Crashing ships as weapons

[Otto Harkaman]

Why do you have to jump from another system? Couldn't you jump to some distance in outer space from your target planet that you could accelerate from toward the planet at close to C?

And to take it further since I know someone or something is going to stop me. Why don't I accelerate towards to planet and my spaceship is really a Mirv type missile, once I get up to speed I release several "Collapsium" metal beams from my ship that are now also travelling at near C speed. Or shotgun out thousands of "Collapsium" pellets :CoW::devil:

 

[Lycanorukke]

Would ships have something like TCAS built into the computers to prevent C-ships in the first place?

If your projected course has to hitting a planet, the computer gives an alert, and if the alert is ignored before 'course terminal' the ships computer takes over and changes course to avoid the impact, while sending an alert to the nearest authority.

As for run up-jump-run up it would be unusual for an ordinary ship to do that, so perhaps the computer drops a quiet message in the transponder signal to be picked up by military types for investigation and monitoring. Switch off the transponder to prevent this, and the IN will be very interested in your activity if they detect you.

 

[Brandon C]

Would ships have something like TCAS built into the computers to prevent C-ships in the first place?

That depends on who is sending the ship. If it is a government, sending a modified civilian ship or a custom-build vessel, they can install a computer of their own making, which would be free of any restrictions.

 

[Lycanorukke]

That depends on who is sending the ship. If it is a government, sending a modified civilian ship or a custom-build vessel, they can install a computer of their own making, which would be free of any restrictions.

True, but governments would tend to be more careful with C-ship scenarios against neighbours due to the 'MAD' situation. If it is just a local planet they wouldn't care about a C-ship strategy when they just roll up with a fleet to glass the planet.

On an individual/group level, while the computer could be reprogrammed by a tech-savvy culprit, it would prevent 'spur of the moment' and disorganised attacks. And as a bonus - it would act as a safety measure during a ghost ship/ghost flight scenario.

As for enforcement, well that's what all those IN ships doing 'customs checks' are for. The IN tech hooks up a basic computer diagnostic during a random stop and if they find the TCAS has been tampered with - you are totally [insert expletive here], even more so than with transponder tampering.

 

[Brandon C]

True, but governments would tend to be more careful with C-ship scenarios against neighbours due to the 'MAD' situation. If it is just a local planet they wouldn't care about a C-ship strategy when they just roll up with a fleet to glass the planet.

Actually, if such weapons were effective , the Darrians and Sword Worlds would have used them on each other repeatedly and the K'kree would have used them against planets crawling with meat eaters.

 

[McPerth]

Again, to evaluate the accuracy for any jump involving such a plan:

• How precise must be timing in jump?
• How precisely are time dilatation effects are known when you reach relativistic speeds?

I guess the combination of those answers are quite important for the fact, as if the timing must be quete precise and the time dilatation effects are not exactly known, the possibility of a missjump is quite high.

CT Beltstrike EXPLICITLY gives us particle shielding fields as part of M-Drives.

Other versions seem to not have those fields. in MT, to give you an example, ships need a mínimum armor to sustain the micromeeor damage expected in space, so hinting that there is no such field to stop it. Any versión allowing for the sandcasters to damage a ship or the use of railguns (e.g. MgT) also seems to discount those fields.

And, even if it exists, is it enough to stop anything at such high speeds? I guess it is designed to stpo quite slower objects.

And, even if those fields are able to stop them, I guess there wil lbe some effect in form of acceleration due to impact, and, as low as it may be (probably higher as speed increases), any small change of vector may ruin the precise calculations needed to hit at such speeds.

 

[McPerth]

Actually, if such weapons were effective , the Darrians and Sword Worlds would have used them on each other repeatedly and the K'kree would have used them against planets crawling with meat eaters.

I don't believe Darrians or Sword Worlds to be willing to use them, even if only out of fear to retaliation (also, the political effects on their allied I and Zhodani would have to be considered).

As for the K'Kree, they are the ones more likely to use them against meat eaters, but as this would involve also to exterminate their fellow herbibores in the planet, not sure if they woun't try it, except as a last resort.

 

[Carlobrand]

It better be doing it in an unihabited system, because a SDB or patrol cruiser will notice this and probably guess what the ship is up to.



The problem here is that in some editions, the time spent in jump is variable by around half a day either side of a week. The timing will be way off and the ship will be going too fast to correct course. A miss is probable, even if the planet mounts no defense.

Again, a nuke on a free trader landing in a starport is much more likely to succeed.

Neutrino detector or densitometer sweep picks that up in orbit, leading to an orbital inspection. Leave your assigned flight path and you become a legitimate target. So, that only works where the local starport is of a class too low to have such monitoring systems - and therefore not very promising as a target. It's like the difference between setting off a nuke in New York City and setting one off in Estancia, New Mexico: you scare them, but they figure you struck somewhere small because the larger place was too difficult for you, which tends to defeat your purpose.

For that purpose, a near miss on a big target is more effective than a successful strike on an out-of-the-way target of no value. Making a failed near-C attempt and leaving the target planet in an uproar about what almost happened is probably more useful than nuking some out of the way place in terms of the impact on the social and political structure.

Would ships have something like TCAS built into the computers to prevent C-ships in the first place? ...

It's hard to imagine something one can build that someone else couldn't defeat, given tools, training and motivation.

...As for run up-jump-run up it would be unusual for an ordinary ship to do that, so perhaps the computer drops a quiet message in the transponder signal to be picked up by military types for investigation and monitoring. Switch off the transponder to prevent this, and the IN will be very interested in your activity if they detect you.

There seem to be two views on this. Either the ship is doing it somewhere in the target system with intent to approach through normal space - and there are any number of ways to detect and defeat it - or it plans to jump from some other region of space. In the latter case, the IN is going to have about as much warning from that transponder as the target system. That doesn't really accomplish anything.

 

[whulorigan]

Why do you have to jump from another system? Couldn't you jump to some distance in outer space from your target planet that you could accelerate from toward the planet at close to C?

Yes, you could. But the issues to consider would be:

1) Jumping in at 100 diameters with an existing relativistic momentum vector minimizes the response time by defenders. With a pre-existing 0.9c velocity, 100 diameters out from a world of 10,000 km diameter yields a 3.7 second response time by defenders of the world before impact;

2) It may or may not be an option depending on what type of maneuvering drive you are using, based on the types and their efficiency constraints mentioned previously in the thread. If you are using a MT Strong-Force based or T5 Dean-type Thruster-Drive, you are fine. Most of the others have limits based on carried reaction mass or gravity gradient.​

 

[Brandon C]

Neutrino detector or densitometer sweep picks that up in orbit, leading to an orbital inspection.

For a fission bomb, radioactives are legitimate cargo. For a fusion bomb, the ship has a fusion reactor.

 

[Carlobrand]

Legitimate or not, a customs inspection would be warranted. The Imperium is rather strict about nuclear devices and would likely frown on shipments of plutonium or uranium of weapons grade. I think a cargo of reactor grade uranium would generate a lower and more dispersed neutrino emission profile than a bomb containing weapons grade uranium, and plutonium deserves close monitoring both because the stuff is incredibly dangerous and because they need to be careful about who receives it. The plutonium they use in radioisotope generators is not the same as the stuff they use in bombs; it would read differently than bomb material in a neutrino scan.

 

[Brandon C]

I think we need to take a more structured look at the scenario.

Attacker
I. Nature (motive)
a) Terrorist
b) Government
II. Equipment (means)
a) Stock ship
b) Modified stock ship
c) Custom ship
III. Method of attack (opportunity)
a) build up to speed in same system as target
b) build up to speed in different system than target

III is really the one that most influences defense.

a) A ship taking a month to accelerate will be noticed by a TL8+ world or any patrolling IN ships. The ship will be dealt with well before it can reach it's target. The few systems that are potentially vulnerable are unlikely to have anything worth targeting.

b) the problem comes when the ship exits jump. The target world can be hours ahead or hours behind where it was expected to be, leaving the pilot seconds to correct course and not a lot of distance to do it in. And this assumes an IN ship on anti-piracy patrol doesn't show up in the origination system during run-up and intercept it.

I see the chance of success being quite small. Much smaller than other means.

 

[Cryton]

Now here is the real question. Why bother with a near c planet buster? Since CT, the Imperium has has A-PAWs. Its the alternate spinal mount for the Tigress class dreadnought. I believe there was even a published adventure where you are sent to secure A-PAWS from a nearby Naval Depot for the defense of the Marches during the Second Civil War.

How they worked in CT was that they strip off one atmosphere code per round, when that hits zero, they strip off one planetary size code per round until you have an asteroid belt. By the way, that stripping is PER A-PAW. Ships or objects hit, even up to the millions of tons size simply vaporize.

So you have to imagine the response when a BatRon of 12 Tigress Class Dreadnoughts and all their accompanying ships (A HUGE number of ships) arrives in your system in response to your near C weapon use.

Heck, imagine the response from ANY insterstellar power. Near C weapons are just not worth it. (And the Darrians do eventually get the Star-Trigger back as well, which if used will destroy one world quickly and will keep any interstellar polity busy for DECADES with world scale evacuations.)

In a TU, using a near C weapon just isn't worth it. To clunky and the reactions to it's use, entirely to final.

 

[Adam Dray]

But a scout courier with a 4-week runup at 1 G (this is a suicide mission, after all) and then exit will have been noted at run-up by week two... and a decent astrogator with the course angle will be able to say, "Hey, he's going to jump at this point"... and the computers are likely to note anyone doing any singular course in N-space for 2 weeks+... because once they hit day 16, it's likely they are on an "unstoppable" course. Jump a ship to just ahead of their day 23 position, and drop a missile at them. End of them.

How does that work? We can detect incoming jumps four weeks out? Incoming jump arrivals at all? (I just don't know the canon here.)

 

[aramis]

Did that make it into any later ruleset, because I don't remember it.

Yes, conceptually, but not worded as such. See T5.09 p.340, Normal Scatter for the T5 version.

Note that Hop and Skip scatter at worse accuracy.

 

[Adam Dray]

III. Method of attack (opportunity)
a) build up to speed in same system as target
b) build up to speed in different system than target

III is really the one that most influences defense.

a) A ship taking a month to accelerate will be noticed by a TL8+ world or any patrolling IN ships. The ship will be dealt with well before it can reach it's target. The few systems that are potentially vulnerable are unlikely to have anything worth targeting.

I'm not yet convinced a ship could intercept and redirect an incoming threat.

Also, every brachistochrone trajectory looks like a normal approach until the halfway point, if the ship fails to flip and burn. By that time, you could have a ship accelerating at 1G for 20 AU (about 2 billion miles or 3 billion km) without anyone really caring.

vfinal^2 = vinitial^2 + 2*a*d
vfinal^2 = 0 + 2 * 9.8 m/s^2 * [1km/1000m unit conversion] * 3*10^9 km

Let's just round acceleration to 10 m/s^2.

vfinal^2 = 2 * 10/1000 * 3 * 10^9 = 6 * 10^6 km^2/s^2 = 6 million (km/s)^2

Taking the square root of both sides:
vfinal = about 2500 km/s (0.0083 c) for 1G acceleration for 20AU.

Compare to Asteroid 2010 NY65, which has a mass of 1.5e+10 kg but is moving "only" around 20-22 km/s.

I found a cool "Asteroid Impact Calculator," in case someone who understands the sizes and densities of starships better than I do, wants to play with it.


Kinetic energy (K) is:

K = (1/2) m * v^2

For K in joules, you need m in kg and v in m/s. Checking a 1000 kg ship at 2500 kps:

K joules = 1/2 * 1000 kg * (2500 * 1000)^2 m/s = 3.125 x 10^15 Joules

1 Joule = 2.39006e-10 Ton TNT, so:

747 kTon explosion per 1000 kg of ship, if I did all my math right. And that's if you accept that the explosion is exactly like a nuclear bomb, which it isn't, because at that speed it's more like a bullet, punching into the crust, creating liquefaction and plasma effects, and so on.

 

[McPerth]

Now here is the real question. Why bother with a near c planet buster? Since CT, the Imperium has has A-PAWs. Its the alternate spinal mount for the Tigress class dreadnought.

I remember having read about A-PAWs (I assume you mean Antimater Particle Accelerator Systms) in JTAS article, but never in other Traveller materials, and, as I understood it, they were just a possibility, probably higher TL than the Imeprium

I believe there was even a published adventure where you are sent to secure A-PAWS from a nearby Naval Depot for the defense of the Marches during the Second Civil War.

I guess you mean the adventure in MT:RS. If so, the weapons system they need the pieces for are disintegrators, not A-PAWs (and BTW, quite less powerful than a single J MG in MT rules).

 

[Carlobrand]

...I see the chance of success being quite small. Much smaller than other means.

I agree, but the attempt alone would create major political ripples, the kind that would change the character of the Traveller setting. A near miss on Regina would prompt the Imperium to park resources in every system within jump range of a significant target, in quantities large enough to block any attempt at a run-up, to avoid even the slight chance that someone might get lucky. There are things about which one might be willing to live with a very low probability of their occurring. Extinction-level events are not on that list, not in a space-faring civilization that has been around long enough to have seen some occur by natural means.

Since the Vilani have been in space for over 10 thousand years, someone's probably already tried and failed somewhere a long time ago, and those resources have already been committed routinely for millenia. That paints a very different picture from the Imperium as it's portrayed in the game settings.

...In a TU, using a near C weapon just isn't worth it...

... to an organization that might be targeted for reprisal. To some terrorist group with nothing to aim at and nothing to lose...

 

[Brandon C]

I agree, but the attempt alone would create major political ripples, the kind that would change the character of the Traveller setting.

Every now and then, in threads on piracy, someone points out that the Imperial Navy is excessively large and as such should have completely wiped out piracy centuries ago.

What if, even though the general public has forgotten about the threat of near-C ships, the Navy hasn't, and stopping them is actually a higher priority than stopping pirates? This would explain why there are SDBs and patrol cruisers all over the place but piracy thrives. Further, when a ship attempting a near_C attack is intercepted and destroyed it is logged as "suspected pirate destroyed after refusal to be boarded and attempting to flee".

 

[Condottiere]

This is the kind of scheme a Vargr might come up with.

It sounds like fun, and they have no institutional memory.