I've been thinking about how to handle the jump drive, and I think this concept mostly covers what has been established or suggested so far. I'll use spoiler blocks to improve readability and so it's not so wall-of-text-ish. Also, I broke the forum post length limit- I've never managed that before.
What do you think?
Part One
Hyperplasma Conduit Jump Drive
This is a version of the
Keyhole Drive type explained on
Space p39, except that it needs to include the 'random divergence with range' condition proposed by ericthered. How about if, in the 7-dimensional spacetime manifold utilised by the drive, gravity becomes a repulsive force?
Basic Concept
So, the drive creates a beam of charged hyperspace plasma that it shoots along its destination vector. This looks like the streamers that come off a
plasma ball- straight and direct near the root, but splaying around randomly like silly string at the tips. The hyperplasma beam makes a pathway through space, in generally the right direction, but is repulsed and deviated by gravitational sources along its path. This means that being in orbit of a large body can severely deviate the beam path at the outset, so jumping out from a point with a flat gravitational gradient is preferred- such as an L4 or L5. It also means you can't directly jump to a destination which is locally occulted by a planet or star, or to destinations on the far side of the galactic core. The beam channel takes a number of minutes to establish before it's ready to receive the ship.
Next, the ship's drive system creates a magnetic field surrounding the ship which couples with the mouth of the plasma conduit. The interaction of the magnetic field with the plasma expands the plasma conduit and draws the ship along, propelling it along like squeezing a cherry pip. Observers near the ship's departure see a bright flash of light, extending through UV and X-rays, with a ghostly red-shifted attenuated afterimage streak pointing along the ship's flight vector. Passengers on board the ship are subjected to an initial jolt of several G's, then a few hours of a rather bumpy ride as the ship traverses the snaking, winding conduit to their destination.
Construction
The ship's drive has 4 components.
Spoiler:
- A supply of gas stored as a coherent quantum crystal lattice. This requires one fuel tank module for every 3(?) jumps worth of fuel. Fuel requirements scale directly with SM of the ship. Also, PK talks a bit about using on-board Chemical Refineries or Engine Rooms for processing collected hydrogen into fuel
here, which we could steal, otherwise a ship would have to purchase jump fuel from a space station
- a plasma cannon which accelerates the gas to plasma temperature, usually mounted on the ship's nose
- a superscience matter inverter ring, which converts the plasma into our hyperplasma somehow (by rotating the plasma's Charge Parity Time Mass value by √-1, say) projecting it directly into 7-dimensional spacetime. (Alternatively, the inverter is a module which extracts quantum-aligned gas and inverts it before feeding it to the plasma cannon, either way is good.)
- a magnetic field generator, for enveloping the ship to couple it with the plasma tube. This could also be a superscience force field, if we prefer- say, a sheath of plasma bearing the opposite imaginary charge to that of the hyperplasma.
The last 3 components comprise the jump drive itself and count as one Stardrive module, requiring 1 power point to charge and activate, as per Stardrive Engines on
Starships p25. Super stardrives can expend further power points to increase the plasma velocity (by also using more energy in the inverter) which gives the hyperplasma beam more stability and thus accuracy, in the stem part of the hyperplasma tendril, or more range, at the end of the tendril.
Game Effects of this Jump Drive
So with this paradigm, we get a number of consequences and answer many of the questions posed thus far:
Plotting a Course
Spoiler:
- Navigators need to know, either by their own calculations or from a jump traffic controller (JTC),
- their exact location in galactic coordinates;
- the location of their destination- which may be directly observed but may have evolved due to motion around the galaxy;
- the gravimetric contour profile of their location. This may be provided by JTC, or calculated with TGLS's Dirk-Scales equations, which I suggest give a gravimetric solution to the N-body problem if provided with positions of all the main local bodies of mass. Lagrange points L4 and 5 are the simplest solutions, but similarly to the Interplanetary Transport Network, there are other gravimetric flat points scattered around a solar system.
- the gravitational landscape between departure and destination. This can partly be determined by accurate star charts, but unobserved masses can also affect the hyperplasma beam path, such as clumps of dark matter, brown dwarfs, dust clouds & nebula or hyperspace anomalies. This is where a "rutter program" becomes useful. Intervening gravity distortions can generally only be mapped by statistical analysis of many jump logs, compiled by a navigation company that collects jump log data from subscribers and by using survey scouts. They provide this data in regular updates to ship captains and JTC's who subscribe to their service. The rutter would say, for example, "the Jupiter-L5 - Yarra route appears to have a 5 deg corewise bias due to intervening dark matter accumulations, adjust accordingly."
- the jump vector solution for a 7 dimensional spacetime manifold taking into account all of the above position and perturbation data.
Where possible, and especially for smaller ships, the captain will just advise JTC of his planned destination and let them use their superior computational, observational and cartographic resources, who then reply with an optimal launch solution for the ship to take.
Continued next post...