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  • Other Sources  (193)
  • SPACECRAFT PROPULSION AND POWER  (193)
  • 2010-2014
  • 1980-1984  (193)
  • 1981  (193)
  • 1
    Publication Date: 2006-01-16
    Description: The hydraulic actuation system of the space shuttle main engine is discussed. The system consists of five electrohydraulic actuators and a single engine filter used to control the five different propellant valves, which in turn control thrust and mixture ratio of the space shuttle main engine. The hydraulic actuation system provides this control with a precision of 98.7 percent or an error in position no greater than 1.3 percent of full scale rotational travel for critical positions.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: the 15th Aerospace Mech. Symp.; p 291-301
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  • 2
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    In:  CASI
    Publication Date: 2006-01-16
    Description: The system components and operation of the space shuttle solid rocket booster (SRB) dewatering set are described. The SRB dewatering set consists of a nozzle plug, control console, remote control unit, power distribution unit, umbilical cable, interconnect cables, and various handling and storage items. The nozzle plug (NP) is a remotely controlled, tethered underwater vehicle that is launched from the retrieval vessel (RV) by a crane, descends down the side of the SRB, and is positioned below the SRB nozzle. A TV camera mounted at the top of the NP central core is used by the control console operator to visually guide the NP during descent and docking. The NP is then driven up and locked into the nozzle. Compressed air is passed through the umbilical from the RV, through the NP and into the SRB motor. The water inside the SRB is expelled causing the SRB to rotate to a near horizontal attitude on the surface of the water.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA. Marshall Space Flight Center The 15th Aerospace Mech. Symp.; p 279-289
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  • 3
    Publication Date: 2006-01-16
    Description: Zero gravity testing in the KC-135 aircraft of flat fold flexible solar array test specimens sufficiently demonstrated the adequacy of the panel design. The aircraft flight crew provided invaluable assistance and significantly contributed to the design and development of the flexible solar array, and ultimately to the potential success of the solar electric propulsion solar array shuttle flight experiment program.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: The 15th Aerospace Mech. Symp.; p 115-136
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  • 4
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 13 p
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  • 5
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 19 p
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  • 6
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 19 p
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  • 7
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 11 p
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  • 8
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 22 p
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  • 9
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 15 p
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  • 10
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 5 p
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  • 11
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 16 p
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  • 12
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 5 p
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  • 13
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 21 p
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  • 14
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 13 p
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  • 15
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 6 p
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  • 16
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 4 p
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  • 17
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 7 p
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  • 18
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 10 p
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  • 19
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 16 p
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  • 20
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 25 p
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  • 21
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 7 p
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  • 22
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 33 p
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  • 23
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 100 p
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  • 24
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 13 p
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  • 25
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 109 p
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  • 26
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 39 p
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  • 27
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 12 p
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  • 28
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 13 p
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  • 29
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 19 p
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  • 30
    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 27 p
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  • 31
    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAFF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 5 p
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  • 32
    Publication Date: 2011-08-19
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JANNAFF Handbook: Rocket Exhaust Plume Technol., Chapter 5; 5 p
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  • 33
    Publication Date: 2011-08-18
    Description: The subject interface measurements are described for the Ion Auxiliary Propulsion System (IAPS) flight test of two 8-cm thrusters. The diagnostic devices and the effects to be measured include: 1) quartz crystal microbalances to detect nonvolatile deposition due to thruster operation; 2) warm and cold solar cell monitors for nonvolatile and volatile (mercury) deposition; 3) retarding potential ion collectors to characterize the low energy thruster ionic efflux; and 4) a probe to measure the spacecraft potential and thruster generated electron currents to biased spacecraft surfaces. The diagnostics will also assess space environmental interactions of the spacecraft and thrusters. The diagnostic data will characterize mercury thruster interfaces and provide data useful for future applications.
    Keywords: SPACECRAFT PROPULSION AND POWER
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  • 34
    Publication Date: 2011-08-18
    Description: A charge-exchange plasma, generated by an ion thruster, is capable of flowing upstream from the ion thruster and therefore represents a source of contamination to a spacecraft. An analytical model of the charge-exchange plasma density around a spacecraft was used to estimate the contamination which various spacecraft materials may be exposed to. Measurements of plasma density around an ion thruster were compared to this model. Results of experimental studied regarding the effects on various spacecraft materials' properties due to exposure to expected mercury contamination levels are presented.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: Exptl. and Anal. Evaluation of Ion Thruster(Spacecraft Interactions; p 231-241
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  • 35
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    Publication Date: 2011-08-18
    Description: A study was performed to determine the effects of a mercury ion thruster plume on an S-band telecommunication carrier. Experiments were carried out on a 30 cm thruster in a JPL test chamber. Results from simple analytical models were compared with the above measurements and major discrepancies were discovered. Modifications to the electron density model provided a qualitative explanation, but further work is necessary for a quantitative answer. The results indicate the effects of the plume, on S and X Band telecommunications will be minor, with the possible exception of critical angle blockage.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: Exptl. and Anal. Evaluation of Ion Thruster(Spacecraft Interactions; p 191-215
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  • 36
    Publication Date: 2011-08-18
    Description: An electric propulsion thrust system has the capability of providing a high specific impulse for long duration scientific missions in space. The EMI from the elements of an ion engine was characterized. The compatibility of ion drive electric propulsion systems with typical interplanetary spacecraft engineering was predicted.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: Exptl. and Anal. Evaluation of Ion Thruster(Spacecraft Interactions; p 185-190
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  • 37
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    Publication Date: 2011-08-18
    Description: In order to properly assess the interaction of a spacecraft with the EMI environment produced by an ion thruster, the EMI environment was characterized. Therefore, radiated and conducted emissions were measured from a 30-cm mercury ion thruster. The ion thruster beam current varied from zero to 2.0 amperes and the emissions were measured from 5 KHz to 200 MHz. Several different types of antennas were used to obtain the measurements. The various measurements that were made included: magnetic field due to neutralizer/beam current loop; radiated electric fields of thruster and plume; and conducted emissions on arc discharge, neutralizer keeper and magnetic baffle lines.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: Exptl. and Anal. Evaluation of Ion Thruster(Spacecraft Interactions; p 167-183
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  • 38
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    Publication Date: 2011-08-18
    Description: These facility produced ions are created by charge-exchange collisions between neutral atoms and energetic thruster beam ions. The result of the electron transfer is an energetic neutral atom and an ion of only thermal energy. There are true charge-exchange ions produced by collisions with neutrals escaping from the ion thruster and being charge-exchange ionized before the neutral intercepts the tank wall. The facility produced charge-exchange ions will not exist in space and therefore, represent a source of error where measurements involving ion thruster plasmas and their density are involved. The quantity of facility produced ions in a test chamber with a 30 cm mercury ion thruster was determined.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: Exptl. and Anal. Evaluation of Ion Thruster(Spacecraft Interactions; p 147-166
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  • 39
    Publication Date: 2011-08-18
    Description: Under the proper conditions there is an end-effect of a long, cylindrical Langmuir probe which allows a significant increase in collected ion current when the probe is aligned with a flowing plasma. This effect was used to determine the charge-exchange plasma flow direction at various locations relative to the ion thruster. The ion current collected by the probe as a function of its angle with respect to the plasma flow allows determination of the plasma density and plasma flow velocity at the probe's location upstream of the ion thruster optics. The density values obtained from the ion current agreed to within a factor of two of density values obtained by typical voltage-current Langmuir probe characteristics.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: Exptl. and Anal. Evaluation of Ion Thruster(Spacecraft Interactions; p 67-72
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  • 40
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    Publication Date: 2011-08-18
    Description: Biasing techniques and their application to the control of spacecraft potential is discussed. Normally when a spacecraft is operated with ion thrusters, the spacecraft will be 10-20 volts negative of the surrounding plasma. This will affect scientific measurements and will allow ions from the charge-exchange plasma to bombard the spacecraft surfaces with a few tens of volts of energy. This condition may not be tolerable. A proper bias system is described that can bring the spacecraft to or near the potential of the surrounding plasma.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: Exptl. and Anal. Evaluation of Ion Thruster(Spacecraft Interactions; p 11-28
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  • 41
    Publication Date: 2019-06-28
    Description: A liquid injection thrust vector control (LITVC) system for the shuttle solid rocket booster (SRB) was analyzed. The LITVC was compared with the SRB baseline flexible seal. A table of LITVC advantages and disadvantages is presented. It is concluded that the LITVC performs well at low to moderate duty cycles, but not for high duty cycle requirements.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-TP-1912 , M-354
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  • 42
    Publication Date: 2019-06-28
    Description: Because of the advantage of the Advanced Expander Cycle Engine brought out in initial studies, further design optimization and comparative analyses were undertaken. The major results and conclusion derived are summarized. The primary areas covered are (1) thrust chamber geometry optimization, (2) expander cycle optimization, (3) alternate low thrust capability, (4) safety and reliability, (5) development risk comparison, and (6) cost comparisons. All of the results obtained were used to baseline the initial design concept for the OTV Advanced Expander Cycle Engine Point Design Study.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-161699 , REPT-32999-F-E1
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  • 43
    Publication Date: 2019-06-28
    Description: The deformation process observed in the hot gas side wall of rocket combustion chambers was investigaged for three different liner materials. Five thrust chambers were cycled to failure by using hydrogen and oxygen as propellants at a chamber pressure of 4.14 MN/cu m. The deformation was observed nondestructively at midlife points and destructively after failure occurred. The cyclic life results are presented with an accompanying discussion about the problems of life prediction associated with the types of failures encountered in the present work. Data indicating the deformation of the thrust chamber liner as cycles are accumulated are presented for each of the test thrust chambers. From these deformation data and observation of the failure sites it is evident that modeling the failure process as classic low cycle thermal fatigue is inadequate as a life prediction method.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-TP-1834 , E-553
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  • 44
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    Publication Date: 2019-06-28
    Description: Analytical models to predict performance and operating characteristics of dual nozzle concepts were developed and improved. Aerodynamic models are available to define flow characteristics and bleed requirements for both the dual throat and dual expander concepts. Advanced analytical techniques were utilized to provide quantitative estimates of the bleed flow, boundary layer, and shock effects within dual nozzle engines. Thermal analyses were performed to define cooling requirements for baseline configurations, and special studies of unique dual nozzle cooling problems defined feasible means of achieving adequate cooling.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-161677 , REPT-33553F
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  • 45
    Publication Date: 2019-06-28
    Description: The propagation of the charge-exchange plasma from an electrostatic ion thruster is crucial in determining the interaction of that plasma with the associated spacecraft. A model that describes this plasma and its propagation is described, together with a computer code based on this model. The structure and calling sequence of the code, named PLASIM, is described. An explanation of the program's input and output is included, together with samples of both. The code is written in ASNI Standard FORTRAN.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: Exptl. and Anal. Evaluation of Ion Thruster(Spacecraft Interactions; p 73-145
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  • 46
    Publication Date: 2019-06-28
    Description: A model was reviewed which describes the propagation of the mercury charge-exchange plasma and extended to describe the flow of the molybdenum component of the charge-exchange plasma. The uncertainties in the models for various conditions are discussed. Such topics as current drain to the solar array, charge-exchange plasma material deposition, and the effects of space plasma on the charge-exchange plasma propagation are addressed.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: JPL-PUB-79-90 , Exptl. and Anal. Evaluation of Ion Thruster(Spacecraft Interactions; p 29-66
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  • 47
    Publication Date: 2019-06-28
    Description: Studies were conducted to both identify the environment produced by ion thrusters and to assess the interaction of this environment on a typical spacecraft and typical science instruments. Spacecraft charging and the charge exchange that accompanies it is discussed in detail. Electromagnetic interference was characterized for ion engines. The electromagnetic compatibility of ion thrusters with spacecraft instruments was determined. The effects of ion thruster plumes on spacecraft were studied with particular emphasis on external surface currents.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-163975 , JPL-PUB-80-92
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  • 48
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    Publication Date: 2019-06-28
    Description: The physical processes governing ion extraction from a plasma have been examined experimentally. The screen hole plasma sheath (the transition region wherein significant ion acceleration and complete electron retardation occurs) has been defined by equipotential plots for a variety of ion accelerator system geometries and operating conditions. It was found that the screen hole plasma sheath extends over a large distance, and influences ion and electron trajectories at least 15 Debye lengths within the discharge chamber. The electron density variation within the screen hole plasma sheath satisfied a Maxwell-Boltzmann density distribution at an effective electron temperature dependent on the discharge plasma primary-to-Maxwellian electron density ratio. Plasma ion flow up to and through the sheath was predominantly one-dimensional, and the ions entered the sheath region with a modified Bohm velocity. Low values of the screen grid thickness to screen hole diameter ratio were found to give good ion focusing and high extracted ion currents because of the effect of screen webbing on ion focusing.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: Journal of Applied Physics; 52; Apr. 198
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  • 49
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    Publication Date: 2019-06-28
    Description: A sequence of events, occurring over the last 25 years, are described that chronicle the evolution of ion-bombardment electric propulsion technology. Emphasis is placed on the latter phases of this evolution, where special efforts were made to pave the way toward the use of this technology in operational space flight systems. These efforts consisted of a planned program to focus the technology toward its end applications and an organized process that was followed to transfer the technology from the research-technology NASA Center to the user-development NASA Center and its industry team. Major milestones in this evolution, which are described, include the development of thruster technology across a large size range, the successful completion of two space electric rocket tests, SERT I and SERT II, development of power-processing technology for electric propulsion, completion of a program to make the technology ready for flight system development, and finally the technology transfer events.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-TM-82618 , E-870
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  • 50
    Publication Date: 2019-06-28
    Description: The engine requirements are emphasized and include: high specific impulse within a restricted installed length constraint, long life, multiple starts, different thrust levels, and man-rated reliability. The engine operating characteristics and the major component analytical design are summarized.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-161832 , FR-14615-VOL-2
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  • 51
    Publication Date: 2019-06-28
    Description: The engine operating characteristics were examined. Inlet pressure effects, tank pressurization effects, steady-state specific impulse, and the steady-state cycle were studied. The propellant flow schematic and operating sequence are presented. Engine hardware drawings are included.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-161833 , FR-14615-VOL-3
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  • 52
    Publication Date: 2019-06-28
    Description: The objective of the study was to generate the system design of a performance-optimized, advanced LOX/hydrogen expander cycle space engine. The engine requirements are summarized, and the development and operational experience with the expander cycle RL10 engine were reviewed. The engine development program is outlined.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-161831 , FR-14615-VOL-1
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  • 53
    Publication Date: 2019-06-28
    Description: Analytical results are presented which predict cumulative plastic deformation characteristic of damage observed in coolant channel walls of regeneratively cooled rocket thrust chambers. The damage consists of bulging and plastic flow which leads to thinout and rupture of the channel wall under the combined effects of high pressures, high temperatures and temperature gradients experienced during cyclic firings of actual test chambers. Analytical predictions correlate with test results.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-165241 , LMSC-HREC-TR-D698400-VOL-2
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  • 54
    Publication Date: 2019-06-28
    Description: The liquid rocket propulsion technology needs to support anticipated future space vehicles were examined including any special action needs to be taken to assure that an industrial base in substained. Propulsion system requirements of Earth-to-orbit vehicles, orbital transfer vehicles, and planetary missions were evaluated. Areas of the fundamental technology program undertaking these needs discussed include: pumps and pump drives; combustion heat transfer; nozzle aerodynamics; low gravity cryogenic fluid management; and component and system life reliability, and maintenance. The primary conclusion is that continued development of the shuttle main engine system to achieve design performance and life should be the highest priority in the rocket engine program.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-164550
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  • 55
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    In:  CASI
    Publication Date: 2019-06-28
    Description: Engine data and information are presented to perform system studies on cargo orbit-transfer vehicles which would deliver large space structures to geosynchronous equatorial orbit. Low-thrust engine performance, weight, and envelope parametric data were established, preliminary design information was generated, and technologies for liquid rocket engines were identified. Two major engine design drivers were considered in the study: cooling and engine cycle options. Both film-cooled and regeneratively cooled engines were evaluated. The propellant combinations studied were hydrogen/oxygen, methane/oxygen, and kerosene/oxygen.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-165276
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  • 56
    Publication Date: 2019-06-28
    Description: A parametric analysis was performed to compare the costs of silicon and gallium arsenide arrays for Earth orbital missions. The missions included electric power in low Earth orbit (LEO), electric power in geosynchronous Earth orbit (GEO), and power for electric propulsion of a LEO to GEO orbit transfer mission. Inputs to the analysis for all missions included launch and purchase costs of the array. For the orbit transfer mission, the launch and purchase costs of the electric propulsion system were added. Radiation flux as a function of altitude and rediation tolerance as a function of cell type were used to determine power degradation for each mission. Curves were generated that show the sensitivity of launch-array cost and total mission cost to a variety of input parameters for each mission. These parameters included mission duration, cover glass thickness, array specific cost, array specific mass, and solar cell efficiency. Solar concentration was considered and the sensitivities of cost to concentration ratio, concentrator costs, and concentrator mass were also evaluated. Results indicate that solar cell development should give a high priority to reducing array costs and that the development of low cost, lightweight, solar concentrators should be pursued.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-TP-1811 , E-536
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  • 57
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    In:  CASI
    Publication Date: 2019-06-28
    Description: A complete definition of the LBM plume is important for many Shuttle design criteria. The exhaust plume shape has a significant effect on the vehicle base pressure. The LBM definition is also important to the Shuttle base heating, aerodynamics and the influence of the exhaust plume on the launch stand and environment. For these reasons a knowledge of the LBM plume characteristics is necessary. A definition of the sea level LBM plume as well as at several points along the Shuttle trajectory to LBM, burnout is presented.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-161646 , LMSC-HREC-TR-D784066
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  • 58
    Publication Date: 2019-06-28
    Description: The performance of quasisteady multimegawatt MPD thrusters is significantly affected by anode thickness, location, and orifice radius, and by cathode length. Terminal voltage oscillations and electrode erosion are deferred until higher currents by anodes at more downstream locations and of smaller orifice radius and by cathodes of greater length. Without an optimized geometry, specific impulses of 3300 s and thrust efficiencies up to 31% are implied by the best data.
    Keywords: SPACECRAFT PROPULSION AND POWER
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  • 59
    Publication Date: 2019-06-28
    Description: As a consequence of endurance and structural tests performed on 900-series engineering model thrusters (EMT), several modifications in design were found to be necessary for achieving performance goals. The modified thruster is known as the J-series EMT. The most important of the design modifications affect the accelerator grid, gimbal mount, cathode polepiece, and wiring harness. The paper discusses the design modifications incorporated, the condition(s) they corrected, and the characteristics of the modified thruster.
    Keywords: SPACECRAFT PROPULSION AND POWER
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  • 60
    Publication Date: 2019-06-28
    Description: The LeRC/Hughes 30-cm mercury ion thruster has been developed to a state of maturity such that is has become meaningful to formulate models for describing the performance characteristics of the major subassemblies. The thruster hollow cathode and the ion optics subassemblies have been investigated with this objective and conceptual, semiquantitative models have been formulated for relating lifetime and performance capabilities to design and operating parameters. This paper summarizes the investigations, discusses the factors considered for inclusion in the models, and describes the status of the models.
    Keywords: SPACECRAFT PROPULSION AND POWER
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  • 61
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    In:  CASI
    Publication Date: 2019-06-28
    Description: The failure of two communication satellites during firing sequence were examined. The correlation/comparison of the circumstances of the Ayame incidents and the failure of the STAR 48 (DM-2) motor are reviewed. The massive nozzle failure of the AKM to determine the impact on spacecraft performance is examined. It is recommended that a closer watch is kept on systems techniques,
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-166735
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  • 62
    Publication Date: 2019-06-28
    Description: The critical evaluation and subsequent redesign of the power conversion subsystem of the spacecraft are covered. As part of that evaluation and redesign, prototype heat pipe components for the heat rejection system were designed fabricated and tested. Based on the results of these tests in conjunction with changing mission requirements and changing energy conversion devices, new system designs were investigated. The initial evaluation and redesign was based on state-of-the-art fabrication and assembly techniques for high temperature liquid metal heat pipes and energy conversion devices. The hardware evaluation demonstrated the validity of several complicated heat pipe geometries and wick structures, including an annular-to-circular transition, bends in the heat pipe, long heat pipe condensers and arterial wicks. Additionally, a heat pipe computer model was developed which describes the end point temperature profile of long radiator heat pipes to within several degrees celsius.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-164878
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  • 63
    Publication Date: 2019-06-28
    Description: A summary of the design analyses for a liquid rocket injector using oxygen and RP-1 propellants at high chamber pressures of 20,682 kPa (3000 psia) is presented. This analytical investigation includes combustion efficiency versus injector element type, combustion stability, and combustor cooling requirements. The design and fabrication of a subscale injector/acoustic resonantor assembly capable of providing a nominal thrust of 222K N (50,000 lbF) is presented.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-161877 , REPT-33651F
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  • 64
    Publication Date: 2019-06-28
    Description: A system of three computer programs is described for use in conjunction with the BOPAGE finite element program. The programs are demonstrated by analyzing cumulative plastic deformation in a regeneratively cooled rocket thrust chamber. The codes provide the capability to predict geometric and material nonlinear behavior of cyclically loaded structures without performing a cycle-by-cycle analysis over the life of the structure. The program set consists of a BOPACE restart tape reader routine, and extrapolation program and a plot package.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-165242 , LMSC-HREC-TR-D698440-VOL-3
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  • 65
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    In:  CASI
    Publication Date: 2019-06-28
    Description: Developmental considerations for the magneto-plasma-dynamic (MPD) thruster are defined. General characteristics of an MPD engine are compared to those of chemical propulsion and ion bombardment engines and performance criteria which are mission specific are examined. Requirements for thruster ground testing facilities are discussed and the utilization of the space shuttle for an orbital flight test is addressed.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-164581 , JPL-9950-563
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  • 66
    Publication Date: 2019-06-28
    Description: Specific rocket engine hardware and test facility system failures are described which were caused by high pressure liquid and/or gaseous oxygen reactions. The failures were encountered during the development and testing of the space shuttle main engine. Failure mechanisms are discussed as well as corrective actions taken to prevent or reduce the potential of future failures.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-TM-82424
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  • 67
    Publication Date: 2019-06-28
    Description: Results are discussed for a Ni-Cd battery test over a period of 8 years, 2 months and 44,213 simulated low Earth orbits. The battery cells were protected against overdischarge and reversal at discharge rates up to 25 amperes (1.25C) by a battery protection and reconditioning circuit. The circuit performed flawlessly during the test, and proved its value, both as a battery reconditioner and a cell protection device. Battery cell failures are also discussed. The test demonstrated the viability of using Ni-Cd batteries at depth-of-discharge up to 25 percent for over 5 years in a low Earth orbit.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-TP-1873 , M-350
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  • 68
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    In:  CASI
    Publication Date: 2019-06-28
    Description: Two versions of a Nasvytis multiroller traction drive were tested in liquid oxygen for possible application as cryogenic boost pump speed reduction drives for advanced hydrogen-oxygen rocket engines. The roller drive, with a 10.8:1 reduction ratio, was successfully run at up to 70,000 rpm input speed and up to 14.9 kW (20 hp) input power level. Three drive assemblies were tested for a total of about three hours of which approximately one hour was at nominal full speed and full power conditions. Peak efficiency of 60 percent was determined. There was no evidence of slippage between rollers for any of the conditions tested. The ball drive, a version using balls instead of one row of rollers, and having a 3.25:1 reduction ratio, failed to perform satisfactorily.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-TM-81704 , E-730
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  • 69
    Publication Date: 2019-06-28
    Description: This study identifies and evaluates promising LO2/HC rocket engine cycles, produces a consistent and reliable data base for vehicle optimization and design studies, demonstrates the significance of propulsion system improvements, and selects the critical technology areas necessary to realize an improved surface to orbit transportation system. Parametric LO2/HC engine data were generated over a range of thrust levels from 890 to 6672 kN (200K to 1.5M 1bF) and chamber pressures from 6890 to 34500 kN (1000 to 5000 psia). Engine coolants included RP-1, refined RP-1, LCH4, LC3H8, LO2, and LH2. LO2/RP-1 G.G. cycles were found to be not acceptable for advanced engines. The highest performing LO2/RP-1 staged combustion engine cycle utilizes LO2 as the coolant and incorporates an oxidizer rich preburner. The highest performing cycle for LO2/LCH4 and LO2/LC3H8 utilizes fuel cooling and incorporates both fuel and oxidizer rich preburners. LO2/HC engine cycles permitting the use of a third fluid LH2 coolant and an LH2 rich gas generator provide higher performance at significantly lower pump discharge pressures. The LO2/HC dual throat engine, because of its high altitude performance, delivers the highest payload for the vehicle configuration that was investigated.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-161748 , REPT-33452F
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  • 70
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    In:  CASI
    Publication Date: 2019-06-28
    Description: The multipole discharge chamber of an electrostatic ion thruster is discussed. No reductions in discharge losses were obtained, despite repeated demonstration of anode potentials more positive than the bulk of the discharge plasma. The penalty associated with biased anode operation was reduced as the magnetic integral above the biased anodes was increased. The hollow cathode is discussed. The experimental configuration of the Hall current thruster had a uniform field throughout the ion generation and acceleration regions. To obtain reliable ion generation, it was necessary to reduce the magnetic field strength, to the point where excessive electron backflow was required to establish ion acceleration. The theoretical study of ion acceleration with closed electron drift paths resulted in two classes of solutions. One class has the continuous potential variation in the acceleration region that is normally associated with a Hall current accelerator. The other class has an almost discontinuous potential step near the anode end of the acceleration region. This step includes a significant fraction of the total acceleration potential difference.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-165603 , NAS 1.26:165603
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  • 71
    Publication Date: 2019-06-28
    Description: An analytical design procedure for predicting thrust chamber life considering cyclically induced thinning and bulging of the hot gas wall is developed. The hot gas wall, composed of ligaments connecting adjacent cooling channel ribs and separating the coolant flow from the combustion gas, is subjected to pressure loading and severe thermal cycling. Thermal transients during start up and shut down cause plastic straining through the ligaments. The primary bending stress superimposed on the alternate in-plane cyclic straining causes incremental bulging of the ligaments during each firing cycle. This basic mechanism of plastic ratcheting is analyzed and a method developed for determining ligament deformation and strain. The method uses a yield surface for combined bending and membrane loading to determine the incremental permanent deflection and pregressive thinning near the center of the ligaments which cause the geometry of the ligaments to change as the incremental strains accumulate. Fatigue and tensile instability are affected by these local geometry changes. Both are analyzed and a failure criterion developed.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-165585 , NAS 1.26:165585 , ODAI-1403-12-81
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  • 72
    Publication Date: 2019-06-28
    Description: The development of technology for a fail-operatonal power system controller (PSC) utilizing microprocessor technology for managing the distribution and power processor subsystems of a large multi-kW space electrical power system is discussed. The specific functions which must be performed by the PSC, the best microprocessor available to do the job, and the feasibility, cost savings, and applications of a PSC were determined. A limited function breadboard version of a PSC was developed to demonstrate the concept and potential cost savings.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-TP-1939
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  • 73
    Publication Date: 2019-07-27
    Description: A heat rejection system for space is described which uses a recirculating free stream of liquid droplets in place of a solid surface to radiate waste heat. By using sufficiently small droplets (less than about 100 micron diameter) of low vapor pressure liquids (tin, tin-lead-bismuth eutectics, vacuum oils) the radiating droplet sheet can be made many times lighter than the lightest solid surface radiators (heat pipes). The liquid droplet radiator (LDR) is less vulnerable to damage by micrometeoroids than solid surface radiators, and may be transported into space far more efficiently. Analyses are presented of LDR applications in thermal and photovoltaic energy conversion which indicate that fluid handling components (droplet generator, droplet collector, heat exchanger, and pump) may comprise most of the radiator system mass. Even the unoptimized models employed yield LDR system masses less than heat pipe radiator system masses, and significant improvement is expected using design approaches that incorporate fluid handling components more efficiently. Technical problems (e.g., spacecraft contamination and electrostatic deflection of droplets) unique to this method of heat rejection are discussed and solutions are suggested.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: IAF PAPER 81-185 , International Astronautical Congress; Sept. 6-12, 1981; Rome; Italy
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  • 74
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    In:  Other Sources
    Publication Date: 2019-07-27
    Description: The Delta launch vehicle has played a significant role in spaceand airborne studies since its first launch in 1960, and a high volume period of service is planned for the 1980s. The historical role played by Delta in launching satellites from 1960 to the present is discussed, and vehicle modifications made during this period are summarized. It is shown that out of 154 launches, 143 proved successful for an overall reliability of 93%. The forecasted launch schedule through 1985 is also presented. Various modifications are now under way to provide spacecraft interchangeability with the Shuttle: a Payload Assist Module (PAM) is proposed to provide an orderly transition from the Delta expendable vehicle to the Shuttle reusable vehicle; the new Delta 3920 Improved Second Stage is the result of a need for improved Delta performance to meet 3910 payload capabilities; the firing sequence of the solid rocket motors was altered from five at liftoff and four during ascent to a sequence of six and three, thereby increasing spacecraft weight in geosynchronous transfer orbit. Potential future improvements discussed include the Delta 4920, 9-ft-diam fairing, booster engine performance, PAM solid motor performance, a universal second stage, a hydrogen-oxygen second stage, and large strap-on solids.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: IAF PAPER 81-13 , International Astronautical Congress; Sept. 6-12, 1981; Rome; Italy
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  • 75
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    In:  Other Sources
    Publication Date: 2019-06-28
    Description: Liquid oxygen/hydrocarbon (LO2/HC) rocket engine cycles for a surface to orbit transportation system were evaluated. A consistent engine system data base is established for defining advantages and disadvantages, system performance and operating limits, engine parametric data, and technology requirements for candidate engine systems. Preliminary comparisons of the engine cycles utilizing delivered specific impulse values are presented. Methane and propane staged combustion cycles are the highest LO2/HC performers. The hydrogen cooled LO2/methane dual throat engine was found to be the highest performing. Technology needs identified in the study include: high temperature turbines; oxidizer-rich preburners; LO2, methane, and propane cooling; methane and propane fuel-rich preburners; the HC fuel turbopump; and application of advanced composite materials to the engine system. Parametric sensitivity analysis data are displayed which show the effect of variations in engine thrust, mixture ratio, chamber pressure, area ratio, cycle life, and turbine inlet temperature on specific impulse and engine weight.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: APL The 1981 JANNAF Propulsion Meeting, Vol. 1; p 499-514
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  • 76
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    In:  CASI
    Publication Date: 2019-06-28
    Description: The design, development, fabrication, testing, evaluation and flight qualification of the space shuttle booster separation motor is discussed. Delivery of flight hardware to support the research and development flights of the space shuttle is discussed.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-162000 , NAS 1.26:162000 , CSD-5180-81-1
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  • 77
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    In:  CASI
    Publication Date: 2019-06-28
    Description: 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.
    Keywords: SPACECRAFT PROPULSION AND POWER
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  • 78
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    In:  CASI
    Publication Date: 2019-06-28
    Description: A breadboard power system incorporating autonomous functions of monitoring, fault detection and recovery, command and control was developed, tested and evaluated to demonstrate technology feasibility. Autonomous functions including switching of redundant power processing elements, individual load fault removal, and battery charge/discharge control were implemented by means of a distributed microcomputer system within the power subsystem. Three local microcomputers provide the monitoring, control and command function interfaces between the central power subsystem microcomputer and the power sources, power processing and power distribution elements. The central microcomputer is the interface between the local microcomputers and the spacecraft central computer or ground test equipment.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-168423 , JPL-PUB-81-106
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  • 79
    Publication Date: 2019-06-28
    Description: The concept of an ultrahigh-temperature solar electric heat-engine converter is examined in which an alkali plasma would serve as both the high-temperature collector of solar radiation and as the working fluid for a high-temperature working cycle. The working cycle would be a simple magnetohydrodynamic Rankine cycle. Theoretical and experimental results obtained to date are summarized. These include: (1) an experimental confirmation of the theoretical prediction that a plasma temperature of about 2800 K can be reached through heating cesium vapor by sunlight concentrated to approximately 300 W per sq cm; and (2) the establishment of a theoretical model of the complete solar heated plasma magnetohydrodynamic cycle.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: Journal of Applied Physics; 52; Dec. 198
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  • 80
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    In:  Other Sources
    Publication Date: 2019-07-13
    Description: A truncated pentahedral pyramidal solar concentrator configuration has been selected as the most favorable candidate capable of providing low-cost multi-hundred-kilowatts (kW) solar array in low earth orbit. This concentrator has the advantages of: commonality for applications using either gallium arsenide (GaAs) or silicon (Si) solar cells, cost effectiveness, structural simplicity, and compatibility with the Shuttle. Results of concentrator optical ray trace, benefit of radiator, deployment mechanism, array power, and cost analysis are discussed.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: Photovoltaic Specialists Conference; May 12, 1981 - May 15, 1981; Kissimmee, FL
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  • 81
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    Publication Date: 2019-07-13
    Description: An analysis based on percent GaAs solar cell weight and cost is performed to assess the utility of this cell for future space missions. It is shown that the GaAs substrate cost and the end-of-life (EOL) advantage the cell can provide over the space qualified silicon solar cell are the dominant factors determining potential use. Examples are presented to show that system level advantages resulting from reduction in solar panel area may warrant the use of GaAs at its current weight and projected initial cost provided the EOL advantage over silicon is at least 20 percent.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: Photovoltaic Specialists Conference; May 12, 1981 - May 15, 1981; Kissimmee, FL
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  • 82
    Publication Date: 2019-07-13
    Description: The results of an effort to determine the mechanisms involved in the flat spot (FS) effect are given. It is suggested that the FS effect is due to a resistive metal-semiconductor-like (MSL) interface in parallel with the cell PN junction. Regions responsible for the FS effect lie under the front surface metallization in these cells, where the PN junction has been destroyed and replaced with a metal silicide-semiconductor interface. Such structural changes, which appear to be due to the thermally activated dissolution of the silicon, have been induced in cells as a result of isochronal heat treatments at temperatures between 450 C and 560 C. It has been found that a 650 A layer of Ta2O5 evaporated over the metallization is sufficient to prevent the underlying silicon from pitting during the subsequent heat treatment, although pitting at the metal silicon ambient interface could still be observed.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: Photovoltaic Specialists Conference; May 12, 1981 - May 15, 1981; Kissimmee, FL
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  • 83
    Publication Date: 2019-07-13
    Description: A system utilizing a pumped, two-phase single component working fluid for heat exchange and transport services necessary to meet the temperature control requirements of typical orbiting instrument payloads on space platforms is described. The design characteristics of the system is presented, together with a presentation of a laboratory apparatus for demonstration of proof of concept. Results indicate that the pumped two-phase design concept can meet a wide range of thermal performance requirements with the only penalty being the requirement for a small liquid pump.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: In: Advances in heat pipe technology; Sep 07, 1981 - Sep 10, 1981; London
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  • 84
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    In:  Other Sources
    Publication Date: 2019-07-13
    Description: Heat pipe performance data taken during the 8 1/2 years of flight of the OAO-C (Copernicus) spacecraft are presented. Three fixed conductance heat pipes (FCHP), each with different wicking concepts (axial groove, pedestal artery, and self-priming spiral artery), and one variable conductance heat pipe (VCHP) are onboard. Aluminum tubes (1/2 in. diameter) rolled into a 48 in. loop containing ultra high purity ammonia as the heat transfer fluid comprise all FCHP, whose purpose is to circumferentially isothermalize the central tube housing the telescope. The VCHP is a hot, non-wicked reservoir concept including a composite artery and methanol heat transfer fluid, and is used to maintain the temperature of the onboard processor. Flight thermal data analysis reveals that no degradation in performance occurred since launch and agrees well with pre-flight data; the onboard processor still shows an offset in control range of 4 F, and the pipes perform the same after 8 1/2 years in orbit.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: In: Advances in heat pipe technology; Sep 07, 1981 - Sep 10, 1981; London
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  • 85
    Publication Date: 2019-07-13
    Description: The vibration characteristics of the SSME (Space Shuttle main engine) are dealt with. The Space Shuttle engine consists of a main rocket nozzle and attached to it are high pressure fuel and oxygen pumps. Various vibration problems have been encountered with both the hydrogen and oxygen pumps. The vibration spectrum of the hydrogen and oxygen pumps has been analyzed by various techniques using synchronous tracking filters and FFT analyzers. The experimental data has been correlated to theoretical predictions of resonance frequencies.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: In: International Instrumentation Symposium; Apr 27, 1981 - Apr 30, 1981; Indianapolis, IN
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  • 86
    Publication Date: 2019-07-13
    Description: Design features and performance of the Shuttle main engines first flight are presented. Each of the three engines produces 470,000 lb of thrust, operates at 3,012 psia, and has a 77.5 to 1 nozzle expansion ratio. The engines are designed for a 7.5 hr operational life, and will be tested at 109% capacity in future Shuttle flights. The developmental program is outlined, and includes 127,000 sec of operational testing on 19 engines. Engine operations and components are described, noting 100% burning of the hydrogen and oxidizer, high pressure fuel turbopumps, the controller assembly, etc.; details of solutions to fatigue failures and subsequent certification are provided. The nine minute first flight firing revealed a radiant heating of a control sensor transducer, which was shielded for succeeding flights. Alternatives are given for thrust augmentation, for which each 1% yields an additional 800 lb payload increase capability, and can be implemented by 1987.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: AIAA PAPER 81-2471 , Flight Testing Conference; Nov 11, 1981 - Nov 13, 1981; Las Vegas, NV
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  • 87
    Publication Date: 2019-07-13
    Description: GaAlAs/GaAs heteroface solar cells used in space offer advantages of higher operating temperatures and recovery from radiation damage using thermal annealing. Elevated temperature experiments were conducted to evaluate the electrical stability of cells with different contact materials. These experiments indicate that for operation of GaAs heteroface solar cells at elevated temperatures, front contact metals must be carefully chosen. The short circuit current varied by only about 3% for cells with Pd/Ag contacts that were heated to 240 C for a total of 500 hours. However, a total decrease in the open circuit voltage of about 20% was observed for these cells. After heating cells to 400 C, large changes in open circuit voltage were observed for cells with Pd/Ag, Pd/Au, Pd, Ag, and Ti contacts; however, preliminary results indicate more stable open circuit voltages for cells with Au, Cr, Zn, and Cr/Au contacts.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: In: Intersociety Energy Conversion Engineering Conference; Aug 09, 1981 - Aug 14, 1981; Atlanta, GA
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  • 88
    Publication Date: 2019-07-13
    Description: The paper demonstrates the feasibility of producing high-efficiency GaAs solar cells with high power-to-weight ratios by organic metallic chemical vapor deposition (OM-CVD) growth of thin epi-layers on suitable substrates. An AM1 conversion efficiency of 18% (14% AM0), or 17% (13% AM0) with a 5% grid coverage is achieved for a single-crystal GaAs n(+)/p cell grown by OM-CVD on a Ge wafer. Thin GaAs epi-layers OM-CVD grown can be fabricated with good crystallographic quality using a Si-substrate on which a thin Ge epi-interlayer is first deposited by CVD from GeH4 and processed for improved surface morphology
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: In: Intersociety Energy Conversion Engineering Conference; Aug 09, 1981 - Aug 14, 1981; Atlanta, GA
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  • 89
    Publication Date: 2019-07-13
    Description: The Power Extension Package (PEP), a 32-kilowatt, flexible-substrate, retrievable solar array system for use on the Space Shuttle, is described. It is noted that solar cell costs will be reduced by increasing cell area and simplifying cell and coverglass fabrication processes and specifications. The tests that have been carried out on the cells are described, among them a unique radiation damage test and a side-by-side comparison of candidate cell types with pre- and post-irradiation airplane calibration of outer space short-circuit current
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: In: Intersociety Energy Conversion Engineering Conference; Aug 09, 1981 - Aug 14, 1981; Atlanta, GA
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  • 90
    Publication Date: 2019-07-13
    Description: An experiment to verify the operational performance of a full-scale Solar Electric Propulsion (SEP) solar array is described. Scheduled to fly on the Shuttle in 1983, the array will be deployed from the bay for ten orbits, with dynamic excitation to test the structural integrity being furnished by the Orbiter verniers; thermal, electrical, and sun orientation characteristics will be monitored, in addition to safety, reliability, and cost effective performance. The blanket, with aluminum and glass as solar cell mass simulators, is 4 by 32 m, with panels (each 0.38 by 4 m) hinged together; two live Si cell panels will be included. The panels are bonded to stiffened graphite-epoxy ribs and are storable in a box in the bay. The wing support structure is detailed, noting the option of releasing the wing into space by use of the Remote Manipulator System if the wing cannot be refolded. Procedures and equipment for monitoring the array behavior are outlined, and comprise both analog data and TV recording for later playback and analysis. The array wing experiment will also aid in developing measurement techniques for large structure dynamics in space.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: In: Intersociety Energy Conversion Engineering Conference; Aug 09, 1981 - Aug 14, 1981; Atlanta, GA
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  • 91
    Publication Date: 2019-07-13
    Description: An estimate, based on optimistic projections of current technology, is given for the specific power of photovoltaic blankets which might be achieved if the SPS concept was to be implemented. A simultaneous consideration of cost and technical requirements is used to identify key blanket technologies which must be developed for this reference system. The terrestrial photovoltaic experience coupled with new technology is used to develop cost estimates for the blanket, assuming an annual demand of 5 GW and a manufacturing industry dedicated to blanket production. The results indicate that blanket specific power goals may be exceeded, but there is little prospect that the cost goals can be met. This argues for a reconsideration of the photovoltaic option based on more expensive but higher performance blankets.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: In: Intersociety Energy Conversion Engineering Conference; Aug 09, 1981 - Aug 14, 1981; Atlanta, GA
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  • 92
    Publication Date: 2019-07-13
    Description: It is pointed out that spacecraft utilization projections for the 1980s and beyond show a trend toward extended lifetimes and larger electric power systems. The need for improved power management and energy transfer arising in connection with this trend has resulted in the conduction of a Solar Array Switching Power Management study. A description is presented of initial development work performed in the study, taking into account the characteristics for three mission classes. Attention is given to the manned LEO platform (250-kW average load), the unmanned GEO platform (50-kW average load), and an ion propulsion orbit transfer vehicle (50- to 250 kW load).
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: In: Intersociety Energy Conversion Engineering Conference; Aug 09, 1981 - Aug 14, 1981; Atlanta, GA
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  • 93
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-07-13
    Description: A Power Extension Package (PEP) has been designed to provide additional electrical power and energy during Shuttle sortie missions. The considered investigation was conducted to determine the most suitable allocation of PEP monitoring and control functions between the Orbiter's existing (centralized) Systems Management General Purpose Computer and an embedded PEP processor. PEP monitoring and control functions are examined, and a configuration definition is considered, taking into account the 'functional migration' process, function allocation criteria, and candidate functional configurations. A trade study is conducted, giving attention to an assessment of four candidate configurations. Assessment factors are related to cost, development risk, aspects of reliability and safety, PEP design complexity, PEP/STS integration complexity, flight operations, and launch/landing site operations. A thorough (subjective) assessment of the PEP system life cycle indicates substantial benefits from a distributed processing approach.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: AIAA PAPER 81-2140 , In: Computers in Aerospace Conference; Oct 26, 1981 - Oct 28, 1981; San Diego, CA
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  • 94
    Publication Date: 2019-07-13
    Description: The calculation approach is described for parametric analysis of candidate electric propulsion systems employed in LEO to GEO missions. Occultation relations, atmospheric density effects, and natural radiation effects are presented. A solar cell cover glass tradeoff is performed to determine optimum glass thickness. Solar array and spacecraft pointing strategies are described for low altitude flight and for optimum array illumination during ascent. Mass ratio tradeoffs versus transfer time provide direction for thruster technology improvements. Integrated electric propulsion analysis is performed for orbit boosting, inclination change, attitude control, stationkeeping, repositioning, and disposal functions as well as power sharing with payload on orbit. Comparison with chemical auxiliary propulsion is made to quantify the advantages of integrated propulsion in terms of weight savings and concomittant launch cost savings.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-167889-VOL-2 , NAS 1.26:167889-VOL-2 , TRW-37255-6002-UT-VOL-2
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  • 95
    Publication Date: 2019-07-13
    Description: Tradeoffs between electric propulsion system mass ratio and transfer time from LEO to GEO were conducted parametrically for various thruster efficiency, specific impulse, and other propulsion parameters. A computer model was developed for performing orbit transfer calculations which included the effects of aerodynamic drag, radiation degradation, and occultation. The tradeoff results showed that thruster technology areas for integrated propulsion should be directed towards improving primary thruster efficiency in the range from 1500 to 2500 seconds, and be continued towards reducing specific mass. Comparison of auxiliary propulsion systems showed large total propellant mass savings with integrated electric auxiliary propulsion. Stationkeeping is the most demanding on orbit propulsion requirement. At area densities above 0.5 sq m/kg, East-West stationkeeping requirements from solar pressure exceed North-South stationkeeping requirements from gravitational forces. A solar array pointing strategy was developed to minimize the effects of atmospheric drag at low altitude, enabling electric propulsion to initiate orbit transfer at Shuttle's maximum cargo carrying altitude. Gravity gradient torques are used during ascent to sustain the spacecraft roll motion required for optimum solar array illumination. A near optimum cover glass thickness of 6 mils was established for LEO to GEO transfer.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-167889-VOL-1 , NAS 1.26:167889-VOL-1 , TRW-37255-6001-UT-VOL-1
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  • 96
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-07-13
    Description: Experiments showed that stray magnetic fields can adversely affect the capacity of a hollow cathode neutralizer to couple to an ion beam. Magnetic field strength at the neutralizer cathode orifice is a crucial factor influencing the coupling voltage. The effects of electrostatic accelerator grid aperture diameters on the ion current extraction capabilities were examined experimentally to describe the divergence, deflection, and current extraction capabilities of grids with the screen and accelerator apertures displaced relative to one another. Experiments performed in orificed, mercury hollow cathodes support the model of field enhanced thermionic electron mission from cathode inserts. Tests supported the validity of a thermal model of the cathode insert. A theoretical justification of a Saha equation model relating cathode plasma properties is presented. Experiments suggest that ion loss rates to discharge chamber walls can be controlled. A series of new discharge chamber magnetic field configurations were generated in the flexible magnetic field thruster and their effect on performance was examined. A technique used in the thruster to measure ion currents to discharge chamber walls is described. Using these ion currents the fraction of ions produced that are extracted from the discharge chamber and the energy cost of plasma ions are computed.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-165584 , NAS 1.26:165584
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  • 97
    Publication Date: 2019-07-13
    Description: Six 30 cm mercury thrusters were modified to the J-series design and evaluated using standardized test procedures. The thruster performance meets the design objectives (lifetime objective requires verification), and documentation (drawings, etc.) for the design is completed and upgraded. The retrofit modifications are described and the test data for the modifications are presented and discussed.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-165259
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  • 98
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-07-13
    Description: Inert gas tests are conducted with several magnetoelectrostatic containment discharge chamber geometries. The configurations tested include three discharge chamber lengths; three boundary magnet patterns; two different flux density magnet materials; hemispherical and conical shaped thrusters having different surface-to-volume ratios; and two and three grid ion optics. Argon mass utilizations of 60 to 79% are attained at 210 to 280 eV/ion in different test configurations. Short hemi thruster configurations are found to produce 70 to 92% xenon mass utilization at 185 to 220 eV/ion.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: AIAA PAPER 81-0753 , International Electric Propulsion Conference; Apr 21, 1981 - Apr 23, 1981; Las Vegas, NV; US
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  • 99
    Publication Date: 2019-07-13
    Description: A phenomenological model is presented which describes the emission processes occurring within the orificed, hollow cathode. The model defines a region of ion production inside the cathode and assumes that the cathode emission current can be accounted for by considering the ion and electron currents which cross the boundary of this region. Most of the current (approximately 72%) comes from electrons produced by field-enhanced, thermionic emission from a well-defined emission surface at the downstream end of the insert which circumscribes the ion product region. The electrons produced at the emission surface feed the ionization process in the region of ion production; the rest of the current (approximately 28%) is carried by the ions produced in the process. Moving at the Bohm velocity, these ions leave the production volume; they then complete the current path by being collected at various cathode potential surfaces, including the emission surface. The model establishes the ratio of ion to electron currents at the emission surface on the basis of the energy balance at that surface. Experimental results corroborating the principal assumptions of the model are presented and discussed.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: AIAA PAPER 81-0746 , International Electric Propulsion Conference; Apr 21, 1981 - Apr 23, 1981; Las Vegas, NV; US
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  • 100
    Publication Date: 2019-07-13
    Description: The SERT II spacecraft, launched in 1970, has been maintained in an operational, but intermittent status since 1971. This paper presents the flight results obtained from mid 1979 through December 1980. Near continuous solar power in 1979 and 1980 has enabled long periods of thruster endurance testing. Three of four propellant tanks have been exhausted with no significant change in thruster system operation before being empty. A new plasma mode thrust has been characterized and direct thrust measurements obtained. Other tests, including beam neutralization by various neutralizer sources, give insight to electron conduction across plasmas in space and provide a basis to model neutralization of thruster arrays.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: AIAA PAPER 81-0665 , International Electric Propulsion Conference; Apr 21, 1981 - Apr 23, 1981; Las Vegas, NV; US
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