Attacking Darius:

ThinksMarkedly wrote:

Relax wrote: For super close in shots, Initial velocity is just as important as high acceleration in terms of distance. So, if super worried about close in shots, seems increasing Initial Velocity from your missile tube is very important. Since we have all been looking at MDM combat, initial velocity as a requirement of ship design has disappeared, but in the age of Spider ships, and close in combat, or at least the prospect of close in combat, initial velocity once again becomes VERY important. Of course acceleration is ultra important for vector control of said missiles. We have to assume a missile cannot be fired off vector of pure broadside. Maybe one can change orientation from pure normal/perpendicular to broadside by a couple degrees, but more than this? Seems improbable.

Unless it's a spinal rail launcher, physics are going to get in the way. Even if your rail launcher could impart 10 million gravities of acceleration and your broadside launchers were 100 m in length, the missile would come out of the tube at a mere 140 km/s. Even one billion gravities would only bring it up to 1400 km/s.

140 km/s plus 10 seconds of one million gravities of acceleration results in a delta-v of 98207 km/s (0.32c) and a range of 491732 km. That means the launching ship can't fire if the target is over 520,000 km away.

The only way to make this work is if the launching ship's base velocity towards the target is already very high. If said ship has a radial velocity vector towards its targets of 0.1c, the range increases to 790,332 km, which starts to put it outside of energy range. Except that it's moving towards the target at 0.1c, so it will be in energy range in 3 to 5 seconds... so why fire missiles 3 seconds early and advertise you're there?

Another simple calculation: for regular anti-ship missiles, their two modes have an easy relationship: double the acceleration and it lasts one third of the time. A CM lasts 75 seconds, so if we get a third of a third of that time (8⅓ seconds), we should see the acceleration maybe quadruple. The Cataphract CM stage is said to have an acceleration of under 100,000 gravities, so quadrupling it only puts at 400,000. They'd need to start with a CM that already has a quarter million gravity of acceleration to get there.

EDIT: fixed "tangential" with "radial"

cthia wrote:That's the gist of what I was saying! Thank you Relax, for polishing, publishing, and validating the notion!

I was going to suggest that an intensely focused and directed tube of gravity could be used to launch the missile. Since gravity seems to have more uses than duct tape in the HV. Giving us a gravity launched missile from the LD. Dunno whether each pulse of gravity would be detected, or if there is a way to mask it. All in all, I guess that would be a gravity-powered rail gun.

But I suppose a launch tube pumping out that much gravity would require as much handwavium as the missile itself.

Loren Pechtel wrote:Big practical problem: The human body isn't capable of actually breathing liquid. There are liquids that probably could provide the O2/CO2 exchange, but the lungs aren't strong enough to pump it. I haven't heard whether the lungs could survive it being pumped in and out but I certainly wouldn't want to count on that being survivable.

Relax wrote:

cthia wrote:That's the gist of what I was saying! Thank you Relax, for polishing, publishing, and validating the notion!

I was going to suggest that an intensely focused and directed tube of gravity could be used to launch the missile. Since gravity seems to have more uses than duct tape in the HV. Giving us a gravity launched missile from the LD. Dunno whether each pulse of gravity would be detected, or if there is a way to mask it. All in all, I guess that would be a gravity-powered rail gun.

But I suppose a launch tube pumping out that much gravity would require as much handwavium as the missile itself.

Sorry, I did not validate it at all as that would require math. Thinksmarkedly did so if you wish to look at validification. I remember doing said math many years ago and the accelerations are stupendous just for the normal missile firing. So... The math is not hard, go for it.

Joat42 wrote:

Loren Pechtel wrote:Big practical problem: The human body isn't capable of actually breathing liquid. There are liquids that probably could provide the O2/CO2 exchange, but the lungs aren't strong enough to pump it. I haven't heard whether the lungs could survive it being pumped in and out but I certainly wouldn't want to count on that being survivable.

What I've read about the subject is that any practical liquid breathing solution would necessitate a mechanical ventilator.

There have been animal experiments using PFCs (perfluorocarbons) that shows it's entirely survivable with no real harmful side-effects.

I would say that liquid breathing in Honorverse is something that should be practical since it has the theoretical advantage of 2 millennia of research.

cthia wrote:I was going to suggest that an intensely focused and directed tube of gravity could be used to launch the missile. Since gravity seems to have more uses than duct tape in the HV. Giving us a gravity launched missile from the LD. Dunno whether each pulse of gravity would be detected, or if there is a way to mask it. All in all, I guess that would be a gravity-powered rail gun.

But I suppose a launch tube pumping out that much gravity would require as much handwavium as the missile itself.

Broadside missile tubes incorporated powerful mass drivers to get the weapon outside the warship's wedge quickly, and, in theory, a vertical launcher could have used a mass driver with an internally curved path to throw a missile out a top-mounted tube at an angle which would clear the wedge. In practice, it was impossible to align the missile flight path precisely enough with a sidewall gunport, and the additional mass required by the longer, curved mass driver was prohibitive, and efforts to devise "swim out" missiles which dispensed with mass drivers and relied on conventional thrusters for their initial acceleration proved universally disappointing.

runsforcelery wrote:First, missile acceleration at launch. Missile acceleration at launch is designed to get them clear of the firing ship's wedge and of one another as rapidly as possible. Missiles are launched on diverging tracks to get separation before they bring their wedges up. They are fired through sidewall "gunports" which open in the sidewall just long enough for the missile to pass through. Those gunports are at least 10KM from the side of the ship and the physical launcher is "connected" to the sidewall by what is, in effect, an extended grav driver which helps push the missiles' velocity upward. They are fired in a single salvo instead of being staggered because it allows the gunports to be opened and closed simultaneously, thus imposing a briefer window of vulnerability in which a Bad Thing Incoming is going to find a hole.

tlb wrote:

cthia wrote:I was going to suggest that an intensely focused and directed tube of gravity could be used to launch the missile. Since gravity seems to have more uses than duct tape in the HV. Giving us a gravity launched missile from the LD. Dunno whether each pulse of gravity would be detected, or if there is a way to mask it. All in all, I guess that would be a gravity-powered rail gun.

But I suppose a launch tube pumping out that much gravity would require as much handwavium as the missile itself.

I do not know if the differences between a mass driver and a gravity tube are ever explained, there may be none. There is a maximum acceleration to which missile components can be subjected (I do not know what that value is). There is a compensator effect built into missiles to protect their workings from the acceleration produced by their wedges. That means that there is a maximum acceleration that the tube can impart and since the tube is not much longer than the missile, there is a maximum starting velocity that can be imparted. In a ship with a wedge, there is an additional acceleration until the missile passes the sidewall. Here are some discussions of both:

The Short Victorious War, "Honor Harrington's Navy" chapter 34:

Broadside missile tubes incorporated powerful mass drivers to get the weapon outside the warship's wedge quickly, and, in theory, a vertical launcher could have used a mass driver with an internally curved path to throw a missile out a top-mounted tube at an angle which would clear the wedge. In practice, it was impossible to align the missile flight path precisely enough with a sidewall gunport, and the additional mass required by the longer, curved mass driver was prohibitive, and efforts to devise "swim out" missiles which dispensed with mass drivers and relied on conventional thrusters for their initial acceleration proved universally disappointing.

runsforcelery wrote:First, missile acceleration at launch. Missile acceleration at launch is designed to get them clear of the firing ship's wedge and of one another as rapidly as possible. Missiles are launched on diverging tracks to get separation before they bring their wedges up. They are fired through sidewall "gunports" which open in the sidewall just long enough for the missile to pass through. Those gunports are at least 10KM from the side of the ship and the physical launcher is "connected" to the sidewall by what is, in effect, an extended grav driver which helps push the missiles' velocity upward. They are fired in a single salvo instead of being staggered because it allows the gunports to be opened and closed simultaneously, thus imposing a briefer window of vulnerability in which a Bad Thing Incoming is going to find a hole.

Location of RFC quote:
LAC not so useful after all?

cthia wrote:I was going to suggest that an intensely focused and directed tube of gravity could be used to launch the missile. Since gravity seems to have more uses than duct tape in the HV. Giving us a gravity launched missile from the LD. Dunno whether each pulse of gravity would be detected, or if there is a way to mask it. All in all, I guess that would be a gravity-powered rail gun.

tlb wrote:

cthia wrote:But I imagine inside energy range would be considered as absurdly short. But there does appear to be a chance for detection by RDs. I was wrong about that. Unless the Spider can keep its most stealthy face forward of the RD while inside those absurdly short ranges; which may be possible for a Spider that can move in eerie ways. Maybe not move quickly, but well enough.

Also consider that the GA will not have the MA's specially designed sensors.

Consider that the Grand Alliance did see Galton's stealthiest drones. Also that the GA can flood the zone of interest with Ghost Rider drones, so a surrounded spider drive ship does not have the option of keeping "its most stealthy face" toward every drone.

Jonathan_S wrote:

kzt wrote:In terms of penetrating bubble fields, well, we have never heard anything more detailed than:
1) they exist
2) You can use then in grav waves (How this works??)
3) They are very large, and are a problem to fit even when you are dealing with a massive ship that has lots of space.
4) Forts have them.
5) The destroyed stations had them.
7) They are extremely rare outside of forts and military stations.
6) It's perfectly feasible to fit them on a LD.

How effective they are is very unclear. How effective they are compared to a sidewall is very unclear. How big the field is or can be is unclear.

For that matter, how effective a sidewall is against a CA class graser vs a CA class x-ray head is not at all clear.

Jonathan_S wrote:8) An LD's spider drive wouldn't be able to operate through them.
9) [bonus fun fact] Manticore can't generate a sidewall bubble around a moon eight thousand kilometers in diameter [HotQ]

cthia wrote:Since historically subs have been known to operate in Wolfpacks, and since the LDs may also use that tactic, is there a reason that two or more LDs can't form up as close as possible to each other like two cowboys standing back to back?

They could enjoy mutual support: Which for an LD would include CM support. And stealth support, since a certain face of an LD is less stealthy to a passing drone.

Spiders should be able to get very close to each other since they don't have the same limitation of proximity imposed by a wedge.

This invokes the scary image of a nest of Spiders all intertwined together. "OMG! GET 'EM OFF ME!"


P.S. Are we sure that Galton would have the stealthiest drones?