The evolution of space simulation

Thirty years have passed since the first large (more than 15 ft diameter) thermal vacuum space simulation chambers were built in this country. Many changes have been made since then, and the industry has learned a great deal as the designs have evolved in that time. I was fortunate to have been part of that beginning, and have participated in many of the changes that have occurred since. While talking with vacuum friends recently, I realized that many of the engineers working in the industry today may not be aware of the evolution of space simulation because they did not experience the changes that brought us today's technology. With that in mind, it seems to be appropriate to take a moment and review some of the events that were a big part of the past thirty years in the thermal vacuum business. Perhaps this review will help to understand a little of the 'why' as well as the 'how' of building and operating large thermal vacuum chambers.