. The principles of the magnetic propulsion (Prog Aerospace Sci 2001;37:245 61) allow to substantiate the proposed application and variant of design of the magnetic flight vehicle, to clarify its advantageous properties and to determine the main problems to be solved for its creation. The reviewed questions of its theory show a number of its important advantages. One of them is the possible performance of aerospace and interplanetary flights by the same unit. The proposed calculation basis for the numerical estimations and corresponding numerical examples would allow to image this vehicle structural features and to compare variants.

Pulatov, V.

2005-01-01

151

A History of Full-Scale Aircraft and Rotorcraft Crash Testing and Simulation at NASA Langley Research Center  

Microsoft Academic Search

This paper summarizes 2-1\\/2 decades of full-scale aircraft and rotorcraft crash testing performed at the Impact Dynamics Research Facility (IDRF) located at NASA Langley Research Center in Hampton, Virginia. The IDRF is a 240-ft.-high steel gantry that was built originally as a lunar landing simulator facility in the early 1960's. It was converted into a full-scale crash test facility for

Karen E. Jackson; Richard L. Boitnott; Edwin L. Fasanella; Lisa E. Jones; Karen H. Lyle

152

Laser Space Propulsion Overview (Postprint).  

National Technical Information Service (NTIS)

In this paper, we review the history of laser space propulsion from its earliest theoretical conceptions to modern practical applications. Applications begin with the 'Lightcraft' flights of Myrabo and include practical thrusters for satellites now comple...

C. Phipps J. Luke W. Helgeson

2006-01-01

153

Laser Space Propulsion Overview (Preprint).  

National Technical Information Service (NTIS)

In this paper, we review the history of laser space propulsion from its earliest theoretical conceptions to modern practical applications. Applications begin with the 'Lightcraft' flights of Myrabo and include practical thrusters for satellites now comple...

C. Phipps J. Luke W. Helgeson

2006-01-01

154

Competitive Marine Propulsion Systems Analysis.  

National Technical Information Service (NTIS)

The systems analysis project reported herein is a part of the Maritime Administration's overall program to bring about the development of marine propulsion systems offering superior economic advantage relative to state-of-the-art systems. This Supplementa...

1973-01-01

155

Overview of the small engine component technology (SECT) studies. [Commuter, rotorcraft, cruise missile and auxiliary power applications in year 2000  

SciTech Connect

The objectives of the joint NASA/Army SECT studies were to identify high payoff technologies for year 2000 small gas turbine engine applications and to provide a technology plan for guiding future research and technology efforts applicable to rotorcraft, commuter and general aviation aircraft and cruise missiles. Competitive contracts were awarded to Allison, AVCO Lycoming, Garrett, Teledyne CAE and Williams International. This paper presents an overview of the contractors' study efforts for the commuter, rotorcraft, cruise missile, and auxiliary power (APU) applications with engines in the 250 to 1000 horsepower size range. Reference aircraft, missions and engines were selected. Advanced engine configurations and cycles with projected year 2000 component technologies were evaluated and compared with a reference engine selected by the contractor. For typical commuter and rotorcraft applications, fuel savings of 22 percent to 42 percent can be attained. For $1/gallon and $2/gallon fuel, reductions in direct operating cost range from 6 percent to 16 percent and from 11 percent to 17 percent respectively. For subsonic strategic cruise missile applications, fuel savings of 38 percent to 54 percent can be achieved which allows 35 percent to 60 percent increase in mission range and life cycle cost reductions of 40 percent to 56 percent. High payoff technologies have been identified for all applications. 5 references.

Vanco, M.R.; Wintucky, W.T.; Niedwiecki, R.W.

1986-01-01

156

Oil-free generation of small polymeric particles using a coaxial microfluidic channel.  

PubMed

In this study, a microfluidic method to generate small polymeric particles ( approximately 10 mum in diameter) via the control of interfacial tension without using oil and in situ photopolymerization immediately after drop generation was introduced. For the reduction in size, the selection of proper sample and sheath liquid to minimize the interfacial tension is extremely important, and 4-HBA (4-hydroxybutyl acrylate) and PVA (poly(vinyl acrylate)) were employed as core and sheath fluid pair because of much smaller surface tension than the case using oil. In addition, PVA is easily washable by aqueous solution, which is a strong advantage when the particle is applied in biomedical fields. The viscosity effect of sheath flow was also examined for further size reduction. The loading and release properties of proteins were evaluated using fluorescently labeled bovine serum albumin for the potential application as drug carrier. The protein was uniformly loaded into particles, and the protein release rate was dependent on the particle size. For utility in the biomedical area, the cyto-compatibility test of 4-HBA was performed by culturing glioma cells on the 4-HBA sheet, and the cells were alive well after 4 days culture. Conclusively, this oil-free particle generation methods facilitates the generation of uniform and small particles in a simple way without an oil-washing process. PMID:19821631

Shin, SuJung; Hong, Joung Sook; Lee, Kwang-Ho; Lee, Sang-Hoon

2009-10-20

157

Emerging Propulsion Technologies  

NASA Astrophysics Data System (ADS)

The Emerging Propulsion Technologies (EPT) technology area is a branch of the In-Space Program that serves as a bridge to bring high-risk/high-payoff technologies to a higher level of maturity. Emerging technologies are innovative and, if successfully developed, could result in revolutionary science capabilities for NASA science missions. EPT is also charged with the responsibility of assessing the technology readiness level (TRL) of technologies under consideration for inclusion in the ISP portfolio. One such technology is the Momentum-eXchange/Electrodynamic Reboost (MXER) tether concept, which is the current, primary investment of EPT. The MXER tether is a long, rotating cable placed in an elliptical Earth orbit, whose rapid rotation allows its tip to catch a payload in a low Earth orbit and throw that payload to a high-energy orbit. Electrodynamic tether propulsion is used to restore the orbital energy transferred by the MXER tether to the payload and reboost the tether's orbit. This technique uses solar power to drive electrical current collected from the Earth's ionosphere through the tether, resulting in a magnetic interaction with the terrestrial field. Since the Earth itself serves as the reaction mass, the thrust force is generated without propellant and allows the MXER facility to be repeatedly reused without re-supply. Essentially, the MXER facility is a 'propellantless' upper stage that could assist nearly every mission going beyond low Earth orbit. Payloads to interplanetary destinations could especially benefit from the boost provided by the MXER facility, resulting in launch vehicle cost reductions, increased payload fractions and more frequent mission opportunities. Synergistic tether technologies resulting from MXER development could include science sampling in the upper atmosphere, remote probes or attached formation flying, artificial gravity experiments with low Coriolis forces, and other science needs that use long, ultra-light strength or conducting cables in space. Tether development additionally embraces the science investigation of ionospheric physics, micrometeorite and space particulates in LEO and precise earth environment knowledge of gravity fields, solar flux, .thermal environments and magnetic fields.

Bonometti, J. A.

2004-11-01

158

Advanced rotorcraft helmet-mounted display sighting system (HMDSS) optical distortion correction methodology  

NASA Astrophysics Data System (ADS)

Helmet Mounted Displays (HMDs) typically utilize off axis optical systems that result in distorted images. In order to minimize the weight on the pilot's head, a pixilated display, such as an Active Matrix liquid Crystal Display (AMLCD), is utilized as the imaging source. Pixelated displays based on AMLCDs cannot correct distortions or perform spatial transformations as easily as an analog CRT-based systems using electron beam deflection. An advanced rotorcraft HMDSS is a digital system where correcting the distortion within the digital domain is desired to eliminate the inaccuracies of converting to analog, correcting the distortion and converting back to digital. Other system requirements necessitate that the input video be rescaled to provide the proper image to the optical system in order to have the FLIR imagery overlay the real world as the pilot looks through the canopy. To optimize image resolution with minimum sensor size, the FLIR system scans in column mode. As this is not compatible with conventional AMLCD scanning, the FLIR video data must be converted to a row scan. This function, which normally results in additional frame delay, will also be described, together with methods for reducing the latency. The physical constrains of the helmet and the desire to use identical AMLCD devices meant that the devices are rotated between sides of the helmet. This rotation requires that the video image be scanned horizontally and vertically flipped creating another complexity in the design. Requirements for a helmet mounted image intensified television camera to be displayed as an image by itself or overlaid with symbology provided from external video creates additional complexity for distortion correction within the optical chain and will be discussed in this paper. All of these modes require that the video be manipulated in varying degrees of complexity. The enabling technology described in this paper is a complex integrated circuit that allows the user to program the required functions of rotation, scaling, overlays and distortion with minimum latency achieving an effective solution for an advanced rotorcraft Helmet Mounted Display Sight Subsystem (HMDSS).

Hebson, Robert T.; Lee, Louie

2002-08-01

159

Internal combustion propulsion engine  

SciTech Connect

An internal combustion propulsion engine is described which includes: a spherical engine body having an internal combustion chamber, the engine body being provided with a radially projecting nozzle which has an outwardly divergent conical exhaust opening centrally disposed therein, the nozzle being an extension in the wall of the engine body; a plurality of spaced support struts attached to and outwardly projecting from the spherical engine body parallel to the central axis of the exhaust opening in the nozzle; a planar annular ring carried by the plurality of support struts, the annular ring being fixedly spaced from the projecting nozzle and being positioned so that its plane is orthogonal to the central axis of the conical exhaust opening; a plurality of cross-rib members attached to, extending radially inwardly from, and coplanar with, the annular ring, the cross-rib members being joined at the center of the annular ring; a piston cylinder fixedly mounted centrally on the plurality of cross-rib members coaxially with and facing the exhaust opening in spaced relation thereto.

Sing, P.

1988-07-05

160

Swimming & Propulsion in Viscoelastic Media  

NASA Astrophysics Data System (ADS)

Many microorganisms have evolved within complex fluids, which include soil, intestinal fluid, and mucus. The material properties or rheology of such fluids can strongly affect an organism's swimming behavior. A major challenge is to understand the mechanism of propulsion in media that exhibit both solid- and fluid-like behavior, such as viscoelastic fluids. In this talk, we present experiments that explore the swimming behavior of biological organisms and artificial particles in viscoelastic media. The organism is the nematode Caenorhabditis elegans, a roundworm widely used for biological research that swims by generating traveling waves along its body. Overall, we find that fluid elasticity hinders self-propulsion compared to Newtonian fluids due to the enhanced resistance to flow near hyperbolic points for viscoelastic fluids. As fluid elasticity increases, the nematode's propulsion speed decreases. These results are consistent with recent theoretical models for undulating sheets and cylinders. In order to gain further understanding on propulsion in viscoelastic media, we perform experiments with simple reciprocal artificial `swimmers' (magnetic dumbbell particles) in polymeric and micellar solutions. We find that self-propulsion is possible in viscoelastic media even if the motion is reciprocal.

Arratia, Paulo

2012-02-01

161

Performance evaluation of a W-band monopulse radar in rotorcraft brownout landing aid application  

NASA Astrophysics Data System (ADS)

BAE Systems recently developed a rotorcraft brownout landing aid system technology (BLAST) to satisfy the urgent need for brownout landing capability. BLAST uses a W-band monopulse (MP) radar in conjunction with radar signal processing and synthetic display techniques to paint a three-dimensional (3-D) perspective of the landing zone (LZ) in real time. Innovative radar signal processing techniques are developed to process the radar data and generate target data vectors for 3-D image synthesis and display. Field tests are conducted to characterize the performance of BLAST with MP and non-MP (only using the sum channel of the MP radar) modes in clear and brownout conditions. Data processing and analysis are performed to evaluate the system's performance in terms of visual effect, signal-to-noise ratio (SNR), target height estimation, ground-mapping effect, and false alarm rate. Both MP and non-MP modes reveal abilities to sufficiently display the 3-D volume of the LZ; the former shows advantage over the latter in providing accurate ground mapping and object height determination.

Liu, Guoqing; Yang, Ken; Sykora, Brian; Salha, Imad

2009-05-01

162

Magnetohydrodynamic sea water propulsion  

SciTech Connect

An experimental and theoretical investigation of a large scale MHD propulsor has been undertaken whose objectives are to (1) investigate the transient and steady state performance of the thruster over operating parameter ranges that are compatible with achievement of high efficiency, (2) to quantify the principal loss mechanisms within the thruster and (3) to obtain preliminary hydroacoustic data. The performance of the thruster was first investigated theoretically with a 3-D code to quantify the loss mechanisms and identify experimental parameter ranges of interest. The loss mechanisms of interest are ohmic losses within the channel and those resulting from electrical currents at the entrance and exit of the thruster, and enhanced frictional losses. The analysis indicated that the relative importance of the loss mechanisms was a function of the thruster design and operating parameters. The experimental investigation of the large scale propulsor is being conducted on a sea water test facility that was designed to match the capabilities of a large 6-T superconducting magnet. The facility design was such that {approximately}90{degrees} of all losses occurred within the propulsion test train (inlet nozzle, propulsor and diffuser) thus facilitating isolation of the loss mechanisms. The test thruster itself is heavily instrumented to provide local measurements of velocity, pressure, and electric fields. The predicted overall thruster performance and value of the loss mechanisms will be compared with measured values. Comparisons will also be presented of the voltage gradients between electrodes, overall thruster efficiency, axial pressure gradients across the propulsor, change in velocity profiles, axial and vertical current distributions and exit distribution of the electrolytic gases.

Petrick, M.; Thomas, A.; Genens, L.; Libera, J.; Nietert, R.; Bouillard, J.; Pierson, E.; Hill, D.; Picologlou, B.; Ohlsson, O.; Kasprzyk, T.; Berry, G.

1991-01-01

163

Recent Developments in Electric Propulsion under NASA's In-Space Propulsion Technology Project  

Microsoft Academic Search

The primary source of electric propulsion development throughout NASA is managed by the In-Space Propulsion Technology Project at the NASA GRC for the Science Mission Directorate. The objective of the Electric Propulsion project area is to develop near-term electric propulsion technology to enhance or enable science mission while minimizing risk and cost to the end user. Major hardware tasks include

Leonard A. Dudzinski; John W. Dankanich

2007-01-01

164

Overview of Pulse Detonation Propulsion Technology.  

National Technical Information Service (NTIS)

Propulsion systems based on the pulsed detonation cycle offer the potential to provide increased performance while simultaneously reducing engine weight, cost, and complexity, relative to conventional propulsion systems currently in service. The increased...

M. L. Coleman

2001-01-01

165

Overview of Doe Space Nuclear Propulsion Programs.  

National Technical Information Service (NTIS)

An overview of Department of Energy space nuclear propulsion programs is presented in outline and graphic form. DOE's role in the development and safety assurance of space nuclear propulsion is addressed. Testing issues and facilities are discussed along ...

A. R. Newhouse

1993-01-01

166

A New Propulsion System for Ships.  

National Technical Information Service (NTIS)

Contents: Executive Summary; Introduction -- Limitation of Existing Propulsion Systems, Trends in Ship Power Requirements, Propeller Configuration, Supercavitating Propellers, Water Jet Propulsion, Integrate Ship and Propeller Into a Single System; The Ne...

H. E. Sheets T. Kowalski A. P. Davis

1980-01-01

167

Flow Analysis of Solar Thermal Propulsion System  

Microsoft Academic Search

A commercial CFD scheme FLUENT was used to simulate the working fluid (H2) flow process in solar thermal propulsion system. According to the ground test operating conditions and parameters of the solar thermal propulsion system, the system properties such as hydrogen flow, heat transfer in the solar thermal propulsion system were studied. The flow field structure of the system and

Dai Jian-feng; Li Xing; Zhao Pei; Sun Yi-bin; Mu Xiao-wen; Wang Jun-hong

2010-01-01

168

Propulsion systems for Light Electric Vehicles  

Microsoft Academic Search

The paper is concerned with the development of the propulsion system for two Light Electric Vehicles (LEVs), namely a city scooter and an electric bicycle. The propulsion system of the city scooter consists of a wheel motor for the traction and a lithium-ion battery for the energy storage. The propulsion system of the electric bicycle utilizes a fuel cell assisted

Manuele Bertoluzzo; Giuseppe Buja

2010-01-01

169

Field Emitter Cathodes and Electric Propulsion Systems  

Microsoft Academic Search

Replacing hollow and filament cathodes with field emitter (FE) cathodes could significantly improve the scalability, power, and performance of some meso- and microscale Electric Propulsion (EP) systems. This article discusses the motivation and challenges of integrating of FE and Electric Propulsion systems. The demands on cathode performance and lifetime and the propulsion system environments are described in this article. The

Colleen M. Marrese; James E. Polk; Juergen Mueller

2000-01-01

170

Turbulence program for propulsion systems  

NASA Astrophysics Data System (ADS)

Program goals at the Center for Modeling of Turbulence and Transition (CMOTT), NASA Lewis Research Center, are (1) to develop reliable turbulence (including bypass transition) and combustion models for complex flows in propulsion systems and (2) to integrate developed models into deliverable CFD tools for propulsion systems in collaboration with industry. This viewgraph presentation covers the following topics: development of turbulence and combustion models; collaboration with industry and technology transfer; isotropic eddy viscosity models; algebraic Reynolds stress models; scalar turbulence models; second order closure models; multiple scale k-epsilon models; and PDF modeling of turbulent reacting flows.

Shih, Tsan-Hsing

1995-03-01

171

Hierarchical flight control system synthesis for rotorcraft-based unmanned aerial vehicles  

NASA Astrophysics Data System (ADS)

The Berkeley Unmanned Aerial Vehicle (UAV) research aims to design, implement, and analyze a group of autonomous intelligent UAVs and UGVs (Unmanned Ground Vehicles). The goal of this dissertation is to provide a comprehensive procedural methodology to design, implement, and test rotorcraft-based unmanned aerial vehicles (RUAVs). We choose the rotorcraft as the base platform for our aerial agents because it offers ideal maneuverability for our target scenarios such as the pursuit-evasion game. Aided by many enabling technologies such as lightweight and powerful computers, high-accuracy navigation sensors and communication devices, it is now possible to construct RUAVs capable of precise navigation and intelligent behavior by the decentralized onboard control system. Building a fully functioning RUAV requires a deep understanding of aeronautics, control theory and computer science as well as a tremendous effort for implementation. These two aspects are often inseparable and therefore equally highlighted throughout this research. The problem of multiple vehicle coordination is approached through the notion of a hierarchical system. The idea behind the proposed architecture is to build a hierarchical multiple-layer system that gradually decomposes the abstract mission objectives into the physical quantities of control input. Each RUAV incorporated into this system performs the given tasks and reports the results through the hierarchical communication channel back to the higher-level coordinator. In our research, we provide a theoretical and practical approach to build a number of RUAVs based on commercially available navigation sensors, computer systems, and radio-controlled helicopters. For the controller design, the dynamic model of the helicopter is first built. The helicopter exhibits a very complicated multi-input multi-output, nonlinear, time-varying and coupled dynamics, which is exposed to severe exogenous disturbances. This poses considerable difficulties for the identification, control and general operation. A high-fidelity helicopter model is established with the lumped-parameter approach. With the lift and torque aerodynamic model of the main and tail rotors, a nonlinear simulation model is first constructed. The control models of the RUAVs used in our research are derived by the application of a time-domain parametric identification method to the flight data of target RUAVs. Two distinct control theories, namely classical control theory and modern linear robust control theory, are applied to the identified model. The proposed controllers are validated in a nonlinear simulation environment and tested in a series of test flights. With the successful implementation of the low-level vehicle controller, the guidance layer is designed. The waypoint navigator, which decides the adequate flight mode and the associated reference trajectory, serves as an intermediary between the low-level vehicle control layer and the high-level mission-planning layer. In order to interpret the abstract mission planning to commands that are compatible with the low-level structure, a novel framework called Vehicle Control Language (VCL) is developed. The key idea of VCL is to provide a mission-independent methodology to describe given flight patterns. The VCL processor and vehicle control layer are integrated into the hierarchical control structure, which is the backbone of our intelligent UAV system. The proposed idea is validated in the simulation environment and then fully tested in a series of flight tests.

Shim, Hyunchul

172

Prediction of acoustic scattering in the time domain and its applications to rotorcraft noise  

NASA Astrophysics Data System (ADS)

This work aims at the development of a numerical method for the analysis of acoustic scattering in the time domain and its applications to rotorcraft noise. This purpose is achieved by developing two independent methods: (1) an analytical formulation of the pressure gradient for an arbitrary moving source and (2) a time-domain moving equivalent source method. First, the analytical formulation for the pressure gradient is developed to fulfill the boundary condition on a scattering surface to account for arbitrary moving incident sources. A semi-analytical formulation was derived from the gradient of the Ffowcs Williams-Hawkings (FW-H) equation. This formulation needs to calculate the observer time differentiation outside the integrals numerically. A numerical algorithm is developed to implement this formulation in an aeroacoustic prediction code. A new analytical formulation is presented in the thesis. In this formulation, the time differentiation is taken inside the integrals analytically. This formulation avoids the numerical time differentiation with respect to the observer time, which is computationally more efficient. The acoustic pressure gradient predicted by these two formulations is validated through comparison with available exact solutions for a stationary and moving monopole sources. The agreement between the predictions and exact solutions is excellent. One of the advantages of this analytic formulation is that it efficiently provides the boundary condition for the acoustic scattering of sound generated from an arbitrary moving source, such as rotating blades, which undergoes rotation, flapping and lead-lag motions. The formulation is applied to the rotor noise problems for two model rotors (UH-1H and HART-I). For HART-I rotor, CFD/CSD coupling was used to provide unsteady aerodynamics and trim solutions of the blade motion. A purely numerical approach is compared with the analytical formulations. The agreement between the analytical formulations and the numerical method is excellent for both stationary and moving observer cases. The formulation for the pressure gradient is first used to predict acoustic scattering in the frequency domain. The prediction is validated with the exact solution for acoustic scattering generated by a monopole source by a stationary sphere. A Bo105 helicopter and a notional heavy lift quad tilt rotor are considered to demonstrate a potential significance of acoustic scattering of rotorcraft noise. NASA's Fast Scattering Code is used for the frequency-domain scattering solver. Secondly, a new and efficient time domain acoustic scattering method using a moving equivalent source is developed to predict acoustic scattering in the time domain efficiently. The time-domain method provides entire frequency solutions in a single computation and is able to predict acoustic scattering of aperiodic signals. The method assumes an acoustically rigid surface for a scattering body and neglects the refraction effect by non-uniform flow around the scattering body. The pressure-gradient boundary condition is determined on a scattering surface and then the scattered field is calculated by using equivalent sources located within the scattering surface. Linear shape functions are used to discretize the strength of the equivalent sources in time and singular value decomposition is used to overcome potential numerical instability. The detailed numerical algorithm is addressed in the thesis. The method is more efficient numerically and easier to implement than other time-domain methods using a finite difference scheme or boundary integral equations because it is not necessary to find the solution in the entire domain, it uses a fewer number of equivalent sources than the surface mesh points, and it does not involve surface integrals. The method is validated against exact solutions for various cases including a single frequency monopole source, a dipole source, multiple sources, beat, and broadband noise sources. The predictions are found to be in excellent agreement with the exact solutions. The effect of

Lee, Seongkyu

173

Improved gas core propulsion model  

SciTech Connect

A thermodynamic, radiation transport model of a gas core nuclear propulsion reactor has been developed in one-dimensional, spherical geometry, which satisfies local energy balance and allows for arbitrary variation of fuel/propellant ratio and flow rate as functions of radius. Initial cases calculated yield specific impulses of about 1150 sec, but very low thrusts ranging 5--10 kN.

Tanner, J.E.

1993-10-01

174

Electric-bicycle propulsion power  

Microsoft Academic Search

In a human-powered hybrid electric vehicle (HPHEV) the travel distance available from a single battery charge can be lengthened with power from another source, the cyclist's leg muscles. In a battery-powered electric bicycle the propulsion power goes mostly into overcoming aerodynamic drag. For example, at 18 km per hour (11 miles per hour) this drag represents 200 watts at the

Henry Oman; William C. Morchin; Frank E. Jamerson

1995-01-01

175

In-space nuclear propulsion  

NASA Astrophysics Data System (ADS)

The past and the recent status of nuclear propulsion (NP) for application to space mission is presented. The case for using NP in manned space missions is made based on fundamental physics and on the necessity to ensure safe radiation doses to future astronauts. In fact, the presence of solar and galactic-cosmic radiation poses substantial risks to crews traveling for months in a row to destinations such as asteroids and Mars. Since passive or active shields would be massive to protect against the more energetic part of the radiation energy spectrum, the only alternative is to reduce dose by traveling faster. Hence the importance of propulsion systems with much higher specific impulse than that of current chemical systems, and thus the use of nuclear propulsion. Nuclear-thermal and nuclear-electric propulsions are then discussed in view of their potential application to missions now in the preliminary planning stage by space agencies and industries and being considered by the ISECG international panel. In this context, recent ideas for future use of the ISS that may require NP are also presented.

Bruno, C.; Dujarric, C.

2013-02-01

176

MAP Propulsion System Thermal Design  

NASA Astrophysics Data System (ADS)

The propulsion system of the Microwave Anisotropy Probe (MAP) had stringent requirements that made the thermal design unique. To meet instrument stability requirements the system had to be designed to keep temperatures of all components within acceptable limits without heater cycling. Although the spacecraft remains at a fixed 22° sun angle at L2, the variations in solar constant, property degradation, and bus voltage range all significantly affect the temperature. Large portions of the fuel lines are external to the structure and all components are mounted to non-conductive composite structure. These two facts made the sensitivity to the MLI effective emissivity and bus temperature very high. Approximately two years prior to launch the propulsion system was redesigned to meet MAP requirements. The new design utilized hardware that was already installed in order to meet schedule constraints. The spacecraft design and the thermal requirements were changed to compensate for inadequacies of the existing hardware. The propulsion system consists of fuel lines, fill and drain lines/valve, eight thrusters, a HXCM, and a propulsion tank. A voltage regulator was added to keep critical components within limits. Software was developed to control the operational heaters. Trim resistors were put in series with each operational heater circuits and the tank survival heater. A highly sophisticated test program, which included ``real time'' model correlation, was developed to determine trim resistors sizes. These trim resistors were installed during a chamber break and verified during thermal balance testing.

Mosier, Carol L.

2003-01-01

177

Moment generation in wheelchair propulsion.  

PubMed

Wheelchair propulsion is a man machine interaction in which chair design and fit affect the relative positions and orientations of the upper extremity relative to the handrim and wheel axle. To understand these relationships better, experimental data were collected in five hand positions from five subjects exerting maximal effort to propel an instrumented wheelchair with its wheel in a locked position. The results of experiments revealed that the progression moment was greater at both initial and terminal propulsion positions and smaller in the mid-propulsion position. The vertical and horizontal force components were directed radially away from the wheel axle posterior to the dead centre position and radially towards the wheel axle anterior to top dead centre. Subsequently, a subject-specific quasi-static model of the upper extremity which maximized wheel progression moment was developed to augment our understanding of experimental measures. Model-predicted trends in progression moments and hand force direction were similar to experiment. Model predictions revealed that the optimal progression moment generation could potentially be affected by an individual's anthropometric parameters, joint strengths and also the direction of force applied by the hand on the handrim. Through wheelchair fitting and training of wheelchair users, it may be possible to improve propulsion technique. PMID:14558653

Guo, Lan-Yuen; Zhao, K D; Su, Fong-Chin; An, Kai-Nan

2003-01-01

178

Propulsion Method for Swimming Microrobots  

Microsoft Academic Search

This paper presents a novel swimming method mediated by traveling waves in elastic tails. The propulsion method is potentially appropriate for maneuvering microrobots inside the human body. The swimming action relies on the creation of a traveling wave along a piezoelectric layered beam divided into several segments. This requires that a voltage with the same frequency, but different phases and

Gábor Kósa; Moshe Shoham; Menashe Zaaroor

2007-01-01

179

Nuclear space propulsion critical technologies  

Microsoft Academic Search

The National Aeronautics and Space Administration (NASA) has actively pursued technology development for nuclear rocket propulsion systems for possible use on lunar outpost missions, for exploration missions to Mars, and for outer planet and other solar system exploration missions. A number of these technologies have been broadly identified by the ANS National Critical Technologies Panel, as well as the Department

J. S. Clark; S. K. Borowski; M. P. Doherty

1993-01-01

180

Status Report Radioisotopic Propulsion Systems  

Microsoft Academic Search

Preliminary analysis of radioisotopic propulsion systems indicates considerable potential for application to scientific probes provided current engineering postulations can be realized. Typical applications, as indicated by analysis to date, would be high energy space missions such as solar probes to distances of approximately 0.05 A. U. and explorer probes in deep space out to the vicinity of Saturn. In order

J. C. Whiton

1965-01-01

181

OTV propulsion tecnology programmatic overview  

Microsoft Academic Search

An advanced orbit transfer vehicles (OTV) which will be an integral part of the national space transportation system to carry men and cargo between low Earth orbit and geosynchronous orbit will perform planetary transfers and deliver large acceleration limited space structures to high Earth orbits is reviewed. The establishment of an advanced propulsion technology base for an OTV for the

L. P. Cooper

1984-01-01

182

Unsteady aerodynamics of rotorcraft at low advance ratios in ground effect  

NASA Astrophysics Data System (ADS)

The aerodynamic characteristics of rotorcraft flying at low speed close to the ground are investigated. This will help better understand and quantify the flow field structures and unsteadiness associated with various in ground effect flight conditions. This study aims to separate out the various phenomena according to their causal factors. Experimental investigations first involved flow visualization, which helped in identifying the various flight regimes and in getting an approximate estimate of the unsteadiness. It was found that there was considerably more unsteadiness in the flowfield while in ground effect. The problem was thereafter divided into its unsteady and quasi-steady aspects. Hotwire measurements were performed and the unsteadiness in the flow structure was quantified. It was found that there were long time scale fluctuations in the upwind side of the rotor disk, with significant changes in the inflow. These fluctuations were quantified and related to the flow parameters, which will help scale the results. On the quasi-steady side, the fuselage loads for two fuselage cross-sectional shapes were investigated both in and out of ground effect. The fuselage cross-section shape had a significant effect on the loads felt by the fuselage in ground effect. It was found that the sideforce on a circular cross-section fuselage was considerably different when flying close to the ground. The power required for the experimental configuration was measured to provide a basis for comparison. Finally, the flowfield around the ground vortex was quantified, and the structure of the ground vortex was investigated using Particle Image Velocimetry. It was found that tip vorticity was ingested by the ground vortex and that the strength of the ground vortex was considerably more than the tip vortex.

Ganesh, Balakrishnan

183

Laser Propulsion Activities in Germany  

NASA Astrophysics Data System (ADS)

Activities related to laser supported propulsion concentrate on investigations of the fundamental phenomena arising from the interaction of high-power CO2 laser pulses with a simple bell engine. Breakdown dynamics, plasma, and lightcraft accelerations are carefully measured using optical and laser diagnostics. In a first-order approach the expanding plasma can be described by the point explosion model with counterpressure. Wire guided vertical flight experiments in the laboratory have been undertaken and analyzed. Comparative impulse measurements in ambient air and ablated material are presented for a series of experiments performed either at atmospheric pressure or at reduced pressures down to vacuum. Impulse coupling coefficients, average exhaust velocities,specific impulse, and jet efficiencies are derived from the experimental data. The repetitively-pulsed CO2 laser device used in all experiments shows a potential of achieving 50 kW average power. Finally, long-term perspectives of laser propulsion will be addressed.

Bohn, Willy L.; Schall, Wolfgang O.

2003-05-01

184

OTV propulsion tecnology programmatic overview  

NASA Astrophysics Data System (ADS)

An advanced orbit transfer vehicles (OTV) which will be an integral part of the national space transportation system to carry men and cargo between low Earth orbit and geosynchronous orbit will perform planetary transfers and deliver large acceleration limited space structures to high Earth orbits is reviewed. The establishment of an advanced propulsion technology base for an OTV for the mid 1990's is outlined. The program supports technology for three unique engine concepts. Work is conducted to generic technologies which benefit all three concepts and specific technology which benefits only one of the concepts. Concept and technology definitions to identify propulsion innovations, and subcomponent research to explore and validate their potential benefits are included.

Cooper, L. P.

1984-04-01

185

POTENTIALS OF RADIOISOTOPE ELECTROSTATIC PROPULSION  

Microsoft Academic Search

The potentialities and problems of a radioisotope electrostatic ; propulsion system for future space missions are discussed. The proposed ; operation of an electrogenerator using Ce¹⁴⁴ -- Pr¹⁴⁴ fuel is ; described. The availability and cost of Ce¹⁴⁴ are considered, along with ; payload radiation damage, spacecraft design, launch-pad and boost hazards, and ; interplanetary mission performance. The anticipated availability

W. R. Mickelsen; C. A. Jr. Low

1963-01-01

186

Field propulsion systems for space travel  

NASA Astrophysics Data System (ADS)

Field propulsion systems were proposed by many researchers to overcome the speed limit of the conventional space propulsion system. Field propulsion system can be propelled without mass expulsion; its propulsion principle can induce a propulsive force (i.e., thrust) that arises from the interaction of the substantial physical structure. This notion is based on the assumption that space as a vacuum possesses a substantial physical structure. This evaluation examines the substantial physical structure regarding the space-time from both General Relativity in the view of a macroscopic structure and Quantum Field Theory in the view of a microscopic structure. Thus, several kinds of field propulsion system can be proposed by making these choices considering the structure of physical space.

Minami, Yoshinari; Musha, Takaaki

2013-02-01

187

Radioisotope electric propulsion (REP): A near-term approach to nuclear propulsion  

Microsoft Academic Search

Studies over the last decade have shown radioisotope-based nuclear electric propulsion to be enhancing and, in some cases, enabling for many potential robotic science missions. Also known as radioisotope electric propulsion (REP), the technology offers the performance advantages of traditional reactor-powered electric propulsion (i.e., high specific impulse propulsion at large distances from the Sun), but with much smaller, affordable spacecraft.

George R. Schmidt; David H. Manzella; Hani Kamhawi; Tibor Kremic; Steven R. Oleson; John W. Dankanich; Leonard A. Dudzinski

2010-01-01

188

HTS Ship Propulsion Motors for Podded Applications  

Microsoft Academic Search

Pod propulsion systems have been adapted for both commercial and naval vessels. Pod propulsion de-couples engines from the shaft line and replaces rudders, external shafts and maneuvering thrusters with easy-to-install rotatable pods. Pods offer higher overall propulsion efficiency (at all loads) and more flexible maneuvering. Even higher hydrodynamic efficiency is possible by the use of smaller diameter pods. Smaller diameter

Swarn S. Kalsi

189

A Conceptual Tree of Laser Propulsion  

SciTech Connect

An original attempt to develop a conceptual tree for laser propulsion is offered. The tree provides a systematic view for practically all possible laser propulsion concepts and all inter-conceptual links, based on propellant phases and phase transfers. It also helps to see which fields of laser propulsion have been already thoroughly explored, where the next effort must be applied, and which paths should be taken with proper care or avoided entirely.

Pakhomov, Andrew V.; Sinko, John E. [Department of Physics, The University of Alabama in Huntsville (United States)

2008-04-28

190

Propulsion of liposomes using bacterial motors  

NASA Astrophysics Data System (ADS)

Here we describe the utilization of flagellated bacteria as actuators to propel spherical liposomes by attaching bacteria to the liposome surface. Bacteria were stably attached to liposomes using a cross-linking antibody. The effect of the number of attached bacteria on propulsion speed was experimentally determined. The effects of bacterial propulsion on the bacteria-antibody-liposome complex were stochastic. We demonstrated that liposomal mobility increased when bacteria were attached, and the propulsion speed correlated with the number of bacteria.

Zhang, Zhenhai; Li, Zhifei; Yu, Wei; Li, Kejie; Xie, Zhihong; Shi, Zhiguo

2013-05-01

191

Mirror fusion propulsion system - A performance comparison with alternate propulsion systems for the manned Mars mission  

Microsoft Academic Search

The performance characteristics of several propulsion technologies applied to piloted Mars missions are compared. The characteristics that are compared are Initial Mass in Low Earth Orbit (IMLEO), mission flexibility, and flight times. The propulsion systems being compared are both demonstrated and envisioned: Chemical (or Cryogenic), Nuclear Thermal Rocket (NTR) solid core, NTR gas core, Nuclear Electric Propulsion (NEP), and a

M. Deveny; S. A. Carpenter; T. O'Connell; N. Schulze

1993-01-01

192

Mirror fusion propulsion system: A performance comparison with alternate propulsion systems for the manned Mars Mission  

Microsoft Academic Search

The performance characteristics of several propulsion technologies applied to piloted Mars missions are compared. The characteristics that are compared are Initial Mass in Low Earth Orbit (IMLEO), mission flexibility, and flight times. The propulsion systems being compared are both demonstrated and envisioned: Chemical (or Cryogenic), Nuclear Thermal Rocket (NTR) solid core, NTR gas core, Nuclear Electric Propulsion (NEP), and a

Norman R. Schulze; Scott A. Carpenter; Marc E. Deveny; T. Oconnell

1993-01-01

193

Indications of Propulsion System Malfunctions - Sustained Thrust Anomaly Study.  

National Technical Information Service (NTIS)

The feasibility of providing specific indications to flight crews when a propulsion system malfunction occurs was evaluated. The Boeing Phase 1 Report, Indications of Propulsion System Malfunctions, DOT/FAA/AR-03/72, reviewed and analyzed propulsion syste...

G. B. Ostrom J. Mason S. Clark S. Clark

2007-01-01

194

Distributed Propulsion: New Opportunities for an Old Concept.  

National Technical Information Service (NTIS)

Distributed propulsion can be broadly defined as distributing the airflows and forces generated by the propulsion system about an aircraft in such a way as to improve the vehicle's aerodynamics, propulsive efficiency, structural efficiency, and aeroelasti...

A. H. Epstein

2007-01-01

195

NASA In-Space Propulsion Technologies and Their Infusion Potential.  

National Technical Information Service (NTIS)

The In-Space Propulsion Technology (ISPT) program has been developing in-space propulsion technologies that will enable or enhance NASA robotic science missions. The ISPT program is currently developing technology in four areas that include Propulsion Sys...

D. Vento D. J. Anderson E. J. Pencil J. W. Dankanich L. J. Glaab M. M. Munk T. Peterson

2012-01-01

196

High Power Electric Propulsion System for NEP (systemes propulsifs electriques de forte puissance pour propulsion nucleo-electrique).  

National Technical Information Service (NTIS)

Recent US initiatives in Nuclear Propulsion lend themselves naturally to raising the question of the assessment of various options and particularly to propose the High Power Electric Propulsion Subsystem (HPEPS) for the Nuclear Electric Propulsion (NEP). ...

C. R. Koppel O. Duchemin D. Valentian

2005-01-01

197

Dynamic Design: Launch and Propulsion  

NSDL National Science Digital Library

This module focuses on the launch and propulsion of the Genesis spacecraft. Students will become familiar with how rockets are launched, learn how and why specific rockets are chosen for varying payloads, learn about the history of rocketry, and work with variables that might affect the performance of a launch vehicle. They will work in teams to test a single variable involved in launching a rocket and learn the variables involved with constructing and launching a water rocket. Each activity includes a teacher's guide and students handouts. Video and audio clips are provided.

2005-12-01

198

Propulsion at low Reynolds number  

NASA Astrophysics Data System (ADS)

We study the propulsion of two model swimmers at low Reynolds number. Inspired by Purcell's model, we propose a very simple one-dimensional swimmer consisting of three spheres that are connected by two arms whose lengths can change between two values. The proposed swimmer can swim with a special type of motion, which breaks the time-reversal symmetry. We also show that an ellipsoidal membrane with tangential travelling wave on it can also propel itself in the direction preferred by the travelling wave. This system resembles the realistic biological animals like Paramecium.

Najafi, Ali; Golestanian, Ramin

2005-04-01

199

Review of Propulsion Applications of Detonation Waves  

Microsoft Academic Search

Applications of detonations to propulsion are reviewed. First, the advantages of the detonation cycle over the constant pressure combustion cycle, typical of conventional propulsion engines, are discussed. Then the early studies of standing normal detonations, intermittent (or pulsed) detonations, rotating detonations, and oblique shock-induced detonations are reviewed. This is followed by a brief discussion of detonation thrusters, laser- supported detonations

K. Kailasanath

2000-01-01

200

Missions to asteroids using solar electric propulsion  

Microsoft Academic Search

Future interplanetary missions will use conventional rockets to leave the Earth's sphere of influence, and solar electric propulsion to carry out deep-space maneuvers. Optimization of this kind of mission is the subject of the paper. Attention is mainly paid to a mission concept that exploits high specific impulse and steering capabilities of electric propulsion to obtain a gravity assist from

Guido Colasurdo; Lorenzo Casalino

2002-01-01

201

Overview of Electric Propulsion Activities at NASA.  

National Technical Information Service (NTIS)

This paper provides an overview of NASA s activities in the area of electric propulsion with an emphasis on project directions, recent progress, and a view of future project directions. The goals of the electric propulsion programs are to develop key tech...

J. W. Dunning J. A. Hamley R. S. Jankovsky S. R. Oleson

2004-01-01

202

Ultrahigh Specific Impulse Nuclear Thermal Propulsion  

Microsoft Academic Search

Research on nuclear thermal propulsion systems (NTP) have been in forefront of the space nuclear power and propulsion due to their design simplicity and their promise for providing very high thrust at reasonably high specific impulse. During NERVA-ROVER program in late 1950's till early 1970's, the United States developed and ground tested about 18 NTP systems without ever deploying them

Anne Charmeau; Brandon Cunningham; Samim Anghaie

2009-01-01

203

Propulsion Structure Rapid Model Generation Tool (RMG)  

Microsoft Academic Search

Demands of airplane customers have necessitated compaction of the design-and-build cycle of commercial airplane manufacturers. This shorter design cycle requires innovative robust automated analysis tools. The Propulsion Structures Group at Boeing Commercial Company has developed a Propulsion Structure Modeling & Analysis Tool, Rapid Model Generation (RMG), an automated design process that is both accurate and efficient. Utilizing CATIA, FORTRAN, MSC.

Shaun Allahyari; Donald T. Powell

204

Modeling of Spacecraft Advanced Chemical Propulsion Systems.  

National Technical Information Service (NTIS)

This paper outlines the development of the Advanced Chemical Propulsion System (ACPS) model for Earth and Space Storable propellants. This model was developed by the System Technology Operation of SAIC-Huntsville for the NASA MSFC In-Space Propulsion Proj...

M. P. J. Benfield J. A. Belcher

2004-01-01

205

Institute for Computational Mechanics in Propulsion (ICOMP)  

NASA Astrophysics Data System (ADS)

The Institute for Computational Mechanics in Propulsion (ICOMP) is operated by the Ohio Aerospace Institute (OAI) and funded under a cooperative agreement by the NASA Lewis Research Center in Cleveland, Ohio. The purpose of ICOMP is to develop techniques to improve problem-solving capabilities in all aspects of computational mechanics related to propulsion. This report describes the activities at ICOMP during 1994.

Feiler, Charles E.

1995-03-01

206

Institute for Computational Mechanics in Propulsion (ICOMP)  

NASA Astrophysics Data System (ADS)

The Institute for Computational Mechanics in Propulsion (ICOMP) is operated by the Ohio Aerospace Institute (OAI) and the NASA Lewis Research Center in Cleveland, Ohio. The purpose of ICOMP is to develop techniques to improve problem-solving capabilities in all aspects of computational mechanics related to propulsion. This report describes the accomplishments and activities at ICOMP during 1993.

Feiler, Charles E.

1994-04-01

207

NASA's nuclear electric propulsion technology project  

Microsoft Academic Search

The National Aeronautics and Space Administration (NASA) has initiated a program to establish the readiness of nuclear electric propulsion (NEP) technology for relatively near-term applications to outer planet robotic science missions with potential future evolution to system for piloted Mars vehicles. This program was initiated in 1991 with a very modest effort identified with nuclear thermal propulsion (NTP); however, NEP

James R. Stone; James S. Sovey

1992-01-01

208

28th Joint Propulsion Conference and Exhibit  

Microsoft Academic Search

The National Aeronautics and Space Administration (NASA) has initiated a program to establish the readiness of nuclear electric propulsion (NEP) technology for relatively near-term applications to outer planet robotic science missions with potential future evolution to system for piloted Mars vehicles. This program was initiated in 1991 with a very modest effort identified with nuclear thermal propulsion (NTP); however, NEP

J. R. Stone; J. S. Sovey

1992-01-01

209

Cryogenic upper stage propulsion systems evolution  

NASA Astrophysics Data System (ADS)

A variety of cryogenic propulsion system evolution features that offer significant stage benefits for improving Atlas ELV international posture is discussed. Incorporation of a single RL10C engine is considered to offer the greatest cumulative benefits. Particular attention is given to a Centaur upper stage incorporating structure and avionics evolution features, as well as propulsion and fluids.

Eidson, Robert L.

1992-07-01

210

Prototyping and Laboratory Testing an Oil-Free, Reciprocating Compressor Developed Specifically for Refueling Commercial Natural Gas for Vehicles (NGV) Fleets. Final Report, May 1994-March 1996.  

National Technical Information Service (NTIS)

Addressing a need for a compressor designed specifically for high pressure natural gas in the 20 to 50 standard cubic feet per minute (scfm) range, components were designed and successfully tested in the laboratory for an oil-free 50 scfm compressor. It w...

M. D. Pennington T. C. Ender

1996-01-01

211

Robust LPV H? gain-scheduled hover-to-cruise conversion for a tilt-wing rotorcraft in the presence of CG variations  

Microsoft Academic Search

This paper describes the development and analysis of gain-scheduled, multi-variable Hinfin control law for the conversion of a linear parameter varying (LPV) model of a high-speed autonomous rotorcraft vehicle (HARVee), an experimental tilt-wing aircraft. Tilt-wing aircraft combine the high-speed cruise capabilities of a conventional airplane with the vertical takeoff and station keeping abilities of a helicopter by rotating their wings

Jeffrey J. Dickeson; David Miles; Oguzhan Cifdaloz; Valana L. Wells; Armando A. Rodriguez

2007-01-01

212

Robust LPV H Gain-Scheduled Hover-to-Cruise Conversion for a Tilt-Wing Rotorcraft in the Presence of CG Variations  

Microsoft Academic Search

This paper describes the development and analysis of gain-scheduled, multi-variable Hinfin control law for the conversion of a linear parameter varying (LPV) model of a high-speed autonomous rotorcraft vehicle (HARVee), an experimental tilt-wing aircraft. Tilt-wing aircraft combine the high-speed cruise capabilities of a conventional airplane with the vertical takeoff and station keeping abilities of a helicopter by rotating their wings

Jeffrey J. Dickeson; David Miles; Oguzhan Cifdaloz; Valana L. Wells; Armando A. Rodriguez

2007-01-01

213

Space Nuclear Thermal Propulsion Test Facilities Subpanel  

NASA Astrophysics Data System (ADS)

On 20 Jul. 1989, in commemoration of the 20th anniversary of the Apollo 11 lunar landing, President George Bush proclaimed his vision for manned space exploration. He stated, 'First for the coming decade, for the 1990's, Space Station Freedom, the next critical step in our space endeavors. And next, for the new century, back to the Moon. Back to the future. And this time, back to stay. And then, a journey into tomorrow, a journey to another planet, a manned mission to Mars.' On 2 Nov. 1989, the President approved a national space policy reaffirming the long range goal of the civil space program: to 'expand human presence and activity beyond Earth orbit into the solar system.' And on 11 May 1990, he specified the goal of landing Astronauts on Mars by 2019, the 50th anniversary of man's first steps on the Moon. To safely and ever permanently venture beyond near Earth environment as charged by the President, mankind must bring to bear extensive new technologies. These include heavy lift launch capability from Earth to low-Earth orbit, automated space rendezvous and docking of large masses, zero gravity countermeasures, and closed loop life support systems. One technology enhancing, and perhaps enabling, the piloted Mars missions is nuclear propulsion, with great benefits over chemical propulsion. Asserting the potential benefits of nuclear propulsion, NASA has sponsored workshops in Nuclear Electric Propulsion and Nuclear Thermal Propulsion and has initiated a tri-agency planning process to ensure that appropriate resources are engaged to meet this exciting technical challenge. At the core of this planning process, NASA, DOE, and DOD established six Nuclear Propulsion Technical Panels in 1991 to provide groundwork for a possible tri-agency Nuclear Propulsion Program and to address the President's vision by advocating an aggressive program in nuclear propulsion. To this end the Nuclear Electric Propulsion Technology Panel has focused it energies; this final report summarizes its endeavor and conclusions.

Allen, George C.; Warren, John W.; Martinell, John; Clark, John S.; Perkins, David

1993-04-01

214

Philosophy for nuclear thermal propulsion  

SciTech Connect

The philosophy used for development of nuclear thermal propulsion will determine the cost, schedule and risk associated with the activities. As important is the impression of the decision makers. If the development cost is higher than the product value, it is doubtful that funding will ever be available. On the other hand, if the development supports the economic welfare of the country with a high rate of return, the probability of funding greatly increases. The philosophy is divided into: realism, design, operations and qualification. Realism'' addresses such items as political acceptability, potential customers, robustness-flexibility, public acceptance, decisions as needed, concurrent engineering, and the possible role of the CIS. Design'' addresses minimum requirement,'' built in safety and reliability redundancy, emphasize on eliminating risk at lowest levels, and the possible inclusion of electric generation. Operations'' addresses sately, environment, operations, design margins and degradation modes. Qualification'' addresses testing needs and test facilities.

Buden, D.; Madsen, W. (Idaho National Engineering Laboratory, EG G Idaho, Inc., P.O. Box 1625, Idaho Falls, Idaho 83415-3413 (United States)); Redd, L. (Department of Energy, Office of Space, Idaho Field Office, 785 D.O.E. Place, Idaho Falls, Idaho 83402 (United States))

1993-01-10

215

Breakthrough propulsion physics workshop preliminary results  

SciTech Connect

In August, 1997, a NASA workshop was held to assess the prospects emerging from physics that might lead to creating the ultimate breakthroughs in space transportation: propulsion that requires no propellant mass, attaining the maximum transit speeds physically possible, and breakthrough methods of energy production to power such devices. Because these propulsion goals are presumably far from fruition, a special emphasis was to identify affordable, near-term, and credible research that could make measurable progress toward these propulsion goals. Experiments and theories were discussed regarding the coupling of gravity and electromagnetism, vacuum fluctuation energy, warp drives and wormholes, and superluminal quantum tunneling. Preliminary results of this workshop are presented, along with the status of the Breakthrough Propulsion Physics program that conducted this workshop.

Millis, Marc G. [NASA Lewis Research Center, 21000 Brookpark Rd., MS 60-4, Cleveland, Ohio 44135 (United States)

1998-01-15

216

46 CFR 130.120 - Propulsion control.  

Code of Federal Regulations, 2012 CFR

...propeller-shaft rotation; (3) Control of propeller pitch, if a controllable-pitch propeller is fitted; and (4) Shutdown of each...system allows the propulsion engine to overspeed or the pitch of the propeller to...

2012-10-01

217

Advanced Propulsion System for Hybrid Vehicles.  

National Technical Information Service (NTIS)

A number of hybrid propulsion systems were evaluated for application in several different vehicle sizes. A conceptual design was prepared for the most promising configuration. Various system configurations were parametrically evaluated and compared, desig...

L. V. Norrup A. T. Lintz

1980-01-01

218

Advanced Propulsion System for Hybrid Vehicles.  

National Technical Information Service (NTIS)

The objective of this study was to evaluate a number of hybrid propulsion systems for application in several different vehicle sizes. A conceptual design was prepared for the most promising configuration. The program was divided into several tasks during ...

A. T. Lintz L. V. Norrup

1980-01-01

219

Direct Drive Options for Electric Propulsion Systems.  

National Technical Information Service (NTIS)

Power processing units (PPU's) in an electric propulsion system provide many challenging integration issues. The PPU must provide power to the electric thruster while maintaining compatibility with all of the spacecraft power and data systems. Inefficienc...

J. A. Hamley

1995-01-01

220

International Space Station Propulsion Module Procurement Process.  

National Technical Information Service (NTIS)

The National Aeronautics and Space Administration (NASA) initiated the Space Station Program in 1984 to provide for a permanent human presence in an orbiting laboratory. The original U.S. design included a propulsion module that could adjust the orientati...

2001-01-01

221

Thermal Fatigue Durability for Advanced Propulsion Materials.  

National Technical Information Service (NTIS)

A review is presented of thermal and thermomechanical fatigue (TMF) crack initiation life prediction and cyclic constitutive modeling efforts sponsored recently by the NASA Lewis Research Center in support of advanced aeronautical propulsion research. A b...

G. R. Halford

1989-01-01

222

Numerical Investigation on Ship Podded Propulsion  

NASA Astrophysics Data System (ADS)

The paper proposes a numerical investigation based on RANS computation for solving the viscous flow around a ship podded propulsion unit. A set of computations has been performed to better understand the influences exerted by different configurations on the wake structure in the propeller disk in the pushing type case. The RANS computation method is employed to evaluate the flow field structure around the podded propulsion units and the forces acting on it. Hydrodynamic design podded system has not, so far, been fully established in the propeller-pod-strut system. It is necessary to use a reliable procedure in the design of such propulsion systems to increase the propulsion efficiency. In an attempt to meet these needs, the present paper introduces a numerical procedure to analyze the hydrodynamic performance of the propeller and steering system using a combined lifting line and RANS methods.

Pacuraru, Florin; Lungu, Adrian

2010-09-01

223

Propulsion System Choices and Their Implications.  

National Technical Information Service (NTIS)

In defining a space vehicle architecture, the propulsion system and related subsystem choices will have a major influence on achieving the goals and objectives desired. There are many alternatives and the choices made must produce a system that meets the ...

C. R. Joyner D. J. H. Levack J. W. Robinson R. E. Rhodes

2010-01-01

224

SPE (TM) Electrolyzers for Space Propulsion.  

National Technical Information Service (NTIS)

Viewgraphs on SPE electrolyzers for space propulsion are presented. Topics covered include: SPE electrochemical cell reactions; SPE fuel cell/electrolyzer features; SPE cell life capability; SPE cell voltage stability; state-of-the-art SPE cell structure;...

E. M. Shane

1990-01-01

225

Hypersonic Propulsion at Pratt and Whitney: Overview.  

National Technical Information Service (NTIS)

Pratt & Whitney (P&W) is developing the technology for hypersonic components and engines. A supersonic combustion ramjet (scramjet) database was developed during the National Aero Space Plane (NASP) program using hydrogen fueled propulsion systems for spa...

R. R. Kazmar

2002-01-01

226

Kombinationsantriebe fuer Raumflugzeuge (Combined Spacecraft Propulsion Systems).  

National Technical Information Service (NTIS)

The realization possibilities of alternative combined propulsion system configurations for spacecraft which horizontally take off and land and have a payload capacity of 10t for low Earth orbits, are discussed. It is shown that the combined system with ai...

H. Hopmann G. Schmidt W. Schmidt

1986-01-01

227

Solar Electric Propulsion System Thermal Analysis.  

National Technical Information Service (NTIS)

The results of the analysis of thermal control concepts for solar electric propulsion are reported. Thermal control technology is analyzed along with the boundary conditions. The evaluation and selection of thermal control concepts are discussed.

L. E. Ruttner

1975-01-01

228

Interplanetary space transport using inertial fusion propulsion.  

National Technical Information Service (NTIS)

In this paper, we indicate how the great advantages that ICF offers for interplanetary propulsion can be accomplished with the VISTA spacecraft concept. The performance of VISTA is expected to surpass that from other realistic technologies for Mars missio...

C. D. Orth

1998-01-01

229

History of Solid Rocket Propulsion and Aerojet.  

National Technical Information Service (NTIS)

Much of the early history of rocket propulsion has not been the subject of organized historical documentation, and with the passage of time, and proliferation of organizational changes, the prospects for developing a clear picture of past events and fadin...

P. D. Umholtz

1999-01-01

230

Publications of the Jet Propulsion Laboratory 1983.  

National Technical Information Service (NTIS)

The Jet propulsion Laboratory (JPL) bibliography describes and indexes by primary author the externally distributed technical reporting, released during calendar year 1983, that resulted from scientific and engineering work performed, or managed, by the J...

1984-01-01

231

Power technology options for nuclear electric propulsion  

Microsoft Academic Search

On-going studies being conducted under the office of space science (Code S) in-space propulsion program have identified high power (100 kWe) NEP as an enabling technology for space science missions. The benefits of NEP include larger payload fractions, faster and more direct trajectories, and increased power at destination as compared to other propulsion technologies. In order to realize these benefits,

Lee S. Mason

2002-01-01

232

Solar electric propulsion for Mars transport vehicles  

SciTech Connect

Solar electric propulsion (SEP) is an alternative to chemical and nuclear powered propulsion systems for both piloted and unpiloted Mars transport vehicles. Photovoltaic solar cell and array technologies were evaluated as components of SEP power systems. Of the systems considered, the SEP power system composed of multijunction solar cells in an ENTECH domed fresnel concentrator array had the least array mass and area. Trip times to Mars optimized for minimum propellant mass were calculated. Additionally, a preliminary vehicle concept was designed.

Hickman, J.M.; Curtis, H.B.; Alexander, S.W.; Gilland, J.H.; Hack, K.J.; Lawrence, C.; Swartz, C.K.

1990-09-01

233

Altered Growth Rates, Carcass Fatty Acid Concentrations, and Tissue Histology in First-Feeding Steelhead Fed a FishMeal and Fish-Oil-Free Diet  

Microsoft Academic Search

A 12-week feeding trial was conducted to evaluate a fish-meal-free, fish-oil-free diet for use with first-feeding steelhead Oncorhynchus mykiss. The marine-based control diet (marine diet) contained sardine (Sardinops spp.) meal and pollock (Pollachius virens) liver oil as the primary sources of protein and lipid, respectively. The experimental diet (terrestrial diet) contained only terrestrial sources of protein (poultry by-product meal, blood

Ronald G. Twibell; Ann L. Gannam; Susan L. Ostrand; John S. A. Holmes; Jeff B. Poole

2011-01-01

234

Passive propulsion in vortex wakes  

NASA Astrophysics Data System (ADS)

A dead fish is propelled upstream when its flexible body resonates with oncoming vortices formed in the wake of a bluff cylinder, despite being well outside the suction region of the cylinder. Within this passive propulsion mode, the body of the fish extracts sufficient energy from the oncoming vortices to develop thrust to overcome its own drag. In a similar turbulent wake and at roughly the same distance behind a bluff cylinder, a passively mounted high-aspect-ratio foil is also shown to propel itself upstream employing a similar flow energy extraction mechanism. In this case, mechanical energy is extracted from the flow at the same time that thrust is produced. These results prove experimentally that, under proper conditions, a body can follow at a distance or even catch up to another upstream body without expending any energy of its own. This observation is also significant in the development of low-drag energy harvesting devices, and in the energetics of fish dwelling in flowing water and swimming behind wake-forming obstacles.

Beal, D. N.; Hover, F. S.; Triantafyllou, M. S.; Liao, J. C.; Lauder, G. V.

235

Accommodating electric propulsion on SMART-1  

NASA Astrophysics Data System (ADS)

This paper focuses on the technical challenges that arise when electric propulsion is used on a small spacecraft such as SMART-1. The choice of electric propulsion influences not only the attitude control system and the power system, but also the thermal control as well as the spacecraft structure. A description is given on how the design of the attitude control system uses the possibility to control the alignment of the thrust vector in order to reduce the momentum build-up. An outline is made of the philosophy of power generation and distribution and shows how the thermal interfaces to highly dissipating units have been solved. Areas unique for electric propulsion are the added value of a thrust vector orientation mechanism and the special consideration given to the electromagnetic compatibility. SMART-1 is equipped with a thruster gimbal mechanism providing a 10° cone in which the thrust vector can be pointed. Concerning the electromagnetic compatibility, a discussion on how to evaluate the available test results is given keeping in mind that one of the main objectives of the SMART-1 mission is to assess the impact of electric propulsion on the scientific instruments and on other spacecraft systems. Finally, the assembly, integration and test of the spacecraft is described. Compared to traditional propulsion systems, electric propulsion puts different requirements on the integration sequence and limits the possibilities to verify the correct function of the thruster since it needs high quality vacuum in order to operate. Prime contractor for SMART-1 is the Swedish Space Corporation (SSC). The electric propulsion subsystem is procured directly by ESA from SNECMA, France and is delivered to SSC as a customer furnished item. The conclusion of this paper is that electric propulsion is possible on a small spacecraft, which opens up possibilities for a new range of missions for which a large velocity increment is needed. The paper will also present SMART-1 and show how the problems related to the accommodation of electric propulsion have been solved during design and planning of the project.

Kugelberg, Joakim; Bodin, Per; Persson, Staffan; Rathsman, Peter

2004-07-01

236

Nuclear thermal propulsion engine cost trade studies  

SciTech Connect

The NASA transportation strategy for the Mars Exploration architecture includes the use of nuclear thermal propulsion as the primary propulsion system for Mars transits. It is anticipated that the outgrowth of the NERVA/ROVER programs will be a nuclear thermal propulsion (NTP) system capable of providing the propulsion for missions to Mars. The specific impulse (Isp) for such a system is expected to be in the 870 s range. Trade studies were conducted to investigate whether or not it may be cost effective to invest in a higher performance (Isp[gt]870 s) engine for nuclear thermal propulsion for missions to Mars. The basic cost trades revolved around the amount of mass that must be transported to low-earth orbit prior to each Mars flight and the cost to launch that mass. The mass required depended on the assumptions made for Mars missions scenarios including piloted/cargo flights, number of Mars missions, and transit time to Mars. Cost parameters included launch cost, program schedule for development and operations, and net discount rate. The results were very dependent on the assumptions that were made. Under some assumptions, higher performance engines showed cost savings in the billions of dollars; under other assumptions, the additional cost to develop higher performance engines was not justified.

Paschall, R.K. (Rocketdyne Division, Rockwell International Corporation, Mail Stop IB57, 6633 Canoga Avenue, P.O. Box 7922, Canoga Park, California 91309-7922 (United States))

1993-01-10

237

The Future of Hydrazine Propulsion Systems  

NASA Astrophysics Data System (ADS)

CNES micro and mini-satellites platforms already use hydrazine propulsion subsystems. The PLEIADES satellites will also resort to hydrazine technology. For other missions in the future, CNES performs pilot projects in order to define the best technical solution to meet the needs of the mission. Regarding propulsion, hydrazine technology keeps on being valuable for different kinds of applications. After a brief description of the existing subsystems (micro and mini-satellites platforms MYRIADE and PROTEUS, PLEIADES), different examples of pilot projects for which hydrazine is necessary are given. In these examples, the role of the hydrazine propulsion subsystem goes from a complement of the ~H~FV performed by the launcher to attitude control when the main engines are electrical thrusters. Owing to these examples, we can see which values of thrust and which tank volumes are needed. Moreover, Research and Development actions, supported by the Propulsion and Pyrotechnics Department in CNES Toulouse, and which could be applied to hydrazine propulsion, are mentioned.

Gibek, I.

2004-10-01

238

Simplest magnetic propulsion experiment with liquid gallium  

NASA Astrophysics Data System (ADS)

Magnetic propulsion of liquid metal represents a new MHD effect (discovered in Dec. 1998) which allows to drive fast liquid metal (essentially, lithium) flow in the strong toroidal magnetic field. For the fusion research, it suggests a unique way of the power extraction from the tokamak-reactor chamber. Fast flowing liquid lithium can extract at least an order of magnitude more power than typically considered in the conventional concepts, (all oriented toward the divertor configurations). Importance of the problem of the power extraction recently became even more evident when the conventional reactor approach (after 25 years of existence and spending) spent almost 15 years on the ITER next step tokamak project and resulted in a 1 MW/m^2 of the power load on the first wall, too small for the any reasonable fusion reactor. In contrast to this, the power extraction capabilities of magnetic propulsion are fully consistent with the fusion reactor requirements or even exceeding them. The first experiment, which demonstrates the effect of magnetic propulsion has been developed in PPPL based on small coaxial propulsion cell with the magnetic field generated by the current through the cell. The device can work in both propulsion and the current limiting regime.

Zakharov, L. E.; Hoffman, D.; Taylor, J.

2001-10-01

239

Nuclear thermal propulsion engine cost trade studies  

NASA Astrophysics Data System (ADS)

The NASA transportation strategy for the Mars Exploration architecture includes the use of nuclear thermal propulsion as the primary propulsion system for Mars transits. It is anticipated that the outgrowth of the NERVA/ROVER programs will be a nuclear thermal propulsion (NTP) system capable of providing the propulsion for missions to Mars. The specific impulse (Isp) for such a system is expected to be in the 870 s range. Trade studies were conducted to investigate whether or not it may be cost effective to invest in a higher performance (Isp>~870 s) engine for nuclear thermal propulsion for missions to Mars. The basic cost trades revolved around the amount of mass that must be transported to low-earth orbit prior to each Mars flight and the cost to launch that mass. The mass required depended on the assumptions made for Mars missions scenarios including piloted/cargo flights, number of Mars missions, and transit time to Mars. Cost parameters included launch cost, program schedule for development and operations, and net discount rate. The results were very dependent on the assumptions that were made. Under some assumptions, higher performance engines showed cost savings in the billions of dollars; under other assumptions, the additional cost to develop higher performance engines was not justified.

Paschall, Robert K.

1993-01-01

240

NASA's nuclear electric propulsion technology project  

NASA Astrophysics Data System (ADS)

The National Aeronautics and Space Administration (NASA) has initiated a program to establish the readiness of nuclear electric propulsion (NEP) technology for relatively near-term applications to outer planet robotic science missions with potential future evolution to system for piloted Mars vehicles. This program was initiated in 1991 with a very modest effort identified with nuclear thermal propulsion (NTP); however, NEP is also an integral part of this program and builds upon NASA's Base Research and Technology Program in power and electric propulsion as well as the SP-100 space nuclear power program. The NEP Program will establish the feasibility and practicality of electric propulsion for robotic and piloted solar system exploration. The performance objectives are high specific impulse (200 greater than I(sub sp) greater than 10000 s), high efficiency (over 0.50), and low specific mass. The planning for this program was initially focussed on piloted Mars missions, but has since been redirected to first focus on 100-kW class systems for relatively near-term robotic missions, with possible future evolution to megawatt- and multi-megawatt-class systems applicable to cargo vehicles supporting human missions as well as to the piloted vehicles. This paper reviews current plans and recent progress for the overall nuclear electric propulsion project and closely related activities.

Stone, James R.; Sovey, James S.

1992-07-01

241

NASA's nuclear electric propulsion technology project  

NASA Astrophysics Data System (ADS)

The National Aeronautics and Space Administration (NASA) has initiated a program to establish the readiness of nuclear electric propulsion (NEP) technology for relatively near-term applications to outer planet robotic science missions with potential future evolution to system for piloted Mars vehicles. This program was initiated in 1991 with a very modest effort identified with nuclear thermal propulsion (NTP); however, NEP is also an integral part of this program and builds upon NASA's Base Research and Technology Program in power and electric propulsion as well as the SP-100 space nuclear power program. The NEP Program will establish the feasibility and practicality of electric propulsion for robotic and piloted solar system exploration. The performance objectives are high specific impulse (200 greater than I(sub sp) greater than 10000 s), high efficiency (over 0.50), and low specific mass. The planning for this program was initially focussed on piloted Mars missions, but has since been redirected to first focus on 100-kW class systems for relatively near-term robotic missions, with possible future evolution to megawatt-and multi-megawatt-class systems applicable to cargo vehicles supporting human missions as well as to the piloted vehicles. This paper reviews current plans and recent progress for the overall nuclear electric propulsion project and closely related activities.

Stone, James R.; Sovey, James S.

1992-07-01

242

Relativistic propulsion using directed energy  

NASA Astrophysics Data System (ADS)

We propose a directed energy orbital planetary defense system capable of heating the surface of potentially hazardous objects to the evaporation point as a futuristic but feasible approach to impact risk mitigation. The system is based on recent advances in high efficiency photonic systems. The system could also be used for propulsion of kinetic or nuclear tipped asteroid interceptors or other interplanetary spacecraft. A photon drive is possible using direct photon pressure on a spacecraft similar to a solar sail. Given a laser power of 70GW, a 100 kg craft can be propelled to 1AU in approximately 3 days achieving a speed of 0.4% the speed of light, and a 10,000 kg craft in approximately 30 days. We call the system DE-STAR for Directed Energy System for Targeting of Asteroids and exploRation. DE-STAR is a modular phased array of solid-state lasers, powered by photovoltaic conversion of sunlight. The system is scalable and completely modular so that sub elements can be built and tested as the technology matures. The sub elements can be immediately utilized for testing as well as other applications including space debris mitigation. The ultimate objective of DE-STAR would be to begin direct asteroid vaporization and orbital modification starting at distances beyond 1 AU. Using phased array technology to focus the beam, the surface spot temperature on the asteroid can be raised to more than 3000K, allowing evaporation of all known substances. Additional scientific uses of DE-STAR are also possible.

Bible, Johanna; Johansson, Isabella; Hughes, Gary B.; Lubin, Philip M.

2013-09-01

243

Turbine Engine Multi-Mission Propulsion Simulator Wind Tunnel Demonstration.  

National Technical Information Service (NTIS)

A turbine engine multi-mission propulsion simulator, developed by the Air Force Aero Propulsion Laboratory (AFAPL) to permit improved aircraft performance prediction capability through the simultaneous simulation of inlet/airframe/nozzle flowfields, was s...

M. F. Eigenmann R. L. Bear T. C. Chandler

1976-01-01

244

UH-1N Category II Propulsion System Evaluation.  

National Technical Information Service (NTIS)

This report presents the results of the propulsion system evaluation conducted during the UH-1N Category II systems evaluation program. The propulsion system was adequate for accomplishment of mission objectives, but several improvements should be made. F...

J. C. Brandt E. B. Russell

1971-01-01

245

Fluid Distribution for In-space Cryogenic Propulsion.  

National Technical Information Service (NTIS)

The ultimate goal of this task is to enable the use of a single supply of cryogenic propellants for three distinct spacecraft propulsion missions: main propulsion, orbital maneuvering, and attitude control. A fluid distribution system is sought which allo...

W. Lear

2005-01-01

246

46 CFR 111.33-11 - Propulsion systems.  

Code of Federal Regulations, 2012 CFR

...ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Power Semiconductor Rectifier Systems § 111.33-11 Propulsion systems. Each power semiconductor rectifier system in a propulsion system must meet sections...

2012-10-01

247

46 CFR 111.35-1 - Electrical propulsion installations.  

Code of Federal Regulations, 2012 CFR

...111.35-1 Section 111.35-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Electric Propulsion § 111.35-1 Electrical propulsion...

2012-10-01

248

Integrated Magnetic Propulsion and Suspension, Top Suspended Dynamic Test Report.  

National Technical Information Service (NTIS)

The report describes the tests performed on a full scale magnetically suspended vehicle using the Integrated Magnetic Propulsion and Suspension (IMPS) system. The IMPS uses the same Linear Induction Motor (LIM) to provide both suspension and propulsion fo...

G. Ecker R. G. Gilliland G. W. Pearson

1985-01-01

249

Inertial-Electrostatic Confinement (IEC) Fusion For Space Propulsion.  

National Technical Information Service (NTIS)

An Inertial-Electrostatic Confinement (IEC) device was assembled at the Marshall Space Flight Center (MSFC) Propulsion Research Center (PRC) to study the possibility of using IEC technology for deep space propulsion and power. Inertial-Electrostatic Confi...

J. Nadler

1999-01-01

250

Hybrid Propulsion Testing at Marshall Space Flight Center.  

National Technical Information Service (NTIS)

Hybrid propulsion testing involving eleven and twenty-four inch motors performed at the Marshall Space Flight Center (MSFC) from the early 1990's to the present are discussed. Topics covered include: Solid Propulsion Investigation Program, Joint NASA Indu...

A. S. Prince

2002-01-01

251

Hybrid Propulsion Demonstration Program 250K Hybrid Motor.  

National Technical Information Service (NTIS)

The Hybrid Propulsion Demonstration Program (HPDP) program was formed to mature hybrid propulsion technology to a readiness level sufficient to enable commercialization for various space launch applications. The goal of the HPDP was to develop and test a ...

G. Story T. Zoladz J. Arves D. Kearney T. Abel O. Park

2003-01-01

252

Propulsion Physics Under the Changing Density Field Model.  

National Technical Information Service (NTIS)

To grow as a space faring race, future spaceflight systems will requires new propulsion physics. Specifically a propulsion physics model that does not require mass ejection without limiting the high thrust necessary to accelerate within or beyond our sola...

G. A. Robertson

2011-01-01

253

Interplanetary Sample Return Missions Using Radioisotope Electric Propulsion.  

National Technical Information Service (NTIS)

Solar electric propulsion (SEP) is being used for a variety of planetary missions sponsored by ESA, JAXA, and NASA and nuclear electric propulsion (NEP) is being considered for future, flagship-class interplanetary missions. Radioisotope electric propulsi...

R. Williams Y. Gao C. A. Kluever M. Cupples J. Belcher

2005-01-01

254

Transient Region Coverage in the Propulsion IVHM Technology Experiment.  

National Technical Information Service (NTIS)

Over the last several years researchers at NASA Glenn and Ames Research Centers have developed a real-time fault detection and isolation system for propulsion subsystems of future space vehicles. The Propulsion IVHM Technology Experiment (PITEX), as it is...

E. Balaban A. Sweet A. Bajwa W. Maul C. Fulton Chicatelli

2004-01-01

255

A Microwave Thruster for Spacecraft Propulsion  

SciTech Connect

This presentation describes how a microwave thruster can be used for spacecraft propulsion. A microwave thruster is part of a larger class of electric propulsion devices that have higher specific impulse and lower thrust than conventional chemical rocket engines. Examples of electric propulsion devices are given in this presentation and it is shown how these devices have been used to accomplish two recent space missions. The microwave thruster is then described and it is explained how the thrust and specific impulse of the thruster can be measured. Calculations of the gas temperature and plasma properties in the microwave thruster are discussed. In addition a potential mission for the microwave thruster involving the orbit raising of a space station is explored.

Chiravalle, Vincent P [Los Alamos National Laboratory

2012-07-23

256

Solar thermal propulsion for planetary spacecraft  

SciTech Connect

Previous studies have shown that many desirable planetary exploration missions require large injection delta-V. Solar Thermal Rocket (STR) propulsion, under study for orbit-raising applications may enhance or enable such high-energy missions. The required technology of thermal control for liquid hydrogen propellant is available for the required storage duration. Self-deploying, inflatable solar concentrators are under study. The mass penalty for passive cryogenic thermal control, liquid hydrogen tanks and solar concentrators does not compromise the specific impulse advantage afforded by the STR as compared to chemical propulsion systems. An STR injection module is characterized and performance is evaluated by comparison to electric propulsion options for the Saturn Orbiter Titan Probe (SOTP) and Uranus Flyby Uranus Probe (UFUP) missions.

Sercel, J.C.

1985-01-01

257

New propulsion components for electric vehicles  

SciTech Connect

The goal of DOE's Electric and Hybrid Vehicle Program is to advance technologies for electric and hybrid vehicles in order to enhance their potential as transportation options of national significance. Successful achievment of this goal will ultimately result in significant petroleum savings to the nation. However, the design, performance, and cost of propulsion components must be improved before commercially attractive electric vehicles can be built. This paper describes improved and advanced component technology developed under the NASA-managed propulsion portion of the DOE program. This includes electronically commutated permanent magnet motors of both drum and disk configurations, an unconventional brush-commutated motor, ac induction motors, various controllers, transmissions and complete systems. One or more of these new approaches to electric vehicle propulsion may eventually displace presently used controllers and brush commutated dc motors.

Secunde, R.R.

1983-01-01

258

New propulsion components for electric vehicles  

SciTech Connect

The goal of DOE's Electric and Hybrid Vehicle Program is to advance technologies for electric and hybrid vehicles in order to enhance their potential as transportation options of national significance. Successful achievement of this goal will ultimately result in significant petroleum savings to the nation. However, the design, performance, and cost of propulsion components must be improved before commercially attractive electric vehicles can be built. This paper describes improved and advanced component technology developed under the NASA-managed propulsion portion of the DOE program. This includes electronically commutated permanent magnet motors of both drum and disk configurations, an unconventional brush-commutated motor, ac induction motors, various controllers, transmissions and complete systems. One or more of these new approaches to electric vehicle propulsion may eventually displace presently used controllers and brush commutated dc motors.

Secunde, R.R.

1983-08-01

259

Reduced Hazard Propellant -- Propulsion System Impact  

NASA Astrophysics Data System (ADS)

In recent years, there has been an increasing interest in propellants less toxic than conventional propellants. These propellants are potentially easier and safer to handle and are expected to reduce the costs associated with propellant ground operations, transport and spacecraft development. This paper outlines the future applications and the system specific performance as well as propulsion system impact for some of the less toxic propellants proposed. A propulsion system analysis is performed to identify RHP applications. The system specific impulse, Issp, is used to evaluate the propulsion system performance when required velocity increment is assigned. Moreover, a transient finite volume model is developed to evaluate water hammer effects and system pressure drops using a CFD code. Less toxic propellants are hereafter denoted as "reduced hazard propellants - RHP".

Boman, N.; Ford, M.

2004-10-01

260

Laser Propulsion - Is it another myth or a real potential?  

SciTech Connect

This paper discusses different principles of inducing propulsive power using lasers and examines the performance limits along with pros and cons with respect to different space propulsion applications: satellite launching, orbital transfer, space debris clearing, satellite propulsion, and space travels. It concludes that a use of electrical propulsion, in conjunction with laser power beaming, is the most feasible application with technological and economic advantages for commercial use within the next decades.

Cook, Joung R. [J. Cook and Associates, McLean, Virginia 22101 (United States)

2008-04-28

261

Nuclear Electric Propulsion for the Exploration of the Outer Planets  

Microsoft Academic Search

New power and propulsion technology efforts such as the DS-1 ion propulsion system demonstration and renewed interest in space nuclear power sources call for a reassessment of the mission benefits of Nuclear Electric Propulsion (NEP). In this study, a large emphasis has been placed in defining the NEP vehicle configuration and corresponding subsystem elements in order to produce an estimate

M. Noca; J. E. Polk; R. Lenard

2001-01-01

262

Development Status of the NSTAR Ion Propulsion System Power Processor.  

National Technical Information Service (NTIS)

A 0.5-2.3 kW xenon ion propulsion system is presently being developed under the NASA Solar Electric Propulsion Technology Application Readiness (NSTAR) program. This propulsion system includes a 30 cm diameter xenon ion thruster, a Digital Control Interfa...

J. A. Hamley L. R. Pinero V. K. Rawlin J. R. Miller K. C. Cartier

1995-01-01

263

The impact of ion propulsion on high energy interplanetary missions  

Microsoft Academic Search

Interplanetary science missions often require a significant on-board propulsive capability, which results in the need to carry large quantities of propellant. This reduces possible payload mass, or increases the overall size, mass and cost of the mission. Ion propulsion offers an attractive means of avoiding these large propellant masses associated with chemical propulsion systems. Indeed, if a spiral orbit-raising approach

David G Feam

1995-01-01

264

An Object Oriented Extensible Architecture for Affordable Aerospace Propulsion Systems  

Microsoft Academic Search

Summary Driven by a need to explore and develop propulsion systems that exceeded current computing capabilities, NASA Glenn embarked on a novel strategy leading to the development of an architecture that enables propulsion simulations never thought possible before. Full engine 3 Dimensional Computational Fluid Dynamic propulsion system simulations were deemed impossible due to the impracticality of the hardware and software

Gregory J. Follen

265

AN ELECTROSTATIC PROPULSION SYSTEM WITH A DIRECT NUCLEAR ELECTROGENERATOR  

Microsoft Academic Search

A preliminary study is presented to establish the theoretical ; feasibility of the direct nuclear electrostatic propulsion system and to provide ; an estimate of the possible mass\\/power ratio of an overall system. The general ; theory behind the direct nuclear electrogenerator and propulsion system is ; presented and various radioisotopes are evaluated for their suitability for space ; propulsion

C. A. Jr. Low; W. R. Mickelsen

1962-01-01

266

A propulsion technology challenge — An abortable. Continuous use vehicle  

Microsoft Academic Search

Propulsion is the enabling technology for an abortable, continuous use vehicle. Propulsion performance purchases margin in the other material, structural, and system requirements. But what is abortability, and continuous use? Why is it necessary? What are its characteristics? And, what specifically is required in the propulsion system to enable these characteristics? Is the cost of the launcher really trivial, or

H. David Froning

1996-01-01

267

TOPICAL REVIEW: Plasmas for spacecraft propulsion  

NASA Astrophysics Data System (ADS)

This review presents the basics of plasma discharges applied to electric spacecraft propulsion. It briefly reports on the mature and flown technologies of gridded ion thrusters and Hall thrusters before exploring the recent yet immature technology of plasma thrusters based on expansion from low pressure high density inductively coupled and wave-excited plasma sources, e.g. the radiofrequency helicon source. Prototype development of plasma engines for future space travel is discussed using the example of the helicon double layer thruster. A summary of highlights in electric propulsion based space missions gives some insight into the challenges of future high power missions in more remote regions of space.

Charles, C.

2009-08-01

268

A development approach for nuclear thermal propulsion  

SciTech Connect

The cost and time to develop nuclear thermal propulsion systems are very approach dependent. The objectives addressed are the development of an acceptable'' nuclear thermal propulsion system that can be used as part of the transportation system for people to explore Mars and the enhancement performance of other missions, within highly constrained budgets and schedules. To accomplish this, it was necessary to identify the cost drivers considering mission parameters, safety of the crew, mission success, facility availability and time and cost to construct new facilities, qualification criteria, status of technologies, management structure, and use of such system engineering techniques as concurrent engineering.

Buden, D.

1992-01-01

269

A development approach for nuclear thermal propulsion  

SciTech Connect

The cost and time to develop nuclear thermal propulsion systems are very approach dependent. The objectives addressed are the development of an ``acceptable`` nuclear thermal propulsion system that can be used as part of the transportation system for people to explore Mars and the enhancement performance of other missions, within highly constrained budgets and schedules. To accomplish this, it was necessary to identify the cost drivers considering mission parameters, safety of the crew, mission success, facility availability and time and cost to construct new facilities, qualification criteria, status of technologies, management structure, and use of such system engineering techniques as concurrent engineering.

Buden, D.

1992-09-01

270

Propulsion of Microorganisms by Surface Distortions  

SciTech Connect

Swimming strategies of microorganisms must conform to the principles of self-propulsion at low Reynolds numbers. Here we relate the translational and rotational speeds to the surface motions of a swimmer and, for spheres, make evident novel constraints on mechanisms for propulsion. The results are applied to a cyanobacterium, an organism while motile mechanism is unknown, by considering incompressible streaming of the cell surface and oscillatory, tangential surface deformations. Finally, swimming efficiency using tangential motions is related to the surface velocities and a bound on the efficiency is obtained. {copyright} {ital 1996 The American Physical Society.}

Stone, H.A. [Division of Engineering & Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Samuel, A.D. [Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138 and Rowland Institute for Science, Cambridge, Massachusetts 02142 (United States)

1996-11-01

271

Self-propulsion through symmetry breaking  

NASA Astrophysics Data System (ADS)

In addition to self-propulsion by phoretic mechanisms that arises from an asymmetric distribution of reactive species around a catalytic motor, spherical particles with a uniform distribution of catalytic activity may also propel themselves under suitable conditions. Reactive fluctuation-induced asymmetry can give rise to transient concentration gradients which may persist under certain conditions, giving rise to a bifurcation to self-propulsion. The nature of this phenomenon is analyzed in detail, and particle-level simulations are carried out to demonstrate its existence.

de Buyl, Pierre; Mikhailov, Alexander S.; Kapral, Raymond

2013-09-01

272

Radioisotope electric propulsion (REP): A near-term approach to nuclear propulsion  

NASA Astrophysics Data System (ADS)

Studies over the last decade have shown radioisotope-based nuclear electric propulsion to be enhancing and, in some cases, enabling for many potential robotic science missions. Also known as radioisotope electric propulsion (REP), the technology offers the performance advantages of traditional reactor-powered electric propulsion (i.e., high specific impulse propulsion at large distances from the Sun), but with much smaller, affordable spacecraft. Future use of REP requires development of radioisotope power sources with system specific powers well above that of current systems. The US Department of Energy and NASA have developed an advanced Stirling radioisotope generator (ASRG) engineering unit, which was subjected to rigorous flight qualification-level tests in 2008, and began extended lifetime testing later that year. This advancement, along with recent work on small ion thrusters and life extension technology for Hall thrusters, could enable missions using REP sometime during the next decade.

Schmidt, George R.; Manzella, David H.; Kamhawi, Hani; Kremic, Tibor; Oleson, Steven R.; Dankanich, John W.; Dudzinski, Leonard A.

2010-02-01

273

A review of pulse fusion propulsion  

Microsoft Academic Search

During the last forty years there has been considerable interest in both internal and external pulse propulsion systems. Over this time the nuclear devices being considered have grown considerably smaller than those initially examined. Now pellets are normally in the range from 15 cm down to 2 cm in diameter, and fusion devices are generally preferred. High energy density triggers

Brice N. Cassenti

2002-01-01

274

Some perspectives on pulse detonation propulsion systems  

Microsoft Academic Search

Pulse detonation engines and rockets (PDE\\/Rs) can potentially revolutionize air breathing and rocket propulsion [1-6]. While the PDE concept is over five decades old, it has recently enjoyed renewed interest, due mostly to theoretical and computational studies indicating high cycle efficiencies. When modeled by a constant volume, Humphrey cycle, the detonation engine is found to be superior to that of

F. K. Lu; D. R. Wilson

2005-01-01

275

Advanced Supersonic Propulsion Study, Phase 2.  

National Technical Information Service (NTIS)

A continuation of the NASA/P and WA study to evaluate various types of propulsion systems for advanced commercial supersonic transports has resulted in the identification of two very promising engine concepts. They are the Variable Stream Control Engine w...

R. A. Howlett

1975-01-01

276

Swimming propulsion and muscle force moments  

Microsoft Academic Search

Based on 3D video analysis of swimming movements hypotheses on the mechanisms of propulsion are deduced. Body point coordinates and their first and second derivatives are computed. The limb environment where water particle displacement occurs is estimated. We apply the Navier–Stokes equation to compute the total force for those particles. The shoulder torque is calculated by summation over environments of

Falk Hildebrand; Axel Schüler

2010-01-01

277

Propulsive force asymmetry during tethered-swimming.  

PubMed

This study aimed to determine whether: i) tethe-red-swimming can be used to identify the asymmetry during front crawl swimming style; ii) swimmers that perform unilateral breathing present greater asymmetry in comparison to others that use bilateral breathing; iii) swimmers of best performance present smaller asymmetry than their counterparts; iv) repeated front crawl swimming movements influence body asymmetry. 18 swimmers were assessed for propulsive force parameters (peak force, mean force, impulse and rate of force development) during a maximal front crawl tethered-swimming test lasting 2 min. A factorial analysis showed that propulsive forces decreased at the beginning, intermediate and end of the test (p<0.05), but the asymmetries were not changed at different instants of the test. When breathing preference (uni- or bilateral) was analyzed, asymmetry remained unchanged in all force parameters (p>0.05). When performance was considered (below or above mean group time), a larger asymmetry was found in the sub-group of lower performance in comparison to those of best performance (p<0.05). Therefore, the asymmetries of the propulsive forces can be detected using tethered-swimming. The propulsive forces decreased during the test but asymmetries did not change under testing conditions. Although breathing preference did not influence asymmetry, swimmers with best performance were less asymmetric than their counterparts. PMID:23325714

dos Santos, K B; Pereira, G; Papoti, M; Bento, P C B; Rodacki, A

2013-01-16

278

Mars Missions Using Solar Electric Propulsion  

Microsoft Academic Search

Solar Electric Propulsion (SEP) trajectories are shown for Mars missions between late 2004 and 201 1. Mission performance is presented as burn-out mass along contours of constant flight time. These missions are characterized by low injection energies, and therefore with a given launch vehicle, greater injected mass. The superior specific impulse of the SEP results in a larger delivered mass

Steven N. Williams; Victoria Coverstone-Carroll

2000-01-01

279

Heat management concepts for hypersonic propulsion systems  

Microsoft Academic Search

This paper presents preliminary results on the design of heat management and cooling concepts for turbo-ramjet propulsion systems with flight operation up to Mach 7. The studies were conducted with the aim to define the technologies that have to be matured for the final engine design. The results presented in this paper focus on the assessment of the overall cooling

K. Rued; H. Mark; G. Goetz

1991-01-01

280

Autophagous spacecraft composite materials for orbital propulsion  

Microsoft Academic Search

We are developing structural polymer composite materials that can be converted into fuels and combusted with oxidizers for orbital propulsion of spacecraft. We have identified candidate materials and demonstrated sustained combustion with nitrogen tetroxide (NTO) as an oxidizer. To improve reaction chemistry we have evaluated several energetic additives. Detailed material compatibility tests were conducted to identify stable combinations of structural

Prakash Joshi; Bernard L. Upschulte; Alan H. Gelb; B. David Green; Dean M. Lester; Ingvar Wallace; W. David Starrett; David W. Marshall

2002-01-01

281

Hybrid Propulsion System Transmission Evaluation. Phase I.  

National Technical Information Service (NTIS)

The purpose was to assess the practicality of a transmission for use in a heat engine/flywheel propulsion system to reduce emissions. The system was to be suitable for incorporation into a full size 'family car' automobile. The different possible link typ...

M. A. Cordner D. H. Grimm

1972-01-01

282

A concept of ferroelectric microparticle propulsion thruster  

SciTech Connect

A space propulsion concept using charged ferroelectric microparticles as a propellant is suggested. The measured ferroelectric plasma source thrust, produced mainly by microparticles emission, reaches {approx}9x10{sup -4} N. The obtained trajectories of microparticles demonstrate that the majority of the microparticles are positively charged, which permits further improvement of the thruster.

Yarmolich, D.; Vekselman, V.; Krasik, Ya. E. [Physics Department, Technion, 32000 Haifa (Israel)

2008-02-25

283

Direct drive options for electric propulsion systems  

Microsoft Academic Search

Power processing units (PPU's) in an electric propulsion system provide many challenging integration issues. The PPU must provide power to the electric thruster while maintaining compatibility with all of the spacecraft power and data systems. Inefficiencies in the power processor produce heat, which must be radiated to the environment in order to ensure reliable operation. Although PPU efficiencies are generally

John A. Hamley

1995-01-01

284

Direct drive options for electric propulsion systems  

NASA Astrophysics Data System (ADS)

Power processing units (PPU's) in an electric propulsion system provide many challenging integration issues. The PPU must provide power to the electric thruster while maintaining compatibility with all of the spacecraft power and data systems. Inefficiencies in the power processor produce heat, which must be radiated to the environment in order to ensure reliable operation. Although PPU efficiencies are generally greater than 0.9, heat loads are often substantial. This heat must be rejected by thermal control systems which generally have specific masses of 15-30 kg/kW. PPU's also represent a large fraction of the electric propulsion system dry mass. Simplification or elimination of power processing in a propulsion system would reduce the electric propulsion system specific mass and improve the overall reliability and performance. A direct drive system would eliminate all or some of the power supplies required to operate a thruster by directly connecting the various thruster loads to the solar array. The development of concentrator solar arrays has enabled power bus voltages in excess of 300 V which is high enough for direct drive applications for Hall thrusters such as the Stationary Plasma Thruster (SPT). The option of solar array direct drive for SPT's is explored to provide a comparison between conventional and direct drive system mass.

Hamley, John A.

1995-05-01

285

Direct drive options for electric propulsion systems  

Microsoft Academic Search

Power processing units (PPUs) in an electric propulsion system provide many challenging integration issues. The PPU must provide power to the electric thruster while maintaining compatibility with all of the spacecraft power and data systems. Inefficiencies in the power processor produce heat, which must be radiated to the environment in order to ensure reliable operation. Although PPU efficiencies are generally

John A. Hamley

1996-01-01

286

Optimum Propulsion of an Oscillating Hydrofoil.  

National Technical Information Service (NTIS)

A study is made on the optimization aspect of marine propulsion in the light of optimum control theory for distributed parameter systems. In particular, the problem of determining the motion of a thin hydrofoil or a 'thin fish' to maximize the average thr...

P. K. C. Wang

1966-01-01

287

Ion propulsion development in the UK  

NASA Astrophysics Data System (ADS)

Research into several forms of ion propulsion began in the UK in the 1960s, but was soon concentrated on a 10 cm diameter Kaufman-type thruster, using mercury propellant to provide a thrust of 10 mN. This device has now evolved into the T5 Mk 3 variant, using xenon and operating nominally at 25 mN thrust. It is intended primarily for north-south station-keeping and drag compensation missions, with an initial application to ESA's ARTEMIS spacecraft as part of the UK-10 ion propulsion system. A lower cost system may fly on the Nuclear Electric Propulsion Space Test Program satellite. A scaled-up version of 25 cm diameter has also been developed for primary propulsion tasks and has achieved the same high level of performance as the T5 thruster. The paper describes the technical status of these programs, with emphasis on the design and qualification of the systems incorporating the smaller thruster.

Fearn, D. G.; Martin, A. R.; Smith, P.

1993-06-01

288

System model development for nuclear thermal propulsion  

Microsoft Academic Search

The strategy and progress of an interagency NASA\\/DOE\\/DOD team for nuclear thermal propulsion (NTP) system modeling are presented. The main goal of the interagency team is to develop several levels of computer programs for predicting the performance of various NTP systems. These programs are being developed to support the evaluation of conceptual designs and to provide a diagnostic tool for

James T. Walton; Nelson A. Hannan; Ken R. Perkins; John J. Buksa; Brian A. Worley; Dean Dobranich

1992-01-01

289

Nuclear Electric Propulsion Space Environmental Studies  

Microsoft Academic Search

High energy photons emitted from space fission power supplies should not directly interfere with astronomical satellites in an unacceptable way. However, positrons emitted from space fission power and propulsion systems could potentially lead to interference with sensitive astronomical satellites, such as the Gamma Ray Observatory (GRO). Positrons are created when a high energy photon is attenuated by pair production. If

Michael G. Houts; Edward W. Hones; Joachim Birn; Paul Agnew; Gary J. Scrivner; Wesley Fan

1994-01-01

290

Carbide fuels for nuclear thermal propulsion  

Microsoft Academic Search

A renewed interest in manned exploration of space has revitalized interest in the potential for advancing nuclear rocket technology developed during the 1960's. Carbide fuel performance, melting point, stability, fabricability and compatibility are key technology issues for advanced Nuclear Thermal Propulsion reactors. The Rover fuels development ended with proven carbide fuel forms with demonstrated operating temperatures up to 2700 K

R. B. Matthews; H. T. Blair; K. M. Chidester; K. V. Davidson; W. E. Stark; E. K. Storms

1991-01-01

291

Contributions Regarding the Aircraft Nuclear Propulsion  

Microsoft Academic Search

The possibility to use a nuclear reactor for airplanes propulsion was investigated taking in to account 2 possible solutions: the direct cycle (where the fluid pass through the reactor's core) and the indirect cycle (where the fluid is passing through a heat exchanger). Taking in to account the radioprotection problems, the only realistic solution seems to be the indirect cycle,

Bogdan Mitrica; Virgil Stanciu; Marian Petre; Mihai Octavian Dima; Carmelia Petre; Irinel Precup

2010-01-01

292

NASA Spaceliner 100 Propulsion Oriented Technology Assessment.  

National Technical Information Service (NTIS)

In response to a NASA request, the National Space Propulsion Synergy Team (SPST) team agreed to provide technical and programmatic support to NASA in formulating a Spaceliner 100 Technology Program. The SPST offered a broad cross-section of expertise and ...

W. Dankhoff K. Dayton D. Levack P. Odom R. Rhodes J. Robinson

2000-01-01

293

Investigation of Propulsive Aspects of Mach Effects  

SciTech Connect

Results of a continuing investigation of the propulsive potential of Mach effects - the fluctuation of the rest masses of objects that store internal energy as they are accelerated by external forces - obtained in the past year or so are reported. Two chief lines of investigation have been pursued: testing Mach-Lorentz thrusters (MLTs) and exploration of the 'bulk acceleration' conjecture.

Woodward, James F. [Department of Physics California State University Fullerton Fullerton, CA 92834 714-278-3596 (United States)

2009-03-16

294

New propulsion components for electric vehicles  

Microsoft Academic Search

Improved component technology is described. This includes electronically commutated permanent magnet motors of both drum and disk configurations, an unconventional brush commutated motor, ac induction motors, various controllers, transmissions and complete systems. One or more of these approaches to electric vehicle propulsion may eventually displace presently used controllers and brush commutated dc motors. Previously announced in STAR as N83-25982

R. R. Secunde

1983-01-01

295

PEGASES - plasma propulsion with electronegative gases  

Microsoft Academic Search

A new concept of plasma propulsion is proposed, where the thrust is provided by both positive and negative ions resulting in a globally neutral beam downstream (in space). The basic idea is to create an ion-ion plasma (electron free region) at the periphery of a highly ionised plasma core such that positive and negative ions can be extracted either simultaneously

Ane Aanesland; Pascal Chabert; Gary Leray; Albert Meige; Jean-Luc Raimbault

2008-01-01

296

Focus Control System for Solar Thermal Propulsion.  

National Technical Information Service (NTIS)

Solar thermal propulsion (STP) uses a parabolic concentrator like a large magnifying glass to focus the sun's energy and heat a working fluid such as hydrogen to very high temperatures (3,000 K). The hydrogen is then expelled through a nozzle to produce t...

S. R. Wassom

2000-01-01

297

Propulsion System Modeling and Integrated Controls Optimization.  

National Technical Information Service (NTIS)

The demand for higher performance from turbo-propulsion systems has led to development of engines and inlets with more variable geometry features and more modes of operation. As a result the problems of designing suitable control systems have been greatly...

I. E. Marvin A. A. Winkeljohann

1967-01-01

298

On the detectability of antimatter propulsion spacecraft  

Microsoft Academic Search

It is shown that the NASA Gamma-Ray Observatory will be able to detect large interstellar spacecraft at distances up to ~ 300 pc by the ?-ray emission from the propulsion system alone. The distance limit is set by the possibility of recognizing such objects by their proper motions.

Michael J. Harris

1986-01-01

299

Influence of propulsion efficiency on contrail formation  

Microsoft Academic Search

Aircraft cause contrails when flying in an atmosphere colder than a threshold temperature which depends on the overall efficiency ? of propulsion of the aircraft\\/engine combination. Higher ? causes contrails at higher ambient temperatures and over a larger range of flight altitudes. The ratio of temperature increase relative to moisture increase in engine plumes is lower for engines with higher

Ulrich Schumann

2000-01-01

300

Vehicle propulsion system with external propellant supply  

Microsoft Academic Search

A vehicle propulsion system is described, comprising: a vehicle designed for travel along an arranged travel path in a single extended surrounding medium; propellant depositing means for distributing propellant into a propellant trail having no structural constraint in the extended medium and extending along at least part of the travel path in advance of the vehicle; and the vehicle having

Criswell

1993-01-01

301

Jet Propulsion Laboratory: Annual Report 2010.  

National Technical Information Service (NTIS)

This is the Jet Propulsion Lab's annual report for 2010 JPL's accomplishments in 2010 revealed some diverse ways in which its missions and programs explored not only space, but touched the lives of so many people. The year certainly had its exciting momen...

2010-01-01

302

Competitive Marine Propulsion Systems Analysis. Supplementary Report.  

National Technical Information Service (NTIS)

The report covers Phase I of the Maritime Administration's Contract No. 1-35058 entitled A Systems Analysis of Marine Propulsion Systems. The objective of Phase I is to determine the relative economic and technological merit of those competing marine prop...

1973-01-01

303

Computational fluid dynamics for nuclear thermal propulsion  

Microsoft Academic Search

Viewgraphs on computational fluid dynamics (CFD) for nuclear thermal propulsion are presented. Topics covered include: hydrogen mass fraction as a function of chamber temperature; specific enthalpy of hydrogen and mole fraction of hydrogen as a function of chamber pressure; and specific impulse as a function of chamber pressure. Wall configurations of several nozzles are shown.

Robert M. Stubbs; Suk C. Kim

1993-01-01

304

Power and Propulsion for the Cassini Mission  

Microsoft Academic Search

Lockheed Martin contributions to the Cassini mission included power and propulsion for the spacecraft, the Descent Imager \\/ Spectral Radiometer, DISR instrument for the Huygens Probe, as well as the Titan IVB launch vehicle. Cassini is currently in orbit around Saturn performing its primary science mission, investigating Saturn, its many moons, and its complex and beautiful ring system. The Space

Kevin S. Johnson; Robert D. Cockfield

2005-01-01

305

REPORT ON SATELLITE AND SPACE PROPULSION SYSTEMS  

Microsoft Academic Search

Low-thrust propulsion systems that can be used to extend satellite ; orbits, to control or modify satellite orbits, and for lunar and interplanetary ; exploration are surveyed. The most feasible combinations of energy sources ; (chemicals, radioisotopes, solar rays, nuclear fission, and nuclear fusion), ; electric generators (chemical batteries, radioisotope batteries, thermopiles, ; solar batteries, turboelectric generators, and plasma induction),

Partel

1962-01-01

306

PRACTICAL CONSIDERATIONS OF AN ION PROPULSION SYSTEM  

Microsoft Academic Search

driving a 20,000 lb vehicle into space, where the power source stems ; from the direct conversion of nuclear to electric energy, is presented. Cesium ; and potassium are compared as the propellant. A comparison is presented of the ; space propulsion systems of chemical, photon, solar, radioisotope, and plasma ; rockets. (C.J.G.);

Lennert

1959-01-01

307

Mirror fusion propulsion system - A performance comparison with alternate propulsion systems for the manned Mars mission  

NASA Astrophysics Data System (ADS)

The performance characteristics of several propulsion technologies applied to piloted Mars missions are compared. The characteristics that are compared are Initial Mass in Low Earth Orbit (IMLEO), mission flexibility, and flight times. The propulsion systems being compared are both demonstrated and envisioned: Chemical (or Cryogenic), Nuclear Thermal Rocket (NTR) solid core, NTR gas core, Nuclear Electric Propulsion (NEP), and a mirror fusion space propulsion system. The proposed magnetic mirror fusion reactor, known as the Mirror Fusion Propulsion System (MFPS), is described. The description is an overview of a design study that was conducted to convert a mirror reactor experiment at Lawrence Livermore National Lab (LLNL) into a viable space propulsion system. Design principles geared towards minimizing mass and maximizing power available for thrust are identified and applied to the LLNL reactor design, resulting in the MFPS. The MFPS' design evolution, reactor and fuel choices, and system configuration are described. Results of the performance comparison shows that the MFPS minimizes flight time to 60 to 90 days for flights to Mars while allowing continuous return-home capability while at Mars. Total MFPS IMLEO including propellant and payloads is kept to about 1,000 metric tons.

Deveny, M.; Carpenter, S.; O'Connell, T.; Schulze, N.

1993-06-01

308

Mirror fusion propulsion system: A performance comparison with alternate propulsion systems for the manned Mars Mission  

NASA Astrophysics Data System (ADS)

The performance characteristics of several propulsion technologies applied to piloted Mars missions are compared. The characteristics that are compared are Initial Mass in Low Earth Orbit (IMLEO), mission flexibility, and flight times. The propulsion systems being compared are both demonstrated and envisioned: Chemical (or Cryogenic), Nuclear Thermal Rocket (NTR) solid core, NTR gas core, Nuclear Electric Propulsion (NEP), and a mirror fusion space propulsion system. The proposed magnetic mirror fusion reactor, known as the Mirror Fusion Propulsion System (MFPS), is described. The description is an overview of a design study that was conducted to convert a mirror reactor experiment at Lawrence Livermore National Lab (LLNL) into a viable space propulsion system. Design principles geared towards minimizing mass and maximizing power available for thrust are identified and applied to the LLNL reactor design, resulting in the MFPS. The MFPS' design evolution, reactor and fuel choices, and system configuration are described. Results of the performance comparison shows that the MFPS minimizes flight time to 60 to 90 days for flights to Mars while allowing continuous return-home capability while at Mars. Total MFPS IMLEO including propellant and payloads is kept to about 1,000 metric tons.

Schulze, Norman R.; Carpenter, Scott A.; Deveny, Marc E.; Oconnell, T.

1993-06-01

309

Mirror fusion propulsion system - A performance comparison with alternate propulsion systems for the manned Mars mission  

SciTech Connect

The performance characteristics of several propulsion technologies applied to piloted Mars missions are compared. The characteristics that are compared are Initial Mass in Low Earth Orbit (IMLEO), mission flexibility, and flight times. The propulsion systems being compared are both demonstrated and envisioned: Chemical (or Cryogenic), Nuclear Thermal Rocket (NTR) solid core, NTR gas core, Nuclear Electric Propulsion (NEP), and a mirror fusion space propulsion system. The proposed magnetic mirror fusion reactor, known as the Mirror Fusion Propulsion System (MFPS), is described. The description is an overview of a design study that was conducted to convert a mirror reactor experiment at Lawrence Livermore National Lab (LLNL) into a viable space propulsion system. Design principles geared towards minimizing mass and maximizing power available for thrust are identified and applied to the LLNL reactor design, resulting in the MFPS. The MFPS' design evolution, reactor and fuel choices, and system configuration are described. Results of the performance comparison shows that the MFPS minimizes flight time to 60 to 90 days for flights to Mars while allowing continuous return-home capability while at Mars. Total MFPS IMLEO including propellant and payloads is kept to about 1,000 metric tons. 50 refs.

Deveny, M.; Carpenter, S.; O'connell, T.; Schulze, N.

1993-06-01

310

Electric Propulsion Space Experiment (ESEX): Spacecraft design issues for high-power electric propulsion  

NASA Astrophysics Data System (ADS)

Electric propulsion provides high specific impulses, and low thrust when compared to chemical propulsion systems. Therefore, electric propulsion offers improvements over chemical systems such as increased station-keeping time, prolonged on-orbit maneuverability, low acceleration of large structures, and increased launch vehicle flexibility. The anticipated near-term operational electric propulsion system for an electric orbit transfer vehicle is an arcjet propulsion system. Towards this end, the USAF's Phillips Laboratory (PL) has awarded a prime contract to TRW Space & Technology Group to design, build, and space qualify a 30-kWe class arcjet as well as develop and demonstrate, on the ground, a flight-qualified arcjet propulsion flight unit. The name of this effort is the 30 kWe Class Arcjet Advanced Technology Transition Demonstration (Arcjet ATTD) program. Once the flight unit has completed its ground qualification test, it will be given to the Space Test and Transportation Program Office of the Air Force's Space Systems Division (ST/T) for launch vehicle integration and space test. The flight unit's space test is known as the Electric Propulsion Space Experiment (ESEX). ESEX's mission scenario is 10 firings of 15 minutes each. The objectives of the ESEX flight are to measure arcjet plume deposition, electromagnetic interference, thermal radiation, and acceleration in space. Plume deposition, electromagnetic interference, and thermal radiation are operational issues that are primarily being answered for operational use. This paper describes the Arcjet ATTD flight unit design and identifies specifically how the diagnostic data will be collected as part of the ESEX program.

Kriebel, Mary M.; Sanks, Terry M.

1992-02-01

311

Journey into tomorrow - Developing nuclear propulsion for the Space Exploration Initiative  

Microsoft Academic Search

Nuclear propulsion, either nuclear thermal propulsion or nuclear electric propulsion, offers the potential of reduced trip times and\\/or reduced mass into low earth orbit, compared to chemical propulsion systems. In addition, the greater performance benefits of nuclear propulsion can provide the added margin for greater operational flexibility, including mission abort options and increased launch windows. During the 1950s and 1960s

Kathleen F. Harer; Scott R. Graham; Gary L. Bennett

1992-01-01

312

Fluidic electrodynamics: Approach to electromagnetic propulsion  

SciTech Connect

We report on a new methodological approach to electrodynamics based on a fluidic viewpoint. We develop a systematic approach establishing analogies between physical magnitudes and isomorphism (structure-preserving mappings) between systems of equations. This methodological approach allows us to give a general expression for the hydromotive force, thus re-obtaining the Navier-Stokes equation departing from the appropriate electromotive force. From this ground we offer a fluidic approach to different kinds of issues with interest in propulsion, e.g., the force exerted by a charged particle on a body carrying current; the magnetic force between two parallel currents; the Magnus's force. It is shown how the intermingle between the fluid vector fields and electromagnetic fields leads to new insights on their dynamics. The new concepts introduced in this work suggest possible applications to electromagnetic (EM) propulsion devices and the mastery of the principles of producing electric fields of required configuration in plasma medium.

Martins, Alexandre A.; Pinheiro, Mario J. [Institute for Plasmas and Nuclear Fusion and Instituto Superior Tecnico Lisboa, Portugal 351.1.21.841.92.43 (Portugal); Department of Physics and Institute for Plasmas and Nuclear Fusion and Instituto Superior Tecnico Lisboa, Portugal 351.1.21.841.93.22 (Portugal)

2009-03-16

313

On the Mysterious Propulsion of Synechococcus  

PubMed Central

We propose a model for the self-propulsion of the marine bacterium Synechococcus utilizing a continuous looped helical track analogous to that found in Myxobacteria [1]. In our model cargo-carrying protein motors, driven by proton-motive force, move along a continuous looped helical track. The movement of the cargo creates surface distortions in the form of small amplitude traveling ridges along the S-layer above the helical track. The resulting fluid motion adjacent to the helical ribbon provides the propulsive thrust. A variation on the helical rotor model of [1] allows the motors to be anchored to the peptidoglycan layer, where they drive rotation of the track creating traveling helical waves along the S-layer. We derive expressions relating the swimming speed to the amplitude, wavelength, and velocity of the surface waves induced by the helical rotor, and show that they fall in reasonable ranges to explain the velocity and rotation rate of swimming Synechococcus.

Ehlers, Kurt; Oster, George

2012-01-01

314

Hydrodynamics of efficient propulsion in oscillating foils  

NASA Astrophysics Data System (ADS)

The flow field and thrust performance of a pitching and heaving NACA 0012 airfoil at a chord Reynolds number of 30000 are investigated experimentally and numerically. In the experimental work, Digital Particle Image Velocimetry (DPIV) is used to examine the strength and dynamics of shed vorticity. The numerical work consists of Euler simulations using FLUENT in which leading edge separation is inhibited. Three kinematic cases from Anderson et al. (J. Fluid Mech, 360, 1998) are considered, two of which include propulsive efficiency peaks that fall in a Strouhal number range well below that predicted by the stability analysis of Triantafyllou et al. (1991, 1993). By considering the disparate experimental and numerical conditions as well as inviscid model results for these flows in the literature, we will discuss the role of vortex shedding on optimal propulsion.

Eslam Panah, Azar; Buchholz, James

2010-11-01

315

Solar Thermal Propulsion Investigation Activities in NAL  

NASA Astrophysics Data System (ADS)

We successfully developed the ultra-light single shell paraboloidal concentrators made of a sheet of aluminized or silvered polymer membrane, formed via plastic deformation due to stress relaxation under high temperature condition by means of Straight Formation Method. Furthermore, we improved the precision of the concentrators by taking the elastic deformation of residual stress into consideration, and obtained the best concentration performance equivalent to a highly precise paraboloidal glass mirror. In solar concentration, the diameter of solar focal image via the single shell polymer concentrator is almost equal to that via the glass mirror and they are twice as large as that of the theoretical. The ultra-light single shell polymer concentrators are very useful for the concentrator in solar thermal propulsion system and solar power station in particular, and also promising item for beamed energy propulsion.

Sahara, Hironori; Shimizu, Morio

2004-03-01

316

NASA's progress in nuclear electric propulsion technology  

NASA Astrophysics Data System (ADS)

The National Aeronautics and Space Administration (NASA) has established a requirement for Nuclear Electric Propulsion (NEP) technology for robotic planetary science mission applications with potential future evolution to systems for piloted Mars vehicles. To advance the readiness of NEP for these challenging missions, a near-term flight demonstration on a meaningful robotic science mission is very desirable. The requirements for both near-term and outer planet science missions are briefly reviewed, and the near-term baseline system established under a recent study jointly conducted by the Lewis Research Center (LeRC) and the Jet Propulsion Laboratory (JPL) is described. Technology issues are identified where work is needed to establish the technology for the baseline system, and technology opportunities which could provide improvement beyond baseline capabilities are discussed. Finally, the plan to develop this promising technology is presented and discussed.

Stone, James R.; Doherty, Michael P.; Peecook, Keith M.

1993-06-01

317

Elasticity, adhesion and actin based propulsion  

NASA Astrophysics Data System (ADS)

When a cells crawls, its shape re-organizes via polymerization and depolymerization of actin filaments. The growing ends of the filaments are oriented towards the outside of the cell, and their polymerization pushes the cell membrane forwards. The same mechanism comes into play when the bacterial pathogen Listeria monocytogenes infects a cell. The bacterium hijacks the host cell's actin machinery to create an actin network (the actin comet tail) that propels the bacterium through cells and into neighboring cells. We propose a mechanism for how polymerization gives rise to motility that incorporates the effects of inhomogeneous polymerization. We treat the actin comet tail as an elastic continuum tethered to the rear of the bacterium. The interplay of polymerization and tethering gives rise to inhomogeneous stresses calculated with a finite element analysis. We quantitatively reproduce many distinctive features of actin propulsion that have been observed experimentally, including stepped motion, hopping, tail shape and the propulsion of flat surfaces.

Gopinathan, Ajay

2006-03-01

318

Space Experiments to Advance Beamed Energy Propulsion  

NASA Astrophysics Data System (ADS)

High power microwave sources are now available and usable, with modification, or beamed energy propulsion experiments in space. As output windows and vacuum seals are not needed space is a natural environment for high power vacuum tubes. Application to space therefore improves reliability and performance but complicates testing and qualification. Low power communications satellite devices (TWT, etc) have already been through the adapt-to-space design cycle and this history is a useful pathway for high power devices such as gyrotrons. In this paper, space experiments are described for low earth orbit (LEO) and lunar environment. These experiments are precursors to space application for beamed energy propulsion using high power microwaves. Power generation and storage using cryogenic systems are important elements of BEP systems and also have an important role as part of BEP experiments in the space environment.

Johansen, Donald G.

2010-05-01

319

Fast Track'' nuclear thermal propulsion concept  

SciTech Connect

The objective of the Space Exploration Initiative ( America at the Threshold...,'' 1991) is the exploration of Mars by man in the second decade of the 21st century. The NASA Fast Track'' approach (NASA-LeRC Presentation, 1992) could accelerate the manned exploration of Mars to 2007. NERVA-derived nuclear propulsion represents a viable near-term technology approach to accomplish the accelerated schedule. Key milestones in the progression to the manned Mars mission are (1) demonstration of TRL-6 for the man-rateable system by 1999, (2) a robotic lunar mission by 2000, (3) the first cargo mission to Mars by 2005, and (4) the piloted Mars mission in 2007. The Rocketdyne-Westinghouse concept for nuclear thermal propulsion to achieve these milestones combines the nuclear reactor technology of the Rover/NERVA programs and the state-of-the-art hardware designs from hydrogen-fueled rocket engine successes like the Space Shuttle Main Engine (SSME).

Johnson, R.A.; Zweig, H.R. (Rocketdyne Division, Rockwell International Corporation, 6633 Canoga Avenue, P.O. Box 7922, Canoga Park, California 91309-7922 (United States)); Cooper, M.H.; Wett, J. Jr. (Westinghouse Electric Corporation, Post Office Box 158, Madison, Pennsylvania 15663 (United States))

1993-01-10

320

Fuel optimal propulsive reboost of flexible spacecraft  

NASA Astrophysics Data System (ADS)

This paper presents for the first time an exact solution to the fuel optimal propulsive reboost problem for flexible spacecraft. The spacecraft undergoes rigid-body motion and flexible-body motion and reboost is achieved propulsively through the use of reaction control jets. The exact fuel optimal solution to the associated minimization problem is found numerically based on an adaptive grid bisection search. The reboost of the floating harmonic oscillator reveals properties of the fuel optimal solution. Nondimensional plots of minimum fuel versus maneuver time expose the nature of the solution classes depending on the maneuver time. Some very interesting properties are observed, among them, the shifting of impulses to the smaller oscillator mass, and comparisons are made with near fuel optimal solutions obtained by other investigators.

Silverberg, Larry; Redmond, Jim

321

Pivotal air induction for marine propulsion device  

SciTech Connect

This patent describes a marine propulsion device comprising a mounting bracket assembly, a propulsion unit including an internal combustion engine and being rotatably connected to the mounting bracket assembly for rotation relative to the mounting bracket assembly about a generally vertical steering axis. A shroud substantially encloses the engine and has therein a combustion air opening centered on the steering axis, and rigid duct means having opposite first and second ends. The first end communicates with the opening and being rotatably connected to the shroud for rotation about the steering axis, and the second end being adapted for connection and for communication through the transom of a boat to enable the engine to draw combustion air from the interior of the boat.

Ferguson, A.R.

1986-11-18

322

A review of pulse fusion propulsion  

NASA Astrophysics Data System (ADS)

During the last forty years there has been considerable interest in both internal and external pulse propulsion systems. Over this time the nuclear devices being considered have grown considerably smaller than those initially examined. Now pellets are normally in the range from 15 cm down to 2 cm in diameter, and fusion devices are generally preferred. High energy density triggers (such as lasers, particle beams or antiprotons) have been considered for detonating the fusion fuel. When antiprotons are considered it is more efficient to annihilate the antiprotons in a fissionable material, and then use the energy from the fission reaction to drive the fusion reaction in the pellet, than to use the annihilation energy directly. Finally, fissionable material can be used to boost the performance of a fusion system. The early concepts, which used critical mass devices, do not satisfy the ban on nuclear weapons in space, and are only rarely considered today. Concepts based on inertial confinement fusion are heavier than those that use antiprotons for the trigger since the mass associated with the lasers, or particle beams and their power supplies are considerably heavier than the traps used for antiprotons. Hence, from a performance, and even a political, point of view the antiproton-triggered approach is the most desirable, but it also requires more development. Not only is the trigger lighter but an external pulse propulsion rocket does not necessarily need radiators to reject excess heat and, hence, can be even lighter. Propulsion systems based on critical mass devices are clearly feasible, so the primary problem is to reduce the size of the explosive devices so that a critical mass is not required. If pulse nuclear fusion propulsion can become a reality then the performance is enough to complete manned missions to the inner planets in weeks and the outer planets in months. .

Cassenti, Brice N.

2002-01-01

323

System model development for nuclear thermal propulsion  

NASA Astrophysics Data System (ADS)

The strategy and progress of an interagency NASA/DOE/DOD team for nuclear thermal propulsion (NTP) system modeling are presented. The main goal of the interagency team is to develop several levels of computer programs for predicting the performance of various NTP systems. These programs are being developed to support the evaluation of conceptual designs and to provide a diagnostic tool for understanding system tests.

Walton, James T.; Hannan, Nelson A.; Perkins, Ken R.; Buksa, John J.; Worley, Brian A.; Dobranich, Dean

1992-08-01

324

Aluminum-air battery for automotive propulsion  

Microsoft Academic Search

Research on the development of aluminum-air batteries which will be used in energy efficient, economical electric vehicles is reviewed with information on the research strategy, performance characteristics of aluminum-air cells, vehicle design, and the net energy required and energy costs for producing and operating Al-air batteries. The aluminum-air battery is being developed to provide a propulsion source for a general-purpose

J. F. Cooper; E. Behrin

1980-01-01

325

Monopropellant Propulsion System Activities in Alcatel Space  

NASA Astrophysics Data System (ADS)

Since many years, Alcatel Space has been developing skills on the monopropellant propulsion system, in order to be able to design, integrate, test, fill and launch its own sub-system. This following article gives a view on several activities present at Alcatel Space, beginning with the Proteus design and its problematic, following with the tests experience and ending with some reflections on the offloading problem and on the possible ways to optimise the fuelling activities.

Lecardonnel, L.; Baubias, P.-P.; Appaix, F.; Cuffolo, A.; Garnero, P.; Arnaud, R.

2004-10-01

326

Autonomously motile catalytic nanomotors by bubble propulsion  

NASA Astrophysics Data System (ADS)

A bubble propulsion model based on catalyzed hydrogen peroxide decomposition and momentum change via O2 bubbles detaching from the catalytic surface is proposed to explain the autonomous motion of catalytic nanomotors. The propelling force closely depends upon the surface tension of the liquid as well as the bulk concentration of hydrogen peroxide, and the model predictions are supported by the experimental data of Pt-coated spherical silica microbead motors.

Gibbs, J. G.; Zhao, Y.-P.

2009-04-01

327

Propulsion trades for space science missions  

Microsoft Academic Search

This study evaluated the relative benefits of proposed deep space propulsion technology improvements in three areas: advanced chemical, solar electric, and solar sail. Within each area, specific states, representing current technology (present-1999), mid-term (2000–2004), and far term (2005+), were selected for evaluation. The figures of merit used were net spacecraft mass delivered, size of the launch vehicle needed, trip time,

Robert Gershman; Calina Seybold

1999-01-01

328

Facility requirements for hypersonic propulsion system testing  

Microsoft Academic Search

Facility requirements and capabilities for hypersonic propulsion system testing are reviewed with emphasis on short-duration test facilities. Past and current hypersonic facility studies are reviewed, and some of the many problems currently associated with wing-body hypersonic aircraft and several currently operational ground-based facilities or facilities in the development stage are described. Limitations on the short-duration shock tunnel are examined, including

M. G. Dunn; J. A. Lordi; C. E. Wittliff; M. S. Holden

1991-01-01

329

Applications of coilgun electromagnetic propulsion technology  

Microsoft Academic Search

Exciting and important applications of pulsed power and high voltage technology are found in the growing area of electromagnetic launch and propulsion. These applications include small-scale, precision staging devices (magnetically driven), low-speed, large mass catapult launchers, low-speed and high-speed trains, high-speed, long-range fire support naval guns, and the futuristic application of high-speed, direct satellite launch to space. The force requirements

R. J. Kaye; Bob N. Turman; Steven L. Shope

2002-01-01

330

SERAPHIM: A propulsion technology for fast trains  

SciTech Connect

The Segmented Rail Phased Induction Motor (SERAPHIM) is a compact, pulsed linear induction motor (LIM) offering a unique capability for very high speed train propulsion. It uses technology developed for the Sandia coilgun, an electromagnetic launcher designed to accelerate projectiles to several kilometers per second. Both aluminum cylinders and plates were accelerated to a kilometer per second (Mach 3) by passing through a sequence of coils which were energized at the appropriate time. Although this technology was developed for ultra-high velocity, it can be readily adapted to train propulsion for which, at sea level, the power required to overcome air resistance limits the operational speed to a more modest 300 mph. Here, the geometry is reversed. The coils are on the vehicle and the ``projectiles`` are fixed along the roadbed. SERAPHIM operates not by embedding flux in a conductor, but by excluding it. In this propulsion scheme, pairs of closely spaced coils on the vehicle straddle a segmented aluminum reaction rail. A high frequency current is switched on as a coil pair crosses an edge and remains off as they overtake the next segment. This induces surface currents which repel the coil. In essence, the pulsed coils push off segment edges because at the high frequency of operation, the flux has insufficient time to penetrate. In contrast to conventional LIMs, the performance actually improves with velocity, even for a minimal motor consisting of a single coil pair reacting with a single plate. This paper will present results of proof-of-principle tests, electromagnetic computer simulations, and systems analysis. It is concluded that this new linear induction motor can be implemented using existing technology and is a promising alternative propulsion method for very high speed rail transportation.

Kelly, B.; Turman, B.; Marder, B.; Rohwein, G.; Aeschliman, D.; Cowan, B.

1995-06-01

331

‘‘Fast Track’’ nuclear thermal propulsion concept  

Microsoft Academic Search

The objective of the Space Exploration Initiative (‘‘America at the Threshold...,’’ 1991) is the exploration of Mars by man in the second decade of the 21st century. The NASA ‘‘Fast Track’’ approach (NASA-LeRC Presentation, 1992) could accelerate the manned exploration of Mars to 2007. NERVA-derived nuclear propulsion represents a viable near-term technology approach to accomplish the accelerated schedule. Key milestones

Richard A. Johnson; Herbert R. Zweig; Martin H. Cooper; Jack Wett

1993-01-01

332

``Fast Track'' nuclear thermal propulsion concept  

Microsoft Academic Search

The objective of the Space Exploration Initiative (``America at the Threshold...,'' 1991) is the exploration of Mars by man in the second decade of the 21st century. The NASA ``Fast Track'' approach (NASA-LeRC Presentation, 1992) could accelerate the manned exploration of Mars to 2007. NERVA-derived nuclear propulsion represents a viable near-term technology approach to accomplish the accelerated schedule. Key milestones

Richard A. Johnson; Herbert R. Zweig; Martin H. Cooper; Jack Wett

1993-01-01

333

Electric Sail Propulsion Modeling and Mission Analysis  

Microsoft Academic Search

The electric sail1,2 is a new propulsion concept that uses the solar wind momentum flux for producing thrust. Like the more conventional solar sail, it allows a spacecraft to perform high-energy orbit transfers without a need for reaction mass. The electric sail could accelerate small (10-100 kg) payloads to substantial final speeds, larger than that are possible with conventional (either

Pekka Janhunen; Giovanni Mengali; Alessandro A. Quarta

334

Impact of dynamic loads on propulsion integration  

NASA Astrophysics Data System (ADS)

Aircraft dynamic loads produced by engine exhaust plumes are examined for a class of military fighter and bomber configurations in model and full scale. The configurations examined are associated with the USAF F-15 and B-1B aircraft, and the US F-18 HARV and ASTOVL programs. The experience gained as a result of these studies is used to formulate a level of understanding concerning this phenomena that could be useful at the preliminary stage of propulsion/airframe design.

Seiner, J. M.

1994-09-01

335

Advanced propulsion system concept for hybrid vehicles  

Microsoft Academic Search

The results of a nine-month study to identify and evaluate advanced propulsion systems for on-the-road hybrid vehicles are presented. Two concepts, both utilizing Stirling engines, were evaluated for five of reference mission\\/vehicles ranging from a two-passenger commuter car to a large bus, each had its own performance specification. Selection of the best hybrid configuration and reference mission\\/vehicle was made against

S. Bhate; H. Chen; G. Dochat

1980-01-01

336

Propulsion of a Swimming Micro Medical Robot  

Microsoft Academic Search

Medical doctors use radiology, endoscopy and smart pills to inspect the human body's inner content. Nowadays, self-propelled micro robots are developed to fulfill these tasks which use types of crawling techniques to advance. This paper suggests a novel swimming method, which creates a traveling wave in an elastic tail made of piezo-electric actuators, for propulsion of a micro-robot in the

Gábor Kósa; Moshe Shoham; Menashe Zaaroor

2005-01-01

337

Machine Learning for Rocket Propulsion Health Monitoring  

Microsoft Academic Search

This paper describes the initial results of applying two machine-learning-based unsupervised anomaly detection algorithms, Orca and GritBot, to data from two rocket propulsion testbeds. The first testbed uses historical data from the Space Shuttle Main Engine. The second testbed uses data from an experimental rocket engine test stand located at NASA Stennis Space Center. The paper describes four candidate anomalies

Mark Schwabacher

2005-01-01

338

Application of SDI technology in space propulsion  

NASA Astrophysics Data System (ADS)

Numerous technologies developed by the DOD within the SDI program are now available for adaptation to the requirements of commercial spacecraft; SDI has accordingly organized the Technology Applications Information System data base, which contains nearly 2000 nonproprietary abstracts on SDI technology. Attention is here given to such illustrative systems as hydrogen arcjets, ammonia arcjets, ion engines, SSTO launch vehicles, gel propellants, lateral thrusters, pulsed electrothermal thrusters, laser-powered rockets, and nuclear propulsion.

Klein, Allen J.

339

Ion Emissive Membranes for Propulsion Applications  

NASA Astrophysics Data System (ADS)

Experiments show electrostatic thrusters with components such as the discharge chamber or acceleration channel, solenoid or permanent magnets, hollow cathode, and keeper can be replaced by a simple, propellant-selective, solid-state, ion-conducting membrane (Wilbur et al., 2007; Wilbur, Wilson, and Williams, 2005). In addition, analyzes show these membranes can be shaped, structured, and assembled into integrated thruster systems that will operate at much greater thrust densities and thruster efficiencies than those for state-of-the-art, Hall and ion thrusters (Wilbur, Farnell, and Williams, 2005). The implications of these findings are revolutionary and promise an electrostatic propulsion system much less massive, more reliable, and less costly than ion and Hall thruster systems as they can be fabricated readily using traditional ceramic manufacturing techniques. The status of the Emissive Membrane Ion Thruster (EMIT) concept is described and recent measurements are used to estimate the performance of a propulsion system based on this concept. Estimates are also provided for the specific masses of various components required for it to perform typical satellite missions and comparisons are made to conventional electric propulsion systems currently in use. The emissive membrane thruster is shown to enable operation at 20% to 50% greater thrust-to-power ratios at specific impulses from 1000 s to 5000 s. Related performance advantages will also be discussed and analyses will be presented that show why an EMIT system is less expensive, more reliable, easily scalable, and simpler compared to existing electric thruster systems.

Williams, John D.; Wilbur, Paul J.; Farnell, Cody C.; Farnell, Casey C.; Wilson, Merrill; Hutchings, Kent

2009-03-01

340

Propulsion of microorganisms by a helical flagellum  

NASA Astrophysics Data System (ADS)

Many microorganisms are propelled by rotating helical flagella. We examine this propulsion in laboratory measurements on macroscopic rotating helices (typical diameter, 12 mm) in a fluid with viscosity 10^5 times that of water; thus the Reynolds number in the experiments is much less than unity, just as for bacteria. We directly measure the propulsive force and torque generated by a rotating flagellum, and the drag force on a translating flagellum, i.e. elements of the propulsion matrices. Our results differ significantly from the predictions of Lighthill's Resistive Force Theory (1975), which treats each segment as an independent slender rod and neglects hydrodynamic interactions between segments of the flagellum. The difference between our measurements and Resistive Force Theory is especially large for helices with small pitch/diameter ratios, which is the regime of many bacteria. We also compute force, torque and drag using the regularized Stokelets method of Cortez et al. (2005). Our numerical results from the regularized Stokelets method are in excellent agreement with the laboratory measurements for helices with parameters (pitch/diameter and length/pitch) in the biologically relevant regime.

Rodenborn, Bruce; Chen, Chih-Hung; Swinney, Harry L.; Zhang, H. P.

2011-11-01

341

Magnetic Nozzle Simulation Studies for Electric Propulsion  

NASA Astrophysics Data System (ADS)

Electric Propulsion has recently re-gained interest as one of the key technologies to enable NASA's long-range space missions. Options are being considered also in the field of aneutronic fusion propulsion for high-power electric thrusters. To support these goals the study of the exhaust jet in a plasma thruster acquires a critical importance because the need of high-efficiency generation of thrust. A model of the plasma exhaust has been developed with the 3D magneto-fluid NIMROD code [1] to study the physics of the plasma detachment in correlation with experimentally relevant configurations. The simulations show the role of the plasma diamagnetism and of the magnetic reconnection process in the formation of a detached plasma. Furthermore, in direct fusion-propulsion concepts high-energy (MeV range) fusion products have to be efficiently converted into a slower and denser plasma jet (with specific impulse down to few 1000's seconds, for realistic missions in the Solar System). For this purpose, a two-stage conversion process is being modeled where high-energy ions are non-adiabatically injected and confined into a magnetic duct leading to the magnetic nozzle, transferring most of their energy into their gyro-motion and drifting at slower speed along with the plasma propellant. The propellant acquires then thermal energy that gets converted into the direction of thrust by the magnetic nozzle. [1] C. R. Sovinec et al., J. Comput. Phys. 195, 355 (2004).

Tarditi, Alfonso

2010-11-01

342

Propulsion of microorganisms by a helical flagellum  

NASA Astrophysics Data System (ADS)

Many bacteria (e.g. E. coli and Salmonella) swim by rotating rigid helical flagella, which are typically several ?m long and 0.4 ?m in diameter. We investigate this propulsion in laboratory measurements on macroscopic rotating helices (typical diameter, 12 mm) in a fluid with viscosity 10^5 times that of water; thus the Reynolds number in the experiments is much less than unity, just as for bacteria. We measure the propulsive force and torque generated by a rotating flagellum, and the drag force on a translating flagellum; thus we can determine all elements of the propulsion matrices along the axial direction. We also compute force, torque and drag using the regularized Stokeslets method of Cortez et al. (2005). Our experimental and numerical results are in excellent agreement. However, these results differ significantly from the predictions of resistive force theories developed by Gray and Hancock (1953) and Lighthill (1975). The difference between our measurements and resistive force theory is especially large for helices with small pitch/diameter ratios, which is the regime of many bacteria.

Chen, Chih-Hung; Rodenborn, Bruce; Swinney, Harry; Liu, Bin; Zhang, Hepeng

2012-02-01

343

Integrated propulsion technology demonstrator. Program plan  

NASA Astrophysics Data System (ADS)

NASA and Rockwell have embarked on a cooperative agreement to define, develop, fabricate, and operate an integrated propulsion technology demonstrator (IPTD) for the purpose of validating design, process, and technology improvements of launch vehicle propulsion systems. This program, a result of NRA8-11, Task Area 1 A, is jointly funded by both NASA and Rockwell and is sponsored by the Reusable Launch Vehicle office at NASA Marshall Space flight Center. This program plan provides to the joint NASA/Rockwell integrated propulsion technology demonstrator (IPTD) team a description of the activities within tasks / sub tasks and associated schedules required to successfully achieve program objectives. This document also defines the cost elements and manpower allocations for each sub task for purpose of program control. This plan is updated periodically by developing greater depth of direction for outyear tasks as the program matures. Updating is accomplished by adding revisions to existing pages or attaching page revisions to this plan. In either case, revisions will be identified by appropriate highlighting of the change, or specifying a revision page through the use of footnotes on the bottom right of each change page. Authorization for the change is provided by the principal investigators to maintain control of this program plan document and IPTD program activities.

1994-08-01

344

Development status of the NSTAR ion propulsion system power processor  

Microsoft Academic Search

A 0.5-2.3 kW xenon ion propulsion system is presently being developed under the NASA Solar Electric Propulsion Technology Application Readiness (NSTAR) program. This propulsion system includes a 30 cm diameter xenon ion thruster, a Digital Control Interface Unit, a xenon feed system, and a power processing unit (PPU). The PPU consists of the power supply assemblies which operate the thruster

John A. Hamley; Luis R. Pinero; Vincent K. Rawlin; John R. Miller; Kevin C. Cartier; Glen E. Bowers

1995-01-01

345

Brushless DC Motor Propulsion Using Synchronous Motors for Transit Systems  

Microsoft Academic Search

In this paper, a brushless dc motor propulsion system using synchronous motors is described which is suitable for transit applications. The propulsion system consists of two-quadrant transistorized front-end chopper and a three-phase transistorized inverter (forming the electronic commutator for the synchronous machine phase currents) to provide both controlled propulsion and regenerative braking. The control scheme makes the system operate stably

W. R. PEARSONAND; Paresh C. Sen

1984-01-01

346

Electric propulsion for lunar exploration and lunar base development  

NASA Astrophysics Data System (ADS)

Using electric propulsion to deliver materials to lunar orbit for the development and construction of a lunar base was investigated. Because the mass of the base and its life-cycle resupply mass are large, high specific impulse propulsion systems may significantly reduce the transportation system mass and cost. Three electric propulsion technologies (arcjet, ion, and magnetoplasmadynamic (MPD) propulsion) were compared with oxygen/hydrogen propulsion for a lunar base development scenario. Detailed estimates of the orbital transfer vehicles' (OTV's) masses and their propellant masses are presented. The fleet sizes for the chemical and electric propulsion systems are estimated. Ion and MPD propulsion systems enable significant launch mass savings over O2/H2 propulsion. Because of the longer trip time required for the low-thrust OTV's, more of them are required to perform the mission model. By offloading the lunar cargo from the manned O2/H2 OTV missions onto the electric propulsion OTV's, a significant reduction of the low Earth orbit (LEO) launch mass is possible over the 19-year base development period.

Palaszewski, Bryan

1992-09-01

347

40 CFR Appendix II to Part 1045 - Duty Cycles for Propulsion Marine Engines  

Code of Federal Regulations, 2013 CFR

... Duty Cycles for Propulsion Marine Engines II Appendix II...AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS...SPARK-IGNITION PROPULSION MARINE ENGINES AND VESSELS Pt...Duty Cycles for Propulsion Marine Engines (a) The...

2013-07-01

348

15 CFR 744.5 - Restrictions on certain maritime nuclear propulsion end-uses.  

Code of Federal Regulations, 2010 CFR

...Restrictions on certain maritime nuclear propulsion end-uses. 744.5 Section...Restrictions on certain maritime nuclear propulsion end-uses. (a) General...connection with a foreign maritime nuclear propulsion project. This...

2009-01-01

349

15 CFR 744.5 - Restrictions on certain maritime nuclear propulsion end-uses.  

Code of Federal Regulations, 2010 CFR

...Restrictions on certain maritime nuclear propulsion end-uses. 744.5 Section...Restrictions on certain maritime nuclear propulsion end-uses. (a) General...connection with a foreign maritime nuclear propulsion project. This...

2010-01-01

350

15 CFR 744.5 - Restrictions on certain maritime nuclear propulsion end-uses.  

Code of Federal Regulations, 2013 CFR

...Restrictions on certain maritime nuclear propulsion end-uses. 744.5 Section...Restrictions on certain maritime nuclear propulsion end-uses. (a) General...connection with a foreign maritime nuclear propulsion project. This...

2013-01-01

351

Space Propulsion Systems. Present Performance Limits and Application and Development Trends.  

National Technical Information Service (NTIS)

Typical spaceflight programs and their propulsion requirements as a comparison for possible propulsion systems are summarized. Chemical propulsion systems, solar, nuclear, or even laser propelled rockets with electrical or direct thermal fuel acceleration...

R. D. Buehler R. E. Lo

1981-01-01

352

Method for Calculating the Probability of Successfully Completing a Rocket Propulsion Ground Test.  

National Technical Information Service (NTIS)

Propulsion ground test facilities face the daily challenge of scheduling multiple customers into limited facility space and successfully completing their propulsion test projects. Over the last decade NASA s propulsion test facilities have performed hundr...

B. Messer

2007-01-01

353

Chemical and Solar Electric Propulsion Systems Analyses for Mars Sample Return Missions.  

National Technical Information Service (NTIS)

Conceptual in-space transfer stages, including those utilizing solar electric propulsion, chemical propulsion, and chemical propulsion with aerobraking or aerocapture assist at Mars, were evaluated. Roundtrip Mars sample return mission vehicles were analy...

B. B. Donahue S. E. Green V. L. Coverstone B. Woo

2004-01-01

354

Feasibility of MHD submarine propulsion. Phase II, MHD propulsion: Testing in a two Tesla test facility  

Microsoft Academic Search

This report describes the work performed during Phase 1 and Phase 2 of the collaborative research program established between Argonne National Laboratory (ANL) and Newport News Shipbuilding and Dry Dock Company (NNS). Phase I of the program focused on the development of computer models for Magnetohydrodynamic (MHD) propulsion. Phase 2 focused on the experimental validation of the thruster performance models

E. D. Doss; W. C. Sikes

1992-01-01

355

Propulsion and aerodynamic performance evaluation of jet-wing distributed propulsion  

Microsoft Academic Search

Distributed propulsion is the idea of redistributing the thrust across the drag producing elements of a vehicle. Our configuration has a modest number of engines with part of the exhaust flow vented from thick trailing edges of the wings to cancel the local profile drag and the rest of the exhaust flow providing thrust to cancel the induced drag and

Joseph A. Schetz; Serhat Hosder; Vance Dippold III; Jessica Walker

2010-01-01

356

Microdischarge plasma thrusters for small satellite propulsion  

NASA Astrophysics Data System (ADS)

Small satellites weighing less than 100 kg are gaining importance in the defense and commercial satellite community owing to advantages of low costs to build and operate, simplicity of design, rapid integration and testing, formation flying, and multi-vehicle operations. The principal challenge in the design and development of small satellite subsystems is the severe mass, volume, and power constraints posed by the overall size of the satellite. The propulsion system in particular is hard to down scale and as such poses a major stumbling block for small satellite technology. Microdischarge-based miniaturized plasma thrusters are potentially a novel solution to this problem. In its most basic form a microdischarge plasma thruster is a simple extension of a cold gas micronozzle propulsion device, where a direct or alternating current microdischarge is used to preheat the gas stream to improve to specific impulse of the device. We study a prototypical thruster device using a detailed, self-consistent coupled plasma and fluid flow computational model. The model describes the microdischarge power deposition, plasma dynamics, gas-phase chemical kinetics, coupling of the plasma phenomena with high-speed flow, and overall propulsion system performance. Unique computational challenges associated with microdischarge modeling in the presence of high-speed flows are addressed. Compared to a cold gas micronozzle, a significant increase in specific impulse (50 to 100 %) is obtained from the power deposition in the diverging supersonic section of the thruster nozzle. The microdischarge remains mostly confined inside the micronozzle and operates in an abnormal glow discharge regime. Gas heating, primarily due to ion Joule heating, is found to have a strong influence on the overall discharge behavior. The study provides a validation of the concept as simple and effective approach to realizing a relatively high-specific impulse thruster device at small geometric scales.

Raja, Laxminarayan

2009-10-01

357

Nuclear pulse propulsion for interplanetary travel  

NASA Astrophysics Data System (ADS)

Over the last forty years there has been continuous interest in both internal and external pulse propulsion systems. The nuclear devices being considered are now considerably smaller than those initially examined. Pellets are normally in the range from 15 cm down to 2 cm in diameter, and fusion is generally preferred. Detonation can occur using high energy density triggers such as lasers, particle beams or antiprotons. In inertial confinement fusion the energy can be provided using laser beams or particle beams. When antiprotons are considered it is more efficient to annihilate the antiprotons in a fissionable material, and then use the energy from the fission reaction to drive the fusion reaction in the pellet. Finally, it is also possible to include fissionable material that can boost the performance of a fusion system. The early concepts, which used critical mass devices, do not satisfy the ban on nuclear weapons in space, and are only rarely considered today. Concepts based on inertial confinement fusion are heavier than those that use antiprotons for the trigger due to the mass associated with the lasers, or particle beams and their power supplies. Hence, from a performance, and political, point of view the antiproton triggered approach is the most desirable, but it also requires more development. Propulsion systems based on critical mass devices are clearly feasible, so the primary problem is to reduce the size of the explosive devices so that a critical mass is not required. If pulse nuclear fusion propulsion can become a reality then the performance is enough to complete manned missions to the inner planets in weeks and the outer planets in months. .

Cassenti, Brice N.

2001-02-01

358

An ion propulsion orbit manoeuvring vehicle  

NASA Astrophysics Data System (ADS)

It is shown that the concept of a reusable ion propulsion orbit maneuvering vehicle (OMV) can fulfill two particular orbital dynamics needs for the coming decades. On is the boosting of nonoperational satellites out of GEO in order to reduce GEO crowding and frequency transmission crosstalk. The other is the ability to maneuver certain satellites and other orbital debris out of the area in which the Space Station is to be located. The vehicle is flexible in operation, far less expensive than a chemical OMV, and requires very little fuel and maintenance.

Holdaway, R.; Flaherty, M.

1990-10-01

359

Vehicle propulsion system with external propellant supply  

SciTech Connect

A vehicle propulsion system is described, comprising: a vehicle designed for travel along an arranged travel path in a single extended surrounding medium; propellant depositing means for distributing propellant into a propellant trail having no structural constraint in the extended medium and extending along at least part of the travel path in advance of the vehicle; and the vehicle having combustion means for immediate combustion and expansion of at least some of the propellant distributed along the path to produce thrust on the vehicle, and exhaust means for expelling burnt propellant from the vehicle.

Criswell, D.R.

1993-07-06

360

Advanced computational techniques for hypersonic propulsion  

NASA Astrophysics Data System (ADS)

Computational Fluid Dynamics (CFD) has played a major role in the resurgence of hypersonic flight, on the premise that numerical methods will allow performance of simulations at conditions for which no ground test capability exists. Validation of CFD methods is being established using the experimental data base available, which is below Mach 8. It is important, however, to realize the limitations involved in the extrapolation process as well as the deficiencies that exist in numerical methods at the present time. Current features of CFD codes are examined for application to propulsion system components. The shortcomings in simulation and modeling are identified and discussed.

Povinelli, Louis A.

1989-03-01

361

Advanced computational techniques for hypersonic propulsion  

NASA Astrophysics Data System (ADS)

Computational Fluid Dynamics (CFD) has played a major role in the resurgence of hypersonic flight, on the premise that numerical methods will allow performance of simulations at conditions for which no ground test capability exists. Validation of CFD methods is being established using the experimental data base available, which is below Mach 8. It is important, however, to realize the limitations involved in the extrapolation process as well as the deficiencies that exist in numerical methods at the present time. Current features of CFD codes are examined for application to propulsion system components. The shortcomings in simulation and modeling are identified and discussed.

Povinelli, Louis A.

362

Loading operations for spacecraft propulsion subsystems  

NASA Astrophysics Data System (ADS)

This paper provides a broad overview of loading operations for pressurized blowdown monopropellant and pressure regulated integral bipropellant propulsion subsystems used in geosynchronous communication satellites. Propellant chemical composition, cleanliness, processing, and handling requirements are addressed. Ground servicing equipment (GSE) and propellant transfer procedures for the various loading configurations are discussed. Effects of helium solubility and helium saturation levels in both GSE carts and propellant tanks are examined. Predicted equilibrium pressures for actual postload tank pressures are compared against extensive loading data on Hughes bipropellant spacecraft. Helium tank pressurization and manifold pressurization practices are described. Propellant loading facility requirements and safety requirements are discussed.

Purohit, G. P.; Nordeng, H. O.; Ellison, J. R.

1992-07-01

363

Jet Propulsion Laboratory Technical Report Server  

NSDL National Science Digital Library

The Jet Propulsion Laboratory Technical Report Server currently contains close to 8,000 online reports. This "database of Abstracts, Citations and full text Technical Reports written by and for the scientific and technical community" is searchable by keyword, and users may scan technical report abstracts and citations by year. Related technical reports systems linked here are the NASA Technical Reports Server (described in the September 17, 1997 Scout Report) and the Telecommunications & Mission Ops Progress Report. Also included are links to other NASA centers.

364

Nuclear propulsion tradeoffs for manned Mars missions  

NASA Astrophysics Data System (ADS)

A conjunction class split/sprint manned Mars exploration mission was studied to evaluate tradeoffs in performance characteristics of nuclear thermal rockets. A Particle Bed Reactor-based nuclear thermal rocket was found to offer a 38% to 52% total mass savings compared with a NERVA-based nuclear thermal rocket for this mission. This advantage is primarily due to the higher thrust-to-weight ratio of the Particle Bed Reactor nuclear rocket. The mission is enabled by nuclear thermal rockets. It cannot be performed practically using chemical propulsion.

Walton, Lewis A.; Malloy W Nuclear Technologies, John D.

1991-01-01

365

Nuclear propulsion tradeoffs for manned Mars missions  

NASA Astrophysics Data System (ADS)

A conjunction class split/sprint manned Mars exploration mission was studied to evaluate tradeoffs in performance characteristics of nuclear thermal rockets. A Particle Bed Reactor-based nuclear thermal rocket was found to offer a 38 to 52 percent total mass savings compared with a NERVA-based nuclear thermal rocket for this mission. This advantage is primarily due to the higher thrust-to-weight ratio of the Particle Bed Reactor nuclear rocket. The mission is enabled by nuclear thermal rockets. It cannot be performed practically using chemical propulsion.

Walton, Lewis A.; Malloy, John D.

366

Polar lunar power ring: Propulsion energy resource  

NASA Astrophysics Data System (ADS)

A ring shaped grid of photovoltaic solar collectors encircling a lunar pole at 80 to 85 degrees latitude is proposed as the primary research, development, and construction goal for an initial lunar base. The polar Lunar Power Ring (LPR) is designed to provide continuous electrical power in ever increasing amounts as collectors are added to the ring grid. The LPR can provide electricity for any purpose indefinitely, barring a meteor strike. The associated rail infrastructure and inherently expandable power levels place the LPR as an ideal tool to power an innovative propulsion research facility or a trans-Jovian fleet. The proposed initial output range is 90 Mw to 90 Gw.

Galloway, Graham Scott

1990-04-01

367

Chemical rocket propulsion and the environment  

SciTech Connect

Results are presented from the examination by the Chemical Rocket Propulsion and the Environment Workshop conducted by AIAA in June 1991 of the impact of rocket launches and ground testing on the earth's environment. The major conclusions of this workshop were: (1) at projected rocket launch rates, neither the liquid- nor the solid-rocket motors will significantly impact stratospheric ozone; (2) there is no global acid rain problem associated with rocket exhaust; and (3) the local launch site and static test site acidification is a minor problem and can be managed.

Mcdonald, A.J. (Thiokol Corp., Brigham City, UT (United States))

1992-03-01

368

Solar Thermal Propulsion Transfer Stage for the first Pluto mission  

Microsoft Academic Search

The Solar Thermal Propulsion Transfer Stage (STPTS) provides an attractive propulsion concept for the First Mission to Pluto. For a Pluto Fast Flyby mission, the STPTS offers a launch vehicle down-sizing from a Titan IV\\/Centaur (reference launch vehicle) to a Delta 7925 with a significant launch cost savings. In addition, the STPTS enables a Pluto Orbiter mission using the Titan

P. E. Frye; J. A. McClanahan

1993-01-01

369

Propulsive Small Expendable Deployer System (ProSEDS)  

Microsoft Academic Search

The Propulsive Small Expendable Deployer System (ProSEDS) space experiment will demonstrate the use of an electrodynamic tether propulsion system to generate thrust in space by decreasing the orbital altitude of a Delta II Expendable Launch Vehicle second stage. ProSEDS, which is planned on an Air Force GPS Satellite replacement mission in June 2002, will use the flight proven Small Expendable

Leslie Curtis; Les Johnson

2002-01-01

370

Propulsion Systems Design and Simulation Tools in Alcatel Space  

NASA Astrophysics Data System (ADS)

With the arrival of the Spacebus 4000 and Proteus platforms, ALCATEL SPACE has developed its own propulsion systems (electric, bi propellant and mono propellant). This paper presents the different tools used in Propulsion systems design loop, their validation levels and their main functionality's.

Appaix, F.; Iffly, A.; Lecardonnel, L.

2004-10-01

371

Distributed Turboelectric Propulsion for Hybrid Wing Body Aircraft  

Microsoft Academic Search

Meeting future goals for aircraft and air traffic system performance will require new airframes with more highly integrated propulsion. Previous studies have evaluated hybrid wing body (HWB) configurations with various numbers of engines and with increasing degrees of propulsion-airframe integration. A recently published configuration with 12 small engines partially embedded in a HWB aircraft, reviewed herein, serves as the airframe

Hyun Dae Kim; Gerald V. Brown; James L. Felder

372

Capability of solar electric propulsion for planetary missions  

Microsoft Academic Search

Historically, deep space exploration was initiated by a series of flyby missions that were propulsively and energetically modest. The basic energy barrier given by the use of chemical propulsion system was not a limiting factor. Later on, the use of gravity assists has enabled missions with enlarged velocity increments. Unfortunately, multiple gravity assists have the drawback to narrow dramatically the

Giuseppe D Racca

2001-01-01

373

Surface electromyography activity of trunk muscles during wheelchair propulsion  

Microsoft Academic Search

BackgroundTrunk instability due to paralysis can have adverse effects on posture and function in a wheelchair. The purpose of this study was to record trunk muscle recruitment patterns using surface electromyography from unimpaired individuals during wheelchair propulsion under various propulsion speed conditions to be able to design trunk muscle stimulation patterns for actual wheelchair users with spinal cord injury.

Yu-Sheng Yang; Alicia M. Koontz; Ronald J. Triolo; Jennifer L. Mercer; Michael L. Boninger

2006-01-01

374

A comparison of propulsion systems for potential space mission applications  

SciTech Connect

A derivative of the NERVA nuclear rocket engine was compared with a chemical propulsion system and a nuclear electric propulsion system to assess the relative capabilities of the different propulsion system options for three potential space missions. The missions considered were (1) orbital transfer from low earth orbit (LEO) to geosynchronous earth orbit (GEO), (2) LEO to a lunar base, and (3) LEO to Mars. The results of this comparison indicate that the direct-thrust NERVA-derivative nuclear rocket engine has the best performance characteristics for the missions considered. The combined high thrust and high specific impulse achievable with a direct-thrust nuclear stage permits short operating times (transfer times) comparable to chemical propulsion systems, but with considerably less required propellant. While nuclear-electric propulsion systems are more fuel efficient than either direct-nuclear or chemical propulsion, they are not stand-alone systems, since their relatively low thrust levels require the use of high-thrust ferry or lander stages in high gravity applications such as surface-to-orbit propulsion. The extremely long transfer times and inefficient trajectories associated with electric propulsion systems were also found to be a significant drawback.

Harvego, E.A.; Sulmeisters, T.K.

1987-01-01

375

Budget, economics, technology all affect alternate propulsion systems  

Microsoft Academic Search

The Department of Energy has been investigating alternate propulsion systems and alternate propulsion systems and alternate fuel systems in terms of research and development and vehicle integration. Proposed budget cuts may leave only RandD programs intact and it will be up to industry to prove the technologies to be commercially viable. All Stirling and gas turbine engine development work will

Greenberg

1981-01-01

376

Research on propulsion effect of exploding wire in water  

Microsoft Academic Search

For analyzing the mechanical effect caused by discharge in water, an experimental set is established which is consist of capacitor energy storage high pulsed power supply, propulsion accelerator and measurement system. To enhance propulsion effect, the mechanical restriction and magnetic restriction have been used and a particular discharge reactor with special electrode structure has been constructed. The pressure, discharge current,

Zhang Chunxi; Yang Jiaxiang

2006-01-01

377

Antimatter Production for Near-term Propulsion Applications  

Microsoft Academic Search

The superior energy density of antimatter annihilation has often been pointed to as the ultimate source of energy for propulsion. Unfortunately, the limited capacity and very low efficiency of present-day antiproton production methods suggest that antimatter may be too costly to consider for near-term propulsion applications. We address this issue by assessing the antimatter requirements for six different types of

G. R. Schmidt; H. P. Gerrish; J. J. Martin; G. A. Smith; K. J. Meyer

378

"Packetized Propulsion" for Human and Robotic Mars Exploration  

NASA Astrophysics Data System (ADS)

This is a proposal to modularize propulsion elements of Mars missions into ~50 kg packets to autonomously self-deliver and self-assemble over time in Earth and Mars orbit, providing a Mars return propulsion system years before the need.

Riedel, J. E.; Marrese-Reading, C.; Mueller, J.; Eisenman, D.; Lee, Y. H.

2012-06-01

379

Test facilities for evaluating nuclear thermal propulsion systems  

Microsoft Academic Search

Interagency panels evaluating nuclear thermal propulsion (NTP) development options have consistently recognized the need for constructing a major new ground test facility to support fuel element and engine testing. This paper summarizes the requirements, configuration, and baseline performance of some of the major subsystems designed to support a proposed ground test complex for evaluating nuclear thermal propulsion fuel elements and

D. F. Beck; G. C. Allen; L. R. Shipers; D. Dobranich; C. A. Ottinger; C. D. Harmon; W. C. Fan; M. Todosow

1992-01-01

380

Test facilities for evaluating nuclear thermal propulsion systems  

Microsoft Academic Search

Interagency panels evaluating nuclear thermal propulsion (NTP) development options have consistently recognized the need for constructing a major new ground test facility to support fuel element and engine testing. This paper summarizes the requirements, configuration, and baseline performance of some of the major subsystems designed to support a proposed ground test complex for evaluating nuclear thermal propulsion fuel elements and

David F. Beck; George C. Allen; Larry R. Shipers; Dean Dobranich; Cathy A. Ottinger; Charles D. Harmon; Wesley C. Fan; Michael Todosow

1993-01-01

381

Use of cermet fueled nuclear reactors for direct nuclear propulsion  

Microsoft Academic Search

There has been a renewal of interest in Direct Nuclear Propulsion (DNP) because of the Air Force Forecast II recommendation for the development of the technology. Several nuclear concepts have been proposed to meet the Direct Nuclear Propulsion challenge. In this paper we will present results of an initial study of the potential of a cermet fueled nuclear system in

S. K. Bhattacharyya; L. W. Carlson; K. D. Kuczen; N. A. Hanan; R. G. Palmer; J. Von Hoomissen; W. Chiu; R. Haaland

1988-01-01

382

Recent advances in nuclear powered electric propulsion for space exploration  

Microsoft Academic Search

Nuclear and radioisotope powered electric thrusters are being developed as primary in space propulsion systems for potential future robotic and piloted space missions. Possible applications for high-power nuclear electric propulsion include orbit raising and maneuvering of large space platforms, lunar and Mars cargo transport, asteroid rendezvous and sample return, and robotic and piloted planetary missions, while lower power radioisotope electric

R. Joseph Cassady; Robert H. Frisbee; James H. Gilland; Michael G. Houts; Michael R. LaPointe; Colleen M. Maresse-Reading; Steven R. Oleson; James E. Polk; Derrek Russell; Anita Sengupta

2008-01-01

383

THERMIONIC CONVERSION IN A NUCLEAR-ELECTRIC SPACE PROPULSION SYSTEM  

Microsoft Academic Search

The theory and experimental performance of the thermionic converter is ; analyzed for use in power conversion in a nuclear-electric space propulsion ; system. Electrical propulsion power requirements are shown to demand a minimum ; ratio of powerplant weight to power in the jet. The elements of a powerplant ; into which the converter must be integrated are discussed, including

J. P. Ditz; T. R. Shukay

1961-01-01

384

Concept for a Laser Propulsion Based Nanosat Launch System  

Microsoft Academic Search

Laser propulsion offers the potential to become a competitive alternative for the rapid, efficient transport of small satellites from ground into low earth orbit. Based on recent laser propulsion experiments in our laboratory at DLR we studied the mission characteristics for a 50 kg satellite launch. This comprises reflections on the available or required laser power, the transition of the

Hans-Albert Eckel; Wolfgang O. Schall

2004-01-01

385

Propulsion system Integration of turboprop aircraft for basic trainer  

Microsoft Academic Search

The propulsion system integration of a turboprop aircraft, which has been developed for the basic trainer, was performed. The proper turboprop engine was selected among worldwide existing engines by the specific developed engine selection technique and trade-off studies such as customer’s request for operational capability (ROC), propulsion system parameters, performance analysis with engine installed effects, future growth potential, integrated logistic

Changduk Kong

2000-01-01

386

Advanced hybrid nuclear propulsion Mars mission performance enhancement  

Microsoft Academic Search

Nuclear electric propulsion (NEP), compared with chemical and nuclear thermal propulsion (NTP), can effectively deliver the same mass to Mars using much less propellant, consequently requiring less mass delivered to Earth orbit. The lower thrust of NEP requires a spiral trajectory near planetary bodies, which significantly increases the travel time. Although the total travel time is long, the portion of

J. E. Dagle; K. E. Noffsinger; D. R. Segna

1992-01-01

387

Mars mission performance enhancement with hybrid nuclear propulsion  

Microsoft Academic Search

Nuclear electric propulsion (NEP), compared with chemical and nuclear thermal propulsion (NTP), can effectively deliver the same mass to Mars using much less propellant, consequently requiring less mass delivered to Earth orbit. The lower thrust of NEP requires a spiral trajectory near planetary bodies, which significantly increases the travel time. Although the total travel time is long, the portion of

Jeffery E. Dagle; Kent E. Noffsinger; Donald R. Segna

1992-01-01

388

Radiation shield requirements for manned nuclear propulsion space vehicles  

Microsoft Academic Search

Manned nuclear propulsion space vehicles require radiation shielding to protect the crew from a number of diverse radiation sources: the propulsion system reactor, the Earth's Van Allen radiation belts, anomalously large solar proton events (ALSPEs), and galactic cosmic radiation (GCR). The sources are characterized not only in terms of species and energy spectrum, but also by frequency, duration, and probability

Paul H. Sager

1992-01-01

389

Radiation shield requirements for manned nuclear propulsion space vehicles  

Microsoft Academic Search

Manned nuclear propulsion space vehicles require radiation shielding to protect the crew from a number of diverse radiation sources: the propulsion system reactor, the Earth’s Van Allen radiation belts, anomalously large solar proton events (ALSPEs), and galactic cosmic radiation (GCR). The sources are characterized not only in terms of species and energy spectrum, but also by frequency, duration, and probability

Paul H. Sager

1992-01-01

390

Multiphase machines in propulsion drives of electric vehicles  

Microsoft Academic Search

Multiphase electric drives have been recently proposed for applications where the highest overall system reliability and power distribution per phase are required. The propulsion drive of an Electric Vehicle (EV) is one of these applications. This paper deals with the use of a five-phase induction machine in the propulsion module of EVs, where the viability of a Predictive Torque Control

J. Riveros; B. Bogado; J. Prieto; F. Barrero; S. Toral; M. Jones

2010-01-01

391

Propulsion by passive filaments and active flagella near boundaries  

Microsoft Academic Search

Confinement and wall effects are known to affect the kinematics and propulsive characteristics of swimming microorganisms. When a solid body is dragged through a viscous fluid at constant velocity, the presence of a wall increases fluid drag, and thus the net force required to maintain speed has to increase. In contrast, recent optical trapping experiments have revealed that the propulsive

Arthur A. Evans; Eric Lauga

2010-01-01

392

A fission fragment reactor concept for nuclear thermal propulsion  

Microsoft Academic Search

The Space Exploration Initiative requires the development of nuclear thermal and nuclear electric technologies for space propulsion for future Luna and Mars missions. Sandia National Laboratories has proposed a new nuclear thermal propulsion concept that uses fission fragments to directly heat the propellant up to 1000 K or higher above the material temperatures. The concept offers significant advantages over traditional

Ahti J. Suo-Anttila; Edward J. Parma; Paul S. Pickard; Steven A. Wright; Milton E. Vernon

1992-01-01

393

RADIOISOTOPE ELECTRIC PROPULSION FOR NEW FRONTIERS CLASS MISSIONS  

Microsoft Academic Search

With the initiation of the New Frontiers Class of space science missions, small radioisotope powered spacecraft for outer planet exploration will become reality. In order for these missions to co-orbit various primitive objects and moons of interest, a highly efficient electric propulsion system is needed. The use of such a radioisotope electric propulsion system is enabled by a new direct

Steven Oleson; Scott Benson; Michael Patterson; Jeffrey Schreiber; Douglas Fiehler

2003-01-01

394

The future of space nuclear power and propulsion - A retrospective  

Microsoft Academic Search

This paper examines the reasons for the cycle of initial enthusiasm, followed by almost complete abandonment, which has characterized the application of nuclear power to satellite propulsion and as power source in space. It is noted that the successful development of nuclear submarines is an exception to the rule that nuclear energy is resistant to propulsion applications. Other exceptions are

John E. Pike; Steven Aftergood

1993-01-01

395

IEC fusion: The future power and propulsion system for space  

Microsoft Academic Search

Rapid access to any point in the solar system requires advanced propulsion concepts that will provide extremely high specific impulse, low specific power, and a high thrust-to-power ratio. Inertial Electrostatic Confinement (IEC) fusion is one of many exciting concepts emerging through propulsion and power research in laboratories across the nation which will determine the future direction of space exploration. This

Walter E. Hammond; Matt Coventry; John Hanson; Ivana Hrbud; George H. Miley; Jon Nadler

2000-01-01

396

Propulsion and stabilization system for magnetically levitated vehicles  

DOEpatents

A propulsion and stabilization system for an inductive repulsion type magnetically levitated vehicle which is propelled and stabilized by a system which includes propulsion windings mounted above and parallel to vehicle-borne suspension magnets. A linear synchronous motor is part of the vehicle guideway and is mounted above and parallel to superconducting magnets attached to the magnetically levitated vehicle.

Coffey, H.T.

1992-12-31

397

Low Cost Electric Propulsion Thruster for Deep Space Robotic Missions  

Microsoft Academic Search

Electric Propulsion has found widespread acceptance by commercial satellite providers for on-orbit station keeping due to the total life cycle cost advantages these systems offer. NASA has also sought to benefit from the use of EP for primary propulsion onboard the Deep Space-1 and DAWN spacecraft. These applications utilized EP systems based on gridded ion thrusters, which offer performance unequaled

David Manzella

398

Some perspectives on pulse detonation propulsion systems  

NASA Astrophysics Data System (ADS)

Pulse detonation engines and rockets (PDE/Rs) can potentially revolutionize air breathing and rocket propulsion [1-6]. While the PDE concept is over five decades old, it has recently enjoyed renewed interest, due mostly to theoretical and computational studies indicating high cycle efficiencies. When modeled by a constant volume, Humphrey cycle, the detonation engine is found to be superior to that of existing constant pressure, Brayton cycles, with claims of as much as 10-40% improvement in specific impulse [4,7-9]. The constant volume process is derived from the Zeldovich-von Neumann-Döring (ZND) model of the detonation wave as a high strength shock wave, followed by a region of chemical reaction and a subsequent isentropic rarefaction. Amongst other advantages of the PDE is simplicity, where the PDE is easy to manufacture and requires few moving parts, with the possibility of eliminating high-pressure pumps in rocket applications, or reducing turbomachinery stages in air-breathing propulsion systems.

Lu, F. K.; Wilson, D. R.

399

An Exploration Perspective of Beamed Energy Propulsion  

SciTech Connect

The Vision for Exploration is currently focused on flying the Space Shuttle safely to complete our Space Station obligations, retiring the Shuttle in 2010, then returning humans to the Moon and learning how to proceed to Mars and beyond. The NASA budget still includes funds for science and aeronautics but the primary focus is on human exploration. Fiscal constraints have led to pursuing exploration vehicles that use heritage hardware, particularly existing boosters and engines, with the minimum modifications necessary to satisfy mission requirements. So, pursuit of immature technologies is not currently affordable by NASA. Beamed energy is one example of an immature technology, from a human exploration perspective, that may eventually provide significant benefits for human exploration of space, but likely not in the near future. Looking to the more distant future, this paper will examine some of the criteria that must be achieved by beamed energy propulsion to eventually contribute to human exploration of the solar system. The analysis focuses on some of the implications of increasing the payload fraction of a launch vehicle, with a quick look at trans-lunar injection. As one would expect, there is potential for benefit, and there are concerns. The analysis concludes with an assessment of the Technology Readiness Level (TRL) for some beamed energy propulsion components, indicating that TRL 2 is close to being completed.

Cole, John [NASA Marshall Space Flight Center Marshall Space Flight Center, AL 35812 (United States)

2008-04-28

400

Propulsion using the electron spiral toroid  

SciTech Connect

A new propulsion method is proposed which could potentially reduce propellant needed for space travel by three orders of magnitude. It uses the newly patented electron spiral toroid (EST), which stores energy as magnetic field energy. The EST is a hollow toroid of electrons, all spiraling in parallel paths in a thin outer shell. The electrons satisfy the coupling condition, forming an electron matrix. Stability is assured as long as the coupling condition is satisfied. The EST is held in place with a small external electric field; without an external magnetic field. The EST system is contained in a vacuum chamber. The EST can be thought of as an energetic entity, with electrons at 10,000 electron volts. Propulsion would not use combustion, but would heat propellant through elastic collisions with the EST surface and eject them for thrust. Chemical rocket combustion heats propellant to 4000 deg. C; an EST will potentially heat the propellant 29,000 times as much, reducing propellant needs accordingly. The thrust can be turned ON and OFF. The EST can be recharged as needed.

Seward, Clint [Electron Power Systems, Inc., 42 Washington Drive, Acton, Massachusetts 01720 (United States)

1998-01-15

401

Anguilliform fish propulsion of highest hydrodynamic efficiency  

NASA Astrophysics Data System (ADS)

It is hypothesized that steady anguilliform swimming motion of aquatic animals is purely reactive such that no net vortex wake is left downstream. This is versus carangiform and tunniform swimming of fish, where vortex streams are shed from tail, fins, and body. But there the animal movements are such to produce partial vortex cancellation downstream in maximizing propulsive efficiency. In anguilliform swimming characteristic of the eel family, it is argued that the swimming motions are configured by the animal such that vortex shedding does not occur at all. However, the propulsive thrust in this case is higher order in the motion amplitude, so that relatively large coils are needed to produce relatively small thrust; the speeds of anguilliform swimmers are less than the carangiform and tunniform, which develop first order thrusts via lifting processes. Results of experimentation on live lamprey are compared to theoretical prediction which assumes the no-wake hypothesis. Two-dimensional analysis is first performed to set the concept. This is followed by three-dimensional analysis using slender-body theory. Slender-body theory has been applied by others in studying anguilliform swimming, as it is ideally suited to the geometry of the lamprey and other eel-like animals. The agreement between this new approach based on the hypothesis of wakeless swimming and the experiments is remarkably good in spite of the physical complexities.

Vorus, William S.; Taravella, Brandon M.

2011-06-01

402

Ultrahigh Specific Impulse Nuclear Thermal Propulsion  

SciTech Connect

Research on nuclear thermal propulsion systems (NTP) have been in forefront of the space nuclear power and propulsion due to their design simplicity and their promise for providing very high thrust at reasonably high specific impulse. During NERVA-ROVER program in late 1950's till early 1970's, the United States developed and ground tested about 18 NTP systems without ever deploying them into space. The NERVA-ROVER program included development and testing of NTP systems with very high thrust (~250,000 lbf) and relatively high specific impulse (~850 s). High thrust to weight ratio in NTP systems is an indicator of high acceleration that could be achieved with these systems. The specific impulse in the lowest mass propellant, hydrogen, is a function of square root of absolute temperature in the NTP thrust chamber. Therefor optimizing design performance of NTP systems would require achieving the highest possible hydrogen temperature at reasonably high thrust to weight ratio. High hydrogen exit temperature produces high specific impulse that is a diret measure of propellant usage efficiency.

Anne Charmeau; Brandon Cunningham; Samim Anghaie

2009-02-09

403

An Exploration Perspective of Beamed Energy Propulsion  

NASA Astrophysics Data System (ADS)

The Vision for Exploration is currently focused on flying the Space Shuttle safely to complete our Space Station obligations, retiring the Shuttle in 2010, then returning humans to the Moon and learning how to proceed to Mars and beyond. The NASA budget still includes funds for science and aeronautics but the primary focus is on human exploration. Fiscal constraints have led to pursuing exploration vehicles that use heritage hardware, particularly existing boosters and engines, with the minimum modifications necessary to satisfy mission requirements. So, pursuit of immature technologies is not currently affordable by NASA. Beamed energy is one example of an immature technology, from a human exploration perspective, that may eventually provide significant benefits for human exploration of space, but likely not in the near future. Looking to the more distant future, this paper will examine some of the criteria that must be achieved by beamed energy propulsion to eventually contribute to human exploration of the solar system. The analysis focuses on some of the implications of increasing the payload fraction of a launch vehicle, with a quick look at trans-lunar injection. As one would expect, there is potential for benefit, and there are concerns. The analysis concludes with an assessment of the Technology Readiness Level (TRL) for some beamed energy propulsion components, indicating that TRL 2 is close to being completed.

Cole, John

2008-04-01

404

Thermal arcjet technology for space propulsion  

SciTech Connect

Advanced space propulsion systems are required to meet projected Air Force needs through the year 2000. Most of these missions require a large, on-orbit impulse capability. High specific impulse (I sub sp) electric engines can provide this impulse while consuming relatively little propellant. An arcjet engine system, which operates in the range of 800 to 2000 s I sub sp, is a promising candidate to meet these projected Air Force mission needs. This electric propulsion system is ideally suited to missions currently under consideration, such as the space-based radar and other space platforms, because sufficient power is already installed for other functions on the spacecraft. Also, arcjet systems are attractive for NASA near-term, low-cost Mariner Mark II missions to Saturn and Uranus. This paper describes thermal arcjet technology as it was developed over two decades ago and points to the direction this technology development should proceed in the future. In particular, operation with storable propellants such as ammonia and hydrazine are considered. The performance, applicability and advantages of these systems in terms of increased payload and/or decreased trip times are discussed.

Pivirotto, T.J.; King, D.Q.

1985-01-01

405

High Energy Propulsion System (HEPS) analysis  

NASA Astrophysics Data System (ADS)

Deep space missions will require high specific impulse (I(sub sp)) and large changes in velocity (delta v). The compact energy storage of nuclear fission systems and advanced fusion reactor concepts make them ideal power source candidates for future space applications. Fusion is particularly attractive because it produces more energy than fission, and does not produce long-lived radioactive waste. The purpose of this study was to produce a FORTRAN computer code to analyze the performance of fusion reactors as propulsion concepts. The code simplifies the task of comparing thruster performance while varying individual or multiple reactor parameters. Two potential candidate fusion reactor concepts were modeled and inserted into the reactor system model: (1) the Dense Plasma Focus (DPF); and (2) the Field-Reversed Configuration (FRC). For a fusion thermal rocket, the propulsion relations were established between fusion output and rocket performance, system mass, and mission capability. By varying fusion plasma temperature, fuel mixture ratio, and mission delta v, performance values for comparison are generated, including thrust, I(sub sp), jet power, jet specific power (alpha), thrust-to-weight ratio, and payload-to-system initial mass ratio.

Nachtrieb, Robert T.

1992-07-01

406

Innovative nuclear thermal propulsion technology evaluation: Results of the NASA\\/DOE Task Team study  

Microsoft Academic Search

In response to findings from two NASA\\/DOE nuclear propulsion workshops held in the summer of 1990, six task teams were formed to continue evaluation of various nuclear propulsion concepts. The Task Team on Nuclear Thermal Propulsion (NTP) created the Innovative Concepts Subpanel to evaluate thermal propulsion concepts which did not utilize solid fuel. The Subpanel endeavored to evaluate each of

S. Howe; S. Borowski; C. Motloch; I. Helms; N. Diaz; S. Anghaie; T. Latham

1991-01-01

407

Fully-propulsive Mars atmospheric transit strategies for high-mass payload missions  

Microsoft Academic Search

A systems analysis focused on the use of propulsion during entry, descent, and landing at Mars is presented. The propellant mass fractions of various fully-propulsive EDL strategies are presented. A key aspect of the study is the propellant costs of meeting specified heat rate constraints and the trade between TPS mass and technology requirements vs those for propulsive deceleration. Propulsive

Christopher L. Marsh; Robert D. Braun

2009-01-01

408

Beamed Energy Propulsion: Research Status And Needs--Part 1  

SciTech Connect

One promising solution to the operationally responsive space is the application of remote electromagnetic energy to propel a launch vehicle into orbit. With beamed energy propulsion, one can leave the power source stationary on the ground or space, and direct heat propellant on the spacecraft with a beam from a fixed station. This permits the spacecraft to leave its power source at home, saving significant amounts of mass, greatly improving performance. This concept, which removes the mass penalty of carrying the propulsion energy source on board the vehicle, was first proposed by Arthur Kantrowitz in 1972; he invoked an extremely powerful ground based laser. The same year Michael Minovich suggested a conceptually similar 'in-space' laser rocket system utilizing a remote laser power station. In the late 1980's, Air Force Office of Scientific Research (AFOSR) funded continuous, double pulse laser and microwave propulsion while Strategic Defense Initiative Office (SDIO) funded ablative laser rocket propulsion. Currently AFOSR has been funding the concept initiated by Leik Myrabo, repetitively pulsed laser propulsion, which has been universally perceived, arguably, to be the closest for mid-term applications. This 2-part paper examines the investment strategies in beamed energy propulsion and technical challenges to be overcome. Part 1 presents a world-wide review of beamed energy propulsion research, including both laser and microwave arenas.

Birkan, Mitat [Air Force Office of Scientific Research, Arlington, Virginia, 22203 (United States)

2008-04-28

409

Can treadmill walking be used to assess propulsion generation?  

PubMed Central

Instrumented treadmills offer significant advantages for analysis of human locomotion, including recording consecutive steady-state gait cycles, precisely controlling walking speed, and avoiding force plate targeting. However, some studies of hemiparetic walking on a treadmill have suggested that the moving treadmill belt may fundamentally alter propulsion mechanics. Any differences in propulsion mechanics during treadmill walking would be problematic since recent studies assessing propulsion have provided fundamental insight into hemiparetic walking. The purpose of this study was to test the hypothesis that there would be no difference in the generation of anterior/posterior (A/P) propulsion by performing a carefully controlled comparison of the A/P ground reaction forces (GRFs) and impulses in healthy adults during treadmill and overground walking. Gait data were collected from eight subjects walking overground and on a treadmill with speed and cadence controlled. Peak negative and positive horizontal GRFs in early and late stance, respectively, were reduced by less than 5% of body weight (p < 0.05) during treadmill walking compared to overground walking. The magnitude of the braking impulse was similarly lower (p < 0.05) during treadmill walking, but no significant difference was found between propulsion impulses. While there were some subtle differences in A/P GRFs between overground and treadmill walking, these results suggest there is no fundamental difference in propulsion mechanics. We conclude that treadmill walking can be used to investigate propulsion generation in healthy and by implication clinical populations.

Goldberg, Evan J.; Kautz, Steven A.; Neptune, Richard R.

2008-01-01

410

Chemical Propulsion Systems for Mars Sample Return  

NASA Astrophysics Data System (ADS)

The European Space Agency (ESA) instigated the Aurora Solar System Exploration Programme in 2001. A cornerstone of the initial robotic phase of Aurora is Mars Sample Return, MSR. ESA has designed the first iteration of a "minimal complexity" (and cost) MSR mission centred around a dual Ariane V launch in 2011. Mission elements include an Orbiter, including an Earth return capsule, and separate descent module / Mars ascent vehicle composite will launch direct to Mars later. A Descent Module (DM) will propulsively slow the composite to a controlled soft landing near the Mars equator for a 14 week surface stay. A two stage Mars Ascent Vehicle (MAV) will then launch a 0.5kg Mars sample onto a rendezvous trajectory with the awaiting Orbiter upper stage for return to Earth. This paper critically examines the demanding propulsion requirements of the Orbiter, DM and MAV mission elements for the ESA MSR mission, which are all sent from Earth fully loaded with propellant. Design issues and suggested solutions from the inventory of European and non-European engines which have been identified in the first phase of the study are outlined. The Orbiter requires a high reliability high Isp engine of around 800N thrust and at least 50 restarts to minimise propulsive losses on the ~4ton platform during deceleration into Mars orbit. There are currently no European engines with this thrust level. The DM system is required to generate a total thrust of 8000-10000N (depending on the MAV mass), with an engine capable of throttling to ~10% of maximum thrust with a rapid response time. An Isp requirement has not been determined. Two MAV's of differing complexity and mass are being studied by European prime contractors, resulting in either first stage a thrust requirement of 2750 or 5500N, depending on the design. A comparable Isp to the Orbiter, in excess of 310s, is common to both, as is the survival a 14 week surface stay. All engines are intended to use storable liquid propellants. A preliminary table of engine options is included in this paper.

Baker, A. M.; Rapposelli, E.; Cervone, A.; D'Agostino, L.; René-Corail, M.; Callot, S.; Caramelli, F.

2004-10-01

411

Space Nuclear Thermal Propulsion Test Facilities Subpanel. Final report  

SciTech Connect

On 20 Jul. 1989, in commemoration of the 20th anniversary of the Apollo 11 lunar landing, President George Bush proclaimed his vision for manned space exploration. He stated, 'First for the coming decade, for the 1990's, Space Station Freedom, the next critical step in our space endeavors. And next, for the new century, back to the Moon. Back to the future. And this time, back to stay. And then, a journey into tomorrow, a journey to another planet, a manned mission to Mars.' On 2 Nov. 1989, the President approved a national space policy reaffirming the long range goal of the civil space program: to 'expand human presence and activity beyond Earth orbit into the solar system.' And on 11 May 1990, he specified the goal of landing Astronauts on Mars by 2019, the 50th anniversary of man's first steps on the Moon. To safely and ever permanently venture beyond near Earth environment as charged by the President, mankind must bring to bear extensive new technologies. These include heavy lift launch capability from Earth to low-Earth orbit, automated space rendezvous and docking of large masses, zero gravity countermeasures, and closed loop life support systems. One technology enhancing, and perhaps enabling, the piloted Mars missions is nuclear propulsion, with great benefits over chemical propulsion. Asserting the potential benefits of nuclear propulsion, NASA has sponsored workshops in Nuclear Electric Propulsion and Nuclear Thermal Propulsion and has initiated a tri-agency planning process to ensure that appropriate resources are engaged to meet this exciting technical challenge. At the core of this planning process, NASA, DOE, and DOD established six Nuclear Propulsion Technical Panels in 1991 to provide groundwork for a possible tri-agency Nuclear Propulsion Program and to address the President's vision by advocating an aggressive program in nuclear propulsion. To this end the Nuclear Electric Propulsion Technology Panel has focused it energies.

Allen, G.C.; Warren, J.W.; Martinell, J.; Clark, J.S.; Perkins, D.

1993-04-01

412

Test facilities for evaluating nuclear thermal propulsion systems  

SciTech Connect

Interagency panels evaluating nuclear thermal propulsion (NTP) development options have consistently recognized the need for constructing a major new ground test facility to support fuel element and engine testing. This paper summarizes the requirements, configuration, and baseline performance of some of the major subsystems designed to support a proposed ground test complex for evaluating nuclear thermal propulsion fuel elements and engines being developed for the Space Nuclear Thermal Propulsion (SNTP) program. Some preliminary results of evaluating this facility for use in testing other NTP concepts are also summarized.

Beck, D.F.; Allen, G.C.; Shipers, L.R.; Dobranich, D.; Ottinger, C.A.; Harmon, C.D.; Fan, W.C. (Sandia National Labs., Albuquerque, NM (United States)); Todosow, M. (Brookhaven National Lab., Upton, NY (United States))

1992-09-22

413

High energy propulsion units for the year 2000  

NASA Astrophysics Data System (ADS)

The future tasks of space navigation propulsion units for the next two decades are discussed. Necessary loss equipment for commercial satellite launching and higher safety for manned missions are emphasized. Technical requirements and their solution statements are reported. New hypersonic and electrical propulsion units are to be developed in the future. New markets for propulsion units are not envisaged. It is shown that new concepts and technologies are to be studied about fifteen years prior to the applications in order to avoid incalculable risks and erroneous developments.

Kramer, P.-A.; Munding, G.; Bassner, H.; Besser, H.-L.; Schmidt, G.; Seidel, A.; Smirra, K.

414

Localized surface plasmon-enhanced propulsion of gold nanospheres  

NASA Astrophysics Data System (ADS)

We experimentally demonstrated the enhanced propulsion of 250 nm gold nanospheres using an optical nanofiber decorated with five gold nanoparticles. By tuning the input laser wavelength to 808 nm, the enhanced propulsion phenomenon occurred due to the excitation of local surface plasmon resonance (LSPR) of the gold nanoparticles. Simulated results indicate considerably enhanced optical scattering force on the gold nanospheres provided by LSPR, which lead to enhanced propulsion velocity. The velocity was measured to be about 10 times larger for the LSPR of gold nanoparticles than the conventional evanescent field around the nanofiber.

Li, Ying; Hu, Yanjun

2013-04-01

415

Options for development of space fission propulsion systems  

NASA Astrophysics Data System (ADS)

Fission technology can enable rapid, affordable access to any point in the solar system. Potential fission-based transportation options include high specific power continuous impulse propulsion systems and bimodal nuclear thermal rockets. Despite their tremendous potential for enhancing or enabling deep space and planetary missions, to date space fission systems have only been used in Earth orbit. The first step towards utilizing advanced fission propulsion systems is development of a safe, near-term, affordable fission system that can enhance or enable near-term missions of interest. An evolutionary approach for developing space fission propulsion systems is proposed. .

Houts, Mike; van Dyke, Melissa; Godfroy, Tom; Pedersen, Kevin; Martin, James; Dickens, Ricky; Salvail, Pat; Hrbud, Ivana

2001-02-01

416

Three-Body Invariant Manifold Transition with Electric Propulsion  

Microsoft Academic Search

\\u000a The advantageous combination of dynamical systems theory of three-body models with Electric Propulsion to design novel spacecraft\\u000a mission in multi-body regimes has been investigated. Combining the advantages of Electric Propulsion with respect to propellant\\u000a requirements and low-energy ballistic trajectories existing in the three-body model, multi-body planetary tours can be designed.\\u000a The employment of power constrained Electric Propulsion at the solar

Pierpaolo Pergola; Koen Geurts; Cosmo Casaregola; Mariano Andrenucci

2010-01-01

417

Three-Body Invariant Manifold Transition with Electric Propulsion  

NASA Astrophysics Data System (ADS)

The advantageous combination of dynamical systems theory of three-body models with Electric Propulsion to design novel spacecraft mission in multi-body regimes has been investigated. Combining the advantages of Electric Propulsion with respect to propellant requirements and low-energy ballistic trajectories existing in the three-body model, multi-body planetary tours can be designed. The employment of power constrained Electric Propulsion at the solar distance of Uranus is enabled by the use of Radioisotope Thermoelectric Generators. This provides continuous availability of sufficient electrical power.

Pergola, Pierpaolo; Geurts, Koen; Casaregola, Cosmo; Andrenucci, Mariano

418

Casimir Energy, Extra Dimensions and Exotic Propulsion  

NASA Astrophysics Data System (ADS)

It is well known that the Casimir effect is an excellent candidate for the stabilization of the extra dimensions. It has also been suggested that the Casimir effect in higher dimensions may be the underlying phenomenon that is responsible for the dark energy which is currently driving the accelerated expansion of the universe. In this paper we suggest that, in principle, it may be possible to directly manipulate the size of an extra dimension locally using Standard Model fields in the next generation of particle accelerators. This adjustment of the size of the higher dimension could serve as a technological mechanism to locally adjust the dark energy density and change the local expansion of spacetime. This idea holds tantalizing possibilities in the context of exotic spacecraft propulsion.

Obousy, R.; Saharian, A.

419

System model development for nuclear thermal propulsion  

SciTech Connect

A critical enabling technology in the evolutionary development of nuclear thermal propulsion (NTP) is the ability to predict the system performance under a variety of operating conditions. This is crucial for mission analysis and for control subsystem testing as well as for the modeling of various failure modes. Performance must be accurately predicted during steady-state and transient operation, including startup, shutdown and post operation cooling. The development and application of verified and validated system models has the potential to reduce the design, testing, cost and time required for the technology to reach flight-ready status. Since October 1991, the US Department of Energy (DOE), Department of Defense (DOD) and NASA have initiated critical technology development efforts for NTP systems to be used on Space Exploration Initiative (SEI) missions to the Moon and Mars. This paper presents the strategy and progress of an interagency NASA/DOE/DOD team for NTP system modeling.

Hannan, N.A. [Argonne National Lab., IL (United States); Worley, B.A. [Oak Ridge National Lab., TN (United States); Walton, J.T. [National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center; Perkins, K.R. [Brookhaven National Lab., Upton, NY (United States); Buksa, J.J. [Los Alamos National Lab., NM (United States); Dobranich, D. [Sandia National Labs., Albuquerque, NM (United States)

1992-11-01

420

System model development for nuclear thermal propulsion  

SciTech Connect

A critical enabling technology in the evolutionary development of nuclear thermal propulsion (NTP) is the ability to predict the system performance under a variety of operating conditions. Since October 1991, US (DOE), (DOD) and NASA have initiated critical technology development efforts for NTP systems to be used on Space Exploration Initiative (SEI) missions to the Moon and Mars. This paper presents the strategy and progress of an interagency NASA/DOE/DOD team for NTP system modeling. It is the intent of the interagency team to develop several levels of computer programs to simulate various NTP systems. An interagency team was formed for this task to use the best capabilities available and to assure appropriate peer review. The vision and strategy of the interagency team for developing NTP system models will be discussed in this paper. A review of the progress on the Level 1 interagency model is also presented.

Walton, J.T. [National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center; Hannan, N.A. [Argonne National Lab., IL (United States); Perkins, K.R. [Brookhaven National Lab., Upton, NY (United States); Buksa, J.J. [Los Alamos National Lab., NM (United States); Worley, B.A. [Oak Ridge National Lab., TN (United States); Dobranich, D. [Sandia National Labs., Albuquerque, NM (United States)

1992-10-01

421

Small low mass advanced PBR's for propulsion  

NASA Astrophysics Data System (ADS)

The advanced Particle Bed Reactor (PBR) to be described in this paper is characterized by relatively low power, and low cost, while still maintaining competition values for thrust/weight, specific impulse and operating times. In order to retain competitive values for the thrust/weight ratio while reducing the reactor size, it is necessary to change the basic reactor layout, by incorporating new concepts. The new reactor design concept is termed SIRIUS (Small Lightweight Reactor Integral Propulsion System). The following modifications are proposed for the reactor design to be discussed in this paper: Pre-heater (U-235 included in Moderator); Hy-C (Hydride/De-hydride for Reactor Control); Afterburner (U-235 impregnated into Hot Frit); and Hy-S (Hydride Spike Inside Hot Frit). Each of the modifications will be briefly discussed below, with benefits, technical issues, design approach, and risk levels addressed. The paper discusses conceptual assumptions, feasibility analysis, mass estimates, and information needs.

Powell, J. R.; Todosow, M.; Ludewig, H.

1993-10-01

422

Low Thrust Orbital Maneuvers Using Ion Propulsion  

NASA Astrophysics Data System (ADS)

Low-thrust maneuver options, such as electric propulsion, offer specific challenges within mission-level Modeling, Simulation, and Analysis (MS&A) tools. This project seeks to transition techniques for simulating low-thrust maneuvers from detailed engineering level simulations such as AGI's Satellite ToolKit (STK) Astrogator to mission level simulations such as the System Effectiveness Analysis Simulation (SEAS). Our project goals are as follows: A) Assess different low-thrust options to achieve various orbital changes; B) Compare such approaches to more conventional, high-thrust profiles; C) Compare computational cost and accuracy of various approaches to calculate and simulate low-thrust maneuvers; D) Recommend methods for implementing low-thrust maneuvers in high-level mission simulations; E) prototype recommended solutions.

Ramesh, Eric

2011-10-01

423

ECR-GDM Thruster for Fusion Propulsion  

SciTech Connect

The concept of the Gasdynamic Mirror (GDM) device for fusion propulsion was proposed by and Lee (1995) over a decade ago and several theoretical papers has supported the feasibility of the concept. A new ECR plasma source has been built to supply power to the GDM experimental thruster previously tested at the Marshall Space Flight Center (MSFC). The new plasma generator, powered by microwaves at 2.45 or 10 GHz. is currently being tested. This ECR plasma source operates in a number of distinct plasma modes, depending upon the strength and shape of the local magnetic field. Of particular interest is the compact plasma jet issuing form the plasma generator when operated in a mirror configuration. The measured velocity profile in the jet plume is bimodal, possibly as a result of the GDM effect in the ECR chamber of the thruster.

Brainerd, Jerome J.; Reisz, Al [Reisz Engineers 2909 Johnson Rd. Huntsville, Alabama 35805 256-325-2531 (United States)

2009-03-16

424

Contributions Regarding the Aircraft Nuclear Propulsion  

NASA Astrophysics Data System (ADS)

The possibility to use a nuclear reactor for airplanes propulsion was investigated taking in to account 2 possible solutions: the direct cycle (where the fluid pass through the reactor's core) and the indirect cycle (where the fluid is passing through a heat exchanger). Taking in to account the radioprotection problems, the only realistic solution seems to be the indirect cycle, where the energy transfer should be performed by a heat exchanger that must work at very high speed of the fluid. The heat exchanger will replace the classical burning room. We had performed a more precise theoretical study for the nuclear jet engine regarding the performances of the nuclear reactor, of the heat exchanger and of the jet engine. It was taken in to account that in the moment when the burning room is replaced by a heat exchanger, a new model for gasodynamic process from the engine must be performed. Studies regarding the high flow speed heat transfer were performed.

Mitrica, Bogdan; Stanciu, Virgil; Petre, Marian; Dima, Mihai Octavian; Petre, Carmelia; Precup, Irinel

2010-01-01

425

Contributions Regarding the Aircraft Nuclear Propulsion  

SciTech Connect

The possibility to use a nuclear reactor for airplanes propulsion was investigated taking in to account 2 possible solutions: the direct cycle (where the fluid pass through the reactor's core) and the indirect cycle (where the fluid is passing through a heat exchanger). Taking in to account the radioprotection problems, the only realistic solution seems to be the indirect cycle, where the energy transfer should be performed by a heat exchanger that must work at very high speed of the fluid. The heat exchanger will replace the classical burning room. We had performed a more precise theoretical study for the nuclear jet engine regarding the performances of the nuclear reactor, of the heat exchanger and of the jet engine. It was taken in to account that in the moment when the burning room is replaced by a heat exchanger, a new model for gasodynamic process from the engine must be performed. Studies regarding the high flow speed heat transfer were performed.

Mitrica, Bogdan; Petre, Marian; Dima, Mihai Octavian [Horia Hulubei National Institute of Physics and Nuclear Engineering-IFIN HH, Magurele, 077125 (Romania); Stanciu, Virgil [POLITEHNICA University of Bucharest, Bucharest, 060042 (Romania); Petre, Carmelia; Precup, Irinel [University of Bucharest, Bucharest, 050107 (Romania)

2010-01-21

426

Propulsion multiplexer (pmux) system - the missing link  

SciTech Connect

The commercial airline emphasis on more efficient and reliable engines with lower maintenance costs has resulted in the use of in-flight engine condition monitoring equipment as part of the Airborne Integrated Data System (AIDS). To accomplish this task, the AIDS system must receive approximately twenty-five engine parameter signals. The integrity of the AIDS input signals from the engine is not the responsibility of a single equipment supplier; therefore, when the user airlines have encountered system problems, solutions have been slow in coming. A viable solution to this problem is to provide a centralized, engine-mounted data processing device for the engine signals. This missing link is under development. It has been named the Propulsion Multiplexer (PMUX) System and has been specified for Pratt and Whitney Aircraft and General Electric engines for the A310 airbus. 7 refs.

Latina, M.S.; Hixson, W.W.

1981-01-01

427

CO2 Laser Ablation Propulsion Tractor Beams  

NASA Astrophysics Data System (ADS)

Manipulation of objects at a distance has already been achieved with no small measure of success in the realm of microscopic objects on the scale size of nanometers to micrometers in applications including laser trapping and laser tweezers. However, there has been relatively little effort to apply such remote control to macroscopic systems. A space tractor beam could be applied to a wide range of applications, including removal of orbital debris, facilitation of spacecraft docking, adjustment of satellite attitude or orbital position, etc. In this paper, an ablative laser propulsion tractor beam is demonstrated based on radiation from a CO2 laser. Cooperative, layered polymer targets were used for remote impulse generation using a CO2 laser. The use of a structured ablatant enabling switching between thrust directional parity (i.e., forward or reverse) and imparting torque to a remote target. Fluence-dependent results are presented in the context of polymer ablation modeling work and with consideration of confined ablation effects.

Sinko, John E.; Schlecht, Clifford A.

2010-05-01

428

Advanced propulsion system concept for hybrid vehicles  

SciTech Connect

The results of a nine-month study to identify and evaluate advanced propulsion systems for on-the-road hybrid vehicles are presented. Two concepts, both utilizing Stirling engines, were evaluated for five of reference mission/vehicles ranging from a two-passenger commuter car to a large bus, each had its own performance specification. Selection of the best hybrid configuration and reference mission/vehicle was made against these requirements, as well as the major goals of reducing petroleum consumption and minimizing total energy consumption. Both parallel and series hybrid systems, utilizing kinematic and free-piston Stirling engines, respectively, were evaluated. Detailed discussion, results and conclusions of the initial parametric studies, the trade-off evaluations, the life-cycle cost studies and the conceptual design definition are presented.

Bhate, S.; Chen, H.; Dochat, G.

1980-12-01

429

Publications of the Jet Propulsion Laboratory, 1980  

NASA Astrophysics Data System (ADS)

This bibliography cites by primary author the externally distributed technical reporting, released during calendar year 1980, that resulted from scientific and engineering work performed, or managed, by the Jet Propulsion Laboratory. Three classes of publications are included: (1) JPL Publications (77-, 78-, 79-series, etc.), in which the information is complete for a specific accomplishment and can e tailored to wide or limited audiences and be presented in an established standard format or special format to meet unique requirements; (2) articles published in the open literature; and (3) articles from the bimonthly Deep Space Network (DSN) Progress Report (42-series) and its successor, the Telecommunications and Data Acquisition (TDA) Progress Report (also 42-series).

1981-07-01

430

The Liquid Annular Reactor System (LARS) propulsion  

NASA Astrophysics Data System (ADS)

A new concept for very high specific impulse (greater than 2,000 seconds) direct nuclear propulsion is described. The concept, termed LARS (Liquid Annular Reactor System) uses liquid nuclear fuel elements to heat hydrogen propellant to very high temperatures (approximately 6,000 K). Operating pressure is moderate (approximately 10 atm), with the result that the outlet hydrogen is virtually 100 percent dissociated to monatomic H. The molten fuel is contained in a solid container of its own material, which is rotated to stabilize the liquid layer by centripetal force. LARS reactor designs are described, together with neutronic and thermal-hydraulic analyses. Power levels are on the order of 200 megawatts. Typically, LARS designs use 7 rotating fuel elements, are beryllium moderated and have critical radii of approximately 100 cm (core L/D is approximately 1.5).

Powell, J.; Ludewig, H.; Horn, F.; Lenard, R.

431

The liquid annular reactor system (LARS) propulsion  

NASA Astrophysics Data System (ADS)

A new concept for very high specific impulse (>~2000 seconds) direct nuclear propulsion is described. The concept, termed LARS (Liquid Annular Reactor System) uses liquid nuclear fuel elements to heat hydrogen propellant to very high temperatures (~6000 K). Operating pressure is moderate (~10 atm), with the result that the outlet hydrogen is virtually 100% dissociated to monatomic H. The molten fuel is contained in a solid container of its own material, which is rotated to stabilize the liquid layer by centripetal force. LARS reactor designs are described, together with neutronic and thermal-hydraulic analyses. Power levels are on the order of 200 megawatts. Typically, LARS designs use 7 rotating fuel elements, are beryllium moderated and have critical radii of ~100 cm (core L/D~=1.5).

Maise, George; Lazareth, Otto W.; Horn, Frederic; Powell, James R.; Ludewig, Hans; Lenard, Roger X.

1991-01-01

432

The Liquid Annular Reactor System (LARS) propulsion  

NASA Astrophysics Data System (ADS)

A new concept for very high specific impulse (greater than 2000 seconds) direct nuclear propulsion is described. The concept, termed LARS (Liquid Annular Reactor System) uses liquid nuclear fuel elements to heat hydrogen propellant to very high temperatures (about 6000 K). Operating pressure is moderate (about 10 atm), with the result that the outlet hydrogen is virtually 100 percent dissociated to monatomic H. The molten fuel is contained in a solid container of its own material, which is rotated to stabilize the liquid layer by centripetal force. LARS reactor designs are described, together with neutronic and thermal-hydraulic analyses. Power levels are on the order of 200 megawatts. Typically, LARS designs use 7 rotating fuel elements, are beryllium moderated and have critical radii of about 100 cm.

Maise, George; Lazareth, Otto W.; Horn, Frederick; Powell, James R.; Ludewig, Hans; Lenard, Roger X.

433

Synchrotron Radiation Drive for Space Propulsion  

NASA Astrophysics Data System (ADS)

Efficient long-range space propulsion requires high-velocity exhaust. Plasmas easily reach such velocities but, in toroidal geometry, direct plasma exhaust requires complicated magnets, possibly at high field. A different approach, called synchrotron radiation fusion drive (SRFD), separates the generator and thruster functions. High-temperature, high-magnetic-field plasmas can produce a large fraction of their fusion power as synchrotron radiation. The synchrotron radiation can be carried by waveguides and absorbed in a magnetic-mirror plasma thruster with appropriately resonant magnetic field profiles. The basic SRFD concept appears feasible using conventional embodiments of the tokamak, but this results in marginal performance. The present paper explores basing the design on a higher specific-power device for the synchrotron generator. Possibilities include high-field, advanced tokamaks or linear fusion devices with high-field cells.

Santarius, J. F.; Emmert, G. A.; Khater, H. Y.; Mogahed, E. A.

1997-11-01

434

A pulsed cathodic arc spacecraft propulsion system  

NASA Astrophysics Data System (ADS)

We investigate the use of a centre-triggered cathodic arc as a spacecraft propulsion system that uses an inert solid as a source of plasma. The cathodic vacuum arc produces almost fully ionized plasma with a high exhaust velocity (>104 m s-1), giving a specific impulse competitive with other plasma or ion thrusters. A centre trigger design is employed that enables efficient use of cathode material and a high pulse-to-pulse repeatability. We compare three anode geometries, two pulse current profiles and two pulse durations for their effects on impulse generation, energy and cathode material usage efficiency. Impulse measurement is achieved through the use of a free-swinging pendulum target constructed from a polymer material. Measurements show that impulse is accurately controlled by varying cathode current. The cylindrical anode gave the highest energy efficiency. Cathode usage is optimized by choosing a sawtooth current profile. There is no requirement for an exhaust charge neutralization system.

Neumann, P. R. C.; Bilek, M. M. M.; Tarrant, R. N.; McKenzie, D. R.

2009-11-01

435

System model development for nuclear thermal propulsion  

NASA Astrophysics Data System (ADS)

A critical enabling technology in the evolutionary development of nuclear thermal propulsion (NTP) is the ability to predict the system performance under a variety of operating conditions. Since October 1991, DOE, DOD, and NASA have initiated critical technology development efforts for NTP systems to be used on Space Exploration Initiative (SEI) missions to the Moon and Mars. This paper presents the strategy and progress of an interagency NASA/DOE/DOD team for NTP system modeling. It is the intent of the interagency team to develop several levels of computer programs to simulate various NTP systems. An interagency team was formed for this task to use the best capabilities available and to assure appropriate peer review. The vision and strategy of the interagency team for developing NTP system models are discussed. A review of the progress on the level 1 interagency model is also presented.

Walton, James T.; Hannan, Nelson A.; Perkins, Ken R.; Buksa, John J.; Worley, Brian A.; Dobranich, Dean

436

High Power Electric Propulsion System for NEP: Propulsion and Trajectory Options  

SciTech Connect

Recent US initiatives in Nuclear Propulsion lend themselves naturally to raising the question of the assessment of various options and particularly to propose the High Power Electric Propulsion Subsystem (HPEPS) for the Nuclear Electric Propulsion (NEP). The purpose of this paper is to present the guidelines for the HPEPS with respect to the mission to Mars, for automatic probes as well as for manned missions. Among the various options, the technological options and the trajectory options are pointed out. The consequences of the increase of the electrical power of a thruster are first an increase of the thrust itself, but also, as a general rule, an increase of the thruster performance due to its higher efficiency, particularly its specific impulse increase. The drawback is as a first parameter, the increase of the thruster's size, hence the so-called 'thrust density' shall be high enough or shall be drastically increased for ions thrusters. Due to the large mass of gas needed to perform the foreseen missions, the classical xenon rare gas is no more in competition, the total world production being limited to 20 -40 tons per year. Thus, the right selection of the propellant feeding the thruster is of prime importance. When choosing a propellant with lower molecular mass, the consequences at thruster level are an increase once more of the specific impulse, but at system level the dead mass may increase too, mainly because the increase of the mass of the propellant system tanks. Other alternatives, in rupture with respect to the current technologies, are presented in order to make the whole system more attractive. The paper presents a discussion on the thruster specific impulse increase that is sometime considered an increase of the main system performances parameter, but that induces for all electric propulsion systems drawbacks in the system power and mass design that are proportional to the thruster specific power increase (kW/N). The electric thruster specific impulse shall be optimized w.r.t. the mission. The trajectories taken into account in the paper are constrained by the allowable duration of the travel and the launcher size. The multi-arcs trajectories to Mars (using an optimized combination of chemical and Electric propulsion) are presented in detail. The compatibility with NEP systems that implies orbiting a sizeable nuclear reactor and a power generation system capable of converting thermal into electric power, with minimum mass and volumes fitting in with Ariane 5 or the Space Shuttle bay, is assessed.

Koppel, Christophe R.; Duchemin, Olivier [Snecma, Groupe Safran, Division Moteurs Spatiaux, Site de Villaroche Nord, Direction Propulsion et Equipements Satellites Aerodrome de Melun Villaroche (France); Valentian, Dominique [Snecma, Groupe Safran, Division Moteurs Spatiaux, Division Grosse Propulsion Liquide, 27000 Vernon (France)

2006-01-20

437

Pulsed Laser Propulsion Studies. Volume I. Thruster Physics and Performance.  

National Technical Information Service (NTIS)

This report describes experimental and analytical studies on pulsed laser propulsion. Volume I describes thruster performance and phenomenology studies. They include theoretical investigations of laser-induced gas breakdown at 10.6 microns and 0.35 micron...

D. I. Rosen N. H. Kemp G. Weyl P. E. Nebolsine G. Kothandaraman

1982-01-01

438

Laser Propulsion to Earth Orbit. Has Its Time Come.  

National Technical Information Service (NTIS)

Recent developments in high energy lasers, adaptive optics, and atmospheric transmission bring laser propulsion much closer to realization. Proposed here is a reference vehicle for study which consists of payload and solid propellant (e.g. ice). A suitabl...

A. Kantrowitz

1989-01-01

439

Anticipated Interceptor Propulsion Technology Advancements by the Late 1990's.  

National Technical Information Service (NTIS)

Advanced components and materials have exciting properties which make their utilization in solid-propelled propulsion subsystems particularly attractive. All of the factors that influence the substitution of a new material for a traditional one must be ca...

D. C. Sayles

1992-01-01

440

Solar Electric Propulsion/Instrument/Subsystems Interaction Study.  

National Technical Information Service (NTIS)

The interactive effects between a solar electric propulsion system and an electrically propelled scientific spacecraft were examined. The operation of the ion thrusters may impact upon the acquisition and interpretation of data by the science payload of t...

J. M. Sellen R. K. Cole R. F. Kemp D. F. Hall H. Shelton

1973-01-01

441

MTR BASEMENT. GENERAL ELECTRIC CONTROL CONSOLE FOR AIRCRAFT NUCLEAR PROPULSION ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

MTR BASEMENT. GENERAL ELECTRIC CONTROL CONSOLE FOR AIRCRAFT NUCLEAR PROPULSION EXPERIMENT NO. 1. INL NEGATIVE NO. 6510. Unknown Photographer, 9/29/1959 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

442

Probabilistic Structural Analysis Methods for Space Transportation Propulsion Systems.  

National Technical Information Service (NTIS)

Information on probabilistic structural analysis methods for space propulsion systems is given in viewgraph form. Information is given on deterministic certification methods, probability of failure, component response analysis, stress responses for 2nd st...

C. C. Chamis N. Moore C. Anis J. Newell V. Nagpal

1991-01-01

443

Diesel-electric marine propulsion grows in popularity  

SciTech Connect

A recent conference on electric ship propulsion held in London highlighted the big strides made in this field in the last few years. What has given the technology a tremendous fillip in recent years is the new generation of ac/ac electrical drives resulting from the development of reliable high-power semiconductor devices and their associated control systems. Diesel-electric propulsion systems provide flexibility both for the operation of the vessel and in the layout of the main components - gen-sets, converters, switchgear and propulsion motors, for example. Furthermore, the system enables the `power station` philosophy to be applied, with propulsion and all ship`s services being supplied from one power source. This paper discusses the main diesel electric systems available today.

Mullins, P.

1996-03-01

444

PEGASUS: A multi-megawatt nuclear electric propulsion system  

SciTech Connect

A propulsion system (The PEGASUS Drive) consisting of a magnetoplasmadynamic (MPD) thruster driven by a multimegawatt nuclear power system is proposed as the propulsion system for a manned Mars mission. The propulsion system described is based on a mission profile containing a 510-day burn time (for a mission time of approximately 1000 days). Electric propulsion systems have significant advantages over chemical systems, because of high specific impulse, lower propellant requirements, and lower system mass. The thermal power for the PEGASUS Drive is supplied by a boiling liquid-metal fast reactor. The system consists of the reactor, reactor shielding, power conditioning, heat rejection, and MPD thruster subsystems. It is capable of providing a maximum of 8,5 megawatts of electrical power of which 6 megawatts is needed for the thruster system, 1.5 megawatts is available for spacecraft system operations and inflight mission applications, leaving the balance for power system operation.

Coomes, E.P.; King, D.Q.; Cuta, J.M.; Webb, B.J.

1986-01-01

445

Performance Assessment of Low Pressure Nuclear Thermal Propulsion.  

National Technical Information Service (NTIS)

A low pressure nuclear thermal propulsion (LPNTP) system, which takes advantage of hydrogen dissociation/recombination, was proposed as a means of increasing engine specific impulse (Isp). The effect of hydrogen dissociation/recombination on LPNTP Isp is ...

H. P. Gerrish G. E. Doughty

1993-01-01

446

Performance Assessment of Low Pressure Nuclear Thermal Propulsion.  

National Technical Information Service (NTIS)

An increase in Isp for nuclear thermal propulsion systems is desirable for reducing the propellant requirements and cost of future applications, such as the Mars Transfer Vehicle. Several previous design studies have suggested that the Isp could be increa...

H. P. Gerrish G. E. Doughty

1993-01-01

447

Design Optimization of Gas Generator Hybrid Propulsion Boosters.  

National Technical Information Service (NTIS)

A methodology used in support of a contract study for NASA/MSFC to optimize the design of gas generator hybrid propulsion booster for uprating the National Space Transportation System (NSTS) is presented. The objective was to compare alternative configura...

V. Weldon D. U. Phillips L. E. Fink

1990-01-01

448

Simulation of Diesel Engine Transient Behavior in Marine Propulsion Analysis.  

National Technical Information Service (NTIS)

Diesel engine simulation models are developed, based on a combination of engine operational principles and manufacturers' operational data. The models are intended to be suitable for use in transient modeling the propulsion engine part of marine propulsio...

J. B. Woodward R. G. Latorre

1983-01-01

449

Deflections of Hull Propulsion Shafting of Great Lakes Ore Carriers.  

National Technical Information Service (NTIS)

Great Lakes bulk carriers of recent construction are propelled by geared diesel machinery. Although this machinery is similar to propulsion sets that have been used successfully in numerous other vessel types, it has experienced failures in sufficient num...

M. J. Kaldjian J. B. Woodward W. R. Reid

1981-01-01

450

Integrated Magnetic Propulsion and Suspension (IMPS) Final Report.  

National Technical Information Service (NTIS)

The report describes the development of critical technology for an Integrated Magnetic Propulsion and Suspension (IMPS) system for automated guideway transportation. Baseline work begun by Rohr Industries, in 1970, was picked up by Boeing Aerospace, begin...

D. D. Lyttle G. W. Pearson R. G. Gilliland

1986-01-01

451

Electro-Magnetic Propulsion System (EMPS) for Spacecrafts and Satellites  

NASA Astrophysics Data System (ADS)

The electro-magnetic propulsion system (EMPS) for driving satellites and other spacecraft has smaller mass, smaller volume, and more efficiency compared with the known systems applied in space technology.

Szentesi, J.

2012-03-01

452

Antiproton Powered Propulsion with Magnetically Confined Plasma Engines.  

National Technical Information Service (NTIS)

Matter-antimatter annihilation releases more energy per unit mass than any other method of energy production, making it an attractive energy source for spacecraft propulsion. In the magnetically confined plasma engine, antiproton beams are injected axiall...

M. R. Lapointe

1989-01-01

453

Preliminary Design Optimization For A Supersonic Turbine For Rocket Propulsion.  

National Technical Information Service (NTIS)

In this study, we present a method for optimizing, at the preliminary design level, a supersonic turbine for rocket propulsion system application. Single-, two- and three-stage turbines are considered with the number of design variables increasing from 6 ...

N. Papila W. Shyy L. Griffin F. Huber K. Tran

2000-01-01

454

Solar Electric Propulsion for Primitive Body Science Missions.  

National Technical Information Service (NTIS)

This paper describes work that assesses the performance of solar electric propulsion (SEP) for three different primitive body science missions: (1) Comet Rendezvous (2) Comet Surface Sample Return (CSSR), and (3) a Trojan asteroid/Centaur object Reconnais...

K. E. Witzberger

2006-01-01

455

Optimization of Waterjet Propulsion Systems for Surface Effect Ships.  

National Technical Information Service (NTIS)

Water-jet propulsion systems using flush inlets suitable for use on surface effect ships are studied. Equations are developed and incorporated into a computer program which optimizes the system on a least total weight basis. Resistance, displacement, rang...

A. D. Carmichael W. R. Johanek

1974-01-01

456

Artist's Concept of a Solar Electric Propulsion System  

NASA Website

Using advanced Solar Electric Propulsion (SEP) technologies is an essential part of future missions into deep space with larger payloads. The use of robotics and advanced SEP technologies like this concept of an SEP-based spacecraft during NASA ...

457

Inertial Electrostatic Confinement as a Power Source for Electric Propulsion.  

National Technical Information Service (NTIS)

The potential use of an INERTIAL ELECTROSTATIC CONFINEMENT (IEC) power source for space propulsion has previously been suggested by the authors and others. In the past, these discussions have generally followed the charged-particle electric-discharge engi...

G. H. Miley R. Burton J. Javedani Y. Yamamoto A Satsangi

1993-01-01

458

Space Vehicle Propulsion Compartment Fire Hazard Investigation, Volume 1.  

National Technical Information Service (NTIS)

The report presents the results of the space fire hazard investigation program. The purpose of the program was to determine if a hazardous condition existed under vacuum conditions with regard to leakage of rocket propellants in space vehicle propulsion c...

P. J. Martinkovic

1964-01-01

459

Overview of the NASA FAP Hypersonics Project Airbreathing Propulsion Research.  

National Technical Information Service (NTIS)

The propulsion research portfolio of the National Aeronautics and Space Administration Fundamental Aeronautics Program Hypersonics Project encompasses a significant number of technical tasks that are aligned to achieve mastery and intellectual stewardship...

A. H. Auslender K. L. Suder S. R. Thomas

2009-01-01

460

Advanced APS (Auxiliary Propulsion System) Impacts on Vehicle Payloads.  

National Technical Information Service (NTIS)

Advanced auxiliary propulsion system (APS) technology has the potential to both, increase the payload capability of earth-to-orbit (ETO) vehicles by reducing APS propellant mass, and simplify ground operations and logistics by reducing the number of fluid...

S. J. Schneider B. D. Reed

1989-01-01

461

Inertial Electrostatic Confinement as a Power Source for Electric Propulsion.  

National Technical Information Service (NTIS)

The potential use of an Inertial Electrostatic Confinement (IEC) power source for space propulsion has previously been suggested by the authors and others. In the past, these discussions have generally followed the charged-particle electric-discharge engi...

G. H. Miley R. Burton J. Javedani Y. Yamamoto A. Satsangi

1993-01-01

462

Uranium ARC Fission Reactor for Space Power and Propulsion.  

National Technical Information Service (NTIS)

Combining the proven technology of solid core reactors with uranium arc confinement and non-equilibrium dissociation and ionization by fission fragments can lead to an attractive power and propulsion system. The benefit ensues from using the high quality ...

R. T. Schneider I. Maya J. Vitali

1992-01-01

463

Benefits of Nuclear Electric Propulsion for Outer Planet Exploration.  

National Technical Information Service (NTIS)

Nuclear electric propulsion (NEP) offers significant benefits to missions for outer planet exploration. Reaching outer planet destinations, especially beyond Jupiter, is a struggle against time and distance. For relatively near missions, such as a Europa ...

L. Kos L. Johnson J. Jones A. Trausch B. Eberle G. Woodcock

2002-01-01

464

Propulsion Flight Research at NASA Dryden From 1967 to 1997.  

National Technical Information Service (NTIS)

From 1967 to 1997, pioneering propulsion flight research activities have been conceived and conducted at the NASA Dryden Flight Research Center. Many of these programs have been flown jointly with the United States Department of Defense, industry, or the ...

F. W. Burcham R. J. Ray T. R. Conners K. R. Walsh

1997-01-01

465

THERMODYNAMIC ANALYSIS OF COMBUSTION PROCESSES FOR PROPULSION SYSTEMS  

Microsoft Academic Search

A key issue in conceptual design and analysis of proposed propulsion systems is the role of the combustion mode in determining the overall e-ciency of the system. Of par- ticular recent interest are detonations and the e-ciency of detonation-based propulsion systems as compared to more conventional systems based on low-speed ?ames. Our goal is to understand, based on thermodynamics, the

E. Wintenberger; J. E. Shepherd

2004-01-01

466

Interstellar propulsion using a pellet stream for momentum transfer  

SciTech Connect

A pellet-stream concept for interstellar propulsion is described. Small pellets are accelerated in the solar system and accurately guided to an interstellar probe where they are intercepted and transfer momentum. This propulsion system appears to offer orders-of-magnitude improvements in terms of engineering simplicity and power requirements over any other known feasible system for transport over interstellar distance in a time comparable to a human lifespan.

Singer, C.E.

1979-10-01

467

Details on spot remote sensing satellite propulsion unit  

NASA Astrophysics Data System (ADS)

The SPOT propulsion system is described. The SPOT platform includes a propulsion module equipped with a hydrazine reaction control system (RCD). This RCS belongs to the attitude and orbit control system. It comprises essentially two branches of catalytic thrusters fed by surface tension tanks through a circuit providing their interconnection by latching insulation valves. It operates in blow-down mode. Each equipment is qualified individually.

Corai, J. C.

1984-03-01

468

The future of vehicle propulsion – combustion engines and alternatives  

Microsoft Academic Search

Increasing shortage on energy resources as well as future emission legislation development increase the pressure to develop\\u000a more efficient, environmentally friendly propulsion systems for vehicles. This requires a further development of current diesel\\u000a and gasoline engines as well as a careful look to alternatives like fuel cell systems or hybrid propulsion systems. This paper\\u000a gives a survey about the current

Stefan Pischinger

2004-01-01

469

Application of delrin in laser plasma micro-propulsion  

NASA Astrophysics Data System (ADS)

The interaction between polymer of Delrin with nano-second pulse laser is investigated in laser plasma micro-propulsion. The coupling coefficient and specific impulse are measured respectively. The coupling coefficient about 42 dyne/W and specific impulse up to 646 s have been obtained. Moreover, the surface images after ablation have been observed. It is found that Delrin has less debris on ablation surface. This indicates that Delrin is a potential polymer material in laser plasma propulsion.

Zheng, Z. Y.; Gao, H.; Gao, L.; Xing, J.; Fan, Z. J.

2013-09-01

470

Nanonewton thrust measurement of photon pressure propulsion using semiconductor laser  

Microsoft Academic Search

To evaluate the thrust produced by photon pressure emitted from a 100 W class continuous-wave semiconductor laser, a torsion-balance precise thrust stand is designed and tested. Photon emission propulsion using semiconductor light sources attract interests as a possible candidate for deep-space propellant-less propulsion and attitude control system. However, the thrust produced by photon emission as large as several ten nanonewtons

K. Iwami; Taku Akazawa; Tomohiro Ohtsuka; Hiroyuki Nishida; Norihiro Umeda

2011-01-01

471

Propulsion system design of electric and hybrid vehicles  

Microsoft Academic Search

There is a growing interest in electric and hybrid-electric vehicles due to environmental concerns. Efforts are directed toward developing an improved propulsion system for electric and hybrid-electric vehicles applications. This paper is aimed at developing the system design philosophies of electric and hybrid vehicle propulsion systems. The vehicles' dynamics are studied in an attempt to find an optimal torque-speed profile

Mehrdad Ehsani; Khwaja M. Rahman; Hamid A. Toliyat

1997-01-01

472

Inner solar system sample return missions using solar electric propulsion  

Microsoft Academic Search

This study evaluated the effects of solar electric propulsion (SEP) and PowerSail solar array technology on four sample return missions. These missions, to the Moon, Mars, Mercury, and Venus, were compared against previous Jet Propulsion Laboratory (JPL) studies. Compared to these baselines, PowerSail\\/SEP missions in general had longer trip times, though the Venus mission was of similar duration. Costs for

Ryan D. McDaniel; Swati Mohan; Jaime Juarez

2003-01-01

473

Propulsion engineering study for small-scale Mars missions  

SciTech Connect

Rocket propulsion options for small-scale Mars missions are presented and compared, particularly for the terminal landing maneuver and for sample return. Mars landing has a low propulsive {Delta}v requirement on a {approximately}1-minute time scale, but at a high acceleration. High thrust/weight liquid rocket technologies, or advanced pulse-capable solids, developed during the past decade for missile defense, are therefore more appropriate for small Mars landers than are conventional space propulsion technologies. The advanced liquid systems are characterize by compact lightweight thrusters having high chamber pressures and short lifetimes. Blowdown or regulated pressure-fed operation can satisfy the Mars landing requirement, but hardware mass can be reduced by using pumps. Aggressive terminal landing propulsion designs can enable post-landing hop maneuvers for some surface mobility. The Mars sample return mission requires a small high performance launcher having either solid motors or miniature pump-fed engines. Terminal propulsion for 100 kg Mars landers is within the realm of flight-proven thruster designs, but custom tankage is desirable. Landers on a 10 kg scale also are feasible, using technology that has been demonstrated but not previously flown in space. The number of sources and the selection of components are extremely limited on this smallest scale, so some customized hardware is required. A key characteristic of kilogram-scale propulsion is that gas jets are much lighter than liquid thrusters for reaction control. The mass and volume of tanks for inert gas can be eliminated by systems which generate gas as needed from a liquid or a solid, but these have virtually no space flight history. Mars return propulsion is a major engineering challenge; earth launch is the only previously-solved propulsion problem requiring similar or greater performance.

Whitehead, J.

1995-09-12

474

IEC Thrusters for Space Probe Applications and Propulsion  

Microsoft Academic Search

Earlier conceptual design studies (Bussard, 1990; Miley et al., 1998; Burton et al., 2003) have described Inertial Electrostatic Confinement (IEC) fusion propulsion to provide a high-power density fusion propulsion system capable of aggressive deep space missions. However, this requires large multi-GW thrusters and a long term development program. As a first step towards this goal, a progression of near-term IEC

George H. Miley; Hiromu Momota; Linchun Wu; Michael P. Reilly; Vince L. Teofilo; Rodney Burton; Richard Dell; William A. Hargus

2009-01-01

475

Optimum cycle frequencies in hand-rim wheelchair propulsion  

Microsoft Academic Search

Summary  To study the effect of different cycle frequencies on cardio-respiratory responses and propulsion technique in hand-rim wheelchair propulsion, experienced wheelchair sportsmen (WS group; n=6) and non-wheel chair users (NW group; n=6) performed wheelchair exercise tests on a motor-driven treadmill. The WS group wheeled at velocities of 0.55, 0.83, 1.11 and 1.39 m · s–1 and a slope of 2°. The

L. H. V. van der Woude; H. E. J. Veeger; R. H. Rozendal; A. J. Sargeant

1989-01-01

476

Air Force Research Laboratory high power electric propulsion technology development  

Microsoft Academic Search

Space solar power generation systems have a significant impact on Electric Propulsion (EP) technology development.1,2,3 Recent advances in solar cell, deployment, and concentrator hardware have led to significant reductions in component mass, thereby decreasing power generation system specific mass. Combined with maneuvering requirements for Air Force and DoD missions of interest, propulsive requirements emerge that provide direction for technology investments.

Daniel L. Brown; Brian E. Beal; James M. Haas

2010-01-01

477

An inertial fusion propulsion scheme for solar system exploration  

SciTech Connect

A novel fusion scheme that combines the favorable aspects of both inertial and magnetic confinement approaches is analyzed as a propulsion device for potential utilization in solar system exploration. Using an appropriate set of equations for the plasma dynamics and the magnetic nozzle, we assess the system's propulsive capability by applying the results to a round trip mission to Mars. We find that such a device would allow a massive vehicle to make the journey in less than five months.

Kammash, T.; Galbraith, D.L. (Department of Nuclear Engineering, The University of Michigan, Ann Arbor, Michigan 48109 (US))

1991-01-05

478

Simplistic propulsion analysis of a breakthrough space drive for Voyager  

Microsoft Academic Search

When considering exploration beyond our solar system, speed is a critical factor. With the speeds achievable with current propulsion technology, interstellar distances cannot be traversed within a human life span. For example, the Voyager spacecraft would take approximately 80,000 years to traverse 4.3 light-years - the distance to our nearest neighboring star. In 1996 NASA established the Breakthrough Propulsion Physics

Malcolm D. K. Boston

2000-01-01

479

Development and Qualification of ATV Propulsion Assemblies  

NASA Astrophysics Data System (ADS)

In the frame of the development and operation of the International Space Station ISS, the European Space Agency ESA is not only contributing experiments and a laboratory module but also logistics capacity. This purpose of supplying the ISS shall be covered by an unmanned, Automated Transfer Vehicle (ATV) that will be launched for the first time in 2004 by Ariane 5. The development of the ATV is in close conjunction to the future Ariane 5 launch capacity of about 20 tons injected into low earth orbit. Thus this unmanned transporter will be a quite large space craft that is subjected to fulfil several mission objectives apart of only delivering cargo such as multiple automatic docking/de-docking, re-boost services and re-fuelling. For those reasons and due to its dimensions the propulsion sub-system is one of the most sophisticated in the field of space propulsion. Even safety issues of manned space flight have to be applied since the pressurised cargo section is part of the ISS when docked to the manned modules. This leads to by far the largest but also the most sophisticated propulsion system ever built in Europe. Astrium as one of the major partners of this european project is responsible for this major system that will be described in the paper. Focusing on the major core assemblies such as multi thruster platforms, pressure control system incl. safety and redundancy mechanisms as well as tanks and other components that completes a propulsion system. System Design and Qualification Starting from the basic criteria the paper will present the major performance requirements such as pressures, thrust levels and other parameters that led to the selection of major components of the system such as thrusters, valves, tanks, etc. Some of the component could be selected from off the shelve, whereas other core components such as the 200N Attitude Control and Braking Thrusters or Propellant Tanks had to be newly developed. The stepwise approach of development and careful qualification will be presented starting from components and assemblies up to sub- system. Exemplarily, the path of the 200N shall be described in more detail since requirements of various kinds are to be applied here. This thruster is used in a total of 28 engines located on 4 thruster cluster assemblies on the bottom and 4 on the front of the space craft delivering steady state thrust as well as impulse bit to the ATV and can be used also as backup for the main thrusters. Safety and thus redundancy is one of the major driver for the design. As a first step i.e. the thrusters are equipped with measures to detect malfunctions and problems by continuous measuring chamber temperature and combustion pressure. The layout of the thruster clusters arrangement in combination with control electronics are such are such that multiple independent branches are controlling the system by which each of them could to fulfil the whole operational objectives. The thruster clusters are also affected by most of the environmental constraints that require careful thermal or mechanical design. For example severe shock loads induced by the stage separation nearby as well as meteorites and debris have to be taken into account for mechanical design. Or large transient pressure spikes and water hammer caused by simultaneous operation of thrusters have to be considered for hydraulic design. As well as extreme conditions for thermal design facing high thermal loads both radiation and conductive during thruster firing and sun exposure of the externally mounted assembly as well as low heater budget and I/F flux limitations when exposed to deep space during long phases. Intensive test programs have been carried out or are under preparation as well as complementary numerical analysis are completing and supporting each step of the development. The paper will describe those design and qualification activities as well as the results as far as available to that time in order to give an overview of the status of the development of the whole propulsion system.

Riehle, M.; Jost, R.

2002-01-01

480

Legal Implications of Nuclear Propulsion for Space Objects  

NASA Astrophysics Data System (ADS)

This paper is intended to examine nuclear propulsion concepts such as "Project Orion", "Project Daedalus", NERVA, VASIMIR, from the legal point of view. The UN Principles Relevant to the Use of Nuclear Power Sources in Outer Space apply to nuclear power sources in outer space devoted to the generation of electric power on board space objects for non-propulsive purposes, and do not regulate the use of nuclear energy as a means of propulsion. However, nuclear propulsion by means of detonating atomic bombs (ORION) is, in principle, banned under the 1963 Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space, and Under Water. The legality of use of nuclear propulsion will be analysed from different approaches - historical (i.e. the lawfulness of these projects at the time of their proposal, at the present time, and in the future - in the light of the mutability and evolution of international law), spatial (i.e. the legal regime governing peaceful nuclear explosions in different spatial zones - Earth atmosphere, Earth orbit, Solar System, and interstellar space), and technical (i.e, the legal regime applicable to different nuclear propulsion techniques, and to the various negative effects - e.g. damage to other space systems as an effect of the electromagnetic pulse, etc). The paper will analyse the positive law, and will also come with suggestions "de lege ferenda".

Pop, V.

2002-01-01

481

Propulsion by passive filaments and active flagella near boundaries  

NASA Astrophysics Data System (ADS)

Confinement and wall effects are known to affect the kinematics and propulsive characteristics of swimming microorganisms. When a solid body is dragged through a viscous fluid at constant velocity, the presence of a wall increases fluid drag, and thus the net force required to maintain speed has to increase. In contrast, recent optical trapping experiments have revealed that the propulsive force generated by human spermatozoa is decreased by the presence of boundaries. Here, we use a series of simple models to analytically elucidate the propulsive effects of a solid boundary on passively actuated filaments and model flagella. For passive flexible filaments actuated periodically at one end, the presence of the wall is shown to increase the propulsive forces generated by the filaments in the case of displacement-driven actuation, while it decreases the force in the case of force-driven actuation. In the case of active filaments as models for eukaryotic flagella, we demonstrate that the manner in which a solid wall affects propulsion cannot be known a priori, but is instead a nontrivial function of the flagellum frequency, wavelength, its material characteristics, the manner in which the molecular motors self-organize to produce oscillations (prescribed activity model or self-organized axonemal beating model), and the boundary conditions applied experimentally to the tethered flagellum. In particular, we show that in some cases, the increase in fluid friction induced by the wall can lead to a change in the waveform expressed by the flagella, which results in a decrease in their propulsive force.

Evans, Arthur A.; Lauga, Eric

2010-10-01

482

PEGASUS: a multi-megawatt nuclear electric propulsion system  

SciTech Connect

With the Space Transportation System (STS), the advent of space station Columbus and the development of expertise at working in space that this will entail, the gateway is open to the final frontier. The exploration of this frontier is possible with state-of-the-art hydrogen/oxygen propulsion but would be greatly enhanced by the higher specific impulse of electric propulsion. This paper presents a concept that uses a multi-megawatt nuclear power plant to drive an electric propulsion system. The concept has been named PEGASUS, PowEr GenerAting System for Use in Space, and is intended as a ''work horse'' for general space transportation needs, both long- and short-haul missions. The recent efforts of the SP-100 program indicate that a power system capable of producing upwards of 1 megawatt of electric power should be available in the next decade. Additionally, efforts in other areas indicate that a power system with a constant power capability an order of magnitude greater could be available near the turn of the century. With the advances expected in megawatt-class space power systems, the high specific impulse propulsion systems must be reconsidered as potential propulsion systems. The power system is capable of meeting both the propulsion system and spacecraft power requirements.

Coomes, E.P.; Cuta, J.M.; Webb, B.J.; King, D.Q.

1985-06-01

483

Beamed Energy Propulsion: Research Status And Needs--Part 2  

SciTech Connect

One promising solution to the operationally responsive space is the application of remote electromagnetic energy to propel a launch vehicle into orbit. With beamed energy propulsion, one can leave the power source stationary on the ground or space, and direct heat propellant on the spacecraft with a beam from a fixed station. This permits the spacecraft to leave its power source at home, saving significant amounts of mass, greatly improving performance. This concept, which removes the mass penalty of carrying the propulsion energy source on board the vehicle, was first proposed by Arthur Kantrowitz in 1972; he invoked an extremely powerful ground based laser. The same year Michael Minovich suggested a conceptually similar 'in-space' laser rocket system utilizing a remote laser power station. In the late 1980's, Air Force Office of Scientific Research (AFOSR) funded continuous, double pulse laser and microwave propulsion while Strategic Defense Initiative Office (SDIO) funded ablative laser rocket propulsion. Currently AFOSR has been funding the concept initiated by Leik Myrabo, repetitively pulsed laser propulsion, which has been universally perceived, arguably, to be the closest for mid-term applications. This 2-part paper examines the investment strategies in beamed energy propulsion and technical challenges to be covers Part 2 covers the present research status and needs.

Birkan, Mitat [Air Force Office of Scientific Research, Arlington, Virginia, 22203 (United States)

2008-04-28

484

Separation of Propulsive and Adhesive Traction Stresses in Locomoting Keratocytes  

PubMed Central

Strong, actomyosin-dependent, pinching tractions in steadily locomoting (gliding) fish keratocytes revealed by traction imaging present a paradox, since only forces perpendicular to the direction of locomotion are apparent, leaving the actual propulsive forces unresolved. When keratocytes become transiently “stuck” by their trailing edge and adopt a fibroblast-like morphology, the tractions opposing locomotion are concentrated into the tail, leaving the active pinching and propulsive tractions clearly visible under the cell body. Stuck keratocytes can develop ?1 mdyn (10,000 pN) total propulsive thrust, originating in the wings of the cell. The leading lamella develops no detectable propulsive traction, even when the cell pulls on its transient tail anchorage. The separation of propulsive and adhesive tractions in the stuck phenotype leads to a mechanically consistent hypothesis that resolves the traction paradox for gliding keratocytes: the propulsive tractions driving locomotion are normally canceled by adhesive tractions resisting locomotion, leaving only the pinching tractions as a resultant. The resolution of the traction pattern into its components specifies conditions to be met for models of cytoskeletal force production, such as the dynamic network contraction model (Svitkina, T.M., A.B. Verkhovsky, K.M. McQuade, and G.G. Borisy. 1997. J. Cell Biol. 139:397–415). The traction pattern associated with cells undergoing sharp turns differs markedly from the normal pinching traction pattern, and can be accounted for by postulating an asymmetry in contractile activity of the opposed lateral wings of the cell.

Oliver, Tim; Dembo, Micah; Jacobson, Ken

1999-01-01

485

Chemical Propulsion Information Agency Bulletin, Volume 26, Number 3. The JHU Applied Physics Laboratory Continues a Long History of Propulsion Research.  

National Technical Information Service (NTIS)

The Johns Hopkins University Applied Physics Laboratory (JHU/APL) has been involved with rocket and missile propulsion as a technology developer, as an evaluator of propulsion technology, and as a user of propulsion units for over fifty years. JHU/APL has...

2000-01-01

486

Exhaust elbow for marine propulsion system  

SciTech Connect

A marine propulsion system is described having an internal combustion engine exhausted through a water jacketed exhaust elbow, an improved exhaust elbow: consisting of: an intake exhaust passage communicating through a bend with a discharge exhaust passage; water jacket means around the exhaust passages; central channel means extending longitudinally along the exterior of the discharge exhaust passage to guide water therealong in the water jacket means to the end of the discharge exhaust passage to mix with exhaust thereat; and means for maintaining the end tip of the discharge exhaust passage dry to prevent water ingestion and creeping back into the discharge exhaust passage due to pulsations of the engine, the last mentioned means comprising transition means at the end of the central channel means creating an outward draw from the central channel means to minimize break-up of outward water flow from the central channel means at the end tip of the discharge exhaust passage which may otherwise deposit water on the end tip of the discharge exhaust passage.

Entringer, D.C.; Gruenwald, D.J.; Felix, D.K.

1986-03-04

487

Actin-based propulsion : experiments and models  

NASA Astrophysics Data System (ADS)

Spatially controlled actin polymerization generates a force that leads to cell protrusions and motility. Such a force is also responsible for the movement of Listeria monocytogenes once inside the cytoplasm of infected cells. By virtue of producing an F-actin filled tail, Listeria constitutes a simple model for studying movement induced by actin polymerization. But the physical properties of this bacterial system, like load-size and surface protein concentration are unalterable. Recent developments in the biochemistry of actin-based motility allowed us to use a simplified system made of beads coated with a protein that promotes actin polymerization (either the bacterial protein ActA, the human protein WASP, or protein fragments). These beads are placed in cell-free extracts or in a buffer containing the minimal number of proteins required for the movement. The size of the beads and the surface concentration of nucleators can be varied. We then studied the physical properties of the movement and we characterized the elastic properties of the actin gel. We show that the elasticity of the actin gel is the basis for the propulsion mechanism and for the symmetry breaking that precedes the formation of a comet that will propel the load. Friction occurs between the actin gel and the surface of the bead or bacteria, leading to various types of movements (from continuous to jerky) that are independent of genes, but depend on the physical parameters of the load.

Bernheim-Groswasser, Anne; Sykes

2002-03-01

488

Project Icarus: Nuclear Fusion Propulsion Concept Comparison  

NASA Astrophysics Data System (ADS)

Project Icarus will use nuclear fusion as the primary propulsion, since achieving breakeven is imminent within the next decade. Therefore, fusion technology provides confidence in further development and fairly high technological maturity by the time the Icarus mission would be plausible. Currently there are numerous (over 2 dozen) different fusion approaches that are simultaneously being developed around the World and it is difficult to predict which of the concepts is going to be the most successful one. This study tried to estimate current technological maturity and possible technological extrapolation of fusion approaches for which appropriate data could be found. Figures of merit that were assessed include: current technological state, mass and volume estimates, possible gain values, main advantages and disadvantages of the concept and an attempt to extrapolate current technological state for the next decade or two. Analysis suggests that Magnetic Confinement Fusion (MCF) concepts are not likely to deliver sufficient performance due to size, mass, gain and large technological barriers of the concept. However, ICF and PJMIF did show potential for delivering necessary performance, assuming appropriate techno- logical advances. This paper is a submission of the Project Icarus Study Group.

Stanic, M.

489

Magnetized target fusion for advanced space propulsion  

NASA Astrophysics Data System (ADS)

The magnetized target fusion (MTF) concept is an approach to thermonuclear fusion which is intermediate between the two extremes of inertial and magnetic confinement fusion. A magnetic field is used to suppress electron thermal conduction, but the fusion plasma is heated by compression and inertially confined during the fusion burn phase by an imploding liner or shell. Because the major energy loss mechanisms are suppressed, the work rate required to achieve fusion ignition is greatly reduced, which translates to a greatly reduced requirement for power input to the target. This allows electrical pulsed power machines (and possibly other devices) to be used as drivers. The potential advantages that such a relaxation of driver requirements may offer need to be explored. Thio proposed to dynamically form an MTF target plasma and compress it with a dynamically formed spherical liner, which compresses and heats the target plasma to fusion ignition conditions. This paper will discuss the fundamentals of MTF and the feasibility and technical challenges of Thio's novel approach to advanced space propulsion. .

Kirkpatrick, Ronald C.

2001-02-01

490

Nuclear electric propulsion development and qualification facilities  

NASA Astrophysics Data System (ADS)

This paper summarizes the findings of a Tri-Agency panel; consisting of members from the National Aeronautics and Space Administration (NASA), U.S. Department of Energy (DOE), and U.S. Department of Defense (DOD); charged with reviewing the status and availability of facilities to test components and subsystems for megawatt-class nuclear electric propulsion (NEP) systems. The facilities required to support development of NEP are available in NASA centers, DOE laboratories, and industry. However, several key facilities require significant and near-term modification in order to perform the testing required to meet a 2014 launch date. For the higher powered Mars cargo and piloted missions, the priority established for facility preparation is: (1 thruster developmental testing facility, (2 thruster lifetime testing facility, (3 dynamic energy conversion development and demonstration facility, and (4 advanced reactor testing facility (if required to demonstrate an advanced multiwatt power system). Facilities to support development of the power conditioning and heat rejection subsystems are available in industry, federal laboratories, and universities. In addition to the development facilities, a new preflight qualification and acceptance testing facility will be required to support the deployment of NEP systems for precursor, cargo, or piloted Mars missions. Because the deployment strategy for NEP involves early demonstration missions, the demonstration of the SP-100 power system is needed by the early 2000s.

Dutt, Dale; Thomassen, Keith; Sovey, Jim; Fontana, Mario

1992-01-01

491

System model development for nuclear thermal propulsion  

NASA Astrophysics Data System (ADS)

A critical enabling technology in the evolutionary development of nuclear thermal propulsion (NTP) is the ability to predict the system performance under a variety of operating conditions. This is crucial for mission analysis and for control subsystem testing as well as for the modeling of various failure modes. Performance must be accurately predicted during steady-state and transient operation, including startup, shutdown, and post operation cooling. The development and application of verified and validated system models has the potential to reduce the design, testing, and cost and time required for the technology to reach flight-ready status. Since Oct. 1991, the U.S. Department of Energy (DOE), Department of Defense (DOD), and NASA have initiated critical technology development efforts for NTP systems to be used on Space Exploration Initiative (SEI) missions to the Moon and Mars. This paper presents the strategy and progress of an interagency NASA/DOE/DOD team for NTP system modeling. It is the intent of the interagency team to develop several levels of computer programs to simulate various NTP systems. The first level will provide rapid, parameterized calculations of overall system performance. Succeeding computer programs will provide analysis of each component in sufficient detail to guide the design teams and experimental efforts. The computer programs will allow simulation of the entire system to allow prediction of the integrated performance. An interagency team was formed for this task to use the best capabilities available and to assure appropriate peer review.

Walton, James T.; Hannan, Nelson A.; Perkins, Ken R.; Buksa, John H.; Worley, Brian A.; Dobranich, Dean

1992-08-01

492

Propulsion and power for 21st century aviation  

NASA Astrophysics Data System (ADS)

Air transportation in the new millennium will require revolutionary solutions to meet public demand for improving safety, reliability, environmental compatibility, and affordability. NASA's vision for 21st century aircraft is to develop propulsion systems that are intelligent, highly efficient, virtually inaudible (outside airport boundaries), and have near zero harmful emissions (CO2 and NOx). This vision includes intelligent engines capable of adapting to changing internal and external conditions to optimally accomplish missions with either minimal or no human intervention. Distributed vectored propulsion will replace current two to four wing mounted and fuselage mounted engine configurations with a large number of small, mini, or micro engines. Other innovative concepts, such as the pulse detonation engine (PDE), which potentially can replace conventional gas turbine engines, also are reviewed. It is envisioned that a hydrogen economy will drive the propulsion system revolution towards the ultimate goal of silent aircrafts with zero harmful emissions. Finally, it is envisioned that electric drive propulsion based on fuel cell power will generate electric power, which in turn will drive propulsors to produce the desired thrust. This paper reviews future propulsion and power concepts that are under development at the National Aeronautics and Space Administration's (NASA) John H. Glenn Research Center at Lewis Field, Cleveland, Ohio, USA.

Sehra, Arun K.; Whitlow, Woodrow

2004-05-01

493

Propulsion of a flexible foil in a fluid  

NASA Astrophysics Data System (ADS)

The dynamic properties such as time dependent pressure loading, free stream velocity, and local acceleration of the hydrofoil determine the instantaneous deformation of a flexible foil. The present work is concerned with the effect of structural dynamic terms and inertia loads on a flexible foil undergoing large amplitude rigid body harmonic wave-like motion in an unsteady potential flow. The hydrofoil structural dynamics is modeled as an Euler-Bernoulli beam finite element. The unsteady fluid dynamic force is evaluated using a numerical discrete vortex implementation of an unsteady incompressible potential flow model. The hydrofoil is fixed at its leading edge and it moves with velocity parallel to its length in the undeformed state. The propulsion of the hydro-elastic system is studied in terms of the mass ratio of the foil and the fluid, as well as its structural flexibility. It is shown that the thrust coefficient and propulsive efficiency of the flexible foil decreases with increase in structural flexibility. We made a comparison of the effect of structural flexibility on the thrust coefficient and propulsive efficiency considering models of the oscillating foil with inertia and without inertia effects present. Detailed parametric studies of the effect of different parameters on propulsion of the foil were made. Including inertia loads and structural dynamic terms significantly affect the propulsive efficiency and thrust coefficient.

Venkatraman, Kartik; Chaithanya, Ravi

2008-11-01

494

A Propellantless Propulsion Experiment Design and Testing Plan  

SciTech Connect

A propellantless propulsion experiment design and testing plan are described. The concept was initially presented during the Space Technology and Applications International Forum of 2001 and the experiment was initially presented during the Joint Propulsion Conference of 2001. New information is provided on how the experiment relates to the Human Exploration of Development of Space, the results of peer reviews, a cost estimate performed by a major U.S. aerospace company, and an alternative magnet design to reduce the cost of the experiment and potentially improve the reliability of the system. Recent improvements in high power solid state switches and superconducting magnets may have made propellantless propulsion possible. Propulsion may occur during the non-steady state ramp-up of a very rapidly pulsed, high power magnet. Propulsion would not occur after the first 100 nanoseconds of each pulse, since the magnetic field will have reached steady state. The United States Department of Energy Office of High Energy Physics provided some of the funding for the developed a no maintenance superconducting magnet that can carry 2,000 amperes per square millimeter and a switch which can provide 100 nanosecond ramp-ups at a rate of 0.4 megahertz, and at 9,000 volts and 30 amperes.

Goodwin, David P. [United States Department of Energy, Office of High Energy Physics, SC-20/Germantown Building, 1000 Independence Ave SW, Washington, D.C. 20585-1290 (United States)

2004-02-04

495

Reliability comparison of various nuclear propulsion configurations for Mars mission  

SciTech Connect

Currently, trade-offs are being made among the various propulsion systems being considered for the Space Exploration Initiative (SEI) missions. It is necessary to investigate the reliability aspects as well as the efficiency, mass savings, and experience characteristics of the various configurations. Reliability is a very important factor for the SEI missions because of the long duration and because problems will be fixed onboard. The propulsion options that were reviewed consist of nuclear thermal propulsion (NTP), nuclear electric propulsion (NEP) and various configurations of each system. There were four configurations developed for comparison with the NTP as baselined in the Synthesis (1991): (1) NEP, (2) hybrid NEP/NTP, (3) hybrid with power beaming, and (4) NTP upper stage on the heavy lift launch vehicle (HLLV). The comparisons were based more or less on a qualitative review of complexity, stress levels and operations for each of the four configurations. Each configuration included a pressurized NEP and an NTP ascent stage propulsion system for the Mars mission.

Segna, D.R. [USDOE Richland Operations Office, WA (United States); Dagle, J.E. [Pacific Northwest Lab., Richland, WA (United States); Lyon, W.F. III [Westinghouse Hanford Co., Richland, WA (United States)

1992-01-01

496

Prediction of applied forces in handrim wheelchair propulsion.  

PubMed

Researchers of wheelchair propulsion have usually suggested that a wheelchair can be properly designed using anthropometrics to reduce high mechanical load and thus reduce pain and damage to joints. A model based on physiological features and biomechanical principles can be used to determine anthropometric relationships for wheelchair fitting. To improve the understanding of man-machine interaction and the mechanism through which propulsion performance been enhanced, this study develops and validates an energy model for wheelchair propulsion. Kinematic data obtained from ten able-bodied and ten wheelchair-dependent users during level propulsion at an average velocity of 1m/s were used as the input of a planar model with the criteria of increasing efficiency and reducing joint load. Results demonstrate that for both experienced and inexperienced users, predicted handrim contact forces agree with experimental data through an extensive range of the push. Significant deviations that were mostly observed in the early stage of the push phase might result from the lack of consideration of muscle dynamics and wrist joint biomechanics. The proposed model effectively verified the handrim contact force patterns during dynamic propulsion. Users do not aim to generate mechanically most effective forces to avoid high loadings on the joints. PMID:20980008

Lin, Chien-Ju; Lin, Po-Chou; Guo, Lan-Yuen; Su, Fong-Chin

2010-10-25

497

Nuclear powered Mars cargo transport mission utilizing advanced ion propulsion  

SciTech Connect

Nuclear-powered ion propulsion technology was combined with detailed trajectory analysis to determine propulsion system and trajectory options for an unmanned cargo mission to Mars in support of manned Mars missions. A total of 96 mission scenarios were identified by combining two power levels, two propellants, four values of specific impulse per propellant, three starting altitudes, and two starting velocities. Sixty of these scenarios were selected for a detailed trajectory analysis; a complete propulsion system study was then conducted for 20 of these trajectories. Trip times ranged from 344 days for a xenon propulsion system operating at 300 kW total power and starting from lunar orbit with escape velocity, to 770 days for an argon propulsion system operating at 300 kW total power and starting from nuclear start orbit with circular velocity. Trip times for the 3 MW cases studied ranged from 356 to 413 days. Payload masses ranged from 5700 to 12,300 kg for the 300 kW power level, and from 72,200 to 81,500 kg for the 3 MW power level.

Galecki, D.L.; Patterson, M.J.

1987-01-01

498

Pellet bed reactor concepts for nuclear propulsion applications  

NASA Astrophysics Data System (ADS)

Pellet bed reactor (PeBR) concepts have been developed for nuclear thermal and nuclear electric propulsion, and bimodal applications. This annular core, fast spectrum reactor offers many desirable design and safety features. These features include high-power density, small reactor size, full retention of fission products, passive decay heat removal, redundancy in reactor control, negative temperature reactivity feedback, ground testing of the fully assembled reactor using electric heating and nonnuclear fuel elements, and the option of fueling on the launch pad or fueling and refueling in orbit. In addition to these features, the concepts for nuclear electric propulsion and for bimodal power and thermal propulsion have no single point failure. The average power density in the reactor for nuclear thermal propulsion ranges from 2.2 to 3.3 MW/I and for a 15-MWe nuclear electric propulsion system the total power system specific mass is about 3.3 kg/kWe. The bimodal-PeBR system concepts offer specific impulse in excess of 650 s, tens of Newtons of thrust, and total system specific power ranging from 11 to 21.9 We/kg at the 10- and 40-kWe levels, respectively.

El-Genk, Mohamed S.; Morley, Nicholas J.; Pelaccio, Dennis G.; Juhasz, Albert

1994-11-01