The Kardashev scale is a method of measuring a civilization's level of technological advancement, based on the amount of energy a civilization is able to utilize. The scale has three designated categories called Type I, II, and III. A Type I civilization uses all available resources impinging on its home planet, Type II harnesses all the energy of its star, and Type III of its galaxy. The scale is only hypothetical, but it puts energy consumption in a cosmic perspective.
Electricity generation vs. direct thrust Many spacecraft propulsion methods such as ion thrusters require an input of electric power to run but are highly efficient. In some cases their maximum thrust is limited by the amount of power that can be generated (for example, a mass driver). An electric generator that ran on fusion power could be installed purely to drive such a ship. One disadvantage is that conventional electricity production requires a low-temperature energy sink, which is difficult (i.e. heavy) in a spacecraft. Fusion rocket
Naturalistic science fiction - Battlestar Wiki From Battlestar Wiki, the free, open content Battlestar Galactica encyclopedia and episode guide Ron Moore's Essay on NSF Battlestar Galactica: Naturalistic Science Fiction or Taking the Opera out of Space Opera Our goal is nothing less than the reinvention of the science fiction television series. We take as a given the idea that the traditional space opera, with its stock characters, techno-double-talk, bumpy-headed aliens, thespian histrionics, and empty heroics has run its course and a new approach is required. That approach is to introduce realism into what has heretofore been an aggressively unrealistic genre.
Hard science fiction Today, the term "soft science fiction" is often used to refer to science fiction stories which lack a scientific focus or rigorous adherence to known science. The categorization "hard science fiction" represents a position on a broad continuum--ranging from "softer" to "harder". Scientific rigor The heart of the "hard SF" designation is the relationship of the science content and attitude to the rest of the narrative, and (for some readers, at least) the "hardness" or rigor of the science itself. One requirement for hard SF is procedural or intentional: a story should try to be accurate, logical, credible and rigorous in its use of current scientific and technical knowledge about which technology, phenomena, scenarios and situations that are practically and/or theoretically possible, and later discoveries do not necessarily invalidate the label.