I’m about to start investigating liner operations and interstellar transport costs in Flat Black. This is going to involve committing to facts and numbers about the Eichberger drive and the things liners have to do to use it, beyond the existing¹ “it goes about 1,000 times lightspeed, and is dearer than surface ships but cheaper than air liners”. There is going to be a bit of fiddling around to do, assumptions to experiment with and alter. If you notice anything about the specification below that might have implications that I haven’t thought of, please let me know about them and I’ll try to nip the problems in the bud.
This is mostly a set-up to (a) writing what manœuvre drives liners and warships have to effect their evolutions on the pre-FTL and post-FTL legs of any trips, (b) writing a description of what a liner journey is like for PC passengers, and © writing a statement of typical fares and freight rates. I’m fiddling around with GURPS Spaceships rules as a starting-point, but I feel free to change things if I don’t like the results, and no obligation to be compatible with the GURPS Spaceships approach.
- The Eichberger Drive is used by ships in space, thousands of kilometres from any atmosphere. If for no other reason, this is because if it used in/near an atmosphere it causes all the elements from hydrogen to about xenon within a large distance to undergo fusion at room temperature.
- For its drive to function as a drive (rather than a type of fusion warhead) the ship has to be not gravitationally bound to the solar system² it’s in, which means that it has to be travelling at above the escape velocity for the joint gravitational field of the planet and star at its origin. In the case of Earth/Sol that’s about 17 kilometres per second, towards which orbital speed around Earth contributes if you choose the right direction — liners head east from the night side. (Earth’s orbital speed is already taken into account in that 17 km/s figure. You can make the requirement more demanding by heading in the wrong direction if you want to.)
- The drive functions as what GURPS Spaceships calls a “hyperdrive”, i.e. the ship travels at finite speed and cannot interact with intervening objects (including detecting them), but it does not involve being in a “hyperspace” that is shared in any way with other ships. Essentially a ship in drive is temporarily in a pocket universe.
- The speed of the ship in drive is about 1,000c. That’s reasonably close to the 1 parsec-per-day suggested by GURPS Spaceships for FTL-1, but that’s coincidence and I’d certainly be happy to change it if I needed to. This is a situation like the use of “quantum I hyperdrive” and “quantum II hyperdrive” in Larry Niven’s Known Space. That is, all ships travel at the same speed; bigger drives don’t give you greater speed.
- When the ship arrives it is at rest with respect to the barycentre of its destination system, so it needs delta-vee equal to the orbital velocity of its destination planet minus low-orbit velocity around its destination planet.
- Energy is conserved in the following way: upon the arrival of a ship its excess energy is released in a violent convulsion heralding its arrival, and producing gravitational waves and a brief flash of black-body radiation with temperature characteristics related to the ship’s energy and drive size.
- The mass of the drive required is 5% of ship mass. This is a GURPSism, I may change it, and may have drive size diminishing with increasing tech level.
- The cost of Eichberger drives is as given in GURPS Space for stardrive systems. I will very likely alter this assumption to tune the results. Very likely the cost of Eichberger drives will diminish with increasing technology.
- Eichberger drives require no fuel and are not high-energy systems in GURPS Spaceships terms. However, they do require periodic maintenance to replenish consumables and replace fatigues parts. I’ll start with an assumption that overhauls cost 1% of drive cost per 1,000 engine hours.
¹ Previous versions of Flat Black had various specifications of the Eichberger Drive, which differed from each other and from what I’m about to specify now. The first few were instantaneous. Their quirks produced features that I didn’t like, so if you remember them from previous versions please disregard those recollections. We have always been at war with Eastasia.
² But not to the Galaxy. The physics is complicated and a classified. You are not cleared to hear the engineer explain it, and not cleared to be able to understand it if he did. Report to the food vat.