TL 10 Kinetic kill missile

[Carlobrand]

At TL 10, it becomes possible to design a kinetic kill missile using MegaTraveller's design system, given certain assumptions: the canon missile body is too small to carry much detection gear and must depend on a launcher for guidance to target (at least until terminal phase), and the missile body is too small for communications gear that can range back to the launcher, so the communications gear is assumed to be receive-only.

At 10G, these missiles have a range of over 54,000 km. They can chase down fleeing 6G spacecraft within 21,000 km in deep space and still hit with considerable power. Moreover, they become quite deadly in planetary defense, where the stronger gravity within 10 diameters allows them to achieve 20G and a potential range of 109,000 km. At 20G, they impact with energy equivalent to almost half a ton of TNT per kg. after 10,000 km flight and 50 kg of TNT after only 1000 km flight. Higher tech missiles can achieve greater acceleration and greater range as stronger, lighter materials become available for the shell and battery life increases.

Attackers must essentially stand out of range of the missile for safety and then close rapidly to close orbit to conduct bombardment or troop-insertion missions at a range that minimizes potential damage. They are vulnerable during the approach and again while departing.

Missile	TL 10	Wt. (kg.)	Vol. (m3)	Pwr (Mw)	Cost (Cr)	Comment
Hull:	0.1m3=0.007dT	10.582			423
Config.:	cylinder			0
Streamlined?	Yes	[TD]		+Cr85
Airframe?	No
Armor:	TL 10 Crystaliron, F. 8	-4.02 (can be negative)			+Cr 610
Environment:		0.50	0.0005	-0.0001	Cr 1
Computer:	none
Densitometer:	TL 10 Low-P	1.00	0.020	-0.0020	Cr 10,000
Radio	TL 10 V Distant (50km)	0.20	0.000	-0.0002	Cr 250
Laser Comm.	TL 10 Distant (5km)	1.50	0.003	-0.0015	Cr 1,200
EMM	No	0.00	0.000	0.0000	Cr 0
TL 10 Low Power H-Grav	1.01 t. thr.	30.30	0.051	-0.0202	Cr 25,250	20.22 Gs; 23,040 kph in standard atm.
Batteries	TL 10	9.90	0.0099	0.0070 MwH	Cr 51.98	0.29 Hours
[TD]	49.96 kg.	0.084 m3	-0.0240 Mw	Cr 37,870

[/TD] [/TD]

Drives: 20.22 Gs; 23,040 kph in standard atm. (10.11 Gs when more than 10 diameters from planet)
Battery duration: 0.29 Hours
Remote: controller needs 4 CP

 

[Hyphen]

Cool! Sort of halfway between "Advanced Civilian" and the "Sprint"!

trendi Missiles

I *do* like the 10G in space/20G in atmosphere trick. It enables a GM to provide low-TL worlds with teeth against raiders. The missile doesn't even leave the 10 diameter limit to target orbiting ships!

 

[McPerth]

Nice.

Just one comment: according MT:RM page 86, top speed (while it says vacuum, errata tells us that is for standard atmosphere) for 6G is 4200 kph (and the progression is not lineal), and caped at 1000 kph for streamlined but not airframe crafts. So I doubt this missil can reach the 23040 kph in standard atmosphere you talk about...

 

[AnotherDilbert]

Should work, remains to determine how much damage it would do in your preferred combat system.


The only disadvantage I can see is that it is a fairly short-ranged weapon. At 100 000 km the remote control loop delay would be close to a second, which would make it difficult to hit a manoeuvring target.

Taking inspiration from the Honorverse, you might make a bigger "control missile" with a computer, AI, control panels, and sensors necessary to control the missiles in flight, removing the remote control delay, and hence make extended range practical.


If launched from the ground the limited speed in atmosphere would probably make it easy to kill for point defence, but it would be very difficult to detect close to the planet so that might not be a problem.

 

[Carlobrand]

...
I *do* like the 10G in space/20G in atmosphere trick. It enables a GM to provide low-TL worlds with teeth against raiders. The missile doesn't even leave the 10 diameter limit to target orbiting ships!

Technically it's 20G within 10 diameters, but yeah, it worked out nicely. Except of course around the smaller worlds.

Nice link.

Nice.

Just one comment: according MT:RM page 86, top speed (while it says vacuum, errata tells us that is for standard atmosphere) for 6G is 4200 kph (and the progression is not lineal), and caped at 1000 kph for streamlined but not airframe crafts. So I doubt this missil can reach the 23040 kph in standard atmosphere you talk about...

Oop, you're right, I got that wrong.

I think I'll delete the speed figure as irrelevant, though. 1000 kph is about 278 m/s, and at 20G straight up (19G after overcoming gravity) the missile hits that velocity at 1.46 seconds, ~200 meters altitude. However, by the time it reaches about 2800 meters - 9.3 seconds later - it's in thin atmosphere (0.7 atm) and should be able to reach 1500 kph, 417 m/s. When it hits 7200 meters about 12-13 seconds later, it's in very thin atmosphere (0.42 atm). In less than 30 seconds it's cleared the layer of atmosphere braking it and can proceed at pretty much maximum acceleration. It's only lost about 21-22 seconds escaping a standard atmosphere. If a ground launcher wants to use it against a ground-based enemy, they're actually better off launching it straight up and then dropping it straight down on the target.

Should work, remains to determine how much damage it would do in your preferred combat system. ...

Still thinking on that one.

The only disadvantage I can see is that it is a fairly short-ranged weapon. At 100 000 km the remote control loop delay would be close to a second, which would make it difficult to hit a manoeuvring target.

Taking inspiration from the Honorverse, you might make a bigger "control missile" with a computer, AI, control panels, and sensors necessary to control the missiles in flight, removing the remote control delay, and hence make extended range practical. ...

It's a consideration for a ground-launched weapon, but I was trying to confine myself to canon ship missile size to see what I could come up with. 100,000 km is close to its maximum range, and at that range the delay's about 2/3 of a second. A 6G target with 2/3 of a second to play with can move about 13 meters, which for most things of destroyer size and larger isn't going to make much difference, and it does have a densitometer for terminal guidance, which appears to be about the same thing as what they're calling a "mass sensor" in SS3, Missiles, except it costs a lot more.

 

[AnotherDilbert]

100,000 km is close to its maximum range, and at that range the delay's about 2/3 of a second. A 6G target with 2/3 of a second to play with can move about 13 meters, which for most things of destroyer size and larger isn't going to make much difference, and it does have a densitometer for terminal guidance, which appears to be about the same thing as what they're calling a "mass sensor" in SS3, Missiles, except it costs a lot more.

Yes, it will have moved ~14 m in 0.7 s, but then it will take the missile another ~0.3 s to match the targets speed and another ~0.5 s to match the targets position, but then you have greater sideways speed than the target so you will overshoot. It will take almost 2 s to compensate for the 0.7 s lag, IFF the target maintains a constant acceleration vector, which it will probably not be obliging enough to do. Every change in acceleration within that 2 s will slide you farther and farther off course.


With no two-way communication nor any control panels I don't think the missile can use the densitometer to guide itself.

 

[McPerth]

With no two-way communication nor any control panels I don't think the missile can use the densitometer to guide itself.

WOuld a robot brain (just with some piloting skill wil lbe enough, I guess) and just termal sensor work?

Robot brains use to be quite small (though they will increase cost), and any ship (unless it has a BG at full effect) will show up in a termal sensor against the blakness of space...

 

[AnotherDilbert]

WOuld a robot brain (just with some piloting skill wil lbe enough, I guess) and just termal sensor work?

There must be Control Panels somewhere in the loop for a complete craft. In case the craft is only remote controlled they can be in the remote control station, else they must be in the craft. Hence a self controlled missile must have Control Panels and that does not fit in a 0.1 m³ craft.

 

[Carlobrand]

Yes, it will have moved ~14 m in 0.7 s, but then it will take the missile another ~0.3 s to match the targets speed and another ~0.5 s to match the targets position, but then you have greater sideways speed than the target so you will overshoot. It will take almost 2 s to compensate for the 0.7 s lag, IFF the target maintains a constant acceleration vector, which it will probably not be obliging enough to do. Every change in acceleration within that 2 s will slide you farther and farther off course.


With no two-way communication nor any control panels I don't think the missile can use the densitometer to guide itself.

A few thoughts on that:

• Closing velocity at 100,000 km range is in the vicinity of 200 KPS. Essentially, the last ground-based directions that make any difference will occur 140 - 150 km out from target. Ground is dealing with a ~14 meter CEP at that range, assuming a 6G target. Assuming no course corrections after the last ground instruction, CEP is more like 59 meters, so the question of impact therefore depends on the quality of the terminal guidance in the last 0.7 seconds of flight - or maybe a bit longer if ground has confidence in the terminal guidance. If the terminal guidance is effective enough to keep the target centered for the last 140 or so km of flight, it will impact.
  
• The game's existing missile, at the same size, is clearly impacting successfully, and it has the same problem with time delay if it is being controlled by the launcher - worse if you assume longer ranges - so something exists that permits a missile to have a chance at impact at long range. The only thing featured in MT that can fit a missile for this purpose without being so high tech as to make missiles unavailable below about TL15 is a 1 kg device. Coincidentally the same device - or something nearly identical - exists at the same TL in CT and is used by missiles, so this is not an unreasonable assumption. If it isn't that, then there exists some other device which is not identified in MT, and the design then depends on the size of that unknown device.
  
• I hadn't planned for this missile to have any better chance at hitting than a standard missile; the damage is where I'm scratching my head. Assuming no computer advantage, a standard missile at long range has a 1 in 36 chance of hitting an agility-6 target of destroyer size; one generally prefers to fire several to have a reasonable chance at one hitting.

All in all, I'd say your concerns are already reflected in the game mechanic.

Add: the CT missile includes a 3 kg controller. MT gets a little difficult on the subject because one presumes a human is sitting at a control panel. Nonetheless, something must exist to control a device absent human hands, as occurs in missiles. It's not unreasonable to assume drives can be linked directly to a sensor to achieve as simple an outcome as keeping the sensor centered on the object sensed. We seem to be able to accomplish something like that that today, so I see no reason to assume it can't be done at TL10; we just don't know how much volume it would take.

 

[McPerth]

There must be Control Panels somewhere in the loop for a complete craft. In case the craft is only remote controlled they can be in the remote control station, else they must be in the craft. Hence a self controlled missile must have Control Panels and that does not fit in a 0.1 m³ craft.

At this price, it will only need less than 10 CPs worth controls. According 101 vehicles, the imput multiplier for a robot brain is 250 x INT, so a singl Electronic linked control panel (0.005 kl) will sufice.

I'll try to design the brain and see if it can fit...

 

[AnotherDilbert]

According 101 vehicles, the imput multiplier for a robot brain is 250 x INT, so a singl Electronic linked control panel (0.005 kl) will sufice.

I'm not familiar with that book. It sounds like it should work.

 

[AnotherDilbert]

[*]Closing velocity at 100,000 km range is in the vicinity of 200 KPS. Essentially, the last ground-based directions that make any difference will occur 140 - 150 km out from target. Ground is dealing with a ~14 meter CEP at that range, assuming a 6G target.

This is not a question of ballistic accuracy, it's a question of a fundamental problem in control systems.

[*]The game's existing missile, at the same size, is clearly impacting successfully, and it has the same problem with time delay if it is being controlled by the launcher - ...

I agree missiles can hit, but I have always assumed they are self-guided since a single gunner can control many missiles and even fire lasers at the same time.

All in all, I'd say your concerns are already reflected in the game mechanic.

I would rule it differently, but it's your game...

Add: the CT missile includes a 3 kg controller. MT gets a little difficult on the subject because one presumes a human is sitting at a control panel.

Hopefully McPerth has solved that problem?

 

[kilemall]

Control panels sounds to me like human interface workstation type elements- not an issue for an autonomous seeking/homing missile. At best it would be the elements for course correction until the terminal homing phase. Do I have that definition right?

 

[mike wightman]

Yes.
The MT design sequence is for crewed vehicles/ships. The CP system details the interfaces needed by the crew to control the machinery.

MT missed out robot brains/drone brains from the design sequence, so you had to go to other rules to make up drone/robot vehicles.

 

[McPerth]

Yes.
The MT design sequence is for crewed vehicles/ships. The CP system details the interfaces needed by the crew to control the machinery.

MT missed out robot brains/drone brains from the design sequence, so you had to go to other rules to make up drone/robot vehicles.

Yet, a drone is listed in MT:101 vehicles (vehicle #23), and sules of how they affect CPs and pannels given i nits introduction (pages 2-3).

And don't forget OjnoTheRed's MT robots book MT robots book (though IDK if it is accepted as "canon")

 

[mike wightman]

That's why I said you had to go to other rules for the robot brains/drones...

As to the excellent MT robots book I would include it in my go to list.

 

[Carlobrand]

...I would rule it differently, but it's your game...

I'm not clear on which part you think is wrong if you agree that missiles can hit, since the missile has a terminal homing system that appears to be identical, other than price, to one offered in CT. Well, SS-3. Is that canon or demi-canon?

I agree that there may be a question of control. However, I consider a robot brain to be a bit over-kill for something that needs what amounts to a hen-peck guidance system. Fundamentally, guidance isn't too different from what Sidewinder is doing except it uses a mass detector instead of IR, and I'd consider Sidewinder to be roughly TL6. Even the simplest brains in MT Robots - which I agree should be canon if it isn't already - do a lot of thinking. The simplest programs in that set are survival, vacc suit, forgery and hovercraft operation, and then you need a command program to accept instruction (which maybe could be omitted) and a logic program to take the information in the skills program and apply it to the data coming in from the sensors. Given visual sensors, these bot brains can see and interpret visual information, which is a very sophisticated level of programming. At the point we're reaching for a brain, I think we're heading into ALCM territory rather than Sidewinder territory.

Since MT draws a lot from Striker, this missile could be built in CT under Striker's rules, with a few differences: neither Striker tac missiles nor Striker drone missiles charge a cost for the hull/shell weight or price - the missile is comprised of warhead, guidance and propellant. Striker requires no control system, or rather the guidance system appears to function as the control system. Striker offers a 1 kg homing guidance of unspecified design, where our MT densitometer is 1 kg (and SS-3's mass sensor is 1 kg and functions in space-range combat). It offers a laser guidance of more limited range, assuming a 2 kg laser receiver at all TLs and a 20 kg laser comm in the launcher, where our MT receiver is 1.5 kg and we depend on larger launcher comms and integration with the ship's computer to maintain a control link over long distances.

So, in CT we'd be looking at either something that was based on SS-3 with Striker's grav propulsion design rules tacked on, or something that was Striker-based as a drone missile using tac-missile guidance in place of the drone brain (which isn't available until TL 13) and that assumed a ship missile mass sensor could function as the homing guidance. If we start from SS-3, we need 3 kg for a control system (which should have been TL 7 to be consistent with HG or at least TL 8 to take full advantage of the TL 8 radar homing guidance, rather than TL 9). SS-3 also has a casing mass charge, but it's unclear whether or how much of that is needed since the casing partly contains the fuel as it burns and partly maintains the missile structure against the G force and varies with the type of propulsion, so that gets difficult and maybe impossible to merge. If we go with Striker, from which MT draws, we don't have an issue of a control system, but we have that 10.582 kg to play with if we want one, since there's no hull charge.

In short, we wouldn't need a control system if this were a Striker-based CT design, and MT draws from Striker.

 

[kilemall]

On the Striker/SS3 interaction front, the integration rules say the turret 50kg missile is a 15cm warhead, and the bay missiles are 25cm.

That doesn't give us a weight/volume value for the bay missiles, my working value for SS3 speculative design is 250 kg, so you are welcome to give that a Striker whirl.

Either 15 or 25cm warheads are pretty scary when given HEAT rounds and compared to Striker/HG armor hulls.

The kinetic power a missile that has been accelerating for 100,000km + is not really conveyed in Striker, you'd really need many row shifts down beyond hypervelocity based on relative speeds.

Not relevant to work out for ship combat, but IS relevant if say that 20G atmo missile from the OP was targeting a Striker grav assault shuttle.

 

[mike wightman]

You have to take into account relative velocity, not just the velocity of the missile.
What sort of range are you envisaging for their use against vehicles? At less then a few thousand km you would be better off with a railgun to launch the 'missile' and use the 20g for terminal guidance.

 

[AnotherDilbert]

...I would rule it differently, but it's your game...

I'm not clear on which part you think is wrong if you agree that missiles can hit, since the missile has a terminal homing system that appears to be identical, other than price, to one offered in CT.

Sorry if I was unclear.

Self-guided missiles can hit, remote controlled missiles would have a severe problem.

A self-guided missile would need some guidance system, just a sensor is not enough.

I would hesitate to mix design systems from different editions when we already have rules for approximately what we want to do.


All my problems could be solved, as McPerth point out, by a simple robot brain and a control panel, making the missile self-guided, saving us the hassle of a remote operator.