Engineering topics

Day, F. D., III

Publications and source records attributed to Day, F. D., III.

4 records

NASA NTRS1979

Voyager design and flight loads comparison

Estimates of flight loads for Voyager 1 and Voyager 2 are summarized. These member loads are obtained by using the measured flight accelerations at the launch vehicle/spacecraft interface as forcing functions for the Voyager mathematical model. The flight loads are compared to the Voyager design loads obtained from the shock spectra/impedance method and to the loads obtained using space vehicle transient loads analysis. Finally, based on these data, an assessment of the shock spectra/impedance loads method used for Voyager is presented.

Chen, J. C.↗

NASA NTRS1978

Summary of Voyager Design and Flight Loads

Estimates of flight loads for Voyager 1 and Voyager 2 are summarized and compared to the Voyager design loads obtained from the shock spectra/impedance method and to the loads obtained using space vehicle transient loads analysis. These estimates were obtained by using the measured flight accelerations at the launch vehicle/spacecraft interface as forcing functions for the Voyager mathematical model. Based on these data, an assessment of the shock spectra/impedance loads method used for Voyager is presented. The following conclusions were reached: (1) the shock spectra approach provided reasonable conservative design loads for Voyager, (2) care has to be executed to insure that all critical events are accounted for in constructing shock spectra envelopes, (3) the selection of critical events is not always obvious, especially for those flight events wherein the spacecraft dynamic characteristics are important, and (4) the success of the method is strongly dependent on the analysts' experience and judgement.

Chen, J. C.↗

NASA NTRS1977

Solar Stirling power generation - Systems analysis and preliminary tests

The feasibility of an electric power generation system utilizing a sun-tracking parabolic concentrator and a Stirling engine/linear alternator is being evaluated. Performance predictions and cost analysis of a proposed large distributed system are discussed. Design details and preliminary test results are presented for a 9.5 ft diameter parabolic dish at the Jet Propulsion Laboratory (Caltech) Table Mountain Test Facility. Low temperature calorimetric measurements were conducted to evaluate the concentrator performance, and a helium flow system is being used to test the solar receiver at anticipated working fluid temperatures (up to 650 or 1200 C) to evaluate the receiver thermal performance. The receiver body is designed to adapt to a free-piston Stirling engine which powers a linear alternator assembly for direct electric power generation. During the next phase of the program, experiments with an engine and receiver integrated into the concentrator assembly are planned.

Selcuk, M. K.↗

NASA NTRS1975

Strain gaged struts and data reduction techniques to maximize quality data from spacecraft flight measurements

The flight instrumentation for the Viking project was established to obtain environmental data, and maximize the data obtainable from the limited number of telemetry channels. To achieve these objectives, a set of six struts were strain gaged and calibrated as load cells to obtain a complete force-time history across an interface. The force-time history can be used with an analytical model to calculate the response of any part of the structure above the instrumented interface. Special matched filters were required to reduce the flight data and derive the phase correlated loads. Flight data results from the Viking Dynamic Simulator flown in February 1974 are described in addition to ground test results used to verify the data reduction process.

Day, F. D., III↗