450
450
Jun 20, 2010
06/10
by
Ash, G. R
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Mathematical statement and computer simulation of low thrust guidance problem - minimum time solutions
Topics: COMPUTERIZED SIMULATION, TIME FUNCTION, FORMULATIONS, GUIDANCE (MOTION), LOW THRUST, LOW THRUST...
257
257
May 6, 2010
05/10
by
Clark, B. J.; Priem, R. J
texts
eye 257
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Injection techniques for 200-pound thrust ammonia- oxygen rocket engine
Topics: AMMONIA, INJECTION, LOW THRUST PROPULSION, OXYGEN, ROCKET ENGINE, BOURDON TUBES, INJECTION,...
188
188
Jun 18, 2010
06/10
by
Grodzovskiy, G. L.; Kiforenko, B. N.; Tokarev, V. V
texts
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Energy accumulator for optimal control of low- thrust space flight
Topics: ACCUMULATORS, PROPULSIVE FLUID ACCUMULATOR /PROFAC/, ENERGY STORAGE, LOW THRUST, LOW THRUST...
422
422
May 6, 2010
05/10
by
Melbourne, W. G
texts
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No Abstract Available
Topics: INTERPLANETARY TRAJECTORIES, LOW THRUST, PAYLOADS, PROPULSION
337
337
Jun 1, 2011
06/11
by
Choi, Sung R.; Zhu, Dong-Ming; Miller, Robert A
texts
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Strength, fracture toughness and fatigue behavior of free-standing thick thermal barrier coatings of plasma-sprayed ZrO2-8wt Y2O3 were determined at ambient and elevated temperatures in an attempt to establish a database for design. Strength, in conjunction with deformation (stress-strain behavior), was evaluated in tension (uniaxial and trans-thickness), compression, and uniaxial and biaxial flexure; fracture toughness was determined in various load conditions including mode I, mode II, and...
Topics: LIQUID HYDROGEN, LOW THRUST, PROPELLANTS, HYPERSONIC SPEED, KEROSENE, LAUNCHING
7
7.0
Feb 26, 2019
02/19
by
Yajur Kumar
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This paper investigates the applicability of the continuous thrust Clohessy-Wiltshire model for the optimal low-thrust rendezvous in the orbit. While simplifying the non-linear equations of relative orbital motion, certain assumptions were taken in account by Clohessy and Wiltshire to linearize the system of equations. When the same model is used for optimization of the trajectory of a relative transfer in the orbit using low-thrust, because of the assumptions in the dynamic model there are...
Topics: Continuous Low-Thrust Transfer, Clohessy-Wiltshire Model, Minimum Propellant Control, Trajectory...
For many problems it is reasonable to expect that the minimum time solution is also the minimum fuel solution. However, if one allows the propulsion system to be turned off and back on, it is clear that these two solutions may differ. In general, high thrust transfers resemble the well-known impulsive transfers where the burn arcs are of very short duration. The low and medium thrust transfers differ in that their thrust acceleration levels yield longer burn arcs which will require more...
Topics: NASA Technical Reports Server (NTRS), LOW THRUST PROPULSION, OPTIMIZATION, PROPULSION SYSTEM...
4,614
4.6K
Jun 27, 2010
06/10
by
KRASNOV, N. F., et al
texts
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BASICS OF HIGH SPEED AERODYNAMIC THEORY AND CHARACTERISTICS OF GAS FLOWS FOR ROCKETS
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Topics: CHEMICAL PROPULSION, LOW THRUST PROPULSION, NUCLEAR PROPULSION, PROPULSION SYSTEM PERFORMANCE,...
This thesis explores using a direct pseudospectral method for the solution of optimal control problems with mixed dynamics. An easy to use MATLAB optimization package known as DIDO is used to obtain the solutions. The modeling of both low thrust interplanetary trajectories as well as aerocapture trajectories is detailed and the solutions for low thrust minimum time and minimum fuel trajectories are explored with particular emphasis on verification of the optimality of the obtained solution....
Topics: Rocket engines, Thrust, Space trajectories, Astrodynamics, Space vehicles, Propulsion systems, Low...
307
307
May 6, 2010
05/10
by
Karp, I. M
texts
eye 307
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Nuclear powered supercritical water cycle for aircraft propulsion
Topics: AIRCRAFT ENGINES, LOW THRUST, MACH NUMBER, NUCLEAR PROPELLED AIRCRAFT, SUPERCRITICAL PRESSURES,...
The use of high thrust, relatively low specific impulse systems, such as chemical or nuclear thermal propulsion, in conjunction with low thrust, high specific impulse nuclear electric propulsion (NEP) was considered for a representative piloted Mars mission. It was concluded that the single burn option in an all-propulsive mission scenario does not yield a significant advantage in reduced trip time for reasonable masses. The multiple burn option allows significant reductions in trip time...
Topics: NASA Technical Reports Server (NTRS), INTERPLANETARY SPACECRAFT, MANNED MARS MISSIONS, PROPULSION...
209
209
Jun 26, 2010
06/10
by
Bahm, E
texts
eye 209
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Long life tape transport for magnetic recorder of outer planet spacecraft
Topics: BURNING RATE, LOW THRUST PROPULSION, SOLID PROPELLANT ROCKET ENGINES, TRANSFER ORBITS, HYDROXIDES,...
219
219
Jun 26, 2010
06/10
by
Brereton, R. G.; Burke, J. D.; Coryell, R. B.; Jaffe, L. D
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eye 219
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Comparison of United States lunar roving vehicle missions with Lunokhod 1 mission
Topics: COMBUSTION CONTROL, IGNITERS, LOW THRUST PROPULSION, SOLID PROPELLANT IGNITION, BURNING RATE, FUEL...
Pulsed plasma thrusters are low thrust propulsive devices which have a high specific impulse at low power. A pulsed plasma thruster is currently scheduled to fly as an experiment on NASA's Earth Observing-1 satellite mission. The pulsed plasma thruster will be used to replace one of the reaction wheels. As part of the qualification testing of the thruster it is necessary to determine the nominal thrust as a function of charge energy. These data will be used to determine control algorithms....
Topics: NASA Technical Reports Server (NTRS), LOW THRUST, ROCKET THRUST, LOW THRUST PROPULSION, PROPULSION...
Three dominant Two Stage To Orbit (TSTO) class architectures were studied: Series Burn (SB), Parallel Bum with crossfeed (PBw/cf), and Parallel Burn, no-crossfeed (PBncf). The study goal was to determine what factors uniquely affect PBncf architectures, how each of these factors interact, and to determine from a performance perspective whether a PBncf vehicle could be competitive with a PBw/cf or a SB vehicle using equivalent technology and assumptions. In all cases, performance was evaluated...
Topics: NASA Technical Reports Server (NTRS), LIQUID HYDROGEN, LOW THRUST, PROPELLANTS, HYPERSONIC SPEED,...
The ISPT project released its low-thrust trajectory tool suite in March of 2006. The LTTT suite tools range in capabilities, but represent the state-of-the art in NASA low-thrust trajectory optimization tools. The tools have all received considerable updates following the initial release, and they are available through their respective development centers or the ISPT project website.
Topics: NASA Technical Reports Server (NTRS), LOW THRUST, TRAJECTORIES, TRAJECTORY ANALYSIS, TRAJECTORY...
365
365
Jun 21, 2010
06/10
by
Fish, R. H
texts
eye 365
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Penetration of porous projectiles in aluminium and plastic targets
Topics: ELECTRIC PROPULSION, OPTIMAL CONTROL, INTERPLANETARY TRAJECTORIES, LOW THRUST, TRAJECTORY ANALYSIS,...
A low-thrust guidance algorithm suitable for operational use was formulated. A constrained linear feedback control law was obtained using a minimum terminal miss criterion and restricting control corrections to constant changes for specified time periods. Both fixed- and variable-time-of-arrival guidance were considered. The performance of the guidance law was evaluated by applying it to the approach phase of the 1980 rendezvous mission with the comet Encke.
Topics: NASA Technical Reports Server (NTRS), LOW THRUST, SPACECRAFT GUIDANCE, ALGORITHMS, ELECTRIC...
A approximate analytic solution to the low thrust constant acceleration energy increase trajectory using a tangential steering program is presented. The solution is based on a two-variable asymptotic expansion of the equations of motion formulated in regularized variables. The high accuracy of the second order solution derived is demonstrated by comparing it with numerically integrated trajectories.
Topics: NASA Technical Reports Server (NTRS), ASYMPTOTIC METHODS, LOW THRUST, SPACECRAFT, TRAJECTORY...
16
16
Jul 23, 2019
07/19
by
Astrophys Space Sci (2018) 363:253
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Low-energy transfers (LET) for lunar and inter-planetary missions has received immense attention of the scientific community during the last few decades as its importance was understood by the success of JAXA’s Hiten, ESA’s SMART-1, NASA’s GRAIL and ARTHEMIS missions, and several proposals, like the BepiColombo, Multi-Moon Orbiter and Europa Orbiter. In this paper the developments in the area of LET and low-thrust trajectories are reviewed. Starting with the basics of the restricted...
Topics: ISRO, VSSC, Weak stability boundary, Ballistic capture, Low thrust, Invariant manifolds,...
On May 16, 1991, the NASA Headquarters Propulsion, Power, and Energy Division and the NASA Lewis Research Center Low Thrust Propulsion Branch hosted a workshop attended by key experts in magnetoplasmadynamic (MPD) thrusters and associated sciences. The scope was limited to high power MPD thrusters suitable for major NASA space exploration missions, and its purpose was to initiate the process of increasing the expectations and prospects for MPD research, primarily by increasing the level of...
Topics: NASA Technical Reports Server (NTRS), CONFERENCES, ELECTRIC ROCKET ENGINES, LOW THRUST PROPULSION,...
The principal characteristics of the 30-centimeter ion propulsion thrust subsystem technology that was developed to satisfy the propulsion needs of future planetary and early orbital missions are described. Functional requirements and descriptions, interface and performance requirements, and physical characteristics of the hardware are described at the thrust subsystem, BIMOD engine system, and component level.
Topics: NASA Technical Reports Server (NTRS), ENGINE DESIGN, ION PROPULSION, MANUALS, SYSTEMS ENGINEERING,...
Asteroids and comets exert such a small gravitational force that it is not practical to survey them from orbit. One must instead continuously accelerate using maneuvering rockets to move around the surface. A space exploration craft in three parts connected by lightweight cables can survey asteroids and comets, and deploy landers, without requiring the large thrusters and the continuous depletion of fuel required by a single craft. The spacecraft is deployed by spinning up from a compact...
Topics: NASA Technical Reports Server (NTRS), ASTEROIDS, COMETS, PROTOPLANETS, SPACECRAFT PROPULSION,...
The resistojet was baselined for Space Station auxiliary propulsion because of its operational versatility, efficiency, and durability. This report was conceived as a guide to designers and planners of the Space Station auxiliary propulsion system. It is directed to the low thrust resistojet concept, though it should have application to other station concepts or systems such as the Environmental Control and Life Support System (ECLSS), Manufacturing and Technology Laboratory (MTL), and the...
Topics: NASA Technical Reports Server (NTRS), AUXILIARY PROPULSION, CATALOGS, RESISTOJET ENGINES, SPACE...
Method for predicting nozzle performance of microthrust rockets is discussed. Method is numerical and uses simplified computer program on IBM 360/65 computer. Analysis is based on slender channel equations with slip boundary conditions at walls. Implicit finite difference scheme is used to calculate pressure and velocity profiles along channel.
Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMS, FORTRAN, IBM 360 COMPUTER, LOW THRUST...
The basic goal was to advance the development status of the 30-cm electron bombardment ion thruster from a laboratory model to a flight-type engineering model (EM) thruster. This advancement included the more conventional aspects of mechanical design and testing for launch loads, weight reduction, fabrication process development, reliability and quality assurance, and interface definition, as well as a relatively significant improvement in thruster total efficiency. The achievement of this goal...
Topics: NASA Technical Reports Server (NTRS), ION ENGINES, LOW THRUST PROPULSION, AUTOMATIC CONTROL,...
For abstract see,
Topics: NASA Technical Reports Server (NTRS), LOW THRUST PROPULSION, SOLAR ELECTRIC PROPULSION, SPACECRAFT...
The ASTOP program (an Arbitrary Space Trajectory Optimization Program) designed to generate optimum low-thrust trajectories in an N-body field while satisfying selected hardware and operational constraints is presented. The trajectory is divided into a number of segments or arcs over which the control is held constant. This constant control over each arc is optimized using a parameter optimization scheme based on gradient techniques. A modified Encke formulation of the equations of motion is...
Topics: NASA Technical Reports Server (NTRS), TRAJECTORY OPTIMIZATION, USER MANUALS (COMPUTER PROGRAMS),...
343
343
Jul 23, 2010
07/10
by
Simons, Rainee N.; Bhasin, Kul. B
texts
eye 343
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Direct current and also the microwave characteristics of optically illuminated AlGaAs/GaAs HEMT are experimentally measured for the first time and compared with that of GaAs MESFET. The results showed that the average increase in the gain is 2.89 dB under 1.7 nW/sq cm optical intensity at 0.83 microns. Further, the effect of illumination on S-parameters is more pronounced when the devices are biased close to pinch off. Novel applications of optically illuminated HEMT as a variable gain...
Topics: CHEMICAL PROPULSION, ORBIT CALCULATION, EXHAUST VELOCITY, ION PROPULSION, MANNED SPACE FLIGHT,...
The methodology and rationale used in the development of costs for engineering, manufacturing, testing and operating a low thrust system for placing automated shuttle payloads into earth orbits are described. Cost related information for the recommended propulsion approach is included.
Topics: NASA Technical Reports Server (NTRS), COST ANALYSIS, LOW THRUST PROPULSION, ORBITAL LAUNCHING,...
A solar electric propulsion system integration technology study is discussed. Detailed analyses in support of the solar electric propulsion module were performed. The thrust subsystem functional description is presented. The space vehicle and the space mission to which the propulsion system is applied are analyzed.
Topics: NASA Technical Reports Server (NTRS), LOW THRUST PROPULSION, SOLAR ELECTRIC PROPULSION, SPACECRAFT...
For many optimal transfer problems it is reasonable to expect that the minimum time solution is also the minimum fuel solution. However, if one allows the propulsion system to be turned off and back on, it is clear that these two solutions may differ. In general, high thrust transfers resemble the well known impulsive transfers where the burn arcs are of very short duration. The low and medium thrust transfers differ in that their thrust acceleration levels yield longer burn arcs and thus will...
Topics: NASA Technical Reports Server (NTRS), ORBIT TRANSFER VEHICLES, SPACECRAFT GUIDANCE, SPACECRAFT...
The results are presented of one phase of research conducted for the JPL Solar Electric Propulsion (SEP) Navigation Software System development program. It deals only with the problem of designing the flight quality trajectory program, which is a major subset of the entire navigation software system. In this phase of research (breadboard development phase), attempts were made to assess the SEP trajectory software functional requirements, to investigate the program design method satisfying these...
Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMS, ELECTRIC PROPULSION, LOW THRUST...
Six small, low specific speed centrifugal pump configurations were designed, fabricated, and tested. The configurations included shrouded, and 25 and 100% admission open face impellers with 2 inch tip diameters; 25, 50, and 100% emission vaned diffusers; and volutes with conical exits. Impeller tip widths varied from 0.030 inch to 0.052 inch. Design specific speeds (N sub s = RPM*GPM**0.5.FT**0.75) were 430 (four configurations) and 215 (two configurations). The six configurations were tested...
Topics: NASA Technical Reports Server (NTRS), CENTRIFUGAL PUMPS, FUEL PUMPS, LOW THRUST, ROCKET ENGINES,...
Results from investigations leading to the definition of low thrust chemical engine concepts are described. From the thrust chamber cooling analyses, regenerative/radiation-cooled LO2/H2 thrust chambers offered the largest thrust and chamber pressure operational envelope primarily due to the superior cooling capability of hydrogen and its low critical pressure. Regenerative/radiation-cooled LO2/CH4 offered the next largest operational envelope. The maximum chamber pressure for...
Topics: NASA Technical Reports Server (NTRS), CHEMICAL PROPULSION, LOW THRUST PROPULSION, ROCKET ENGINES,...
The topics presented are covered in viewgraph form. The objective is to provide technologies for a broad range of future space systems, such as: planetary and earth-orbital spacecrafts; space station and tended large space systems; and earth-to-orbit and orbit transfer vehicles.
Topics: NASA Technical Reports Server (NTRS), AEROSPACE SYSTEMS, LOW THRUST PROPULSION, ORBIT TRANSFER...
An analytical study evaluating thrust chamber cooling engine cycles and preliminary engine design for low thrust chemical rocket engines for orbit transfer vehicles is described. Oxygen/hydrogen, oxygen/methane, and oxygen/RP-1 engines with thrust levels from 444.8 N to 13345 N, and chamber pressures from 13.8 N/sq cm to 689.5 N/sq cm were evaluated. The physical and thermodynamic properties of the propellant theoretical performance data, and transport properties are documented. The thrust...
Topics: NASA Technical Reports Server (NTRS), LIQUID ROCKET PROPELLANTS, LOW THRUST, ROCKET ENGINE DESIGN,...
215
215
Jun 2, 2011
06/11
by
Swartz, William H.; Lloyd, Steven A.; DeMajistre, Rober
texts
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A quantitative understanding of photolysis rate coefficients (or ''j-values'') is essential to determining the photochemical reaction rates that define ozone loss and other crucial processes in the atmosphere. j-Values can be calculated with radiative transfer models, derived from actinic flux observations, or inferred from trace gas measurements. The principal objective of this study is to cross-validate j-values from the Composition and Photodissociative Flux Measurement (CPFM) instrument...
Topics: PERTURBATION, GRAVITATIONAL FIELDS, LOW THRUST PROPULSION, SENSORY PERCEPTION, DRAG REDUCTION,...
The engine has a conventional body and nozzle configuration. The monopropellant fuel is fed into the thruster with dual injection tubes via an injector shell with dual spray jets. The spray jets are positioned generally opposed to each other. A heater screen pack combination thermally decomposes the fuel after injection into the combustion chamber of the thruster.
Topics: NASA Technical Reports Server (NTRS), FUEL INJECTION, LIQUID PROPELLANT ROCKET ENGINES, LOW THRUST,...
Optimal multi-impulse trajectories were investigated as a nominal about which asymptotic expansion was used to obtain approximations of optimal low thrust trajectories. The work consisted of the analysis and description of an optimal 3-impulse trajectory program. A patched-conic trajectory model was specifically designed for compatibility with the subsequent addition of the low thrust expansion approximation.
Topics: NASA Technical Reports Server (NTRS), IMPULSE GENERATORS, ORBITAL MECHANICS, TRAJECTORY...
Recently, various kinds of planetary explorations have become more feasible, taking the advantage of low thrust propulsion means such as ion engines that have come into practical use. The field of space activity has now been expanded even to the rim of the outer solar system. In this context, the Japan Aerospace Exploration Agency (JAXA) has started investigating a Deep Space Port built at the L2 Lagrange point in the Sun-Earth system. For the purpose of making the deep space port practically...
Topics: NASA Technical Reports Server (NTRS), DEEP SPACE, SPACE TRANSPORTATION SYSTEM, SPACE EXPLORATION,...
The options for asteroid missions are evaluated within the constraints of existing or planned launch vehicles and low-thrust propulsion systems. A wide variety of missions is possible, including flyby, rendezvous, and even sample return. The multi-asteroid rendezvous concept requires an ion drive low-thrust propulsion system of the type being developed for a comet rendezvous. It is indicated that there are plentiful opportunities for such missions to visit four asteroids with stay times of...
Topics: NASA Technical Reports Server (NTRS), ASTEROIDS, FLYBY MISSIONS, MISSION PLANNING, SAMPLING, SPACE...
The flowfield and performance characteristics of highly-twisted blades were analyzed at various thrust conditions to improve the fundamental understanding relating the wake effects on rotor performance. Similar measurements made using untwisted blades served as the baseline case. Twisted blades are known to give better hover performance than untwisted blades at high thrust coefficients typical of those found in full-scale rotors. However, the present experiments were conducted at sufficiently...
Topics: NASA Technical Reports Server (NTRS), ROTORS, HOVERING, WAKES, FLOW DISTRIBUTION, LOW THRUST, HIGH...
The natural environment design requirements for the solar electric propulsion stage are presented. Environment criteria for the SEP stage will cover earth orbital operations out to geosynchronous altitudes and also interplanetary missions including comet and asteroid missions.
Topics: NASA Technical Reports Server (NTRS), ENGINE DESIGN, EQUIPMENT SPECIFICATIONS, SOLAR ELECTRIC...
The use of solar electric propulsion as a means of exploring space beyond the reach of ballistic missions was investigated. The method used was to study the application of this new propulsion technology to a future flight project. A 1980 Encke rendezvous mission was chosen because a design successful for Encke could be used for less difficult, but scientifically rewarding, missions. Design points for the mission and for the thrust subsystem were specified. The baseline-vehicle design was...
Topics: NASA Technical Reports Server (NTRS), MISSION PLANNING, SOLAR ELECTRIC PROPULSION, SPACE MISSIONS,...
The influence of basic parameters that govern flap lag stability of hingeless rotor blades in hover is reviewed, and potential methods are studied for improving the lead lag damping of soft inplane configurations for low thrust conditions. These conditions are relevant for ground and air resonance stability of coupled rotor body dynamic systems. Results indicate that the isolated rotor blade lead lag damping can be usefully increased by a combination of flap lag elastic coupling and pitch lag...
Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC STABILITY, RIGID ROTORS, ROTOR BLADES, VIBRATION...
Three thrusters were fabricated to definitized thruster drawings using new rhenium vapor deposition technology. Two of the thrusters were operated using ammonia as propellant and one was operated using hydrogen propellant for performance determination. All demonstrated consistent operational specific impulse performance while demonstrating thermal performance better than the development units from which they evolved. Two of the thrusters were subjected to environmental structural testing...
Topics: NASA Technical Reports Server (NTRS), HIGH TEMPERATURE RESEARCH, LOW THRUST, THERMAL CYCLING TESTS,...
This report presents two numerical methods considered for the computation of fuel-optimal, low-thrust orbit transfers in large numbers of burns. The origins of these methods are observations made with the extremal solutions of transfers in small numbers of burns; there seems to exist a trend such that the longer the time allowed to perform an optimal transfer the less fuel that is used. These longer transfers are obviously of interest since they require a motor of low thrust; however, we also...
Topics: NASA Technical Reports Server (NTRS), BURNING RATE, COMBUSTION EFFICIENCY, FUEL CONSUMPTION,...
An advanced lightweight insulation system suitable for use in long duration, low pressure planetary orbiter-type motor applications was developed. Experiments included the screening of various filler and binder materials with optimization studies combining the best of each. Small scale test motor data were used to judge the degree of success.
Topics: NASA Technical Reports Server (NTRS), INTERPLANETARY SPACECRAFT, SOLID PROPELLANT ROCKET ENGINES,...
360
360
Sep 20, 2010
09/10
by
Margoulis,
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Comparing the results of the calculations for computing the mean pressure of an aviation engine for any number of revolutions, with those of experiment, the writer, by numerous examples, shows the perfect agreement between them. This report will show that, by means of a special abacus, an engineer can instantly plot the characteristics of an engine.
Topics: AEROSPACE ENGINEERING, LOW THRUST PROPULSION, NUCLEAR PROPULSION, TURBOMACHINERY, PROPULSION SYSTEM...
