Rules Only: Missiles and can their operation time be split?

[fantome]

Missiles (question for a GURPS game but not necessarily only for GURPS) have operational power for an hour (three turns). In space combat the three turns will be consecutive from launch and if after three turns they haven't hit, or been destroyed, they will be discarded (or self detonated) as the spaceships travel further away from the now destroyed or spent missiles.

For planetary defense, where the locale won't change, can the operational power of a missile be split rather than simply used consecutively?

The scenario is to launch each missile into an effective low planetary orbit which will use up their first turn (effectively 20 minutes of operational time for power and fuel). Each missile will then continue in its orbit for some duration (typically weeks/months if placed in an effective low planetary orbit). Multiple missiles are intended to be launched to be in orbit in 'close' proximity (over hundreds of miles).

This question is about the missiles which are in orbit after only using up one third of their power and fuel. Can the missiles be powered down (for hours or even days) to be placed in a 'standby mode' until when they need to be reactivated?

This is to use the remaining power (remaining two turns for a total of 40 minutes) and fuel when it would be most useful. eg directed at the incoming pirate vessel which is only coming close to the planet and only in range of the missiles at a later time.

An enhanced communication suite is to be used to control multiple missiles via laser, rather than needing to rely only on a single controlling laser from a missile turret. This question would have been a moot point if a missile bay was in place, but what would have been a very useful missile bay doesn't happen to have been installed on the planet. While one missile doesn't tend to be effective as is likely to get shot down, multiple missiles placed in orbit as needed may be more of a deterrent to give yet another reason that it's spaceships rather than planets which tend to be harrassed by pirates.

 

[BackworldTraveller]

For planetary defence, you could always build 2-stage missiles...or mount them on stealth missile launchers with LOS comms to a targeting array elsewhere.

 

[whartung]

An enhanced communication suite is to be used to control multiple missiles via laser, rather than needing to rely only on a single controlling laser from a missile turret.

This is the nut, in theory.

In theory, there's nothing stopping you from staging, say, 1000 missiles in orbit. Just parked there. For years as long as the orbit is stable.

The hard part is controlling them. The hard part is getting lock on to the target, transferring that to the missile, and then guiding it into its target. Those channels tend to get clogged up. You would need ships/satellites in orbit acting as sensor platforms to gain lock on intruders to direct the missile.

I don't know what GT rules you're using for the missile combat. In TNE you needed fire directors to manage them, but they were able to multitask since they were really only used for maneuver. I also don't know the GT missile tech, but even if they can only "last an hour" once started, you would instead just use a ship to deploy them in orbit rather than launch them.

 

[fantome]

GURPS-Traveller-Corebook-2e and GURPS Traveller: Starships are my starting point for missiles and likely a GURPS Traveller space-combat system based on these books more than anything else. I also just (re)read GURPS-Traveller-InterstellarWars as far as missiles went.

The satellite in high planetary orbit I don't expect to survive very long at all, and it is expected a vessel will be able to provide target lock details for the pirates/raiders not yet within missile range of the planet.

So, a limit to the number of missiles able to be controlled at one time is expected. Though I expected them to have be prepared via a missile turret (or via a bay which isn't available). Like on p53 GURPS Traveller: Starships "One copy of each program must be purchased for the ship (then copies are downloaded to the missiles) if the terminal guidance system is to be used" All missiles TL12 in this case.

GURPS-Traveller-Corebook-2e p167 "Standard missiles use laser communicators. One laser communicator is built into each missile rack and 50 into each mis-sile bay. If a gunner has to drop a missile because he can’t control all the ones he has, he may “reacquire” it on a later round. Missiles can be (and often are) pre-programmed to self-destruct after a certain number of rounds uncontrolled."

p222 GURPS-Traveller-InterstellarWars does have a different flavour, and doesn't like leaving missiles unsupervised. "A missile can only maneuver if it is currently under the direct control of a gunner. It must be within communi- cations range of the ship on which the gunner is working (50 hexes at TL9, or 100 hexes at TL10+). Gunners on board a given ship can only control one missile per installed missile rack, ... " " Control of a missile can be “hand- ed off” from one ship to another, so long as the two ships are within com- munications range of each other. If a missile is dropped because there is no gunner is available to control it, it can be “reacquired” on the next turn. In fact, it must be reacquired on the next turn, otherwise it will automatically self-destruct during the Maneuver Phase. Any one missile may only maneu- ver three times before running out of on-board power. GMs may wish to use a small die or another marker next to each missile counter to keep track of remaining power. Once a missile runs out of power, it will automatically self- destruct after the Point Defense and Collision Phase of that turn"

 

[mike wightman]

Do you have access to the CT Missiles special supplement? There are also missile building rules in Mayday.

A discretionary burn missile engine can turn its engine off and on, so the missile can move like a ship.

A missile can have a homing "fire and forget" targeting system based on passive sensors (eg IR, radio/radar).

 

[fantome]

It seems I do have the 2010 version of the pdf of the CT Special Supplement 3 Missiles by FFE. Thanks for suggesting this and offering up the the alternate targeting methods, and the idea of discretionary burn though I don't think discretionary burn will make a difference on a standard missile in GT. GT has in addition to the fuel limitation, an internal power operational limit on standard missiles which make them last only 3 turns.

 

[mike wightman]

GURPs describes missiles as requiring power rather than fuel because the fuel based missiles of CT break every possible application of the rocket equation and all known physics.
A 50kg chemical rocket that can accelerate at 6g for 3 turns...

by going with a description of missiles being powered and possibky using a reduced size m-drive you can hand wave away the 50kg missile with a 6g 3 turn duration.

 

[whartung]

Sounds like the GURPS rules are reasonably clear, and it sounds like you can't have idle missiles sitting in orbit, from a rules perspective. At least not for very long.

Sounds like you can have as many missiles in flight as you like, but can only control as many missiles as you have gunners/missile racks in your fleet. "Control" mean, notably, maneuver, which is necessary for impact.

In a contrive scenario, you can have, say, two ships. Each with 2 missile racks. The first ship is carrying 2 loads of missiles (total of 4), the second ship is carrying 4 loads.

You launch all 4 missiles, 2 from each ship, on a ballistic course towards your target, which is several turns away.

Next turn, you launch 4 more, and ship 1 is out of missiles, and you have 8 missiles in flight. The 3rd and 4th turn, the 2nd ship launches their missiles. You now have a total of 12 missiles in flight. As they close to the target, each ship takes control of 2 each of the first rounds of missiles and directs the missiles to attack. Similarly, the ships try to attack with the second round of missiles, but the intruder accelerates and gets past them, leaving the last 4 launched by ship 2. Ship 1 and Ship 2 take control of the missiles, and use them to maneuver and attack the intruder all at once in a single round. The fact that the missiles were originally from the second ship doesn't matter, as 2 of them were taken over by the ship 1 which has missile racks, but no missiles.

 

[kilemall]

Just to give you an option, IMTU missiles are mini ships with fusion and mdrive but without the cooling or volume to deal with the heat. So once the missile is started up it has to burn at least some fuel to get rid of waste heat, even if it doesn’t do any accel.

They have the option of having a dumb bridge without computer which corresponds to the dumb constant burn missiles of the SS, or having both bridge and computer which allows discretionary burn. That’s usually used for long range targets not orbital.

The way to go for orbital mining is inserting a box of missiles with comms and possibly sensor/targeting capability. The box orbits until triggered or eventual burn up. I believe they detailed such a system in MgT Traveller companion.

Ultimately decide what game effect you want and justify by rules or weapons design philosophy/doctrine.