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Large-scale physical system development endeavors which employ advanced systems methods require close technical/scientific interaction among a diverse group of mathematical modeling practitioners. A number of highly rigorous, highly rigid methods are available for the “book-keeping” necessary for valid mathematical modeling of systems of power exchanging “continuous” physical processes. Each method is attractive for one or more specialized physical scenarios, but none has become universally accepted because all are awkward in one or more important circumstances. In this paper, a means of incorporating all these representations (including ad hoc representations) into a single system representation is presented.

In this paper, issues and procedures for failure detection and failed item location in a specific category of systems are addressed. Sensor failure as well as system element failure is included. The category of systems addressed are those composed of power exchanging physical processes and those having equivalent mathematical model properties. The material is pertinent to the scenario in which rapid failure detection, rapid failed item identification, and rapid repair/replacement is important, a scenario characteristic of space exploration environmental monitoring and control system operation.

In the multiple control input, multiple controlled output system controller design process, it often happens that control providing acceptable performance can be obtained with a more simple control structure than that of full state feedback. The question that is addressed is whether or not one can rationally and quantitatively establish that such a simplification can be validly used in any design situation. This question is highly relevant to the design process because ignoring irrelevant details of a system reduces system development costs. To a large order, the answer to this question has been provided by perturbation theory; both singular perturbation theory and continuous perturbation theory. In this paper we demonstrate how both these means of simplification can be applied simultaneously.

A two and one half meter diameter centrifuge is a crucial component of the International Space Station (ISS) gravitational research program. It will supply the environment to support research into gravitational effects on plants and animals over the range of 0.01-2.0 g's while scientific control samples can be simultaneously maintained at microgravity levels. Because animals grow and move, unbalances will occur that, without isolation, may result in levels of vibration in the ISS which can affect other science being conducted in the space station. Here we present the results (to the present) of a study which has as its goal the determination of a control strategy which can keep these transmitted forces at or below the required level. We explain the strategy which was fashioned to approach the problem and present results that have been obtained.

Closed, regenerative life support systems as envisioned for space exploration will be required to provide extraordinarily high levels of performance and reliability. Even in a minimum cost development scenario, they will be very expensive. Because presently employed space life support systems are familiar technology, there is danger that during the crucial early planning and conceptualization stages the complexity of the future closed life support system may be overlooked and that the challenge of its development may be underestimated. This expensive oversight could even persist into the early phases of system design, and the resulting consequences would be enormous. In this paper, the elements of our view of the optimal procedure for the development of the space exploration life support system (SELSS) are discussed, put into correct relative position and are related to anticipated potential problems in system development and operation.

The results of an airflow distribution study based on a one-dimensional flow model are presented. The object of study was to characterize the distribution of the airflow emerging from the floor of a crop growth chamber of the type which is relevant in the development of a closed ecological life support system.