Ship vs. Lava

[mike wightman]

According to Striker and MT the minimum for a starship hull is the equivalent of a foot of hard steel.

That copes pretty well with micro impacts at interplanetary velocities.

 

[Omnivore]

Yes and I think they went a bit overboard with that. A beefed up higher tech variant of the stuffed whipple shield used today (ISS, Stardust probe, etc) would, I think, suffice. Though, given grav plates/thrusters and proton proton fusion, heh I guess the extra mass isn't that big of a deal.

 

[Enoki]

No, but you can make some up.

Let's begin with the Striker data that has crystaliron as 4 times "tougher" than hard steel, superdense 7 times, bonded superdense 14 times. Let's note that this applies as well when it's a laser cutting into the armor. This implies that the heats of vaporization for crystaliron, superdense, and bonded superdense are 4, 7, and 14 times higher than that of hard steel - and therefore that the heats of fusion and therefore the melting points are, very roughly, equivalently higher.

Not quite. What it implies, from the names given is that these materials have been made denser than found in nature. This is done today to a limited degree with some materials. One in particular is armor piercing long rod penetrators that have had their density (ie., the atoms pushed closer together) increased beyond what nature provides by using something like a HIP Furnace (Hot Isostatic Press... made several), or Hot Press / Forge furnace where the material is subjected to several thousand psi (HIP furnaces run to about 50,000 to 100,000 psi and they scare the hell out me when they run).
Companies make diamonds this way, make tungsten carbide and DU penetrators that are 5 to 15% denser than in nature, etc.
So, what you have is some material, let's say iron or tungsten carbide for sake of argument, that has been made several times more dense by some method unknown to us but can be done in Traveller. That makes the material far tougher and increases its mass for a given piece. But, it doesn't change the melting point or its chemical properties.
So, you now have a hull made of essentially steel or some other metal that isn't terribly thick but has had almost all of the space between the molecules and atoms removed in the manufacturing process making it incredibly strong and tough. But, it still melts just like before......

 

[Blue Ghost]

Years ago I designed and built high temperature furnaces for industrial and research work for various companies. I could boil platinum in some of them (did in one once because the customer insisted on giving the run parameters to make him a ingot out of bits he accumulated.... but I digress) This assumes that the lava is either in contact with the hull or its heat can convect or radiate such that it acts on the hull.

You are doomed. First, immersed in lava there is no place to heat sink off to so the ship will quickly get hotter....ALL of it; insides, outside, people, stuff, all of it. That is, you have no way to keep the insides cool even if the outside is extremely hot (see Carnot heat engine theory on this).
So, you will last only as long as the insides don't get to say, about 60 to 70 C. After that everybody is toast....Literally.

The time that this will take depends entirely on the insulation efficency of the hull. If it were a true vacuum bottle (like a dewer bottle) you might go a while before things inside got too hot to handle.

The other problem here is going to be structurial failure of the hull. It will heat up fairly rapidly. Once the material reaches the plastic failure temperature (ie., it is now hot enough to bend or deform under some pressure or force) the hull will begin to buckle. That is usually a fraction of the melting point of whatever the material is. The more pressure, the faster it does so. Once it starts you are again pretty much doomed. Things will deform and likely stuff will stop working shortly thereafter like the power plant and engines (assuming the lava just can't flow in through some exhaust port or whatever).

Bottom line: You're DOOMED I tell you! DOOMED! :toast:

Shows you what I know.

 

[HG_B]

According to Striker and MT the minimum for a starship hull is the equivalent of a foot of hard steel.

That copes pretty well with micro impacts at interplanetary velocities.

Nope. I ran the math a while ago and compared kinetic rounds available today (their KE and what they can penetrate). The hull would be Swiss cheese using the values below.

 

[aramis]

Yes and I think they went a bit overboard with that. A beefed up higher tech variant of the stuffed whipple shield used today (ISS, Stardust probe, etc) would, I think, suffice. Though, given grav plates/thrusters and proton proton fusion, heh I guess the extra mass isn't that big of a deal.

And the whipple shield has the issue of being hard to repair, tricky to replace, and high volume for protection, all of which are issues for Traveller craft but not really issues for the Stardust probe.

 

[Enoki]

According to Striker and MT the minimum for a starship hull is the equivalent of a foot of hard steel.

That copes pretty well with micro impacts at interplanetary velocities.

I would think that given what is said about ship's hulls and their necessary qualities it wouldn't be unreasonable to have them using some sort of composite material like modern tanks do that has been made more dense in an extreme gravity field or using extreme heat and pressure with a resulting equivalent to normal steel armor of say 5 to 10 feet thick while remaining a foot or less thick as measured and installed.

After all, in Traveller gravity can be controlled meaning it should be possible to produce very high gravity fields locally for manufacturing purposes. That alone would allow some densification of material. At the extreme, that is what black holes do, densify the atoms that fall in removing the (at atomic levels) vast amount of space between them.

 

[shadowcat20]

My question is about thrusting yourself out once caught.

Between the weight of the lava and possible suction caused by it hardening a little as it comes in contact with the cooler hull things could get sticky.

Would the maneuver drives be up to the job? Or if they are the reaction mass/nozzle type would the extra pressure built by having the nozzles clogged with hot goo deform them till they blew?

 

[Blue Ghost]

My question is about thrusting yourself out once caught.

Between the weight of the lava and possible suction caused by it hardening a little as it comes in contact with the cooler hull things could get sticky.

Would the maneuver drives be up to the job? Or if they are the reaction mass/nozzle type would the extra pressure built by having the nozzles clogged with hot goo deform them till they blew?

I'm going to put my foot in my mouth again, but I think it's a matter for the grav drives to heft the mass upwards, and the maneuvre drive to blast the ship forward. YMMV, but that's how I've always understood Traveller starships to work.

 

[shadowcat20]

Considering I use mostly CT there are only Jump and Maneuver drives on a ship.

I am not sure if the maneuver drives are the reaction mass/ nozzle type or anti grav types. Considering they use fuel as reaction mass IIRC I would assume (Bad habit I know) they are the mass/nozzle type. I am pretty sure thay are not both. ( or I could be wrong as normal)

If they ARE anti grav how would they work in space, what would they push against in deep space, and how much lift would they have to pull a ship out of a sticky spot?

Not trying to be difficult, just hoping the number crunchers have answers for us both....

 

[mike wightman]

The maneuver drive was implied to be a reaction drive in original CT, if you took the time you could calculate how much fuel was used per turn of combat.

First edition HG then flat out stated the maneuver drive is a fusion rocket.

In revised CT and HG2 the maneuver drive changed - the references to fuel use and the statement about fusion rockets was dropped.

The folks at DGP made up that the maneuver drive was actually a reaction-less thruster and this is the model that was used in MT.

GDW went back to a reaction drive for TNE with their HEPlaR based maneuver drive.

 

[warwizard]

Have them do a jump from the middle of the volcano and slag the jump drive and then put them wherever you want , inside a hull thickened with several meters of foamed lava (think pumice, it floats), with the problems of needing to get out, repair antennas rig new ones find out where they are , survey the system they're in and so on, with nearly every antenna melted or destroyed, needing to carve their way out... and under a miminal power usage due to the radiators covered with the foamed lava...

Now for a little basic facts: the Average Density of a typical Merchant ship is about 1 metric ton per cubic meter, loaded, and about .2 metric tons/m3 empty, and the lava starts around 3 tons per cubic meter and goes up from there. The ship will make a splash and bob up like a cork with only about 1/4 of it's volume remaining under the lava. Even SBD's with heavy armors seldom reach 3 tons/m3. so the idea of encasing the whole ship will need to be reconcidered to be a relatively thin coating from the initial dunking, and radiators will still be effective (radiators will most assuredly be made to withstand sustained high tempuratures the watts per m3 to be dissapated require a very high temp for the radiator surface, any lava on the radiators will run off in short order.)

Other hazards to inflict... rock falls of a few hundred meters impacting the hull and damaging surface features, large landslide to carry the ship into the lava and perhaps hold it down with several thousand tons of rock. Tepura pele's hair and other ejecta and ash to abrade air breathing engines and optical surfaces such as camera lenses and view screens. Lightening in the ash cloud to inflict EM hits, knocking sensors offline at critical moments. Methane explosions, steam explosions, lava bombs, and the biggie... a pyroclastic flow, or simply have the volcano pull a Mount St Helens type explosion and put the ship 50 meters deep under hot rocks. They do not even need to be all that near to the volcano 5 to 10 KM will do nicely, as most players will think that's plenty of room.

 

[aramis]

The maneuver drive was implied to be a reaction drive in original CT, if you took the time you could calculate how much fuel was used per turn of combat.

Given that the least efficient combination is a 100Ton ship with Drive A, and that has 20 Tons of fuel, and...
Given that a fuel load is 4 weeks power and maneuver, and...
Given that a week is 168 hours...

That's 672hours and 20 tons... and is moving a ship of at least 100 tons mass (more like 1000 metric tons)...

That's 29.76kg/hour, accelerating a ship of minimum 100Tons at 2G... that's 8.267g/s to produce both the power and the motive force accelerating the ship. All larger Bk2 ships are more efficient still, since it's still 10tons of fuel per 4 weeks per G.

And for the larger ships, presuming all the fuel mass goes out the arse, ISTR that hitting superluminal exhaust speeds.

For comparison, on DS1, the 45mN thrust uses 0.00156g/s or so of xenon; the scout ship is at least 980kN (and probably 10x that)... 21million times the force...

 

[Blue Ghost]

Considering I use mostly CT there are only Jump and Maneuver drives on a ship.

I am not sure if the maneuver drives are the reaction mass/ nozzle type or anti grav types. Considering they use fuel as reaction mass IIRC I would assume (Bad habit I know) they are the mass/nozzle type. I am pretty sure thay are not both. ( or I could be wrong as normal)

If they ARE anti grav how would they work in space, what would they push against in deep space, and how much lift would they have to pull a ship out of a sticky spot?

Not trying to be difficult, just hoping the number crunchers have answers for us both....

Shadow, my intuitive desire to reverse engineer a Traveller starship tells me that the drives are those "burn stuff and kick it out the back" type, only they do it at incredibly high energy states. The grav or anti-grav stuff is probably a separate system from the main drives (maneuver and jump), and doesn't do much else other than heft the ship off of whatever surface its resting on.

How that would effect a ship that's landed in a molten vat is beyond me.

 

[aramis]

Shadow, my intuitive desire to reverse engineer a Traveller starship tells me that the drives are those "burn stuff and kick it out the back" type, only they do it at incredibly high energy states. The grav or anti-grav stuff is probably a separate system from the main drives (maneuver and jump), and doesn't do much else other than heft the ship off of whatever surface its resting on.

How that would effect a ship that's landed in a molten vat is beyond me.

The math says the energy state is more than just extremely high. It's unbelievably high, perhaps impossibly high, in the Bk2 designs.

Thousands of times higher than the DS1 probe's energy density.

 

[mike wightman]

A fully fuelled ship can perform 288 accelerations - LBB2 original edition.

1 acceleration is the sticking point.

I assume 1 acceleration is 1g/turn - that's 1g of acceleration per 10 mins.

288/6 = 48 hours of continual thrust at 1g.

Note that this explains the higher fuel requirements of a higher g rated ship.

A 100t ship with a C drive uses 60t of fuel, but is capable of 6g for 48 hours

A 200t ship with the same C drive has 30t of fuel and is capable of 3g for 48 hours.

 

[Blue Ghost]

The math says the energy state is more than just extremely high. It's unbelievably high, perhaps impossibly high, in the Bk2 designs.

Thousands of times higher than the DS1 probe's energy density.

I would think it possible if it were something akin to a plasma jet sustained in a magnetic field, but that's just speculation. Do we really know the material science of starship hulls in the 3I, or the science of thruster technology?

 

[aramis]

I would think it possible if it were something akin to a plasma jet sustained in a magnetic field, but that's just speculation. Do we really know the material science of starship hulls in the 3I, or the science of thruster technology?

we know they can't exceed the speed of light with their exhaust, so a 5000Td bk 2 ship isn't using any form of reaction drive, and bk5 ships probably aren't, either... the drives are weaponry grade particle beams if they are.

by the Way, the hg fuel rate is 0.4g per td of pp per second. if driving MD, that's 0.4g per g per 100Td per second....an order of magnitude better than Bk2's least efficient, five time worse than the most efficient Bk2 drives.

And with armor, etc, bk5 designed ships should be close to 15 Tons metric per Td.

 

[mike wightman]

In HG1 the maneuver drive is the equivalent of a fusion battery with a factor equal to its drive rating.

We know that CT 'gravitics' technology comes in several varieties:

null grav modules used in air/rafts, grav belts etc

artificial gravity

acceleration compensators.

We also know that the maneuver drive generates a field around the ship that deflects particulate radiation.

 

[Blue Ghost]

I guess I should rephrase; I always understood the thing that actually lifted the ship off the ground was an anti-gravity or "gravitic" system that also helped augment the maneuvre drive when pushing the ship forward (as per air rafts and other grav vehicles). But, that the thing that pushed the ship forward wasn't so much the grav drive, but the maneuvre drive which worked like a jet or rocket in terms of kicking out energy aft.

That's why I speculated that a ship which, for whatever reason, found itself in a volcano, or lava flow, would just be able to lift itself up and then fire up the maneuvre drive to push it forward.

In terms of fuel consumption, well I have to admit I was never a big High Guard fan, but I'll accept whatever's told to me.