[Space] Adapting "Honorverse" Concepts to GURPS

[DaltonS]

I’ve recently been (re-)reading David Weber’s Honor Harrington series and have been thinking about how to incorporate some of his super-science concepts into a GURPS Space campaign. As I don’t want to plagiarize his work (as was done by John Fosgett in his GURPSnet "Hyperspace Physics 101" post many years ago), there will be some changes. Direct quotes from "The Universe of Honor Harrington" in More Than Honor will be marked by "†" while those from "Hyperspace Physics 101" will be marked by "‡".

Hyperspace
"Hyperspace" is a series “of associated but discrete dimensions”† (called "bands") each “which corresponds on a point-by-point basis to "normal-space" but places those points in much closer congruity.”†. Each band has a higher space compression factor¹ relative to normal space (called N-Space for short) than the band "below" it and thus a higher effective light speed limit. The laws of relativity remain in effect using "local" distance measurements, so time dilatation is a factor for c-fractional velocities. The relative motion of stars in N-Space affect “Hyperspace with compressed gravity ‘shadows’, which create ‘corridors’ of compressed gravity ‘currents’ much like currents in an ocean.”‡ These currents can create grav waves that “take the form of wide, deep volumes of space, as much as fifty light-years across and averaging half their width in depth, of focused gravitational stress "moving" through hyper-space.”† This stress can destroy a ship using a gravitic drive (see "Subwarp Drive" on page 24, GURPS Spaceships) that encounters the wave unexpectly, but a ship whose grav drive has the "grav sail" option (increase cost and reduce thrust by 1/3) can actually ride the wave at an effective acceleration of 10× normal without inertial effects (the wave provides an "inertial sump" for the grav compensators [SS:p.29]) or power requirements (power for the drive is drawn from the wave itself).

Hyperspace drives cannot translate (jump to) a higher hyperspace band where the external gravitational stress is greater than 0.0001 G. The hyperlimit is the minimum distance from a star (or planet) at which this can happen. In the Sol system, this occurs at 2.459 AU or 1,227 c-seconds from the sun.² For other systems this can be found by multiplying the above numbers by the mass (in solar units) of the nearest star. A planet’s hyperlimit (which need only be calculated for worlds that orbit outside the star’s hyperlimit) is

1. 100 earth radii (396,319 miles, 637,814 km or 2.1275 c-seconds) times its mass (in Earth units) or,
2. 50 times its diameter times the square root of its surface gravity in Gs

from its core.

Hyperlimits are the anchors of hyperspace, with velocities measured from the nearest one. In any hyperspace translation, the "velocity bleed" multiplier equals the lower compression factor divided by the higher one.³ While this makes upwards translations effectively undetectable, downwards translations shed the excess kinetic energy as a gravitic pulse or "hyper-footprint". Due to gravitational stresses, the maximum upwards translation velocity is 0.3c from N-space to the first hyper-band and 0.6c between higher bands. While downwards translations have no velocity limit, due to particle densities the maximum safe hyperspace velocity is 0.6c for ships with military grade shielding or 0.5c for civilian shields.

New Idea: Extending Hyperlimits into Hyperspace
Since a translation from/to N-Space is impossible inside the hyperlimit, there is no point-to-point congruence between the volume inside the limit and the first hyperband. This can be considered an event-horizon inside which that hyper-band does not exist. The radius of this horizon in local units equals that of the limit in N-space divided by the compression factor. The gravitation stress on space will also be multiplied by this factor, creating hyperlimits for this band with a radius equal to original N-Space ones in local units! To make things even more interesting, let’s say downward translations can only occur between the event horizon and the hyperlimit. This can be extended to higher hyperbands using the hyperlimits of the lower band as the event horizons of the higher.

Wormhole Junctions

“A (wormhole) junction is a "gravity fault," or a gravitic distortion so powerful as to fold hyper-space and breach the interface between it and normal-space. The result is a direct point-to-point congruence between points in normal-space which are seldom separated by less than 100 light-years and may be separated by several thousand.”†

A ship using the junction requires a hyperdrive (see "Stardrive Engine" on page 25, GURPS Spaceships) and a gravitic drive with "grav sails" option (see above). A junction may be connected to several wormholes (in which case it’s called a "wormhole nexus") or only one (called a "hyperbridge") with other end of each wormhole being called a "secondary terminus". The number of wormholes can generally be determined by a careful study of the junction with gravitic sensors, “but the locations of those termini cannot be ascertained without a surveying transit, and such first transits remain very tricky and dangerous.”†

The nexus is connected to each terminus by a unique pattern of gravity waves, one pattern outbound and one inbound, normally referred to as the "terminus route." Each junction has an absolute tonnage ceiling, the maximum mass which can be put through any given terminus (including the central nexus) simultaneously, but the limit applies individually to each terminus route.Ӡ

Author’s Notes:

1. In the "Honorverse" the first "alpha" band had a compression factor of 62 with 705 added for each subsequent level.
2. This works out to a bit less than in the "Honorverse".
3. This makes a bit more sense than D.W.'s flat 92% velocity bleed.

Dalton “who has more to come” Spence