HMLAC 113

cthia wrote:Theemile, this is a very nice explanation. I think I am beginning to see a little light.

What threw me off is when Scotty snuck in an old fashioned nuke against the Peeps. ISTR that Honor was surprised that he was able to do so, since point defense would assign a much higher threat index to the nuke. The nuke could be readily identified because it was so much larger which made it stand out like a sore thumb.

Because it was so much larger, I thought the warhead of an old-fashioned nuke had a much higher yield than a regular missile in boom mode.

Your post enlightened me to an even higher yield from a smaller warhead because of the "grav pinch" design.

But I didn't think the nuclear explosion that pumps the laser heads was as large as an explosion in boom mode. I assumed that the laser heads didn't need or could even use such a large nuclear explosion. Which implies that even a boom mode nuke has a smaller yield than possible.

Does this imply that a pure nuclear missile could be made to yield an even larger explosion? As in a very fat "fat man." Of course, that would put tactical back at trying to sneak a much larger missile in.

Actually the nuke isn't bigger. Nor can the target ship distinguish at long range which missiles carry nukes and which carry laser heads.
In fact when Honor was under fire at Basilisk she could only suspect what kind of warheads the Peeps had on Sirius's missiles.
[quote"On Basilisk Station"] Unless she missed her guess about the warheads those missiles carried, she had to stop them at least twenty thousand kilometers short of her ship, and they looked frighteningly close.
But none of them were getting closer than a hundred thousand . . . yet.
[...]
Honor flinched as Cardones finally missed an incoming missile. It darted in to twenty-two thousand kilometers; then it vanished in a brilliant eyeblink, and she bit her lip as her worst fears were confirmed. Sirius was using laser warheads, turning each missile into a remotely targeted cluster of bomb-pumped x-ray lasers.[/quote]

The reason it's hard to get hits with contact nukes isn't that ship's can ID them and prioritize them. (Though once the missile doesn't explode at laser head range it's likely either a nuke, a jammer, or a decoy); and so a missile that's still there to shoot at might be a nuke and that will push it up the priority list over those final thousands of km. But mostly it's that the closer the missile gets the easier a target it is

Short Victorious War: wrote:Because the chance of knocking a missile down increases geometrically in the last 50,000 or 60,000 kilometers of its run, as it steadies down on its final attack vector, direct hits against modern point defense are virtually unheard of.

And since the nuke has to close that extra 20, 30, or 50,000 km (depending on the generation of laser head) not only is it getting steadily easier to hit but it's also even more time in that point defense sweet spot zone.

And remember, when we're talking about single drive missiles their closing speeds are way lower; less than 0.17c; so we're talking about half a second or more to cover than final 20,000-ish km. Given the cyclic time on PDLCs that's a lot of extra shots they get on a nuke compared to a laser head.



As for warhead power
A laser head still mounts the most powerful nuke it can fit, because the more power it can direct into its lasing rods the more powerful the resulting lasers are. So with a multi-mode warhead like the CA/BC Mark 13 the RMN came up with in the late 1800s the nuclear explosion is going to be the same power whether the warhead is set for boom, burn, or lase mode.
However; with the same physical size of warhead you could make the nuke more powerful if you went with a pure boom design; simply because the extra grav generators you need to direct the blast for burn or lase, and the lasing rods themselves, take up space in the warhead. If you left them out you'd have that room available to instead squeeze in a more powerful nuke.

However the RMN generally views the flexibility to select the warhead mode on the fly, and potentially even after launch, as far more useful than having some slightly more powerful contact nukes; especially given how unlikely it is for a missile to get close enough to hit with the contact nuke.

cthia wrote:
Because it was so much larger, I thought the warhead of an old-fashioned nuke had a much higher yield than a regular missile in boom mode.

Your post enlightened me to an even higher yield from a smaller warhead because of the "grav pinch" design.

But I didn't think the nuclear explosion that pumps the laser heads was as large as an explosion in boom mode. I assumed that the laser heads didn't need or could even use such a large nuclear explosion. Which implies that even a boom mode nuke has a smaller yield than possible.

Does this imply that a pure nuclear missile could be made to yield an even larger explosion? As in a very fat "Fat Man." Of course, that would put tactical back at trying to sneak a much larger missile in.

.

Remember, we're discussing technology across 100 years of development time where huge strides in capability occured.

All missile nukes are Grav pinched. Over time, the grav pinch got better, and a bigger bang could be squezzed into a smaller space with less fuel.

Old Missiles used brute force to achieve their goals - "bigger warheads" (in the same missile bodies) were used and grav fields focused them on their targets so the boom wasn't a 360 degree cloud of explosion - but a focused pulse of energy aimed specifically at the target. Over time, the Plasma jet got more focused, and had a longer standoff - by the advent of the laserhead, the plasma jet had a standoff range of 10,000 KM

For the CL Fearless, a workable "all in one" warhead wasn't able to be produced - the missile body just was too small for the new design, so a larger DD/CL missile was used instead, the mk 34. The older missile was given a replacement warhead so it could have laserhead capability - but both the old boom/burn warhead and the Laserhead warhead used the same missile body and could be interchanged when needed, given time.

And over time the nuke in missile has gotten more powerful - in 190, a CA mk13 had a 10mton nuke - the Mk16 (which originally had the same warhead) carried a 40Mton nuke in the G Varient, and in boom mode, probably focused the explosion better on target than the warhead in the older Mk 13 did.

So in 1900 was the Nuke in the mk50s Boom/Burn warhead more powerful than the one in the Mk 34's All in one warhead - yes

But comparing the old Mk26 (in the LAC) against the Mk 36 LERM's warhead - they have more similiar "Boom modes", despite the smaller LERM nuke's physical size.

tlb wrote:Unlike Jonathan_S, I doubt that there are chemical backup processes that can supply power.

Well we don't know quite what they are - but we know from EoH that the Peep assault shuttle's Honor's crew stole had "emergency power converters" and that those are standard on at least Peep and RMN "lifeboats and shuttles". And

Echoes of Honor wrote:the Peeps who'd planned the equipment list for those shuttles had provided them with at least twice the thermal converter capability an equivalent Manticoran small craft would have boasted. Although the intention had probably been for the converters to provide power to recharge weapon power packs and other small items of personal gear, they also produced—barely—enough power to keep both shuttles' environmental plants on-line.

Whatever they were they were capable of providing power for the environmental plants for the 5 or 6 months they were on Hades; after which the shuttles still had enough power to start up their onboard fusion plants.

I'd be shocked if the starships didn't have similar types of emergency thermal converters which (presumably) turn chemical or other heat into power. But even if the starships don't their small craft and lifeboats would - and if those emergency power converters can run air conditioning for months they'd be able to eventually charge up the small craft's capacitors to the point it can bring it's laser confinement reactor online -- at which point you've got all the power you could need to get the ship's main reactors back online.

tlb wrote:

Jonathan_S wrote:So yeah, a wedge needs a steady input of power from the ship, normally it's reactors. And a larger surge to bring it up.
But you use the ship's reactor(s) to charge up the power you need to bring it up and then discharge to activate. You're not going to need a jumpstart because your capacitors discharged -- you'd just need to charge them back up from the reactor(s).

cthia wrote:It simply seems so self-serving, pardon the pun, that the siphon just so happens to supply just enough energy for the wedge. No less. No more. Really? Sounds kind of odd. Too perfect of a power delivery.

But that is my point. A point I have argued in other threads. What about the perfect storm, like this emergency situation where the reactors had to be shut down, for whatever reason. A cascade failure caused all reactors to shut down. Perhaps a design flaw or a particular component failure. Shit happens. Losing all reactors to a failure is a perfect storm.

I do not believe he stated that the wedge receives enough power to be self-sustaining; because that is not true, additional power still has to be supplied during flight. The only time a ship gets a free ride is in a gravity wave under sails (or briefly through a wormhole).

We have discussed before the case where a ship needs to start up with cold reactors. There are plasma ducts that go to the skin of the ship, so someone needs to supply outside plasma to the proper input.

Unlike Jonathan_S, I doubt that there are chemical backup processes that can supply power.

No matter what, a ship in such a state would be declaring an emergency and surrendering, not declaring war - remember, dropping a wedge is a signal of surrender - so anyone firing on a vessel in such a condition is an act of barbacy and completely against the Deneb accords.

Besides, it's well known that SDs don't travel alone, especially during an assault (which is the basic assertion, the SD is attacking a 3rd party where Honor's LAC was defending.) The SD would be part of a battlegroup, and would have multiple escorts at the minumium, or more likely a full division with screen or full fleet with a squadron of wallers). And we know that Prior to 1920, SLN Wallers only left the core 3 times in 300 ish years.

Jonathan_S wrote:Whatever they were they were capable of providing power for the environmental plants for the 5 or 6 months they were on Hades; after which the shuttles still had enough power to start up their onboard fusion plants.

I'd be shocked if the starships didn't have similar types of emergency thermal converters which (presumably) turn chemical or other heat into power. But even if the starships don't their small craft and lifeboats would - and if those emergency power converters can run air conditioning for months they'd be able to eventually charge up the small craft's capacitors to the point it can bring it's laser confinement reactor online -- at which point you've got all the power you could need to get the ship's main reactors back online.

Possibly, but it would seem quicker to supply the ship with plasma from the outside, if that is feasible. On ships we only know of bunkerage for the hydrogen for fusion reactors and in space we would not want to use up the ship's oxygen to supply chemical power. To me, thermal converters always sounded like thermocouples or some similar device.

Theemile wrote:Besides, it's well known that SDs don't travel alone, especially during an assault (which is the basic assertion, the SD is attacking a 3rd party where Honor's LAC was defending.) The SD would be part of a battlegroup, and would have multiple escorts at the minumium, or more likely a full division with screen or full fleet with a squadron of wallers). And we know that Prior to 1920, SLN Wallers only left the core 3 times in 300 ish years.

Except for the madman who bought a fourth-hand SD that some weak polity decided to sell, then thought himself invincible and decided to take on his enemies...

Jonathan_S wrote:I'd be shocked if the starships didn't have similar types of emergency thermal converters which (presumably) turn chemical or other heat into power. But even if the starships don't their small craft and lifeboats would - and if those emergency power converters can run air conditioning for months they'd be able to eventually charge up the small craft's capacitors to the point it can bring it's laser confinement reactor online -- at which point you've got all the power you could need to get the ship's main reactors back online.

The problem is not power, it's energy. We don't know that those emergency generators can generate sufficient energy to reach the minimum required to start the reactors.

If you had several ships in the same condition, it's possible that their all pooling their energy could start one ship's reactor, which could help all the others. But what are the chances that ALL ships would find themselves in this condition in the first place?

ThinksMarkedly wrote:

Jonathan_S wrote:I'd be shocked if the starships didn't have similar types of emergency thermal converters which (presumably) turn chemical or other heat into power. But even if the starships don't their small craft and lifeboats would - and if those emergency power converters can run air conditioning for months they'd be able to eventually charge up the small craft's capacitors to the point it can bring it's laser confinement reactor online -- at which point you've got all the power you could need to get the ship's main reactors back online.

The problem is not power, it's energy. We don't know that those emergency generators can generate sufficient energy to reach the minimum required to start the reactors.

If you had several ships in the same condition, it's possible that their all pooling their energy could start one ship's reactor, which could help all the others. But what are the chances that ALL ships would find themselves in this condition in the first place?

All I can point to is that Honor & co. spent over 5 months on Hades, with reactors off, and then had the onboard capacity in their stolen assault shuttles to fire them back up.

And even if the emergency power sources can't provide the energy to start a starship's reactor once you've got a shuttle reactor running it should be able to provide plenty of energy to do so.. (Especially since even it shouldn't need to provide peak power; you should just need to charge up the starting system and then let it quickly discharge to get the short burst of high output energy needed to activate. Not entirely unlike how you can trickle charge a battery from a power source that doesn't come close to having the peak amps needed to actually run the starter motor and turn over an engine. But trickle charge long enough and now the battery has the power to provide the necessary short burst of energy)

Jonathan_S wrote:All I can point to is that Honor & co. spent over 5 months on Hades, with reactors off, and then had the onboard capacity in their stolen assault shuttles to fire them back up.

A shuttle probably is designed to restart itself from cold.

And even if the emergency power sources can't provide the energy to start a starship's reactor once you've got a shuttle reactor running it should be able to provide plenty of energy to do so.. (Especially since even it shouldn't need to provide peak power; you should just need to charge up the starting system and then let it quickly discharge to get the short burst of high output energy needed to activate. Not entirely unlike how you can trickle charge a battery from a power source that doesn't come close to having the peak amps needed to actually run the starter motor and turn over an engine. But trickle charge long enough and now the battery has the power to provide the necessary short burst of energy)

Right. If the shuttle can start its own reactor, then it can probably generate sufficient energy to charge the capacitors of a larger ship to restart itself, particularly because it would be inside or next to such a ship and therefore have access to that ship's hydrogen/deuterium/helium supply.

So long as the charge rate is higher than the loss rate.

Jonathan_S wrote:All I can point to is that Honor & co. spent over 5 months on Hades, with reactors off, and then had the onboard capacity in their stolen assault shuttles to fire them back up.

That is partly why I believe that the backup power does not rely on consumables, that it is photoelectric or thermoelectric or some combination of the two. We know from the Silver Bullets that solar power can trickle charge a plasma capacitor.

Please note I am not saying that in an emergency a ship cannot use the shuttles (etc) to generate enough power to startup a reactor; instead I am saying that in all but the worst emergency, there are quicker methods of starting the reactor using an external plasma source.

Also when Honor and Co started the fusion reactors on the shuttles when changing positions to be nearer the punishment camp, they must have done it that time using power from the turbine engines. Which means the backup power output is not always necessary to start the shuttle's reactor.