Hard Space: Starflight

After discussing the subject of sub-light, real-space travel in my Hard Space setting, it is time to discuss the second part of travel, and that means interstellar flight. So how does this work?

• Interstellar travel uses the Jump Drive. The jump drive is a complex contraption manipulating an Antediluvian artifact - a Spindle - to punch a transdimensional between real space and the alien realm called Jump Space. The complexity and size of the drive determines its capability to manipulate its Spindle, hence the different jump rates.

• A jump is approx. 7 days in length and transports the ship one parsec per jump number, as in baseline Traveller.

• Unlike baseline Traveller jump drives, Hard Space jump drives do not require fuel, only energy input from the power plant. However, after a jump, the drive requires time to "spool" and recharge. This time is 1D days minus the attending engineer's skill, to a minimum of one day.

• Jump drives require a gravity well on both sides. A small brown dwarf is sufficient. There are no "empty-hex jumps" or "calibration points" - you need a star on both sides.

• Jumps can be inaccurate. The higher the ship navigator's throw when plotting the jump, the closer to its destination the ship emerges. An unlucky navigator might find their ship in the outer system, while a skilled or lucky navigator might emerge directly into orbit of the target world. Ships do not emerge within large masses or very close to them - so there is no risk of emerging inside a sun or planet.

• Misjumps are dangerous and can result in encounters with the Unknown and insanity. This is messing with barely-understood alien technology and parallel dimensions which defy too many rules of physics. A good jump throw avoids most of the unpleasantness, but a misjump exposes the crew to all sorts of nastiness. Beware.

• Needless to say, I'll have to create my own custom jump throw table to account for accuracy in the target system and to the lack of jump fuel.

• I'm using Little Black Books drive TLs and letters. This means that you can reach Jump-3 at TL9 and Jump-4 at TL10. Humanity in Hard Space is at early-mid TL10. This also means that smaller ships can jump further and are faster than larger ships. Of course, this entails a small-ship universe. This also means that the only drives available are Book 2 A-H drives. The biggest jump capable ship is 1,000 displacement tons in volume. 800-ton ships may achieve Jump-2, while 600-ton ships can achieve Jump-3 and an 400-ton ship may achieve Jump-4.

• If using Cepheus Engine drives with these TLs, ships would be different - the maximum ship tonnage becomes 1,800 tons, but the largest ship capable of Jump-3 is 500 tons in volume and you can have a Jump-2 1,000-ton ship.

• In any case, Drives E-H are very new - Humanity reaches TL10 only 14 years ago. Before that, the largest jump-capable tonnage was 800 displacement tons, and  the largest J-2 ship was 400 tons. This gave rise to the vast expansion of the third generation of colonization, with much larger tonnages at Jump-2 and better.

• In any case, far jumps mean less payload. While there is no jump fuel, ships travelling the fringe require propellant for their engines, especially when not expecting each orbital refueling.