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A canopy of plants may become a vital component of advanced controlled ecological life support systems (CELSS). The interactions of the canopy with its environment need to be modeled so that designers can properly assess alternate configurations and operating strategies. Collective behavior of an entire canopy can sometimes be more expeditiously modeled than microscopic processes while preserving the robustness of the model for analysis of a CELSS. Water transpiration is a particularly important canopy process for which it is possible to link underlying microscopic processes and arrive at a description of canopy-level aggregated behavior. The underlying fundamental processes driving transpiration are relatively well understood. Unfortunately, the usual characterization of transpiration relies on parameters such as stomatal and boundary layer conductivities that are not directly measurable in typical CELSS designs.

Steady advancement over the past several decades in the optimization of controlled ecological life support systems (CELSS) design and performance has resulted in the development of a variety of approaches to CELSS control. This paper reflects this evolution by surveying the approaches used in controlling plant growth chambers currently in use in academia, industry, and government agencies. A table is presented summarizing the control system hardware and software used and the corresponding control laws implemented by these systems. The advantages seen by the science and engineering groups operating several plant growth systems are discussed. Troublesome or cumbersome properties of the control systems of some plant growth systems are also discussed as well as some of the solutions which have been derived or envisioned.

Prototypes of electrically-heated gloves have been designed, constructed, and tested along side other glove designs to evaluate various approaches to glove features. Two glove designs and two heater-controller designs, developed in-house, plus two commercial glove systems and an experimental glove system developed by the Army were tested. Testing consisted of employing the gloves while performing tasks in cold chambers. The results sought and obtained are subjective. Testing indicated that the in-house-designed glove system provided sufficient warmth under the test conditions specified by NASA scientists who are experienced working in Antarctica. The insulating ability of the commercial gloves and the dexterity of the Army-designed gloves were found preferable to those of the NASA prototypes. Additionally, testing showed that a single feedback temperature sensor per glove is adequate, as compared with individual temperature zones for each finger and thumb.