Space Structures 5

These Proceedings are based on the Fifth International Conference on Space Structures, organised by the University of Surrey. Produced as a 2-volume set, they contain original and innovative information on space structures from leading engineers and architects from around the world.

xiv aggregates: this touches on the very nature of things. The concept of statistical symmetry which Loeb develops is particularly important, it emphasizes the limitations in seemingly random aggregates and for permits general statements of which the crystallographer's sym metries are only special cases. The reductionist and holistic approaches to the world have been at war with each other since the times of the Greek philosophers and before. In nature, parts clearly do fit together into real structures, and the parts are affected by their environment. The problem is one of understanding. The mystery that remains lies largely in the nature of structural hierarchy, for the human mind can examine nature on many different scales sequentially but not simultaneously. Arthur Loeb's monograph is a fundamental one, but one can sense a devel opment from the relations between his zero-and three-dimensional cells to the far more complex world of organisms and concepts. It is structure that makes the difference between a cornfield and a cake, between an aggregate of cells and a human being, between a random group of human beings and a society. We can perceive anything only when we perceive its structure, and we think by structural analogy and comparison. Several books have been published showing the beauty of form in nature. This one has the beauty of a work of art, but it grows out of rigorous mathematics and from the simplest of bases-dimensional ity, extent and valency.

The diversity of constructions included in this publication on space structures ranges from anten reflectors and masts positioned in space, to equally exciting terrestrial structures, notably large-span domes, barrel vaults, multi-layered grids, cable and membrane systems, and pneumatic structures. This collection of more than two hundred and twenty papers, presented in to volumes, is the work of leading international experts for presentation at the Fourth International Conference on Space Structures. These two volumes contain a prodigious amount of original and innovative information on space structures that will be of especial interest to engineers, architects and other professionals engaged in the planning, design, fabrication and erection of novel constructions.

Architects are constantly looking for new methods to create large indoor spaces unhindered by columns and other supports. Tensile and cable-strut structures are one method of producing such spaces. They also enable the creation of different shaped spaces allowing architects more scope for innovation. Free-standing Tension Structures: From Tensegrity Systems to Cable-strut Systems provides the background engineering needed to produce these wonderful structures. Providing a complete background to the underlying structural engineering theories of tensegrity, this book will prove invaluable for all architects and engineers working on tensile structures.

This monograph is intended to provide a snapshot of the status and opportunities for advan cement in the technologies of dynamics and control oflarge flexible spacecraft structures. It is a reflection ofthe serious dialog and assessments going on all over the world,across a wide variety of scientific and technical disciplines, as we contemplate the next major milestone in mankind's romance with space: the transition from exploration and experimentation to commercial and defense exploitation. This exploitation is already in full swing in the space communications area. Both military and civilian objectives are being pursued with increasingly more sophisticated systems such as large antenna reflectors with active shape control. Both the NATO and Warsaw pact alliances are pursuing permanent space stations in orbit: large structural systems whose development calls for in-situ fabrication and/or assembly and whose operation will demand innovations in controls technology. The last ten years have witnessed a fairly brisk research activity in the dynamics and control oflarge space structures in orderto establish a technology base forthe development of advanced spacecraft systems envisioned for the future. They have spanned a wide spectrum of activity from fundamental methods development to systems concept studies and laboratory experimentation and demonstrations. Some flight experiments have also been conducted for various purposes such as the characterization of the space enviroment, durability of materials and devices in that environment, assembly and repair operations, and the dynamic behavior of flexible structures. It is this last area that has prompted this monogram.