Launch vehicle optimization, phase II. VOLUME III - Techniques development Final report
Simulation of complex physical systems behavior in launch vehicle system optimization program - digital computer program
LAUNCH VEHICLE↗
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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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Single degree of freedom antenna pointing program /ANTENA/
Computer program optimizes the accuracy of pointing a radio-frequency antenna at a target whose position is time varying but known with respect to a certain reference frame.
Fleishher, G. E.↗
User's manual for COPTRAN, a method of optimum communication system design
User manual for COPTRAN /communication system optimization program translatory
Brinkman, K. L.↗
The flight path control software system of the Lunar Orbiter.
Flight path control in software system for Lunar Orbiter, discussing optimization program for midcourse aim point and lunar injection point
Liebelt, P. B.↗
Application of a nonlinear least-squares method to atmospheric temperature sounding.
Nonlinear least squares optimization program applied to atmospheric temperature sounding, solving for temperatures at various altitudes from simulated carbon dioxide intensity measurements
Barnett, T. L.↗
Microwave circuit design by digital computer
Microwave circuits automatic analysis and design using digital computer in batch mode, describing analysis-optimization program
Kozemchak, E. B.↗
Optimization of self-acting herringbone journal bearings for maximum radial load capacity
Self acting herringbone journal bearings optimization program for maximum radial load capacity and wide operating range via groove configurations
Fleming, D. P.↗
Transonic transport study: Structures and aerodynamics
The structural and aerodynamic aspects of a general study of advanced transonic transports are presented. Aircraft designed to cruise at Mach numbers of 0.90, 0.98, and 1.15 were comparatively analyzed. The wings of all three aircraft employ supercritical sections, and the two aircraft with the highest cruise Mach numbers also employ fuselage area ruling. Structural/aerodynamic characteristics and interactions are investigated both parametrically and with the aid of an automated configuration optimization program. The effects of replacing conventional aluminum airframe structure by advanced filamentary composite (carbon/epoxy) structure receive particular attention. The methods employed in the structural/aerodynamic analysis are discussed.
Ardema, M. D.↗
Maximum noise abatement trajectories.
Minimum noise annoyance trajectories for developing STOL operation procedures are obtained by modulating five control variables in two dimensions. The performance index is formulated such that it explicitly assigns the same relative importance to thrust as it does to distances between discrete listeners and the aircraft. However, using a steepest descent optimization program, results indicate that it is preferable to keep the thrusters at their maximum value to minimize the integrated annoyance rather than to reduce thrust which would lower the instantaneous annoyance. Thrust decreases below its bound only when the instantaneous noise at a listener is limited.
Zeldin, S.↗
Numerical integration routines for near-earth operations
Two general purpose numerical integration schemes were built into the NASA-JSC computer system. The state-of-the-art of numerical integration, the particular integrators built into the JSC computer system, and the use of the new integration packages are described. Background information about numerical integration and the variable-order, variable-stepsize Adams numerical integration technique is discussed. Results concerning the PEACE parameter optimization program are given along with recommendations and conclusions.
Powers, W. F.↗
Approximation for maximum centerline heating on lifting entry vehicles.
A centerline heating approximation is proposed in which only three basic equations need be solved. The heat rates correlate well with those obtained by more complex procedures. The approximation is readily adaptable to existing trajectory optimization programs to provide realistic surface temperature constraint capability with little increase in computer storage capacity and computer time. It is based on an analysis of heat-rate data computed for altitudes from 36,000 to 122,000 m, velocities from 600 to 7900 m/sec, and angles of attack from 0 to 60 degrees.
Helms, V. T., III↗
Investigation of abort procedures for space shuttle-type vehicles
An investigation has been made of abort procedures for space shuttle-type vehicles using a point mass trajectory optimization program known as POST. This study determined the minimum time gap between immediate and once-around safe return to the launch site from a baseline due-East launch trajectory for an alternate space shuttle concept which experiences an instantaneous loss of 25 percent of the total main engine thrust.
Powell, R. W.↗
An assessment of airfoil design by numerical optimization
A practical procedure for optimum design of aerodynamic shapes is demonstrated. The proposed procedure uses an optimization program based on the method of feasible directions coupled with an analysis program that uses a relaxation solution of the inviscid, transonic, small-disturbance equations. Results are presented for low-drag, nonlifting transonic airfoils. Extension of the method to lifting airfoils, other speed regimes, and to three dimensions if feasible.
Hicks, R. M.↗
Stress tests on cylinders and aluminum panels
An optimization study of composite stiffened cylinders is discussed. The mathematical model for the buckling has been coupled successfully with the optimization program AESOP. The buckling analysis is based on the use of the smeared theory for the buckling of stiffened orthotropic cylindrical shells. The loading, radius, and length of the cylinder are assumed to be known parameters. An optimum solution gives the value of cross-sectional dimensions and laminate orientations. The different types of buckling modes are identified. Mathematical models are developed to show the relationships of the parameters.
Sobel, L. H.↗
Mars surface-to-orbit vehicles for sample return missions
Review of the results of a Mars surface-to-orbit launch vehicle study using an upgraded atmospheric density profile and an ascent trajectory optimization program. Orbit insertion was achieved with velocity losses less than those found in an earlier study. Values of thrust-to-mass ratio which minimize velocity losses for dual-burn vehicles were found to be significantly greater than the values of thrust-to-launch-mass ratio for the minimum-velocity-loss continuous-burn vehicle. The use of a two-stage solid-propellant vehicle employing a spin-stabilized second stage offers an attractive design option for a Mars surface-to-orbit launch vehicle.
Weaver, W. L.↗
Application of numerical optimization to the design of low speed airfoils
A practical procedure for the optimum design of low-speed airfoils is demonstrated. The procedure uses an optimization program based on the method of feasible directions coupled with an aerodynamic analysis program that uses a relaxation solution of the inviscid, full potential equation. Results are presented for airfoils designed to have small adverse pressure gradients, high maximum lift, and low pitching moment.
Hicks, R. M.↗
Quaternary and quinary modifications of eutectic superalloys strengthened by delta Ni3Cb lamellae and gamma prime Ni3Al precipitates
By means of a compositional and heat treatment optimization program based on the quaternary gamma/gamma prime-delta, a tantalum modified gamma/gamma prime-delta alloy with improved shear and creep strength combined with better cyclic oxidation resistance was identified. Quinary additions, quaternary adjustments, and heat treatment were investigated. The tantalum modified gamma/gamma prime-delta alloy possessed a slightly higher liquidus temperature and exhibited rupture strength exceeding NASA VIA by approximately three and one-half Larson-Miller parameters (C = 20) above 1000 C. Although improvements in longitudinal mechanical properties were achieved, the shear and transverse strength property goals of the program were not met and present a continuing challenge to the alloy metallurgist.
Lemkey, F. D.↗
A steepest descents method for reentry optimization
A steepest descents optimization program is applied to the problem of a lifting vehicle entering the earth's atmosphere. The program employs penalty functions representing terminal conditions and inflight inequality constraints. During each iteration, it reduces a single performance measure which is the sum of the performance index and the penalty functions. Therefore, only one set of adjoint equations must be integrated per iteration. Values of weight factors, multiplying the penalty functions, are automatically adjusted before each iteration in order that the penalty functions will approach acceptable values. This method is shown to be a form of the classical Lagrange multiplier methods.
Andrus, J. F.↗