Missile velocities

[TheEngineer]

Originally posted by Sigg Oddra:
So a highly efficient mini-fusion rocket may be the propulsion system? Only trouble are the versions of Traveller that have minimum fusion reactor sizes. I think it should be doable using the MT rules for fusion rockets, and FFS of course.
How about antimatter "catalysed" fusion rockets from THS?

Hi Sigg,

I did not really thought of a complete fusion power plant but a kind of device, which uses a fusion process more directly for propulsion.
Just like those fission bomb drive, just more compact.
Perhaps its working pulsed, too, like:
- create magnetic trap
- feed in fuel
- ignite with laser
- fractional fusion
- open backdoor of magnetic trap
- and again....
Maybe the trapping field could be controlled in a way to allow constant thrust...


@Flykiller:
Really right.
Perhaps their advantage is the tiny size ?
I guess it was the Mayday game, where you could also control movement of missiles, wasnt it ?
Somehow they are just unmanned, oneway fighters on self-destruct mission.

Regards,

Mert

 

[flykiller]

Perhaps their advantage is the tiny size ?

if it makes them very hard to detect, possibly. one is reminded of the WWII japanese "long lance" torpedo. perhaps one could say that their small size allows the use of certain stealth techniques that simply don't work on larger ships. it will depend on whatever sensor rule set is used.

this would get back to the propulsion method. a fusion rocket will be detectable from a huge distance.

 

[marginaleye]

So, then, should missles be struck down for the same reason that fighters ought to be? (that is, that they're not much faster than the targets they're supposed to be hitting).

Introducing a special high-performance handwavium-powered engine just for missles probably would probably cause more trouble than it's worth.

Perhaps redefining missles as "stealthy mines, with limit target-interception capabilities." As defensive weapons, stealthy "sleeping missles" make a certain amount of sense. Offensively, missles are harder to justify, except when being used against intrinsically slow targets with lousy point-defense systems (so in other words, missles, like fighters, would be idea for quickly killing merchant ships, but not real warships).

I could live without missles. Of course, I would also be heretically quite happy if those pesky handwavium-powered meson guns also evaporated, too, so perhaps my opinion isn't worth very much.

 

[flykiller]

So, then, should missles be struck down for the same reason that fighters ought to be?

Introducing a special high-performance handwavium-powered engine just for missles probably would probably cause more trouble than it's worth.

well, I don't know about "struck down". traveller was meant to be an RPG, with only incidental wargame features and only a passing nod to any notion of hard science. attempting to bring a fantasy sci-fi RPG up to hard-science wargame standards is problematic.

Perhaps redefining missles as "stealthy mines, with limit target-interception capabilities." As defensive weapons, stealthy "sleeping missles" make a certain amount of sense. Offensively, missles are harder to justify.

those ideas are similar to the conclusions I'm reaching. I'll probably wind up with a stealthy "long lance" approach, with "fighters" being better described as mini-subs.

 

[vegascat]

Sigg Oddra

Any idea what the maximum range of an AtA missile would be and how long it could maintain a 6G acceleration?

Sorry, to answer those questions would be trouble.
If you check this site, you should find some of the answers you are loking for.
http://www.fas.org/man/dod-101/sys/missile/index.html

TheEngineer

Hope You did not present classified stuff here and going to be arrested for beeing a traitor.

Nothing classified in my missile explanation. The site mentioned above does get a bit more exact.

I do think it is important to have missiles in the game to maintain balance. Their place is as a weapon system type capable of inflicting significant damage on targets at long range. They make sense in a game theory sort of way. It makes you make a choice between shooting at an incoming missile and the enemy. You also should have the opportunity to add countermeasures to your ship to decrease your chances of being destroyed. Countermeasures are more represented by comparing computer sizes.

I use the old CT missile rules, but multiply the trust by a factor of to give them a usable long range.

 

[TheEngineer]

Hi,

thinking about stealth abilities of a missile, I believe propulsion should be pulsed, meaning that the drive will only be engaged for major acceleration and navigation purpose.
The missile should drift silently the rest of the time, approaching the target slowly...just waiting for a last sprint to catch the target.
So, I really like to sub mode

Regarding the propulsion system:
Do we have any official information regarding missile propulsion anyway ?
Is fusion propulsion really handwavium stuff ?
I thought fusion as a quite controlled process in near future Traveller and it might be even easier to use it for propulsion as for energy generation.

Well, I will check other hard-science ways.
Perhaps ionic propulsion systems...

Regards,

Mert

 

[marginaleye]

Is fusion propulsion really handwavium stuff ?
I thought fusion as a quite controlled process in near future Traveller and it might be even easier to use it for propulsion as for energy generation.

Didn't Larry Niven write that a good reaction drive can be used as a weapon, too? I haven't read any Niven in years, but I vaguely recall this idea actually turns up in a couple of his stories. In one, a "primitive" sublight colony ship uses its photon drive (a huge laser, if I recall correctly) to literally chop a more "modern" warship with some sort of gravitic drive to bits, and in another story a supposedly "harmless" exploration vessel is fitted with numerous "attitude control jets" (or some such thing), that also happen to be fusion guns.

I believe there were rules for using maneuver drives as fusion guns in the first edition of Book 5: High Guard (this was, I assume, before a consensus emerged that the "maneuver drives" of Classic Traveller were actually reactionless thrusters). Personally, I think adding rules for a HEPlaR-like "thruster-and/or-weapon" to the High Guard design system might be an interesting experiment. Imagine, say, what a battleship "armed" with a Factor-T Fusion Gun might do (assuming it could get close enough).

 

[marginaleye]

But if missles are redefined as "stealthy semi-mobile mines," then wouldn't it be fairly unusual to actually deploy them in the midst of battle? I can easily imagine the defenders of a star system scattering them around (like tiny, unmanned, suicidal system defense boats, as it were), in anticipation of trouble, but would "offensive" warships carry many (any?) missles -- there wouldn't be many opportunities to use them.

I suppose, however, (1) great hordes of missles might be usable as "instant terrain," to "herd" enemy ships in the right direction (towards ships armed with beam weapons of one sort or another, that would do most of the actual killing), and (2) missles might also be deployed to discourage pursuit and thus cover a retreat. But using missles as one's primary offensive weapon seems harder to envision (however, I certainly do not claim to be a tactician of any sort, and am probably overlooking something clever).

 

[TheEngineer]

Hi,

well, in my thoughts the major difference between "my" fusion propulsion system and a fusion gun is, that the exhausted material does not fuse any more. But its still a plasma, so hmmmmm, we really would have something like a badly focused plasma gun.

O.k. but taking a look at different propulsion concepts and extrapolating them a bit into Traveller near future I am quite optimistic now, that effective 50 kg missiles could be produced at late TL8.

Links:
http://www.vectorsite.net/tarokt2.html
http://wildcat.phys.nwu.edu/classes/2002Fall/Phyx135-2/Projects/Ion_Propulsion/ion_propulsion/engineering.htm
http://www.uic.com.au/nip82.htm
etc.

Regards,

Mert

 

[flykiller]

But if missles are redefined as "stealthy semi-mobile mines," then wouldn't it be fairly unusual to actually deploy them in the midst of battle? I can easily imagine the defenders of a star system scattering them around (like tiny, unmanned, suicidal system defense boats, as it were), in anticipation of trouble, but would "offensive" warships carry many (any?) missles -- there wouldn't be many opportunities to use them.

depends on the sensor rules being used. if missiles are easy to see then given the distances involved their utility in any role is questionable. if missiles are difficult to see then they become quite dangerous, if slow, and nukes can be made outright terminal. screening vessels, so often mentioned in canon, become viable and valuable.

I suppose, however, (1) great hordes of missles might be usable as "instant terrain," to "herd" enemy ships in the right direction (towards ships armed with beam weapons of one sort or another, that would do most of the actual killing), and (2) missles might also be deployed to discourage pursuit and thus cover a retreat.

natural conclusions. a horde of .01c missiles approaching one's formation will tend to restrict maneuver and lower agility ratings.

 

[TheDS]

In order for a beam to hit something, it must know EXACTLY where a target will be (margin of error is equal to the size of the target) when the beam arrives. The beam must track WHILE FIRING. Am I the only person who read the article in Challenge describing the difficulty of hitting targets?

Never mind that, aside from the craziness of gravity-focused lasers, your beam is going to be a spotlight outside a few hundred KM, unless you're using X-rays, and then you can go to about 1-2 light-seconds (iirc). That's with a 1-2 meter focal diameter, mind you. Something that big is going to have to have a hellacious support structure to keep the whole unit aimed in the exact right direction. Even a warp of a micron is going to render the weapon useless.

Now consider the sensor task to GET that exact location. To resolve a small target like a missile at a distance of a light-second, you need a pretty good-sized sensor. That's just to SEE it as a single pixel. You want exact location, so you're going to need a target a LOT less ambiguous than a single pixel. This is the most important part of the problem, because if your aim is off by an attoradian, you will miss. Spotting may be easy, especially for a real loud (bright) missile, but that doesn't make the firing solution any easier to obtain.

So even using a laser in beam-mode does you no good. Beam mode is used to heat the target rather than try and penetrate it. Heat up the target enough and it can't keep itself cool enough; circuits break down, the reactor has to power down, and worst of all, what if your recycling system goes? You're dead in a few days without it, so beam-mode is handy when the target is too far away for pulse-mode.

All this adds up to the effective range of a laser being about 1000 km or so. Sure, you can get lucky and hit a lot farther out, but you're not going to do a lot of damage. You're not likely to kill an incoming missile until it gets a lot closer.

Because killing missiles is so tough, one needs only launch a few of them to have a good chance of doing a remote detonation. Basically, it sets off its nuke at a range, and hits you with the lasers generated in the explosion, as described by another poster.

Launch enough of them, and you can quite possible get a contact, and you set the nuke off then and you don't have to worry about the target any more.

With enough lasers and flak and other stuff, you can shoot down missiles. It's a battle in its own right. There is no clear superiority of missile or beam weapon. Each has its tactical uses, and ships are going to carry them both.

Now as regards the usefulness of dropping mines IN battle... If you are accelerating away from some one, and they are accelerating toward you, you drop mines. You don't even have to launch them; your acceleration will carry you away from them, and your target's acceleration will carry it toward them.

Second instance: your target is heading toward a planet, or some other thing that he has to slow down for. His drive is aimed toward his destination, and his bow is aimed at you (along with his main guns). YOU are also slowing down, because you want to catch him, which means your butt is aimed square at his gun. You drop mines. You're accelerating away from them, he is accelerating toward them.

Those are for universes in which velocity is retained by moving objects, and it doesn't much matter how good lasers are.

If lasers are as wussy as I have described, missiles can easily be launched during combat. They give the target something to shoot at besides YOU. That's the most important reason to use missiles in any setting.

 

[Dom]

Originally posted by Sigg Oddra:
So a highly efficient mini-fusion rocket may be the propulsion system? Only trouble are the versions of Traveller that have minimum fusion reactor sizes. I think it should be doable using the MT rules for fusion rockets, and FFS of course.
How about antimatter "catalysed" fusion rockets from THS?

FWIW, neither HG or Bk 2 are specific about what the M-Drives used are. (Okay, so HG1 did mention using the fusion drive as a weapon, but this was quietly dropped).

 

[Dom]

Originally posted by marginaleye:
I believe there were rules for using maneuver drives as fusion guns in the first edition of Book 5: High Guard (this was, I assume, before a consensus emerged that the "maneuver drives" of Classic Traveller were actually reactionless thrusters). Personally, I think adding rules for a HEPlaR-like "thruster-and/or-weapon" to the High Guard design system might be an interesting experiment. Imagine, say, what a battleship "armed" with a Factor-T Fusion Gun might do (assuming it could get close enough).

Somewhere in my Power Projection file notes I've got a conversion of the MT plasma drive into HG (thus T20 format). I'll see if I can find it. However, I think I also posted it to ct-starships a long time ago.

 

[Dom]

Originally posted by marginaleye:
I believe there were rules for using maneuver drives as fusion guns in the first edition of Book 5: High Guard (this was, I assume, before a consensus emerged that the "maneuver drives" of Classic Traveller were actually reactionless thrusters). Personally, I think adding rules for a HEPlaR-like "thruster-and/or-weapon" to the High Guard design system might be an interesting experiment. Imagine, say, what a battleship "armed" with a Factor-T Fusion Gun might do (assuming it could get close enough).

Somewhere in my Power Projection file notes I've got a conversion of the MT plasma drive into HG (thus T20 format). I'll see if I can find it. However, I think I also posted it to ct-starships a long time ago.

 

[mike wightman]

Dom said:

FWIW, neither HG or Bk 2 are specific about what the M-Drives used are. (Okay, so HG1 did mention using the fusion drive as a weapon, but this was quietly dropped).

Hi Dom,
the fusion rocket I was referring to is from the "One small step" rules for pre-gravitic spacecraft found in Hard Times and a Challenge mag.
TL9, 2730 tons of thrust per dt, 1.68dt fuel per day of thrust, power output 54.6MW
These numbers assume scaling up to a 14 cubic metre displacement ton.
As an aside,I still view a CT maneuver drive as some sort of inertia reduction field around the ship (ties in with the inertial dampers inside) and a small fusion rocket providing thrust. Quite a lot of early CT non-GDW sources used fusion drives in their descriptons (Judges guild, Dragon magazine and Paranoia press IIRC), the thruster plate was a DGP/MT invention AFAIK that came along much later
I'm interested in this MT plasma drive conversion, the more options the better

 

[Dom]

Originally posted by Sigg Oddra:
Hi Dom,
the fusion rocket I was referring to is from the "One small step" rules for pre-gravitic spacecraft found in Hard Times and a Challenge mag.
TL9, 2730 tons of thrust per dt, 1.68dt fuel per day of thrust, power output 54.6MW
These numbers assume scaling up to a 14 cubic metre displacement ton.
As an aside,I still view a CT maneuver drive as some sort of inertia reduction field around the ship (ties in with the inertial dampers inside) and a small fusion rocket providing thrust. Quite a lot of early CT non-GDW sources used fusion drives in their descriptons (Judges guild, Dragon magazine and Paranoia press IIRC), the thruster plate was a DGP/MT invention AFAIK that came along much later
I'm interested in this MT plasma drive conversion, the more options the better

It's the MT Plasma Drive from HT and One Small Step I converted. Looking for it now.

 

[Dom]

Originally posted by Dom:
]It's the MT Plasma Drive from HT and One Small Step I converted. Looking for it now.

Just found it... here you are...

From:   SD Mooney < dom@c... >
Date:   Fri Jun 16, 2000  12:23 am
Subject:   HG Fusion Drives


I just (re)sent this to TML, but realised it predates SCTA /
CT-Starships. So I've cross posted as I'm more likely to get feedback
here. It's an MT Fusion Rocket (from _One Small Step_ in Challenge
and Hard Times) converted back to HG.

Comments welcome!

Dom


At 17:26 +0000 5/11/98, SD Mooney wrote to the TML:

HG Fusion Rocket, TL9
--------------------

Average mass/displacement ton for ships from MT Imperial Encyclopedia entries -

Civilian - 10T/dT, Military 30T/dT

(Averaged and rounded - initially I looked at FSSI but the figures
were all over the place).

Fusion Rocket TL9
TT(Tons Thrust) 195
Vol 1kL
Fuel 0.005 kL/hr
Power Consumed - 0
Power Generated 3.9MW

Covert to 1dT unit (ie x 13.5)
TT = 2632.5
Vol 1dT
Fuel consumed = 0.0675 kL/h
Power Generated = 52.65 MW

Rounding...

TT = 2600
Power = 50MW = 0.2EP

100dT hull
Civilian mass = 1000T
Military mass = 3000T

Accel = (mass Thrust / mass ship)

Civilian -- 1dT drive
2600/1000 = 2.6G

Thus military = 0.9G

Convert to % and expand to get drive dT

Thrust Civilian% Military%
1G 0.4 1.2
2G 0.8 2.4
etc

nG n x (0.4) n x (1.2)

----

Taking dT
--------

Fuel for 1 G Turn (20min)

= 0.0675/3 = 0.0225 kL/h

Fuel consumed in 1 turn = 0.0225 x (drive mass) kL

Hence fuel required = (turns of operation wanted) x 0.0225 x (mass of
drive in dT) /13.5

EP output = 0.2 x (mass of drive in dT)


(c)2000-2004 Dominic Mooney

 

[Dom]

Originally posted by Dom:
Civilian - 10T/dT, Military 30T/dT

(Averaged and rounded - initially I looked at FSSI but the figures
were all over the place).

This is the one grey area, as it is the MT specific bit. You could, if you prefer, just assume an average thrust of 20T per dT to simplify this.

 

[mike wightman]

Thanks for that Dom.
I can see the problem is that military craft are armoured and so more dense.
How about taking the civilian % requirement (0.4% of hull tonnage per G) and multiplying by a factor based on the armour % fitted.
Off the top of my head if you took the armour % and divided by 4, round up, you would get a factor to multiply the maneuver drive requirement tonnage by to get the desired G rating.
I think I'll play around with it a bit more
Thanks once again,
Mike

 

[James Heard]

Another thing that you should be able to take advantage of with missiles is the fact that releasing great big heaping loads of them outfitted with even minimal sensors and communications should allow you acquire targets really outstandingly well thanks to being able to check their targets from lots of different angles. Not only would missiles be bad things to fly through, they'd be a legitimate reason to have missile frigates and such as escorts.