"Obsolete SDs" Waste not...

munroburton wrote:They have four-drive system defense missiles for this exact reason. Three drives are enough to get a missile up to the limits of particle shielding. Even moons around gas giants(eg. Callisto orbits Jupiter at ~1.9m km) can burn a whole drive stage to get around the planet if need be. Plus they can coast between drives, so range is essentially unlimited.

Those were the Apollo system defense missiles, which they hadn't deployed despite how they could be run by their current fire control because reasons.

kzt wrote:

munroburton wrote:They have four-drive system defense missiles for this exact reason. Three drives are enough to get a missile up to the limits of particle shielding. Even moons around gas giants(eg. Callisto orbits Jupiter at ~1.9m km) can burn a whole drive stage to get around the planet if need be. Plus they can coast between drives, so range is essentially unlimited.

Those were the Apollo system defense missiles, which they hadn't deployed despite how they could be run by their current fire control because reasons.

Crazy wacky fun! ... So you launch them a half hour before the invading ship makes turnover so it can intercept it at turnover? Even with Keyhole Two that's extraordinarily ... complicated.

Even the original 3-drive missiles had a continiously-powered range of about 65 million km. That makes the distances between a planet and its moon(s) negligible.

Heck, it was something done back in SDM days. Remember Cerberus' moons and their fixed launchers? That was before MDMs or FTL coms came along. Note: I'm not saying Manticore should have surface-based launchers on its inhabited planets' moons, but to stick the pods in orbit of them.

That allows them to engage without exposing Hephaestus etc. to counter-fire.

I was kind of hoping that was implied by the point that the volume concerned is some 10000x larger than the one you considered - with proportional increases in all your numbers. Even if there were a way to get the stuff out there, you'd probably have to grind up another SD to get the material to create an effective defense. ummmm... err... nope! AAMOF, one Scientist gives you 229mg/cubic km. Not quite astrophysical densities, though: it's still in the neighbourhood of a million atoms per cubic centimetre, and most objects out there are 1000 or less.

MaxxQ wrote:< snip >

Doesn't negate my point though - that's way too much volume to try to cover, even with pinpoint aiming due to being able to detect the wedges of the incoming missiles. Firing a ballistic bullet at a missile from a couple million km away when the missile is only a few cubic meters in volume - even if the damn thing explodes into 1000 fragments - and expecting ANY kind of hit, is just pure opium dream.

I still don't see how a missile can hit anything. Missile wedge is too big, missile travels too fast, wedge gaps are too small and the missiles are only in firing arc for a fraction of a second. The ship is moving, To fire up a wedge gap the missile has to turn without flying into the ship wedge. The size of the missile wedge means it can't get enough missiles within the firing range to burn through the sidewalls....

Lord Skimper wrote:I still don't see how a missile can hit anything. Missile wedge is too big, missile travels too fast, wedge gaps are too small and the missiles are only in firing arc for a fraction of a second. The ship is moving, To fire up a wedge gap the missile has to turn without flying into the ship wedge. The size of the missile wedge means it can't get enough missiles within the firing range to burn through the sidewalls....

Um, a wedge stretched no more than 150 km out from the side of a ship. A laserhead detonates at 30,000 - 50,000 km out from the side of a ship.

Do you see how it works now?

Jonathan_S wrote:

Lord Skimper wrote:I still don't see how a missile can hit anything. Missile wedge is too big, missile travels too fast, wedge gaps are too small and the missiles are only in firing arc for a fraction of a second. The ship is moving, To fire up a wedge gap the missile has to turn without flying into the ship wedge. The size of the missile wedge means it can't get enough missiles within the firing range to burn through the sidewalls....

Um, a wedge stretched no more than 150 km out from the side of a ship. A laserhead detonates at 30,000 - 50,000 km out from the side of a ship.

Do you see how it works now?

Or watch this: https://youtu.be/byq68MjOlJU

The video is a bit simplified, as it was one of my first videos, and I don't know how to do a lot of the things that were needed to show a better attack sequence.

Let's see if I can explain it in a way you can understand.

1. Missile launch
2. Powered flight sequence towards target (for DDM and MDM missiles, there may or may not be a coast phase between drive (wedge) initiation)
3. At a certain amount of time before detonation, the wedge shuts down to allow attitude adjustment of the entire missile - this is to point the nose of the missile more or less in the direction of the target. If the missile is coming in from the side of the target, but trying for a throat or kilt shot, this means the missile is now travelling sideways. If attempting to burn through the sidewalls, then very little adjustment is required.
4. Protective shrouds ejected
5. Laserhead release
6. Laserheads, using built in RCS, move forward approximately 150 meters, while also attempting final, more precise, targeting.
7. Warhead (still back on the missile) detonation (between 30,000 and 50,000 km from target). Grav lenses built into the missile behind the warhead focus as much X-Ray energy from the warhead detonation as possible forward towards the laserheads.
8. X-Ray wavefront reaches the laserheads milliseconds before the blast, and the X-Ray energy is focussed onto the lasing rod using a Wolter Mirror-style reflector.
9. Lasing rod releases it's energy at the target.
10. Laserheads destroyed by nuclear warhead blast front.

Steps 3-6 occur over just a few seconds. Steps 7-10 take just a few milliseconds or less (I'll let someone else do the exact math, if they feel it's necessary).

IOW, the missile gets nowhere near the target, unless you're talking about the old "boom" and "burn" missiles. In that case, a missile wedge is only about 5 km on a side, and just a couple km above and below the missile.

A sidewall is 10km from the side of a ship, which means the gap is 20 km wide, and around 40-60 km high for a throat shot (depending on the target), and maybe 20-30km for the kilt (I don't recall the specifics, but I think I gave distances and sizes of wedges in another thread).

Keep in mind, back in the boom and burn days, accelerations were much lower than in the era of the laserhead. Yes, it's difficult to precisely target something at the current accels, but that's what fire control computers are for, or, in the case of Apollo, the control missile with ITS fire control computers.

In any case, the computers make sure that the maneuvers occurring in the last few seconds allow for relative motion of the target and the missile, just like a duck hunter (no offense Duckk ) leading a flying duck, or how the targeting computers on an M-61 battle tank can stay on a moving target even while moving over rough ground itself.

MaxxQ wrote:...
Let's see if I can explain it in a way you can understand.

1. Missile launch
2. Powered flight sequence towards target (for DDM and MDM missiles, there may or may not be a coast phase between drive (wedge) initiation)
3. At a certain amount of time before detonation, the wedge shuts down to allow attitude adjustment of the entire missile - this is to point the nose of the missile more or less in the direction of the target. If the missile is coming in from the side of the target, but trying for a throat or kilt shot, this means the missile is now travelling sideways. If attempting to burn through the sidewalls, then very little adjustment is required.
4. Protective shrouds ejected
5. Laserhead release
6. Laserheads, using built in RCS, move forward approximately 150 meters, while also attempting final, more precise, targeting.
7. Warhead (still back on the missile) detonation (between 30,000 and 50,000 km from target). Grav lenses built into the missile behind the warhead focus as much X-Ray energy from the warhead detonation as possible forward towards the laserheads.
8. X-Ray wavefront reaches the laserheads milliseconds before the blast, and the X-Ray energy is focussed onto the lasing rod using a Wolter Mirror-style reflector.
9. Lasing rod releases it's energy at the target.
10. Laserheads destroyed by nuclear warhead blast front.

Steps 3-6 occur over just a few seconds. Steps 7-10 take just a few milliseconds or less (I'll let someone else do the exact math, if they feel it's necessary).

This sequence raises a big question I always had about laser heads. If steps 3-6 take a few seconds, light speed roundtrip time at 50000 km is less than 350ms. So the target has quite a bit of time to deploy point defense laser clusters on a non-maneuvering target that is not protected by a wedge. So if laser heads work this way it is a wonder they can hit anything at all.

There would also be no blast effects in a vacuum.

drinksmuchcoffee wrote:There would also be no blast effects in a vacuum.

There would be a pretty big energy release though, remember that bomb-pumped lasers are a pretty real concept.

The E wrote:

drinksmuchcoffee wrote:There would also be no blast effects in a vacuum.

There would be a pretty big energy release though, remember that bomb-pumped lasers are a pretty real concept.

Indeed they are. In the Honorverse those lasers, bomb-pumped or shipboard release enough energy that they don't just heat up a spot like today's do. The descriptions I've read say that the energy released striking a target is very similar to a kinetic strike, it doesn't "burn" or "melt" through the target, it smashes through it like a tank's penetrator round of sufficient size might.