The ultimate weapon

[Carlobrand]

Well for one I don't think there's anything in Traveller to suggest that maneuver drives are capable of anything approaching significantly fractional-c velocities. In fact it's strongly suggested by the background that they top out at a velocity of 6G x 3.5 days. Because if you can't get there in a week or so (half acceleration and half deceleration) then you jump.

Personally I also feel the whole vector preservation through jump later addition is bogus on several levels and that, again supported by the way the game plays, jumping will zero your velocity relative to the destination. So no building up a big vector and jumping in with it to surprise your target.

Besides, in the setting history this scenario has happened... never iirc. There must be a reason or reasons for that. Physics, society, or something else is enough to mean it doesn't happen. Since society is a weak control I'm more of a mind that there are solid physics behind it being practically impossible.

Well, yes, - and no. Here's how I see it:

Interplanetary space is not empty. It has a lot of junk, most of it little sand-grain-sized and smaller stuff left over from comets flashing past, asteroids knocking into each other, the gods alone know what else. Lets use Earth as an example: Earth sweeps up something between 35,000 and 70,000 tons of this stuff annually during its orbit - but Earth is a bit bigger than the average scout/courier.

Figure - with many, many rough approximations to simplify the math - the Earth at ~1.3 x10^14 square meters cross-sectional area, sweeping a circle with a radius of ~150 million kilometers and encountering, say, 50 billion grams of "grains of sand" over the course of a year. So, there are 50 billion grams in a volume of some 6x10^25 square meters - ballpark the puppy at roughly a gram of matter for every 10^15 square meters.

My courier has a cross-sectional area of 90 square meters. I should on average encounter about a gram of mass every 10 billion kilometers. In other words, I'm only expecting to encounter about 0.03 grams of mass in my inbound flight. Now, 0.03 grams - 30 milligrams - can actually make for a lot of little grains and flecks if you figure a grain of sand, for example, might be anything from 0.6 milligrams to 0.3 micrograms or less.

At 11-1200 kps, 16-17 hours into my flight, 0.03 grams mass is 40-million joules, grains of matter becoming tiny specks of hot plasma needling through my hull and through my ship, possibly to be stopped in the hull on the other side. Not a healthy condition for my machinery OR me when it happens - and my plan is to triple my speed. By comparison, the M1 Abrams' main gun delivers a KEAP round with roughly 25.6 million joules of energy to penetrate 540mm of steel (penetration rating >45) - that is of course a much bigger mass at a much slower speed.

The real question becomes: can these few tiny little superheated, superfast (relative to me) specks do enough damage to stop my machinery before it completes its programmed mission?

How the heck should I know? I'm just a gamer.

 

[The Oz]

How the heck should I know? I'm just a gamer.

As it happens, I (among others) have done the math and the short answer is that most Traveller ships are safe.

If you want the math, look here. Max Safe Speed

 

[Omnivore]

Frontal armor would be as good a mass as any for relativistic kinetic kill purposes. Also I believe choosing an approach course that avoided the plane of the ecliptic would reduce probability of larger impacts.

If I recall correctly, in The Killing Star, Pelligrino claimed 80% c as a relatively safe interplanetary speed for a Valkyrie type craft that normally considered 92% c as safe interstellar. I may be off a tad on the exact numbers as its been awhile. The craft design used a droplet shield to absorb the brunt of any impacts, although a multilayer superdense whipple shield would probably suffice.

 

[Carlobrand]

...Besides, in the setting history this scenario has happened... never iirc. There must be a reason or reasons for that. ... Since society is a weak control I'm more of a mind that there are solid physics behind it being practically impossible.

Well, yes, - and no. Here's how I see it:

Interplanetary space is not empty. It has a lot of junk, most of it little sand-grain-sized and smaller stuff left over from comets flashing past, asteroids knocking into each other, the gods alone know what else. ...

At 11-1200 kps, 16-17 hours into my flight, 0.03 grams mass is 40-million joules, grains of matter becoming tiny specks of hot plasma needling through my hull and through my ship, possibly to be stopped in the hull on the other side. ...

The real question becomes: can these few tiny little superheated, superfast (relative to me) specks do enough damage to stop my machinery before it completes its programmed mission?...

As it happens, I (among others) have done the math and the short answer is that most Traveller ships are safe.

If you want the math, look here. Max Safe Speed

Your link analyzes the issue with respect to Traveller/Striker rules, specifically the demo charges. Far-Trader's looking at it more in terms of real-world physics. I'm not sure that we can compare the impact of a dust grain at 1200kps with the effects of an explosive charge on the hull.

For one thing, the impact of the dust grain against a hypervelocity target applies a tremendous lot of energy to an extremely small area. The grain of dust becomes an incredibly hot plasma under the force of impact, vaporizing a trail through the item as its momentum (or maybe inertia's a better word, since it's the ship doing the moving) carries it through. The effect at those speeds is apt to appear more like the effect of a tiny shaped charge than an explosive, which is to say it's more likely to burn straight through than cause widespread damage. Where an explosive is a "sledgehammer", the dust grain is a "foil", and it may be that the impact causes it to burn straight through and out the other side, transmitting only a fraction of the energy along the way.

We really don't know much about extreme hypervelocity impacts. Our knowledge takes us into the tens of KPS, and in those ranges, metals start acting like fluids - which is to say the impact point looks more like what you'd get if you hurled a rock into a body of water and then flash-froze it: a kind of splash-crater as the metal in the immediate area of impact is ejected, with the surrounding metal relatively unaffected.

http://www.esa.int/esaMI/Space_Debris/SEMZFL05VQF_0.html

I'm thinking the impact of a grain at those speeds would be rather like the tracks left by a rifle bullet fired into water: deep, narrow tunnels two to five times as wide as the grain that impacted. Keep in mind that the energy needed to vaporize, say, a 1 mm trail through 33 cm of steel is no more than 18 to 20 kilojoules - levels of energy deliverable by grains with velocities (or rather, velocidy differences between them and your ship) as (relatively) low as 200-300 kps. I've no idea what it might be through crystaliron or superdense armor, of course.

With the energies involved applied against such a small area, I think the most likely result is a drill-through, with the grain passing through and exiting with most of its energy unspent. The question remains: what would be the result of having, say, several 1 mm tunnels drilled through arbitrary parts of a Traveller fusion power plant, maneuver drive, or computer?

For my traveller universe, I'd set a top speed of 200 to 300 kps based on that, with a progressive chance of encountering a drill-through and damaging some component if you exceeded it - and a small chance of suffering injury yourself in a drill-through. Faster for armored ships, of course - that would require a bit more calculation. Still leaves the potential for truly dangerous armored suicide-ships, but the average Ine-Givar type is likely to have easy access only to civilian ships. A 200kps civilian ship is still a potentially lethal puppy, but there's much more time to react and a much better chance of reducing it to tiny debris much farther out so that the effect on the target planet is minimal.

 

[Omnivore]

There's a rather huge difference between a civilian ship designed for non relativistic speeds operating in the ecliptic plane of a system and a purpose built weapon designed for relativistic speeds whose trajectory intersects the ecliptic plane at a relatively steep angle.

* The weapon would be designed to have minimal cross section and its trajectory would be through a region less dense in interplanetary debris.
* The weapon would concentrate all extra armor in the front facing.
* The weapon would use whipple shield (spaced armor with filler).
* The weapon would likely use a droplet** shield ahead of the whipple shield.
* Damage to the weapon during the final approach (at the time of highest speed just prior to impact) would not adversely effect the damage delivered to target by any appreciable degree.
* Likely deployment would be in squadron strength of small weapons rather than a single large weapon - both for better distribution of damage to target and for effectiveness despite losing one or more of the individual weapons.

**Droplet shield: a 'fountain' that sprays out droplets of liquid (possibly liquid metal) in front of the vessel. The droplets are collected and recycled as the vessel accelerates into the spray. A droplet shield is superior to a whipple shield in that any holes are automatically filled in.

The difference between a relativistic weapon and a civilian ship at say 300kps is:
A 6DT (-1DT fuel) relativistic weapon having a dry mass of 70 metric tons impacting a target at 75% c is roughly equivalent to 700 gigatons of TNT.
A 200DT (fully fueled) civilian ship having a mass of 2800 metric tons impacting a target at 300 kps is roughly equivalent to 30 megatons of TNT.

Apple seeds and watermelons.

 

[The Oz]

The calculations I made were only concerned with the maximum safe speed of Traveller ships in an RPG setting, using the Traveller rules themselves. I was not concerned with relativistic-speed bombardments because, as has been said elsewhere, such bombardments do not happen in the OTU.

 

[Carlobrand]

The calculations I made were only concerned with the maximum safe speed of Traveller ships in an RPG setting, using the Traveller rules themselves. I was not concerned with relativistic-speed bombardments because, as has been said elsewhere, such bombardments do not happen in the OTU.

Well, that is the topic of the thread. The fact that an action has not happened does not mean it can't. The MegaTraveller milieu gave us a lot of things that had never happened before in Classic Traveller. Science fiction is the realm of the possible, and it behooves us as gamemasters and storytellers to know what is possible so we can use that to excite the imaginations of our players.

The attack on Regina is a frightening view of what is possible within the classic rules. The question is: is it truly possible, or does it simply represent some problem with the rules' emulation of extreme phemonena? If it is possible, what defense would Regina have against it?

 

[Murphy]

The attack on Regina is a frightening view of what is possible within the classic rules. The question is: is it truly possible, or does it simply represent some problem with the rules' emulation of extreme phemonena? If it is possible, what defense would Regina have against it?

Plot armor.

There is no flaw in the rules, unless you consider drives that are able to provide 10 terajoules of kinetic energy over several days to be a flaw.

IMTU I forbade gravitic technology drives and postulated the use of reaction drives instead, and there is typically only enough reaction mass for 12-24 hours at 2G. Arguably still enough to create splatterships but not nearly as deadly as vanilla rules permit, thus I can safely rule such ships out as largely ineffective.

For anyone interested in technobabble, I put the details below:
[OFFTOPIC]
Gravity manipulation is still allowed, but fields can only be created inbetween two close surfaces, akin to creating electric field in a capacitor. Useful to keep artificial gravity in starships and such.

To be able to build grav vehicles, more advanced tech is avaliable, called the gravity projector. It creates a gravity field between the vehicle and the ground, pushing the vehicle up against it. Of course anything below would feel a force pushing it down, but the pressure is distributed over a large area so it's not really dangerous to people, unless you ride over them at low (1-2 meter) altitude.

As a result, air/rafts would need reaction drives to get higher than a few tens of metres, which I am completely fine with. That also throws a bone to COACC instead of just having grav tanks rule all aspects of warfare. Grav belts, however, would at the very least require a thorough redesign.
[/OFFTOPIC]

 

[BytePro]

Regina defense?

Disaster Averted!
Regina/Regina (0310-A788899-A)
By TNS Staff Writer

Today, fleet press officer, Commander Aia Resortin, confirmed that extra-planetary units of Regina Autonomous Defense commenced meson firing on a high velocity unidentified scout craft jumped into the system on a trajectory that could have intercepted Regina's orbit. The Commander stated "[The craft] was highly blueshifted when it was detected by the System Sensor Network several minutes after jump emergence, and continued to maintain its unauthorized course and acceleration, resulting in automated RAD meson interception approximately 18 light minutes from Regina."

He later added, "...[Meson firing was] followed by intense KE re-vectorization via targeting by three of RAD's Close-in Asteroid Defense Satellite orbital installations using Rail Launched Pellet Munition Storming anti-collision systems." The Commander described CADS RL-PMS as basically millions and millions of tiny balls thrown at very high velocity to one side of the craft in order to shift its course.

When asked about the possibility that the craft was manned, Commander Resortin responded, "There are no life signs at this time and the craft has been redirected on a safe intercept course with Lusor."

In an unrelated story, the inter-system liner, RSS Nautzorukky, had to make an emergency landing at Regina Down today, apparently having experienced multiple extreme space dust collisions.​

 

[Hyphen]

Wow, now I'm really feeling old. Last time I can remember a near-C-rocks debate was ten years ago!

(Did we ever create anything for the near-C-lifeboat issue, like we did the Sunbeard Declaration for pirates? Ranging from "it's never happened in the OTU, so something must have prevented it, plus we'll include a footnote about Trin" thru to "in YTU, anything goes!")

What next, Aslan in comfortable shoes?

 

[Carlobrand]

Regina defense?

Disaster Averted!
Regina/Regina (0310-A788899-A)
By TNS Staff Writer

Today, fleet press officer, Commander Aia Resortin, confirmed that extra-planetary units of Regina Autonomous Defense commenced meson firing on a high velocity unidentified scout craft jumped into the system on a trajectory that could have intercepted Regina's orbit. The Commander stated "[The craft] was highly blueshifted when it was detected by the System Sensor Network several minutes after jump emergence, and continued to maintain its unauthorized course and acceleration, resulting in automated RAD meson interception approximately 18 light minutes from Regina."

He later added, "...[Meson firing was] followed by intense KE re-vectorization via targeting by three of RAD's Close-in Asteroid Defense Satellite orbital installations using Rail Launched Pellet Munition Storming anti-collision systems." The Commander described CADS RL-PMS as basically millions and millions of tiny balls thrown at very high velocity to one side of the craft in order to shift its course.

When asked about the possibility that the craft was manned, Commander Resortin responded, "There are no life signs at this time and the craft has been redirected on a safe intercept course with Lusor."

In an unrelated story, the inter-system liner, RSS Nautzorukky, had to make an emergency landing at Regina Down today, apparently having experienced multiple extreme space dust collisions.​

18 light ... ?? How did ... when did ... who ... ???

You may think you've won, but you haven't! We will keep fighting! We will keep trying until ... Oh, wait, I'm dead now. Never mind.

(add: what is a sunbeard declaration?)

 

[Omnivore]

Wow, now I'm really feeling old. Last time I can remember a near-C-rocks debate was ten years ago!

Yeah I hear you, been playing Traveller since 1979 so everything is old news. Guess no-one should ever post anything or rehash any issue for newcomers? Eh well, nothing new under the sun.

 

[Omnivore]

Ok, something new under the sun. I broke out FF&S and, designed as a spacecraft/missile hybrid I came up with a fusion rocket powered relativistic bombardment vehicle.

High guard USP would look something like:
ZZ-0103001-300000-00000-0 MCr 77.54 95DT TL10

Fuel and battery storage for 1510 hrs operation at 3G.
Terminal velocity: 54.36% c. TNT equivalent: 3 gigatons.

The design isn't by any means optimal, but there's enough volume and mass available to add in 'self-destruct' charges that would be used to split the mass up to get quite a few 100MT range yields over a large area.

A better design might be a smaller vehicle with 1G of acceleration over a longer time with a somewhat higher terminal velocity.

In any event, even without gravitics, it is quite possible under OTU rules.

 

[Murphy]

Heh. I don't have FF&S, but now I say ain't their rocket drives severely unrealistic?

 

[Omnivore]

Heh. I don't have FF&S, but now I say ain't their rocket drives severely unrealistic?

http://www.projectrho.com/rocket/enginelist.php#table

Not outrageously so. Realize that a relativistic bombardment vehicle is basically nothing more than an engine and fuel for a one way trip.

 

[Murphy]

Woah, shiny!

Cool page, thanks for the link!

 

[madmike]

Something of that nature was described in an Ian Douglas novel. a large freighter was accelerated to near C (No FTL in the book trilogy) all the while aimed at the enemy planet.

At .7 or so C, tens of thousands of tonnes of sand was released from the freighter's container holds which stripped away the atmosphere, destroyed orbiting facilities and then the freighter arrived, all 1km+ of it.

 

[mike wightman]

Energy can not be created or destroyed, only change form.

If you are going to generate a trillion kJ of kinetic energy you have to get that energy from somewhere.

Your batteries contain it?

Your fusion power plant can produce it?

There is something very wrong with Traveller drive physics that needs explanation...

n.b. and by energy I do of course mean mass/energy equivalence

 

[Omnivore]

Theoretical max yield from Deuterium-tritium fusion of 73361kg of fuel is roughly 2.48E19. 73361kg is the mass of the fuel carried by the 95DT FF&S design above. The energy yield on impact is roughly 1E19 suggesting an admittedly sky high efficiency of 40% and, of course, is calculated using DT rather than L-Hyd fuel.

Still... given that this is a game... those numbers are at least in the general ballpark.

On the gripping hand, the paltry 1 ton of L-Hyd yielding roughly 3E18J in the 6DT gravitics maneuver drive design I posted earlier is just way wrong.

 

[Hyphen]

Something of that nature was described in an Ian Douglas novel.

Ian Douglas? Isn't that one of Bill Keith's pseudonyms?

As for Sunbeard, it was a case of "let's agree on what we agree on, and agree to disagree on the rest". You can find it on my website here:
--> Best of the TML
--> Background
--> Background - The Sunbeard Declaration