A generalized modal shock spectra method for spacecraft loads analysis

Unlike an earlier shock spectra approach, generalization permits an accurate elastic interaction between the spacecraft and launch vehicle to obtain accurate bounds on the spacecraft response and structural loads. In addition, the modal response from a previous launch vehicle transient analysis with or without a dummy spacecraft - is exploited to define a modal impulse as a simple idealization of the actual forcing function. The idealized modal forcing function is then used to derive explicit expressions for an estimate of the bound on the spacecraft structural response and forces. Greater accuracy is achieved with the present method over the earlier shock spectra, while saving much computational effort over the transient analysis

A frequency domain solution for the linear attitude-control problem of spacecraft with flexible appendages

Linear interaction problem between spacecraft attitude control and flexible appendages solved in frequency domain using Fourier transfor

Electronic analog equalization for vibrational testing

Method of real time equalization involving use of an analog computer achieves effective qualification testing by realistically simulating the effects of the vibrational forces which will actually be experienced in powered flight

A Fourier transform technique for the prediction of torsional transients for a spacecraft from flight data of another spacecraft using the same booster

Fourier transform for predicting torsional transients for one spacecraft based on flight data of another with same booste

Use of analog computer for the equalization of electromagnetic shakers in transient testing

Analog computer to perform open-loop equalization for multishaker environmental vibration testin

A shock spectra and impedance method to determine a bound for spacecraft structural loads

A method to determine a bound of structural loads for a spacecraft mounted on a launch vehicle is developed. The method utilizes the interface shock spectra and the relative impedance of the spacecraft and launch vehicle. The method is developed for single-degree-of-freedom models and then generalized to multidegree-of-freedom models

Analysis of space vehicle structures using the transfer-function concept

Analysis of large complex systems is accomplished by dividing it into suitable subsystems and determining the individual dynamical and vibrational responses. Frequency transfer functions then determine the vibrational response of the whole system

A survey of load methodologies for shuttle orbiter payloads

Loads methods currently being used to design shuttle orbiter payloads are summarized. Methods used for the design of payloads launched by expendable launch vehicles are described in historical perspective. Experiences gained from expendable launch vehicle payloads are used to develop methodologies for the space shuttle orbiter payloads. The objectives for the development of a new methodology for the shuttle payloads are to reduce the cost and schedule for the payload load analysis by decoupling the payload analysis from the launch vehicle to the maximum extent possible. Methods are described for payload member load estimation or obtaining upper bounds for dynamic loads, as well as load prediction or calculating actual transient member load time histories

Use of derived forcing functions at Centaur main engine cutoff in predicting transient loads on Mariner Mars 1971 and Viking spacecraft

Mathematical models for prediction of acceleration responses and reaction forces and moments at base of Mariner Mars 71 and Viking spacecraft from Centaur main engine cutof

New measurement of exotic decay of 225^{225}Ac by 14^{14}C emission

The branching ratio of $^{225}$Ac decay by emission of $^{14}$C was remeasured under improved experimental conditions by using a radioactive source produced at the ISOLDE mass-separator at CERN and a nuclear track detector technique. The result, B=$\lambda_{^{14}\textrm{C}} / \lambda_{\alpha} = (4.5 \pm 1.4) 10^{-12}$, is consistent with the anomalously high value obtained in the 1993 experiment thus confirming the importance of nuclear structure effects in this exotic decay