Roadblocks

[Chaos]

I guess most of you who have played Star Wars games or read any of the later novel are familiar with the Interdictor Cruiser - a ship that projects gravity, which in turn prevents ships from going into hyperspace. I´ve always found this concept fascinating, and thought that, IF this is possible, it would be so useful that nobody could NOT use it.

Now, since Traveller FTL travel works in an entirely different way, I came up with a different but nonetheless very useful application of the principle. I call it the Roadblock Monitor.

The Roadblock Monitor (or RM) is a ship that is essentially a huge gravity generator with minimal maneuver drive, or none at all, in which case it would be towed into position. I envision it being built with Jump-1 capacity, but it would probably shipped to its destination in pieces and assembled locally, as not all systems where it would be used are part of a main; however, it needs Jump-1 to work, as you will see.

The RM would be positioned in a straight line between the inner system it protects and a (potentially) hostile system from which an attack force might be sent. I think 12 light-hour or about 13 billion kilometers would be a good distance. Once in position, the RM would activate its gravity generator, ideally one that is powerful enough to simulate the gravity well of a gas giant.
If I understand jump rules correctly, any ship that jumps "through" the 100 diameter limit of a planetary body is dropped out of jump at the 100 diameter limit. This is precisely what would happen to an attacking force that gets too close to the RM´s simulated gas giant - they drop out of jump far outside the system.
Upon having "caught" the attacking force, the RM switches off its gravity generator, sends a warning message in-system and jumps towards the inner system to escape from the attacking force.

The attacking force now has three possible choices.
The first is, jump further in-system, which takes them a full week, and uses up jump fuel they might want to keep for the return jump.
The second is, fly in-system by normal means, which would probably take even longer.
The third is, jump back where they came from.

If the attackers decide to continue their attack, the inner system will know about them 12 hours after they have appeared, (because the warning will take that long to arrive at the speed of light) and will have at least about a week´s advance warning, which is probably an invaluable advantage.

 

[CosmicGamer]

Let me start with just a personal observation in regards to roleplaying and combat. Some people tend to play their character instead of roleplaying their character. What I mean by this is often people come up with elaborate tactics that their character never would have. The opposite can be true too, a player may not be able to come up with a solution even though their character has Tactics-5 and Int-D.

Personally, I don't think the details should effect the outcome. IMO, the GM should simply compare the abilities and stats of the opposing PCs and NPCs and the tools they have available to give the proper DMs and let the die roll.

I do want to applaud YOU (not your character) for trying to add some details and get players more into the game.

Now, to discuss your Roadblock defense.

I can think of numerous possible tactics to counter it if you know it is there or think it's possible because you possess or have heard of this technology.

Usually any organized attack will include reconnaissance to determine enemy defenses.

Does the device maneuver in order to stay between the two opposing systems as they go about their heavenly dance?

I'm no scientists and don't know the details so here are some things for those who want to get into the details to consider.

Technically, should this device even be possible?

You would need to leave this device in constant operation. How much fuel will it be consuming?

If your simulating the gravity of a gas giant, what effect will it have on the nearby celestial bodies?

Last, It is my opinion that this is a use once item, since once an opponent knows about it there are numerous ways to counter it; how much would it cost to build one and would that be cost effective?

 

[Chaos]

Let me start with just a personal observation in regards to roleplaying and combat. Some people tend to play their character instead of roleplaying their character. What I mean by this is often people come up with elaborate tactics that their character never would have. The opposite can be true too, a player may not be able to come up with a solution even though their character has Tactics-5 and Int-D.

Personally, I don't think the details should effect the outcome. IMO, the GM should simply compare the abilities and stats of the opposing PCs and NPCs and the tools they have available to give the proper DMs and let the die roll.

I do want to applaud YOU (not your character) for trying to add some details and get players more into the game.

Not sure what you are talking about, but thanks.

Now, to discuss your Roadblock defense.

I can think of numerous possible tactics to counter it if you know it is there or think it's possible because you possess or have heard of this technology.

Usually any organized attack will include reconnaissance to determine enemy defenses.

Does the device maneuver in order to stay between the two opposing systems as they go about their heavenly dance?

I'm no scientists and don't know the details so here are some things for those who want to get into the details to consider.

Technically, should this device even be possible?

You would need to leave this device in constant operation. How much fuel will it be consuming?

If your simulating the gravity of a gas giant, what effect will it have on the nearby celestial bodies?

Last, It is my opinion that this is a use once item, since once an opponent knows about it there are numerous ways to counter it; how much would it cost to build one and would that be cost effective?

I am curious to hear about your counters. I can imagine one: having the attacking force jump in two groups, the first forces the Roadblock to retreat, the second is the real attack force.
And the thing is, any weapon or tactic or piece of equipment can be countered - BUT, once you have it, it is up to the enemy to come up with something to counter it, so first of all, it will be uncountered and effective for a while, and second, you have the enemy forced to react to your invention, rather than the other way around.

You are right, though, the Roadblock would need to maneuver. I think its gravity would not be much of an issue, as it is far outside the planetary orbits - any distance up to 182 billion km (one light-week) would work, but the further out, the less the interval between alert and arrival of the enemy.
If I remember correctly, some astronomer determined that binary stars do not affect the movement of each others´ planets if the distance between the stars is at least 3.5 times the orbital radius of the planets - so I guess any Roadblock would be safe stationed at least 3.5 times as far from the star as the furthest planet - that would be 15.75 billion km in our solar system. It might mess up the Oort Cloud a bit, though.

The size and cost of the item would of course depend on how feasible the GM/worldbuilder wants to make them, and how big the gravity well is supposed to be. Artificial gravity and inertial compensators (which use the same general technology) do not seem to be a major cost or size factor in building starships, so a Roadblock of size X may not be more expensive than a warship of the same size.
As I see it, they need not be particularly expendable, either - when the enemy pops up, he is 100 diameters away (5-15 million km, depending on "size") and the Roadblock can jump away any time.
Generally I guess the whole thing would be more feasible for rather narrow borders, such as the Imperium/Zhodani border in the OTU.

 

[far-trader]

The easiest counter to it, and whether you know it's there or not you would probably attack thusly anyway, is to jump from a different origin point. Or several if you are coming in force.

You don't want to be coming in where the defenders are looking or in one big bunch, and space is a big volume. You could jump prior to the attack jump to come in from a "flank" (including "above" or "below") or even "behind" rather than a frontal attack from your side of the border. You don't even have to come in from another star system.

Of course, to make the idea work, and that's a valid goal if it makes the game fun, you could eliminate or counter this tactic in various ways.

 

[far-trader]

For the Interdictor Cruiser role Traveller does have that, at TL21+ in MegaTraveller. In the form of a Jump Damper bay "weapon" (might be available earlier as a spinal mount but it's not listed).

I don't recall actual rules for the use of them though. Just that it denies targeted ships the ability to jump.

 

[CosmicGamer]

I am curious to hear about your counters. I can imagine one: having the attacking force jump in two groups, the first forces the Roadblock to retreat, the second is the real attack force.

strategy 1 for can't go around and have to go through it for some reason

Step 1) First jump can be a single ship or very small fast attack force. If the device you mentions exists they can try to destroy it before it gets away or if the device jumps, it has now been neutralized for quite some time. If there is no device or it was inoperable/refueling, the ship(s) then Jump out or they can try to distract and draw off defenders.

Step 2) A few hours later a second ship or very small fast attack force Jumps away and has the same mission as the first. This is in case there are 2 devices in line with each other.

Step 3) A few hours later the main force Jumps, possibly attacking before the warning message has even arrived. You indicated the device is 12 light-hours away.

strategy 2 for can't go around and have to go through it for some reason

If a RM device is possible then why not an Anti-Grav Generating ship that can lead the attack force and counter any gravity fields.

The easiest counter to it, and whether you know it's there or not you would probably attack thusly anyway, is to jump from a different origin point.

That was also one of the things I thought of and specifically to come in along normal "shipping lanes" with at least part of the attack force.

Also, space isn't completely empty. Would the gravity field possibly pull in meteors, comets, and other space "debris" and could the device handle these impacts? Our planet is constantly getting bombarded by such objects (shooting stars) which usually get burnt up in our atmosphere.

 

[far-trader]

...Also, space isn't completely empty. Would the gravity field possibly pull in meteors, comets, and other space "debris" and could the device handle these impacts? Our planet is constantly getting bombarded by such objects (shooting stars) which usually get burnt up in our atmosphere.

Not completely empty no, just mostly. I'd think simple laser turrets in a point defense role would handle the small stuff no problem. And the bigger stuff would be well mapped and simple to just maneuver the ship around in the unlikely case it came close.

 

[Icosahedron]

Of course, you can build what you want IYTU, but...

If the ship is trying to generate 'the gravity of a gas giant' (eg several G at a distance of tens or hundreds of thousands of km) the gravity at the craft surface would be self-destructive.

Alternatively, with a more manageable gravity field, your ship would only mask at best 100 times its own diameter - which wouldn't be much of a barrier.

My disbelief won't suspend that far, I'm afraid.

 

[Chaos]

Okay, I am beginning to see that the Roadblock isn´t really feasible. *sniff* I liked it, though. But then, I always like my weird idea.

I suppose, though, that this will not stop whacky scientists in a TU from coming up with ideas like this, or whacky dictators from pouring loads of resources into it as their pet Super Secret Weapon project.

 

[far-trader]

Don't give up so easily Chaos

Let's see...

(puts on mad scientist lab coat and wig... )

Vat ve need, af Iam unterstanting currectly ist a vay to make ships com ut of zump, ya?

Hmm, maybe a charged net barrier of sufficient power to affect jump space. It wouldn't be cheap, or small, but if we're talking something the big bosses have that no one else does that works fine.

So off the top of my head I'd say price and power it as a jump drive for the effect. With a hull size determining the volume of ship it'll snare.

For example:

You want to set up a snare (rather than calling it a roadblock as it's a net) for ships up to 200tons with J1 drives. So you build a minimum 200ton hull with J1 drive, P1 powerplant, a bridge and computer model/1 and fuel. Other features (such as maneuver drives and a jump drive to travel with) are optional.

Each time you activate it takes the full J1 fuel (20tons) to provide an interference screen for two (space combat scale) turns across a large (undefined on purpose) area. IF any 200ton or smaller ship crosses the area at J1 during that time they are precipitated out of jump at the line. Probably harshly. If the ship is over 200tons or the jump was greater than J1 then they are unaffected. Scale up fuel as needed for a suitable duration. Perhaps place it close to a gas giant and provide fuel shuttles for ease of maintenance.

If that's clear. Of course it opens up a huge can of gas giant leviathan worms, so be warned you tread into dangerous territory.