Relativistic Weapons

[Gentleman John]

Just following an idea that has come up from the Jump Torp thread: accelerating masses to near-c and using them as weapons. Is it a good idea? Can it be done?

Well, I'm going to lay out my stall here and now on these questions.

Is it a good idea? My answer to that is an emphatic: NO! Tossing around any mass at near-c is a bad idea. It's even worse when you start aiming it at other sophonts as a weapon. This doesn't mean that you can't have them, but I am sure that in most game settings they would be banned weapons (Lensman- and Eschaton-based games not withstanding).

They have been tacitly recognised in the OTU under the heading of "non-conventional attacks" in the Pocket Empires rules for T4, but their use in the Third Imperium and its neighbours seems to be considered in low esteem.

Can it be done? Well, that depends on your interpretation of things in Traveller, specifically the maneuver drives. In the days of CT, when maneuver drives appeared to be reactionless, then it was merely a case of having enough fuel to keep the powerplant going for long enough. In later versions of Traveller, the maneuver drives became more realistic and the use of relativistic weapons became less of an issue. While there is no explicit statement in MT about maneuver drives, the fact that MT is very close to CT suggests that reactionless drives are back - and so is the possibility of relativistic weapons.

However, in the spirit of Winchell Chung's statement, "Friends do not let friends play with reactionless drives in their universe", what do other people think?

 

[rust]

Until now we had two attacks on a planet with unconventional weapons in
our non-OTU campaign, one a (slow and small) asteroid, the other a hy-
perspace drone (= jump torpedo) with a fusion warhead that came in at
near-c.

Both attacks came from the security service of a very powerful, but in al-
most all places illegal "megacorporation" that produces and sells genetic
slaves (= cloned slaves). This "corporation" had an intense dislike for the
colony it attacked because this colony accepted escaped slaves as immi-
grants, which encouraged slaves to flee.

So, I think that this kind of attack is plausible as a kind of terrorist attack,
provided the terrorists in question have lots of money to spare and like
especially mean and spectacular ways to kill and spread fear.

However, I cannot imagine such attacks as legal methods of civilized war-
fare. Like ABC-weapons of mass destruction in our real world, they would
almost certainly be banned in any futuristic setting that does not accept
the idea of total war against civilians.

 

[far-trader]

My simple answer has long been that gravity drives may be reactionless but you'll never get up to a significant fraction of C using them because of efficiency limits. They only work on nearby significant masses and performance falls off sharply as you move further away, to nil long before you could gain any significant velocity. I break it into three groups iirc. Low power (typical of vehicles like the Air/Raft and grav belts) best for no more than 1 diameter of a large mass (drops to zero at 10 diameters). Medium Power (typical of small craft drives) good for no more than 10 diameters (drops to zero at 100 diameters). High power (the large craft drives) good for no more than 100 diameters (dropping to zero at 1000 diameters).

So how fast can you get going at 6g in 100 diameters? That depends on what you're pushing off of. And then your thrust starts dropping off rapidly from there.

Or you could simply rule that like in real physics as you accelerate a mass to C the energy required keeps going up. And iirc the energy needed to achieve C for any mass is infinite. That's a bit more than your Powerplant can put out

So allow a certain velocity to be achieved at the base power requirement, then require double the power to double the speed, and so on. Not a real physics rule, just a quick handwave to muddle through.

Or just peg a maximum velocity for any drive based on it's rating.

It's not so much "friends don't let friends fly reactionless space ships in their universe", as "friends don't let friends fly reactionless space ships at velocities approaching fractions of C in their universe"

 

[Beastttt]

just having a moderate sized object to toss at planets at orbital velocities is going to fo a lot of damage

a 100 ton rock moving under 6 g's of acceleration for a day is going to put a lot o hurt on somebody

 

[Xoph]

If the rock is moving at a sane speed the players could intercept and try to do somthing about it, like in many of your favourite films, sci-fi shows, and video games.

 

[far-trader]

Let's put it this way...

...ignoring the physical impossibility of near-C rocks without magic drives, if it could be done it would have been done. And the universe would be nothing but smoldering ruins of broken planets. The fact that it's not (in most people's universes at least) has to mean near-C rocks and their ilk don't exist.

 

[rust]

If the rock is moving at sane speed the players could intercept and try to do somthing about it, like in many of your favourite films, sci-fi shows, and video games.

Right, but an asteroid of 100 tons is quite small and has no measurable
emissions, and if it comes straight at you there is not much movement
to see from your point of view ...

 

[rust]

The fact that it's not (in most people's universes at least) has to mean near-C rocks and their ilk don't exist.

Or at least that their use is very, very rare. Remember, we do have lots
of nukes here on our planet, but our cities are not all smoldering ruins.
The fact that a certain kind of weapon does exist does not mean that it
is used - at least not often.

 

[Xoph]

the universe would be nothing but smoldering ruins of broken planets..

I thought it was? Isn't that the whole deal with an ancients and their war? Aren't there a few asteroid belts that are most likely made from planets destroyed in the ancient’s mysterious war?

 

[Beastttt]

unless it the rock has a stealth coating radar and Lidar will see
also it may block the light from a star so a careful plot will be needed

also the ship/s tossing the rocks may simply tag along to gaurd/ heard them so any ships coming to deflect them will have to deal with the gaurd/s first

it will be a race can you disable/destroy the gaurds before the rocks hit

 

[rust]

unless it the rock has a stealth coating radar and Lidar will see

True, but with the average equipment of a colony world this would not
give you a lot of time for a meaningful reaction, I think. Provided the
sensors are able to pick up something as small as perhaps 5 m x 5 m
x 4 m (100 cubic meters) at several thousand kilometers distance at
all ...

 

[Beastttt]

I figure there would be the equivilent of the sensors of a 100 ton scout around the colony at 3 points to give good coverage along with what ever ships boats that are left with the colony if the ship either left or was dismantled to make the colony

 

[Beastttt]

more like a few light minutes
since we are talking about a rock moving at orbital velocities
also all the things that could run into the planet in that system would be plotted so a running scan to make sure everything is where it belongs
along with checking for any fusion plant sources

unless it the rock has a stealth coating radar and Lidar will see

True, but with the average equipment of a colony world this would not
give you a lot of time for a meaningful reaction, I think. Provided the
sensors are able to pick up something as small as perhaps 5 m x 5 m
x 4 m (100 cubic meters) at several thousand kilometers distance at
all ...

 

[rust]

Yes, I agree. If I did not misunderstand the rules, these sensors might
pick up the rock at a distance of around 50,000 km at best, and then
it depends on what kind of equipment is available, how fast decisions
are made, and how fast the equipment can be deployed.
To avert the impact could be an easy job under good circumstances,
but it could also be a race against time - or simply impossible.

 

[aspqrz]

Just following an idea that has come up from the Jump Torp thread: accelerating masses to near-c and using them as weapons. Is it a good idea? Can it be done?

Oh my Gawd! :shock:

No! No! NO!

Rocks at Cee alert! :shock:

The End Times are near! :wink:

Phil

 

[rust]

The End Times are near! :wink:

A nice scenario for Cthulhu End Times ? :lol:

 

[far-trader]

The fact that it's not (in most people's universes at least) has to mean near-C rocks and their ilk don't exist.

Or at least that their use is very, very rare. Remember, we do have lots
of nukes here on our planet, but our cities are not all smoldering ruins.
The fact that a certain kind of weapon does exist does not mean that it
is used - at least not often.

That's as much luck over a very short time compared to the age of the OTU for example. But we don't want to cross into (real world) politics and I have a feeling most won't take OTU examples as useful arguments.

To whit the OTU is full of examples of people with grudges and starships. See the thing is you don't need multi billions of dollars of restricted military technology and hardware (nukes) to do it. Just a simple starship that can be easily stolen or bought and a willingness to crash it.

 

[rust]

To whit the OTU is full of examples of people with grudges and starships. See the thing is you don't need multi billions of dollars of restricted military technology and hardware (nukes) to do it. Just a simple starship that can be easily stolen or bought and a willingness to crash it.

True, but then one really does not need to "go relativistic", it is quite suf-
ficient to crash a normal starship at a normal speed into a city or some
vital piece of infrastructure. According to your view of the OTU, such ter-
rorist attacks should be quite common, it seems ?

 

[Xoph]

The Rescue brings it up; so it isn't entirly uncommon.

 

[far-trader]

To whit the OTU is full of examples of people with grudges and starships. See the thing is you don't need multi billions of dollars of restricted military technology and hardware (nukes) to do it. Just a simple starship that can be easily stolen or bought and a willingness to crash it.

True, but then one really does not need to "go relativistic", it is quite suf-
ficient to crash a normal starship at a normal speed into a city or some
vital piece of infrastructure. According to your view of the OTU, such ter-
rorist attacks should be quite common, it seems ?

Excepting my TU civilization is mature. Most people with access to starships are held to rigorous standards and known to be stable, sane, and would never do such a thing. And few who own and operate a starship do so without a high level anti-hijack system in place to prevent unstable persons from doing stupid things with a starship. So it's very very rare that such things happen. But the universe is big enough and old enough that it has happened a lot. Enough times that if near-C velocity was a reality there would be very few intact worlds left.

Naturally I don't expect PCs to be part of the mature, stable, and sane group of starship owners