I've been watching Firefly episodes on DVD and so I had to try to build a "tramp freighter". First pass at a design was fully atmospheric, looking perhaps too much like Serenity, but then I started thinking about the economics of the thing. All that extra mass and high thrust engines, all that extra cost and maintenance. Not likely to be profitable. Specialized ships - shuttles - should go to and from "high gravity" worlds (probably everything bigger than a moon - possibly including the six biggest moons in the solar system). The tramp freighters that plied the deep space would be slow (in acceleration), but sturdy utilitarian things. Again, I spent probably way too much time on things no one will see: the crane that moves, the pivoting habitat sections and too much thought put into containerization. Containerization fascinates me. Maybe because my drive to and from work goes past a major port. But the idea that these standardized boxes go from ship to train to truck to... cheap housing unit, is just very interesting to me. Pure Bryce scene, including the star background, which is three layers of 2D faces with procedural materials. Thanks for viewing, commenting and favoriting. Last two don't seem to have attracted a lot of views, but I'm mostly doing this for me anyhow... --- By the end of the first third of the twenty-second century, Humanity had spread across the Solar System. Some worlds, like Mars and Luna had populations approaching a million people, but over a hundred settlements had sprung up among asteroids, small moons and mining habitats. Commercial routes between major population centers and all the planets from Earth to Saturn were dominated by large corporations hauling thousands of containers a year. But a settlement of one thousand people only needed thirty containers a year to sustain itself, and often suffered from an imbalance of trade - some settlements producing nothing, some mining outposts producing many times what they needed. These scattered settlements were the ideal markets for the Tranquility class freighter. Powered by a single sturdy General Atomics 70XN CNO-catalyzed fusion reactor, this was the first interplanetary craft affordable to smaller enterprises. With crew accommodations for just six, and only another half dozen passenger births, the Tranquility class was purely a freighter. Its four sets of eight container points could hold either 50 ton water propellant tanks or standard 2TEU containers of up to 45 net tons cargo. Performance depended greatly on the mixture of propellant to cargo, but varied from 170kps delta-V to over 500kps. Acceleration was generally limited to .05 gees, restricting operations to smaller bodies or orbital stations. The freighter was equipped for both vertical and horizontal landings, generally only going vertical on higher gravity bodies where a thruster landing was not practical. The habitat section could pivot to match local gravity--if it was significant enough to matter--and to allow a head-over-tail tumble to produce artificial gravity during long coasts between destinations. Using water for propellant, remote refueling was practical, and owner/operators often held claims to water-rich asteroids to serve as a home base. Over three hundred Tranquility class freighters were produced between 2130 and 2160. Many remained in operation through the Colonial War period and some still operated on backwater routes past the dawn of the twenty-third century. Great Big Book of Spaceships (Eleventh Edition), Public Information ePress, 2222