David Weber wrote: Page 13 of finding the torch wormhole's destination"A junction is usually considerably more than 5,000 km across (I think 300,000 qualifies as “considerably more than” 5,000. [G]). Each individual transit lane within a junction/terminus is much smaller than the total volume of the junction, however, and the final size of the transit lane depends on a whole bunch of factors we won’t go into right now. As a general rule of thumb, the “bigger” the junction (i.e., the greater the number of termini, the higher the max tonnage limit, etc.) the wider the junction as a whole is going to be, but the narrower the individual lanes are going to be and the futher into n-space the grav wave of each terminus is going to extend.
Because of the sheer forces involved in transiting a terminus of any type, the maneuver must be executed at a very low velocity and with minmal helm and acceleration changes. Transit speeds are higher for lighter ships (i.e., those with smaller hyper generators producing areas of effect with smaller radii).
If you look at the transits which have been described in the Honorverse, you will find that they have to be made on a very tightly and precisely controlled vector, which is why the transits made in ART without “local pilots” are possible only because the RMN (courtesy in no small part of the Manticoran merchant marine) has very, very good charts on the termini in question. Moreover, a terminus gravity wave is (1) much weaker than a “normal” h-space gravity wave (indeed, little more powerful than an impeller wedge) and (2) not of uniform power throughout its entire area of effect. The first point means that the wave’s “inertial sump” is no deeper than for an impeller wedge and the second point means that there are sharp gradients — effectively, fluctuations — throughout it’s “length,” and those two points in connection mean that the maximum possible acceleration is only about 50% of a ship’s max acceleration under impeller drive (i.e., about 210 gravities for most people’s SDs and about 286 gravities for a current generation Alliance SD). That, however, is the maximum safe acceleration for a typical single terminus “junction,” and the safe acceleration rate drops rather steeply as the number of termini go up, just as the maximum safe transit velocity is lower for a multi-terminus junction’s termini.
Without getting into all the gory details, the MWHJ is about 300,000 km across, and the Mantcore Astro Control Service currently has to handle six incoming and outgoing transit lanes. The good news is that the transit lanes are all separate from one another and that Junction ACS doesn’t have to worry about the vectors of ships leaving Manticore once they make transit. That is, they only have to “catch” the inbound ships and keep the space along their entry route clear. Each actual transit lane is around 9,000 km “across,” has a maximum safe transit “speed limit” of about 20 KPS, a maximum safe acceleration rate of about 60 gravities (for an SD), and extends about 26,000 km into the Junction. And any ship making transit must maintain profile within that transit lane until it clears its far end (i.e., an average of 26,000 km from the arrival threshhold). That means an SD trainsiting the Junction will arrive at a speed of 20 KPS and require 278 seconds (just over 4.5 minutes) to clear the lane, at which point it will be traveling at 175 KPS. Until it clears the lane, it cannot reconfigure to impeller wedge, but there is no limit (aside from simple physical volume constraints and the “reset” time) as to how many ships can be “in the lane” simultaneously. Since JACS imposes a minimum 20 second window for normal transits, there could be no more than 14 or so “in the lane” at any given moment, but we’re talking about SDs here, each of which destabilized the terminus for 113 seconds, which means there can be only two of them in the lane at any given moment.
This means each SD will be forced to leave its wedge and sidewalls down for the better part of 5 minutes, during which it must maintain a steady course and cannot fire impeller drive missiles, and is confined within a 9,000 km-wide “tube.” A despatch boat’s maximum safe transit speed is almost 50 KPS, however, and its max safe acceleration is around 200 gravities, so it could clear the lane in only 2 minutes and 19 seconds. Other ships would lie on a curve between the two extremes, depending upon their tonnages. And for single termini, where the wave is both shorter and less intense, the numbers would be much lower (hence the minimum 20 second number I believe I mentioned earlier, although that is an absolute minimum — for a despatch boat — under ideal conditions on a very “weak” terminus).
This, by the way, is a very siginificant point in the RMN’s decision to use Saganami-Cs and Rolands as its point units in seizing termini under Lacoön Two; they can get in a heck of a lot faster than even a Manty SD, they can put more of them through in the same time interval, and they have the range and the punch to take out even much heavier units once they’re into n-space on the other side. If they were going up against fortified termini which they are not in Lacoön, those CAs would be dead meat before they ever cleared the lanes . . . and anyone trying to take the termini back from them faces exactly the same constraints. This is a fundamental, underlying considertation which led the RMN to formulate Lacoön in the first place as a rapid, inexpensive way to seize control of the wormhole networks while making it extremely costly for anyone to take them back again. It is symptomatic of the changes in the conceptualization of interstellar warfighting doctrine that Manticore had figured this out while the SLN was still thinking in terms of ponderous, unstoppable advances through hyper-space. The notion of attacking through the MWHJ to support Fillareta was another example of how far behind the curve the SLN was in adjusting to the new realities; it was thinking of the MWHJ in the same way that it thought about its own termini’s defenses (or lack thereof) despite the fact that ONI knew (and had warned the mission planners) that the MWHJ was a whole different kind of animal.
The key point here for defensbility with mines and/or missile pods, however, is that the defender knows what the transit lanes are and can pretty much encase them in a cylinder of mines (or missile pods) as dense as it wants to make them and as long as the lane. Before the laser head, “boom or burn” warheads already had a standoff range of well over 9,000 km; first generation laserheads had standoff ranges of 30,000 km against active sidewalls and would make mincemeat out of bare alloy at 9,000 km (4,500, actually, since the entire lane is only 9,000 km across). The missile would never have to enter the gravity wave “tube” to attack, which means missile pods would work just fine in terminus defense, thank you.
And as far as “Mines would be the best solution against a mass tranist, and I have a solution that aparently DW hasn't thought of: slightly expand the sensors and programming on the mines. If the mines detect a mass transit, and the IFF does not respond correctly, blow the mass transit away” is concerned, that’s exactly what mines do . . . in wartime. Forts are to cover the termini in peacetime where a little computer glitch or hardward malfunction could have fairly significant consequences. This is what I’ve been describing from the very first book, so I’m a little at a loss to understand why “apparently DW hasn’t thought” of it.
As for assaults through properly defended termini under wartime conditions are concerned, however, the old cliché about “fshooting fish in a barrel” (in this case, almost literally) comes rather forcibly to mind.
