Honorverse ramblings and musings

kzt wrote:Someone at NASA once posted something saying that the atmosphere of earth had about the same resistance to either X-rays or gamma rays as several meters of aluminum. Your spot size is going to be huge, with the weapon essentially becoming an area weapon as the ionizing radiation scattered off the beam will kill things through radiation poisoning that are quite a ways from the target point.

Optical lasers are a far better choice if you want to precisesly hit things inside the atmosphere, but it doesn't appear the Manticore has these in service.

It looks like various KEW packages are the weapons of choice for hitting things from orbit precisely and with impacts over a range with a modest minimum value. These considerations are likely why energy weapons aren't go-to tools for that, and starship missiles are going to be a bit extreme much of the time.

JeffEngel wrote:

kzt wrote:Someone at NASA once posted something saying that the atmosphere of earth had about the same resistance to either X-rays or gamma rays as several meters of aluminum. Your spot size is going to be huge, with the weapon essentially becoming an area weapon as the ionizing radiation scattered off the beam will kill things through radiation poisoning that are quite a ways from the target point.

Optical lasers are a far better choice if you want to precisesly hit things inside the atmosphere, but it doesn't appear the Manticore has these in service.

It looks like various KEW packages are the weapons of choice for hitting things from orbit precisely and with impacts over a range with a modest minimum value. These considerations are likely why energy weapons aren't go-to tools for that, and starship missiles are going to be a bit extreme much of the time.

I didn't consider the radiation poisoning but just the problem of dispersal, which I thought would be standard computer calculated kill zones.

It just seems odd that a ship-to-ground based laser system isn't standard tech on Honorverse ships. If SDI can accomplish it now (we know it's up there lol) it seems inevitable that it would be standard issue on a ship like Fearless for special case mission-critical ground support. It seems the tech would even be more practical and precise than the current weapons used - like the KEWS. And it'd occupy negligible space on a ship of the wall compared to graser spinal mounts. Sonja gutted Fearless to make room for the nameless weapon, but she could have included a few optical weapons (just in case) which would have been perfect timing. The tech must exist, why it isn't used is beyond me.

Does textev state the standard type orbit of Honorverse ships? Has there ever been a case of a more energetic orbit, spending lots of reaction mass in a tactical attempt to obtain as much of a geostationary orbit as possible with a ground based target?

cthia wrote:It just seems odd that a ship-to-ground based laser system isn't standard tech on Honorverse ships. If SDI can accomplish it now (we know it's up there lol) it seems inevitable that it would be standard issue on a ship like Fearless for special case mission-critical ground support. It seems the tech would even be more practical and precise than the current weapons used - like the KEWS. And it'd occupy negligible space on a ship of the wall compared to graser spinal mounts. Sonja gutted Fearless to make room for the nameless weapon, but she could have included a few optical weapons (just in case) which would have been perfect timing. The tech must exist, why it isn't used is beyond me.

Does textev state the standard type orbit of Honorverse ships? Has there ever been a case of a more energetic orbit, spending lots of reaction mass in a tactical attempt to obtain as much of a geostationary orbit as possible with a ground based target?

Even optical lasers are subject to uncertainty and significant power loss from thermal blooming and the associated atmospheric distortions.

The (canceld) YAL-1 Airborn Laser fired an (IIRC) megawatt chemical laser at IRBMs in the boost phase. But even so it had to fire very brief pulses and at higher altitude where the air was thinner. Trying to fire at the ground involves much more atmospheric interference.


The standard orbit for Honorverse ships hasn't been, that I recall, specified. But if you wanted to hold position over a given target at less that geostationary height ~36,000 km, you could definitely do so. If there wasn't anything else in orbit (and you were willing to stay more than 200-ish km clear of the atmosphere) you could do so almost indefinitely using your wedge. But that'd be really hard on them if there were any low orbit satellites
But if willing to spend the fuel you could use reaction thrusters to do so for a while - you'd need way less power than Honor's insane charge at Cerberus.

Jonathan_S wrote:

cthia wrote:It just seems odd that a ship-to-ground based laser system isn't standard tech on Honorverse ships. If SDI can accomplish it now (we know it's up there lol) it seems inevitable that it would be standard issue on a ship like Fearless for special case mission-critical ground support. It seems the tech would even be more practical and precise than the current weapons used - like the KEWS. And it'd occupy negligible space on a ship of the wall compared to graser spinal mounts. Sonja gutted Fearless to make room for the nameless weapon, but she could have included a few optical weapons (just in case) which would have been perfect timing. The tech must exist, why it isn't used is beyond me.

Does textev state the standard type orbit of Honorverse ships? Has there ever been a case of a more energetic orbit, spending lots of reaction mass in a tactical attempt to obtain as much of a geostationary orbit as possible with a ground based target?

Even optical lasers are subject to uncertainty and significant power loss from thermal blooming and the associated atmospheric distortions.

The (canceld) YAL-1 Airborn Laser fired an (IIRC) megawatt chemical laser at IRBMs in the boost phase. But even so it had to fire very brief pulses and at higher altitude where the air was thinner. Trying to fire at the ground involves much more atmospheric interference.


The standard orbit for Honorverse ships hasn't been, that I recall, specified. But if you wanted to hold position over a given target at less that geostationary height ~36,000 km, you could definitely do so. If there wasn't anything else in orbit (and you were willing to stay more than 200-ish km clear of the atmosphere) you could do so almost indefinitely using your wedge. But that'd be really hard on them if there were any low orbit satellites
But if willing to spend the fuel you could use reaction thrusters to do so for a while - you'd need way less power than Honor's insane charge at Cerberus.

What would they realistically use for station keeping?

Jonathan_S wrote:

cthia wrote:It just seems odd that a ship-to-ground based laser system isn't standard tech on Honorverse ships. If SDI can accomplish it now (we know it's up there lol) it seems inevitable that it would be standard issue on a ship like Fearless for special case mission-critical ground support. It seems the tech would even be more practical and precise than the current weapons used - like the KEWS. And it'd occupy negligible space on a ship of the wall compared to graser spinal mounts. Sonja gutted Fearless to make room for the nameless weapon, but she could have included a few optical weapons (just in case) which would have been perfect timing. The tech must exist, why it isn't used is beyond me.

Does textev state the standard type orbit of Honorverse ships? Has there ever been a case of a more energetic orbit, spending lots of reaction mass in a tactical attempt to obtain as much of a geostationary orbit as possible with a ground based target?

Even optical lasers are subject to uncertainty and significant power loss from thermal blooming and the associated atmospheric distortions.

The (canceld) YAL-1 Airborn Laser fired an (IIRC) megawatt chemical laser at IRBMs in the boost phase. But even so it had to fire very brief pulses and at higher altitude where the air was thinner. Trying to fire at the ground involves much more atmospheric interference.


The standard orbit for Honorverse ships hasn't been, that I recall, specified. But if you wanted to hold position over a given target at less that geostationary height ~36,000 km, you could definitely do so. If there wasn't anything else in orbit (and you were willing to stay more than 200-ish km clear of the atmosphere) you could do so almost indefinitely using your wedge. But that'd be really hard on them if there were any low orbit satellites
But if willing to spend the fuel you could use reaction thrusters to do so for a while - you'd need way less power than Honor's insane charge at Cerberus.

IIRC Standard orbital spacing in the Honorverse puts ~5000Km between ships for wedge clearance. Assume the same would between the ship and the planet.

As for holding the ship in place over any point, yeah - it would only take ~1 G of thrust (depending on the planet).

At All Costs

Second Fleet's brutally winnowed ranks continued onward, but its acceleration had been reduced to less than 2.5 KPS2 by its cripples. At that rate, it would be unable to decelerate for its zero/zero intercept with Sphinx, and the Manticoran System's defenders weren't done with it yet.

This is Tourville's fleet. I don't understand, why can't he make a zero/zero intercept? So his accel is less than 2.5 KPS^2, is it because of the now extended time it would take to achieve the intercept while bloodthirsty enemy LACs are bearing down on him, or because of the time it would take to get back under way? Or one and the same?

Zero/Zero intercept. Couldn't find a formal explanation of this. From what I have gathered and understand, it is just a matter of matching velocity with the planet. Which, in the case of the planet is just obtaining orbit I suppose. But then there are times, IIRC, there's talk of achieving zero/zero intercept with an enemy fleet. How is this achieved?

I know it involves flipping end on end but delta-V isn't instantaneous. Is it just a matter of calculating the point in which to begin decelerating with respect to an enemy fleet's max accel?

Also, the mechanics of deceleration are a bit unclear to me. How long does it take to completely flip? During the flip, why isn't the vector of a ship altered in the varying arc of the wedge, since the wedge cannot be shut down for the duration of the flip?

cthia wrote:At All Costs

Second Fleet's brutally winnowed ranks continued onward, but its acceleration had been reduced to less than 2.5 KPS2 by its cripples. At that rate, it would be unable to decelerate for its zero/zero intercept with Sphinx, and the Manticoran System's defenders weren't done with it yet.

This is Tourville's fleet. I don't understand, why can't he make a zero/zero intercept? So his accel is less than 2.5 KPS^2, is it because of the now extended time it would take to achieve the intercept while bloodthirsty enemy LACs are bearing down on him, or because of the time it would take to get back under way? Or one and the same?

Second Fleet was no longer able to kill enough of its current velocity to match velocity with Sphinx at (practically) zero range.

To get somewhere in a start system - normally, in a hurry, without anything making it hinky - you accelerate as much as you are willing and able half way there, flip, and decelerate the rest of the way. "There" is the point your destination will be at, given its movement, by the time you will have arrived given your acceleration and deceleration. Your velocity when you started is one thing that will normally make the trip a little hinkier.

In this case, Second Fleet's damage introduced the hinkiness: they no longer could decelerate fast enough to lose the velocity they'd built up on the way to Sphinx, so they were not going to make that rendezvous. Bloodthirsty LAC's had no special role to play in that itinerary. (Mind you, they would have plenty of role to play in what would happen along the way.)

Zero/Zero intercept. Couldn't find a formal explanation of this. From what I have gathered and understand, it is just a matter of matching velocity with the planet. Which, in the case of the planet is just obtaining orbit I suppose. But then there are times, IIRC, there's talk of achieving zero/zero intercept with an enemy fleet. How is this achieved?

Planets move, fleets move. Fleets move less predictably - they've got not just orbital mechanics behind their movements, but impellers and officers making decisions about how to use them. But, if you've got a decent prediction to make about where the enemy wants to be and what they have for acceleration to get them there, you can work out a plot for what accelerations in what directions you would need to get to some place very near that fleet going the same direction at the same speed.

I know it involves flipping end on end but delta-V isn't instantaneous. Is it just a matter of calculating the point in which to begin decelerating with respect to an enemy fleet's max accel?

Sorta. Depending on how the other party is maneuvering, you may be accelerating all the way to match vectors with them at trivial range.

Also, the mechanics of deceleration are a bit unclear to me. How long does it take to completely flip? During the flip, why isn't the vector of a ship altered in the varying arc of the wedge, since the wedge cannot be shut down for the duration of the flip?

Punting that one to someone else.

Snipping this interleaved post fairly heavily.

JeffEngel wrote:

cthia wrote:At All Costs
*****quote*****
Second Fleet's brutally winnowed ranks continued onward, but its acceleration had been reduced to less than 2.5 KPS2 by its cripples. At that rate, it would be unable to decelerate for its zero/zero intercept with Sphinx, and the Manticoran System's defenders weren't done with it yet.
***************

This is Tourville's fleet. I don't understand, why can't he make a zero/zero intercept? So his accel is less than 2.5 KPS^2, is it because of the now extended time it would take to achieve the intercept while bloodthirsty enemy LACs are bearing down on him, or because of the time it would take to get back under way? Or one and the same?

Second Fleet was no longer able to kill enough of its current velocity to match velocity with Sphinx at (practically) zero range.

To get somewhere in a start system - normally, in a hurry, without anything making it hinky - you accelerate as much as you are willing and able half way there, flip, and decelerate the rest of the way. "There" is the point your destination will be at, given its movement, by the time you will have arrived given your acceleration and deceleration. Your velocity when you started is one thing that will normally make the trip a little hinkier.

In this case, Second Fleet's damage introduced the hinkiness: they no longer could decelerate fast enough to lose the velocity they'd built up on the way to Sphinx, so they were not going to make that rendezvous. Bloodthirsty LAC's had no special role to play in that itinerary. (Mind you, they would have plenty of role to play in what would happen along the way.)

To expand slightly on this, I believe 2nd fleet was damaged after it had achieved turnover. And 2.5 KPS^2 is about 255 g - pretty damned anemic even for a Havenite SD(P).

Prior to the engagement with Home Fleet the RHN was coming in at "four-point-eight KPS-squared" (489g). If we assume they were crippled at the turnover point the reduced acceleration would cause them to slide past the planet at about 12,890 km/s. (Or to put it another way sliding to a stop 58.5 million km further than planned).

A rough calculation shows that if they get slowed to that accel any later than about 80% of the way towards their planned turnover they won't be able to scrub off the velocity in time to make a zero/zero intercept with the planet.

[Note for these rough calculations I ignore initial velocity or planetary motion; I'm just calculating straight line using the acceleration and planned turnover time numbers from AAC Ch64]

JeffEngel wrote:

cthia wrote:Also, the mechanics of deceleration are a bit unclear to me. How long does it take to completely flip? During the flip, why isn't the vector of a ship altered in the varying arc of the wedge, since the wedge cannot be shut down for the duration of the flip?

Punting that one to someone else.

There's an ancient (1998) infodump from RFC - Maneuver, combat and missiles that includes "The rate of turn for an impeller-drive ship outside a wall of battle is fairly high, although it is considerably higher for a smaller ship than for a larger one. A typical SKM DD can alter her heading (but not necessarily her vector, of course) by 90 degrees in about 100 seconds; an SD would need about twelve minutes for a 90-degree turn."

That would imply that you'd need 24 minutes to change heading by 180 degrees. But that seems an insanely long time and I'm not sure that time is reflected in the recent battle descriptions.

David's garbage barge turn speeds has never made any sense to anyone other then David.

kzt wrote:David's garbage barge turn speeds has never made any sense to anyone other then David.

Thanks Jeff, Johnathan. I was confused. I can see clearly on some aspects thanks to the two of you, but even more confused on others.

If it takes twenty four minutes for an SD to complete a 180 degree turn (and it not alter the vector in that time) how in the universe does it perform maneuvers like "They are breaking off the attack sir!" ?

Now I do remember text stating something akin to "Their plot is slowly crabbing away." I'd think it would be more like "snailing" away.

I suppose that although the wedge cannot be powered down during the turn, its strength is decreased as much as possible to explain the lack of vector change, but then that'd affect the rate of flip...

I give up.