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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Values for solar constant and solar spectral irradiance based on air and spaceborne observations for use in design of spacecraft, space vehicles, subsystems, and experiments
Standardization of structural acceptance tests conducted on flight hardware
Determining heat transfer to space vehicles entering planetary atmospheres for proper design and thermal protection
Technique for relating transient tolerances in inlet throat Mach number and shock position to supersonic unstart frequency due to atmospheric turbulence for supersonic inlet design
Spacecraft structures weight optimization based on fracture mechanics and reliability cost constraints applied to pressure vessel design
Rocket engine propellant injectors with noncircular orifice geometry, presenting experimental spray patterns and predicted performance for noncircular and circular orifice configurations
STOL aircraft electric power variable frequency generation and high voltage DC distribution with secondary square wave AC distribution
Failure Modes, Effects, and Criticality Analysis Model disregards failures of insignificant components. Assumptions used to establish baselines for reliability prediction and analytical method are listed. Techniques are applicable to any commercial design and can be extended into software or management systems.
Monograph was published which summarizes and systematically orders large body of successful techniques and practices developed for design of liquid rocket engine turbopump bearings. Document was written to organize and present significant experience and knowledge accumulated by NASA in development and operational programs.
Summary of large and loosely organized body of existing successful design techniques and practices for solid rocket motor igniters is presented.
Guidelines are presented on probable precipitation extremes and characteristics, applicable for NASA space vehicles and associated equipment development. Information is provided on probability of rainfall rates, drop size, drop rate of fall, associated wind speeds with rainfall, snow loads, hail, laboratory test simulation, and rain erosion.
The guidance, navigation, and control displays associated with manned spaceflight are summarized. Major emphasis were placed on methodologies useful for determining necessary information and its uses, systems analysis techniques, and analytic methods for design and evaluation of such systems.
The advantages and disadvantages of different models of capacitive transducers and of various signal conditioning circuits are discussed with particular emphasis on the field of applications. A practical example of a design procedure is discussed.
The advent of artificial earth orbiting satellites has added a new dimension to electromagnetic compatibility problems. These new EMC problems arise from the necessity of sharing frequency bands between satellite and terrestrial radio systems. The first such sharing arrangement, sharing between communication satellites and line-of-sight radio relay systems in the 4 and 6 GHz bands, has proved the soundness of the sharing concept under a particular set of circumstances and has encouraged frequency management officials to apply the concept to other functional services. This paper discusses a general sharing analysis procedure and illustrates the application of the procedure by presenting an analysis of the sharing feasibility between the Meteorological Satellite and the terrestrial Meteorological Aids services in the 1670-1700 MHz band.
Popov-type sufficient conditions are presented for the absolute stability of a class of closed loop sampled-data systems. The closed loop system consists of a linear distributed element, a feedback controller (linear or nonlinear), a sampler, and possibly a zero-order hold circuit. The distributed element is assumed to be finite Hankel transformable, and such that its dynamics can be represented by a transfer function which is the ratio of the multiple (Laplace and finite Hankel) transforms of output and input. The input is assumed to be distributed. The stability criterion presented here parallels the criterion for distributed systems that are finite Fourier transformable. An example is given to illustrate the applications of the stability criterion.
Surface pressures, heat-transfer rates, and transition locations for a sharp cone (whose semivertex angle is 12 deg) were obtained in a hypervelocity wind tunnel at a free-stream Mach number of 12 and a free-stream Re/ft range of 3,000,000 to 6,000,000. The effects of injecting either methane, nitrogen, or Freon-22 (at rates up to 2.1% of free-stream rate) were studied for a uniform injection-distribution and for a variable injection-distribution. Gaseous injection had little effect on the surface pressure measurements. For a given mass injection distribution, the laminar region heat-transfer decreases as the injection rate increases or as the molecular weight of the injectant decreases. For a given mass-injection rate (integrated over the surface of the entire cone), the transition location and heat-transfer rates were sensitive to the injection distribution. The transition Reynolds numbers were significantly greater when the local injection rate was constant over the surface of the cone.
A significance criterion is proposed that compares the strength parameter against the parameter expected from a random group of vectors in variance matrix applications. The variance matrix technique for determining preference or avoidance directions in space for a group of vectors gives only the parameter indicating the strength of the preference or avoidance, and the proposed criterion is shown to be of help in the achievement of reliability.