[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

[Icelander]

I approve of this effort. In fact, I am intrigued by your ideas and wish to subscribe to your newsletter.

[apoc527]

Ditto. Need a good system for interesting FTL travel translated to GURPS...this could fit the bill!

[warellis]

What TL would Honorverse technology be considered to be at? Are they at TL 10 or 11? For instance how would GURPS classify the pulsers which are "gravity"-accelerated mass drivers?

And what of the impeller wedges? They're obviously a superscience tech, but is there any tech level they fit in?

[Fred Brackin]

Originally Posted by warellis

What TL would Honorverse technology be considered to be at? Are they at TL 10 or 11? For instance how would GURPS classify the pulsers which are "gravity"-accelerated mass drivers?

And what of the impeller wedges? They're obviously a superscience tech, but is there any tech level they fit in?

Honorverse is far beyond TL10. It's just light on laser pistols, probably due to power cell tech or something like that.

Honorverse grav guns are very much the TL11^ guns of that name in UT. It's a very clear port. I've even heard that David Pulver may even have suggested to David Weber the idea of gravity-based projectile weapons before the whole series started.

They have a form of TL11^ barrier shields. Space stations without impeller walls can put up "spherical sidewalls". They're just relatively weak compared to the regular sidewalls anchored to the impeller wedges.

Grasers, even huge ones appropriate to SM16 or 17 SDs designed with Spaceships should be TL12.

The Grav Lances are UT TL11^ Gravity Beams though not in portable form.

Those gawdawful missiles, even though they "only" accelerate at 90,000 Gs rather than instantly going to near C speeds till hit their targets at ridiculous ranges in only 1 game Turn on a Spaceships scale greater than point blank so they're effectively Warp Missiles. They're much faster than simple Super Missiles.

The whole distance scale is much grater than anything considered in Spaceships.

Impeller wedges are more like a form of Sub-warp with their 500G accelerations than anything else.

[cmdicely]

Originally Posted by Fred Brackin

Honorverse is far beyond TL10. It's just light on laser pistols, probably due to power cell tech or something like that.

No, its light on laser pistols because because their gravity-related technology is so ridiculously advanced that artificial gravity propelled projectile sidearms are so much better than lasers would be in the setting that using power cells to power laser pistols in the setting makes about as much sense as using gunpowder charges to provide the energy to cock hand-fired crossbows makes in our world. (And, apparently, the breakthrough happened early enough that laser pistols were never the main sidearm thing.)

[warellis]

Originally Posted by cmdicely

No, its light on laser pistols because because their gravity-related technology is so ridiculously advanced that artificial gravity propelled projectile sidearms are so much better than lasers would be in the setting that using power cells to power laser pistols in the setting makes about as much sense as using gunpowder charges to provide the energy to cock hand-fired crossbows makes in our world. (And, apparently, the breakthrough happened early enough that laser pistols were never the main sidearm thing.)

Regarding lasers, won't they typically do less damage than an exploding bullet anyway? Frankly a bullet that explodes inside your body sounds more damaging than heating up the outside of the body until something boils.

Originally Posted by Fred Brackin

Honorverse is far beyond TL10. It's just light on laser pistols, probably due to power cell tech or something like that.

Honorverse grav guns are very much the TL11^ guns of that name in UT. It's a very clear port. I've even heard that David Pulver may even have suggested to David Weber the idea of gravity-based projectile weapons before the whole series started.

They have a form of TL11^ barrier shields. Space stations without impeller walls can put up "spherical sidewalls". They're just relatively weak compared to the regular sidewalls anchored to the impeller wedges.

Grasers, even huge ones appropriate to SM16 or 17 SDs designed with Spaceships should be TL12.

The Grav Lances are UT TL11^ Gravity Beams though not in portable form.

Those gawdawful missiles, even though they "only" accelerate at 90,000 Gs rather than instantly going to near C speeds till hit their targets at ridiculous ranges in only 1 game Turn on a Spaceships scale greater than point blank so they're effectively Warp Missiles. They're much faster than simple Super Missiles.

The whole distance scale is much grater than anything considered in Spaceships.

Impeller wedges are more like a form of Sub-warp with their 500G accelerations than anything else.

You mention impeller wedges are like a form of sub-warp due to their really high accelerations. What's the acceleration threshold in between what is merely a reactionless engine and a sub-warp engine? For instance in the Prince Roger series, written by Weber and John Ringo, the heaviest military starships, carriers, have a maximum acceleration of 164 Gs, cruisers have an acceleration of 450 Gs, and fighters at 800 Gs. As for missiles, cruiser-sized and capital ship "shipkillers" have an acceleration of 3000 Gs, counter-missiles accelerate to 3500 Gs, and fighter-carried shipkillers, which are bigger but shorter-ranged than the shipkillers carried in capital ships, have an acceleration of 4200 Gs.

[Fred Brackin]

Originally Posted by warellis

You mention impeller wedges are like a form of sub-warp due to their really high accelerations. What's the acceleration threshold in between what is merely a reactionless engine and a sub-warp engine? .

Literally an order of magnitude or more. It goes from primitive "Dean drive" devices at 0.1 Gs per system at tL9^ or lower to generic "thrusters" that deliver 1 G to 2 Gs for a high performance engines a TL later then to a super reactionless that delivers 50Gs a TL later and then to 500G Sub-warp.

Spaceships scales between TL and whole technologies and doesn't distinguish finely within a given TL/Tech paradigm.

[Ulzgoroth]

Originally Posted by Fred Brackin

The Grav Lances are UT TL11^ Gravity Beams though not in portable form.

No they aren't. The 'Grav Lance' is a complete misnomer. The sole function of a grav lance is to disrupt gravetic devices on the target at extremely short range (sidewalls mainly, I forget if they did anything else). You then follow up by firing into their unprotected hull with actual weapons.

Originally Posted by Fred Brackin

Those gawdawful missiles, even though they "only" accelerate at 90,000 Gs rather than instantly going to near C speeds till hit their targets at ridiculous ranges in only 1 game Turn on a Spaceships scale greater than point blank so they're effectively Warp Missiles. They're much faster than simple Super Missiles.

The whole distance scale is much grater than anything considered in Spaceships.

Of course, said scale you've got to represent the travel time of the missiles, fast as it is, because it's an important aspect of the tactics.

[Fred Brackin]

Originally Posted by Ulzgoroth

Of course, said scale you've got to represent the travel time of the missiles, fast as it is, because it's an important aspect of the tactics.

No that just determines the range. The travel time is less than a Spaceships Turn at anything like that distance. It's only 3-4 minutes in RW terms.

Missile volley/missile volley s the right structure for Honorverse ship combat.