Page 84

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Nemo
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Re: Page 84

Post by Nemo »

*Antimatter radiation largely pions, which are unreactive with matter for several dozen meters, and decay into 60% neutrinos, which are completely unreactive with normal mater. A more exotic material might produce even less reactive radiation. IIRC, the Winter Tide is relatively small, and large pieces of it might be inside a (relative) safety zone.
If it was a matter of choice, you would engineer the material the opposite direction. If at all possible you would make it so it was more reactive, more powerful, by mass so you could use less of it to achieve the same output. Regardless, are we discussing putting an uncontrolled annihilation reaction within the ship and engineering the ship to withstand it? Why not just put this miracle feat around the entire hull and not worry about weapons fire in the first place, seems a bit more direct ;)

This kind of reactor failure is not going to be 'deflected' like a chemical explosion/shockwave in an atmosphere. An ammo explosion creates an expansive force and you "simply" allow it to expand in a direction you choose. An uncontrolled annihilation reaction is going to create an intense burst of radiation. You're not going to direct its movement 'away' and any matter it contacts will change energy states. If they find anything of the crew I imagine it would be more in the lines of thermal shadows on whatever decking is left. And even if we had a nice solid chunk of unobtainium to insulate the crew from the radiation with it wouldn't readily dissipate that absorbed energy off into space. Not when there is perfectly good matter it can conduct that energy to right there.
Arioch wrote:I think those would be propellant rather than reactor fuel (even a "mostly" reactionless drive still requires reaction mass, and a matter-annihilation reactor probably doesn't produce any on its own); the struts seem too vulnerable a place to store reactor fuel. I have a notion that the propellant tanks and the engine struts operate as part of the ship's cooling system, which might explain why they seem to be relatively unprotected, and why some ships seem to have redundant struts adjacent to each other.
I can see dumping heat into the reaction fuel and burning it as an active cooling measure. I cant see having reactor fuel separated far from the reactors, not given its volatility. Presuming loss of fuel containment means loss of the ship, why create a third major point of vulnerability? My only question is how much reactor fuel mass do they actually need using anti-matterish reactions.

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Arioch
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Re: Page 84

Post by Arioch »

Nemo wrote: I cant see having fuel storage far separated from the reactors, not given its volatility. Presuming loss of fuel containment means loss of the ship, why create a third major point of vulnerability? My only question is how much reactor fuel mass do they actually need using anti-matterish reactions.
I agree, I think the reactor fuel would be stored in the nacelles right near the reactor... antimatter (or equivalent) doesn't seem like something you want flowing through long pipes all over the ship. The nacelles and the prongs should be the best-protected parts of the ship.

If a 350kt cruiser has, say, enough fuel for 100 hours of full-thrust 30g burn, and if we guess the reactor/engine is 50% efficient, then that's:

Code: Select all

E = mc^2
KE = 1/2mv^2 
v = at
fuel mass doubled for 50% efficiency

m(fuel) = 2 * E/c^2
        = 2 * m(ship)(at)^2/2c^2
        = 2 * (350,000,000kg)(294*100*3600)^2/(2*299,792,458^2)
        = 43,624,081.98 kg
43 kilotonnes of reactor fuel. Not sure if that's right -- feel free to check my math. Doesn't sound right. But that's 12% the mass of the ship, so maybe it is.

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Mjolnir
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Re: Page 84

Post by Mjolnir »

Nemo wrote:If it was a matter of choice, you would engineer the material the opposite direction. If at all possible you would make it so it was more reactive, more powerful, by mass so you could use less of it to achieve the same output. Regardless, are we discussing putting an uncontrolled annihilation reaction within the ship and engineering the ship to withstand it? Why not just put this miracle feat around the entire hull and not worry about weapons fire in the first place, seems a bit more direct ;)
No miracle armor is being suggested.

Nemo wrote:This kind of reactor failure is not going to be 'deflected' like a chemical explosion/shockwave in an atmosphere. An ammo explosion creates an expansive force and you "simply" allow it to expand in a direction you choose. An uncontrolled annihilation reaction is going to create an intense burst of radiation. You're not going to direct its movement 'away' and any matter it contacts will change energy states. If they find anything of the crew I imagine it would be more in the lines of thermal shadows on whatever decking is left. And even if we had a nice solid chunk of unobtainium to insulate the crew from the radiation with it wouldn't readily dissipate that absorbed energy off into space. Not when there is perfectly good matter it can conduct that energy to right there.
The matter exposed to the radiation will absorb it and vaporize, yes. And continue to absorb it as it expands and re-radiates it, mostly to space. With all that mass around the reactor, including radiation shielding and armor, it's quite likely the thing to worry about is the rapidly expanding fireball and accompanying shrapnel accelerated by said fireball, not the radiation. A small, thick wedge of conventional armor could protect a central fuel stockpile from this, and the same armor would also be effective against weapons fire, so it isn't wasted mass.

Nemo wrote:I can see dumping heat into the reaction fuel and burning it as an active cooling measure. I cant see having reactor fuel separated far from the reactors, not given its volatility. Presuming loss of fuel containment means loss of the ship, why create a third major point of vulnerability? My only question is how much reactor fuel mass do they actually need using anti-matterish reactions.
Because by doing that, loss of a reactor does not necessarily mean total loss of the ship. Again, they carry enough fuel for a hundred hours of operation at maximum power, there's no apparent reason for it all to be out in the engine pods. It makes more sense to periodically transfer a small amount of fuel to keep the reactor ready for a few minutes of full-power operation, and keep most of it in a central, extremely well protected location.

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icekatze
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Re: Page 84

Post by icekatze »

hi hi

The fact that the Loroi aboard the Winter Tide thought that they had a chance to recover suggests that the Loroi do have some emergency protections in place, but it is a matter of opportunity cost. You can't make anything 100% safe, not even water. :P Once someone starts shooting holes in your control systems, things don't always go according to plan.

CptWinters
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Re: Page 84

Post by CptWinters »

icekatze wrote:Once someone starts shooting holes in your control systems, things don't always go according to plan.
And if things are going according to plan, you're not in combat. Or so I've been told.

I'm sure it's comforting to know that a vehicle is "safe," but (and I can't claim to speak from experience) combat has to rank as one of the most dangerous environments known, and I'd rather be able to fight effectively than to have a piece of equipment which is bogged down by overly-protective systems.

NOMAD
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Re: Page 84

Post by NOMAD »

CptWinters wrote:
icekatze wrote:Once someone starts shooting holes in your control systems, things don't always go according to plan.
And if things are going according to plan, you're not in combat. Or so I've been told.

I'm sure it's comforting to know that a vehicle is "safe," but (and I can't claim to speak from experience) combat has to rank as one of the most dangerous environments known, and I'd rather be able to fight effectively than to have a piece of equipment which is bogged down by overly-protective systems.
Ahem, er A-ship to that.

now I'm not in the military, but i read alot of soldier experiences, listen to alot of doc with vet interviewed and read up of the vehicle history's. and I've learned ( correct me if I'm wrong here) that military vehicle are, in general, engineered and designed to survive alot of punishment ( IE LAV's APC, IFV MTB, destroyers to Aircraft carriers). but they can;t protect against everything ( or as Arioch has pointed out, combat efficency goes down but a substansal amount). A good ground vehicle example is the tank, designed to be the most mobile, hard hitting and armoured vehicle on the ground. Yet, its track can be blown off ( mobility kill) it can take a hit in the engine in the rear; the but worst is when the main gun ammo is hit ( which is mostly on the inside of the tank) and all you need to see ( or look up) are the picture of Soviet T-72M's turrents being vaulted 10 to 30 ft away from the main hull, because one expossive or power charge got nicked, exploded and detonated the remain ammo in the tank. Their are only a few ways to design a tank to survive that ( the abrams has the ammo in the turrent rear with those blow of panels, the Merkava 4 to 6 have water filled ammo pouches to allow the crew to escape). even with those systems their is no absolute way to safely channel or protect the remaining vehicle from that amount of force. besides, the more rounds that a tank can carry the more damage it can do to the enemy.

now the example above might not apply to Outsider ships, but I would believe the Loroi would construct their ships with some sort of modular construction method/ ship compartmentalization that would allow part of a foundered ships crew to potentially ( very small mind you) survive a fatal reactor breach and evac them to safety ( as arioch as stated in these broads). another point brought up was the pro/cons of placing the engine pod on the outer edges of the ship. I think the odds of the crew surviving could be improved ( 5 - 20 % then normal) if the pods are physically shoot off ( like what happen to the poor bell).
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Nemo
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Re: Page 84

Post by Nemo »

Arioch wrote:43 kilotonnes of reactor fuel. Not sure if that's right -- feel free to check my math. Doesn't sound right. But that's 12% the mass of the ship, so maybe it is.
Its a good starting point. That gets you the acceleration with no primary power left for combat. Consider bingo fuel at 50 hours acceleration, and reduce range as needed to allow for energy spent in combat. Air force reserves something like 5% with 20 minutes sea level loiter. No need to loiter in space, but with weapons and engines drawing from the same source... eh 10% remaining on mission complete?

Distracting myself, more concerned with the volume of the fuel though. More volume makes a larger target aspect. Ill assume anti-protons, and that it behaves similarly to the common one proton hydrogen isotope. Next, I'll outsource my math to wolfram. Ill assume its under high pressure (400 atmosphere), chilled (25K), and split evenly between reactor pods. 21.5 kilotons of hydrogen under those assumptions fills a sphere with a 38 meter radius or a cube with a 62 meter edge. Thats... mighty large. Maybe their "exotic" matter is a bit more dense. Just switching to helium under the same conditions makes it a 28 meter radius or 46 meter edge. Of course I have no idea under what conditions helium can be made to freeze either.

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icekatze
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Re: Page 84

Post by icekatze »

hi hi

Could anti-iron be held in a stable magnetic field?

Aygar
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Re: Page 84

Post by Aygar »

icekatze wrote:hi hi

Could anti-iron be held in a stable magnetic field?
I don't think that that question has ever been scientifically investigated. (Mainly do the serve shortage of anti-iron atoms) I have no idea what the theory says should happen.

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Arioch
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Re: Page 84

Post by Arioch »

Nemo wrote: Maybe their "exotic" matter is a bit more dense.
Yes, I had the same thought at the conclusion of the above math experiment: it would be convenient if the exotic fuel consisted of much heavier particles.

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Mjolnir
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Re: Page 84

Post by Mjolnir »

icekatze wrote:Could anti-iron be held in a stable magnetic field?
Easily. Stacking antiparticles together to form nuclei as heavy as iron would be quite difficult, though...you're talking a much longer reaction chain involving much more difficult reactions than you'd use for fusion power, with high-energy antineutrons spraying out from many of them, and you're fusing particles that will annihilate if they make contact with your fusion reactor...incomplete confinement becomes a somewhat larger issue than a little plasma loss, and a lot of losses along the way. Your best bet for heavy antimatter is probably some process for converting matter into it. (this is despite there being no hints at present as to how you'd do such a thing)

I'm pretty sure even frozen hydrogen is diamagnetic enough to be levitated in this way, though, so you don't need iron. And the even the humans in Outsider have gravity control, making magnetic properties considerably less relevant. And something more exotic (some kind of metastable strange matter that can be induced to decay on demand, for instance) might be easier for the Loroi and Umiak to produce in a dense, somewhat less volatile form.

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Re: Page 84

Post by NOMAD »

good point Mjolnir, starting from smaller basic element might not be possible.

Now, my knowledge of chemintry is high school only but could these solution work out

A) start with more weighty/compact-able lower energy element and make the high density, high-energy particles. IE like the paper investigates
http://www.phy.bnl.gov/edg/samba/z_chen.pdf

B)Given the higher tech of the lorio and Umiak, could their fuels be derived from basic elements, arranged in a compact forms that could provide Alot of power / molecule weight.

C) using a heavier more common element and dividing it into fuel need, while the actual process is a complex but mass production process so production cost are lower; while allowing mass fuel ( say enough to make resupply the whole 51st fleet after coming back in say, 1-2 week time) ?
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