This is the second volume in the Iron Dragon trilogy which began with The Dream of the Iron Dragon. At the end of the first book, the crew of the Andrea Luhman stranded on Earth in the middle ages faced a seemingly impossible challenge. They, and their Viking allies, could save humanity from extinction in a war in the distant future only by building a space program capable of launching a craft into Earth orbit starting with an infrastructure based upon wooden ships and edged weapons. Further, given what these accidental time travellers, the first in history, had learned about the nature of travel to the past in their adventures to date, all of this must be done in the deepest secrecy and without altering the history to be written in the future. Recorded history, they discovered, cannot be changed, and hence any attempt to do something which would leave evidence of a medieval space program or intervention of advanced technology in the affairs of the time, would be doomed to failure. These constraints placed almost impossible demands upon what was already a formidable challenge.
From their ship’s computer, the exiled spacemen had a close approximation to all of human knowledge, so they were rich in bits. But when it came to it: materials, infrastructure, tools, sources of energy and motive power, and everything else, they had almost nothing. Even the simplest rocket capable of achieving Earth orbit has tens to hundreds of thousands of parts, most requiring precision manufacture, stringent control of material quality, and rigorous testing. Consider a humble machine screw. In the 9th century A.D. there weren’t any hardware stores. If you needed a screw, or ten thousand of them, to hold your rocket components together, you needed first to locate and mine the iron ore, then smelt the iron from the ore, refine it with high temperature and forced air (both of which require their own technologies, including machine screws) to achieve the desired carbon content, adding alloying metals such as nickel, chromium, cobalt, tungsten, and manganese, all of which have to be mined and refined first. Then the steel must be formed into the desired shape (requiring additional technologies), heat-treated, and then finally the threads must be cut into the blank, requiring machine tools made to sufficient precision that the screws will be interchangeable, with something to power the tools (all of which, of course, contain screws). And that’s just a screw. Thinking about a turbopump, regeneratively cooled combustion chamber, hydraulically-actuated gimbal mechanism, gyroscopes and accelerometers, or any of the myriad other components of even the simplest launcher are apt to induce despair.... [Read More]