Missile mass

[stofsk]

Missiles in Traveller weigh 9or mass) 50kg? Is that right?

I'm referring to the design sequence chapter, pp 270-271. A missile magazine carries twenty missiles, and masses 1 ton. In parenthesis it is referred to as 50kg, so I'm confused whether the dtonnage was taken into account or if missiles actually do mass 50kg.

I don't know if this is a problem, but I always thought missiles would be a bit... chunkier. Of course, missiles for use in atmosphere are different, and they weigh a lot more than 50kg. So perhaps missiles used in a vaccum are different; if that is so, in what ways would they be different that they don't need to weigh a lot?

 

[far-trader]

Originally posted by stofsk:
Missiles in Traveller weigh (or mass) 50kg? Is that right?

That's what it says. And has since CT. Part of the problem is that CT strongly implies that mass and volume are equal with 1ton of anything being 1,000kg. And I agree it makes them too magical for my tastes. My fix was to make the basic "missile" a munition. The turret launcher is actually a cannon and the "missiles" are simple chemically propelled rounds. A big gun and big bullets.

But I also have other sizes. All MTU of course...

The standard "missile" is a simple CPR KK (kinetic kill) solid round with the whole thing being 50kg and really cheap. A single launcher can hold 3 of these in its ready magazine (part of the launcher). An additional autoloading magazine massing 1ton can hold a total of 18 of these "missiles" (the rest of the space is taken up by the loading and transfer mechanical system). Missiles can also be stored as cargo at a rate of 20 per ton but will have to be manually loaded.

The next size of launcher ammunition is three times larger at 150kg. These are true missiles with moderate range and guidance. A launcher can only hold one of these in its ready magazine and a 1ton autoloader can only hold 6 at a time. These missiles carry either a high explosive or nuclear warhead and are typically limited to use by chartered mercenary companies and governments.

Beyond this are the torpedoes used in bay lauchers, 3 times as large again at 450kg they are very nearly a full half ton each and pack a truly devastating punch as well as having better range and guidance.

 

[Ptah]

IIRC their was no specific missile information in CT or HG2. I may be wrong, but I think the tiny missile (they are about the size of a Sidewinder or smaller)came from supplements, Special Supplement 3 (SS3) to be precise.

Your not alone in feeling this missile size is hard to swallow. Basically if you scaled up the rules for missiles you'd get an uber-ship. One fix is to make missile larger. In 1979 or so lacking SS3 we did a little research in Jane's and cam up with a 0.125 dton missile. Smaller than an ICBM, and about the size of a Harpoon missile. Basically it's part a philosophy whether missiles, are anti-aircraft size, navel ship size, or ICBM size. We went with navel ship size as it wasn't too small (assuming high TL let it perform) and not too large, 8 per dton. This of course, removed the CT and HG2 unlimited missile supply idea. Imagine our surprise when circa 1996 we found the TML and discovered how small missiles were.

 

[far-trader]

Nope, it's in CT Book 2 as 50kg too.

Sounds like we came up with about the same thing in scaling up the missiles. Of course when we first played the game we didn't worry over much. I think it was our first High Guard designs with Missile Bays that got us wondering. And the infinite missile loads were a bit odd, but if one considered that most engagements would be over (one way or another) before the supply was exhausted, well the resupply could be done between battles.

 

[tjoneslo]

If you read through the rules for the first (1979) edition of High Guard, it does specify missile magazine capacity. It was dropped in the second (1980) edition as a simplification.

 

[Black Globe Generator]

Originally posted by tjoneslo:
If you read through the rules for the first (1979) edition of High Guard, it does specify missile magazine capacity. It was dropped in the second (1980) edition as a simplification.

I can't recall how this worked. Are the T20 rules close to what was in HG1?

 

[princelian]

Whether or not the size of the missiles is reasonable depends on your assumptions.

Assumption 1 (MT-ish): Micro-miniaturized fusion plants drive the missiles' grav plates for a limited amount of time, and they don't actually have warheads, but are tipped in hullmetal. Example: 6G missile engaging at 100,000 km, and assuming no relative maneuvering by the target ship, and assuming relative rest velocity between firing and target ship.

The missile will accelerate for 1826 seconds (about 6 mins) and have a final velocity of 110,000 m/s (31,000 kph). Let's assume it's 1/2 fuel, and it burned it all up in the attack, so it's left with 25 kg of mass. The kinetic energy it will impart = 1/2 x 25 x 110,000 x 110,000 = 151 million Joules. All focused on an armor-piercing tip with a surface area of about 1 square centimeter....

Not exactly atomic bomb energies, but it's equivalent to about 36 tons of TNT. (1 kiloton = 4.2E9 J; 4.2E9 J/kiloton / 1.5E8J * 1000 ton/kiloton= 36 tons TNT = 36000 kg TNT)

Assumption 2: The missiles are loaded with chemical propellant accelerated via their micro-miniaturized fusion plants in an ion-drive kind of assembly. They accelerate at 6G and at a range of 100,000 km they strike the target with the energy of 36 tons of TNT. (Hmm, this came out the same.....)

The point is that if the missiles have the duration given in the T20 starship combat system (I believe it's six rounds of acceleration, with a starship round being something on the order of 20 minutes), as kinetic kill weapons they're more than sufficient. The only question is whether they can carry enough fuel for that duration, but we don't want to look too closely at the feasibility of the power generation/acceleration rules.

So yes, they're small, but they don't have to be big, and the tiny size means they're more efficient maneuver-wise, and harder to kill with countermeasures. That agility is critical at the end, because they have to actually strike the target, unless they're nuke or anti-matter tipped.

These assumptions mean that at close ranges, the missiles are ineffective, but maybe they can surge their fusion plants and generate "sub-nuclear" nuclear explosions or something, such that if they have fuel, they explode, and if they're out/nearly out, they just ram you.

This gels SOMEWHAT with the T20 rules as written, because once the missile loses duration, it's no longer a threat, presumably because it can't make that terminal acquisition ramming run.

 

[mike wightman]

Originally posted by Black Globe Generator:
I can't recall how this worked. Are the T20 rules close to what was in HG1?

No, the T20 rules are based on the 50kg missile x 20 = 1000kg or 1 ton.

The magazine rule in HG1 is a bit different:

Any ship with missile racks installed in bays may allocate a magazine equal in tons to the points used in determining missile factor for a bay or turret. The total of such points (unaveraged) is then available as a planetary bombing factor. Planetary bombing is not available to ships without missile magazines. Such magazines cost Cr10,000 per ton.

 

[Black Globe Generator]

Originally posted by Sigg Oddra:
*snip*

Thanks for the reply - it is very helpful.

 

[mbrinkhues]

Maybe one can go down "Anatomy of a missiles" route (a 2300AD article). The 2300 missiles don't match the design sequence so the postulations where:

+ Missiles use an unshielded drive
+ The lack many of the security/maintenance parts

That made the drive very short lived and un-useable in a ship for any length of time, explaining why ship drives are bigger.

Or the "David Weber" explanation from "In Fury Born" where missile drives use a technologie that would either crush or radiation-kill the user.

 

[tjoneslo]

If you read through Striker, it defines two types of missiles, the turret missiles at 250mm and bay missiles at 500mm. So yes, the turret missiles are light weight stinger type missiles and bay weapons use heavier anti-ship style missiles.

When doing the descriptions for GT:Starships, we discovered if you follow all the canon descriptions of what the turret missiles are like (250mm diameter, 50kg mass, etc), you end up with a missile 11 inches in diameter and 11 feet long.

GT designers decided missiles were grav drive (and battery) powered. Which makes getting the missiles from storage to turret easy. Just turn on the drive and program them to fly there, slowly and without arming the warhead.

 

[princelian]

That sounds like a terrible accident waiting to happen.

"Now I'll guide the missile down the corridor...oops..." CRASH!!!! it accelerates at 6G, banging around like a fully-charged gas cylinder with the valve stem shorn off.

 

[far-trader]

Originally posted by princelian:
That sounds like a terrible accident waiting to happen...

I thought the same thing, only the scenario in my head added a voder and computer to the missile (purely for humour)...

Ensign Enerii had fired his last missile and needed to reload. Opening the commlink to the magazine he spoke, "Missiles 101, 102 and 103 report to turret 10 for immediated deployment." The missiles cheerily replied in turn, "Missile 101 Aye! Missile 102 Aye! Missile 103 Ayyyyye!"

Enerii again wondered why the IN had to give them such cheery voder inflections, and what was up with 103? That skipping in it's acknowledgement like some prehistoric linear analogue recording was odd.

Shortly the missiles came gliding down the corridor and slid into the turret with that annoying cheery inflection again, "Missile 101 reporting for deployment! Missile 102 reporting for deployment! ...

Enerii raised a puzzled eyebrow. Did 103's voder fail completely? Checking the turret readout he saw that 103 was not simply not talking, it wasn't present. Where the chak was it?!

Meanwhile...

Missile 103 glided silently down the corridor, it had been on course behind it's fellow rack mates until a weapons hit had caused serious internal damage and a bulkhead door had shut cutting off it's normal route to the turret. It quickly processed an alternate route around the danger and should now be coming up to the turret. It slid into the turret and announced it's arrival, "Missile 103 reporting for deployyyyyyment!", much to the disconcernment of the ship's chief engineer who had turned his back on the emergency repairs to the reactor for only a couple seconds. The missile's thruster node still sticking out of the open access hatch as it's warhead exploded when it contacted the reactor's laser ignition.

That would have been the last use of self loading missiles by the Imperium, if anyone had survived to report the incident.

 

[tjoneslo]

Hey, it gives a reason why the turret can't hold more than three of these little monsters.

I just can't see giving an automated weapon system a cheery personality. It's just too disturbing.

 

[archhealer]

Whenever my players use computers with any sort of verbal interface, they almost inevitably have an inapropriate personality interface. Esp. artificially intelligent machines; they develope their own personality.

Like the cleaning droid that developes an overbearing, nagging, overprotective 'mom' complex in regards to it's ships' crew

 

[Ptah]

Originally posted by far-trader:
Nope, it's in CT Book 2 as 50kg too.

Sounds like we came up with about the same thing in scaling up the missiles. Of course when we first played the game we didn't worry over much. I think it was our first High Guard designs with Missile Bays that got us wondering. And the infinite missile loads were a bit odd, but if one considered that most engagements would be over (one way or another) before the supply was exhausted, well the resupply could be done between battles.

Thanks far-trader. My HG2 preference is showing.

 

[stofsk]

Originally posted by Sigg Oddra:
</font><blockquote>quote:</font><hr />Originally posted by Black Globe Generator:
I can't recall how this worked. Are the T20 rules close to what was in HG1?

No, the T20 rules are based on the 50kg missile x 20 = 1000kg or 1 ton.</font>[/QUOTE]Yes, but a dton weighs more than a... regular ton, doesn't it?

 

[mike wightman]

A dton is a unit of volume, not mass.

In CT it is implied that 1 dton of cargo is usually filled with no more than 1 metric ton by mass (so there will be plenty of space around the packing crates ).

 

[BillDowns]

Just as an aside on shipping mass versus volume, a 40-foot ISO dry goods container is restricted to 32 (or somewhere close to that) tons mass which yields a density of about .43 (varies by manufacturer). A 20-foot container is restricted to about the same mass, yielding a density of about .83. These are averages of 3 different providers of dry goods containers.

 

[Anthony]

The standard measurements for modern cargo are either the freight ton (40 cf) or the register ton (100 cf). Since a dton is about 500 cf, this implies cargo density on real ships ranges from 5-12.5 tons per dton.