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Anonymous
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If there is no friction the thing can stick straight out sideways and should therefore be able to look ahead and behind.
Towed Arrays for starships.
- Thread starter wbnc
- Start date
Condottiere said:
A drone above, below, and to each side would provide far better scanning, as they could look "up" and "down" along the plane that the ship is on. Drone arrays to each side would also be able to look around any object that a potential enemy could be hiding behind.
And that would allow for better scanning capabilities in a globe around the controlling ship. You could also send them in front, behind, or wherever you wanted to in order to get better data or more detailed resolution. If an enemy happened to be there, all you lose is the drone.
Moppy said:
Drone arrays would do all that, too, plus provide superior capabilities through movement and orientation not available by anything towed or attached to the ship.
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Anonymous
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Yea but they aren't towed arrays. As I said earlier I was limiting my response to things on actual cables.
Moppy said:
Well, if you are talking cables, it couldn't stick straight out since a cable has flexibility. Now if you could say run a charge though it that caused the material to become stiff, then you could stick it straight out. But with physics, the amount of stress and energy (potential) at the end of that line would have to be dealt with in some manner. Cable-launching is a 'thing' in real-life, by using the rotational energy of a planet or object you can impart it onto a launched object. A drone out to the side would have the same thing (so would a towed array, but you could pull that in far easier than something to your side(s). Well, depending on your maneuvers you could. But it's easier behind since it would have the same heading and speed as your ship (to start).
Well, I have plenty of input on the towed concept...with all the potential weaknesses, inefficiency, etc...
would a slightly modified system in which the 'tow cable" feeds power to the drone to reduce it's size, and expense, and power internal maneuver systems to allow it to pace with the parent ship be a potential factor.
would a slightly modified system in which the 'tow cable" feeds power to the drone to reduce it's size, and expense, and power internal maneuver systems to allow it to pace with the parent ship be a potential factor.
wbnc said:
Having the cable provide power to the array is certainly an option. Something to consider is would the electrical current cause interference to the sensors that you are trying to keep away from the 'noise' of the towing ship? Easy enough to put batteries on the array if you are trying to make it super-sensitive.
I think so long as your towing ship is stooging around a system at very low velocities (no more than 1G) it would be within reason to say your arrays are physically attached to your ship, that they draw power from the ship and use ion thrusters to keep pace with your ship. That would eliminate a number of problems. When you need more sensitivity, the towing ship simply cuts its drives and the arrays do the same, thus they would stay in the same place relative to the towing ship. The thrusters could be used to offset the gyrations that your towing ship might put them through, within reason, and also allow for a much faster recovery speed since they can decelerate before being pulled onboard.
I am of the opinion powered drones would be superior, but there's nothing to say you couldn't find reasonable and logical ways to make the towed version work out.
when I sat down and started thinking about this.....I had started with the idea that the towed, or tethered arrays, would be more of an add-on, or alternate for a narrow range of applications rather than a replacement for drones.or simply part of another ship option.phavoc said:
Condottiere
Emperor Mongoose
Re: Ship Design Philosophy
Postby Condottiere » Sun Aug 30, 2015 10:09 am
Spaceships: Sensors and Stealth
I had this thought that in order to minimize electronic emissions from a ship, they'd put the sensors in a pod, and trail it a couple of kilometres behind it, but actually, all it probably does is to have a better chance on locating other vessels trying hard to become invisible.
For some reason, I came up with a variant, where you have a five thousand tonne pod acting as the platform for a distributed array, though at that size, it pretty much can be self-propelled and autonomous, so kinda pointless. Though for a dreadnought, it would add another platform for another sensor suite while underway, though I'm sure there much more efficient ways to achieve the same effect.
Though if you keep your velocity, and switch off the manoeuvre drives, the pod could be small enough just to support an extended array, which does seem like a viable option. Though once you want to use the manoeuvre drive, it's time to unextend those arrays.
That would be why there's a cable.
Postby Condottiere » Sun Aug 30, 2015 10:09 am
Spaceships: Sensors and Stealth
I had this thought that in order to minimize electronic emissions from a ship, they'd put the sensors in a pod, and trail it a couple of kilometres behind it, but actually, all it probably does is to have a better chance on locating other vessels trying hard to become invisible.
For some reason, I came up with a variant, where you have a five thousand tonne pod acting as the platform for a distributed array, though at that size, it pretty much can be self-propelled and autonomous, so kinda pointless. Though for a dreadnought, it would add another platform for another sensor suite while underway, though I'm sure there much more efficient ways to achieve the same effect.
Though if you keep your velocity, and switch off the manoeuvre drives, the pod could be small enough just to support an extended array, which does seem like a viable option. Though once you want to use the manoeuvre drive, it's time to unextend those arrays.
That would be why there's a cable.
Condottiere said:
Putting anything on a cable in space, especially if there is movement involved, isn't necessarily the wisest of ideas. The terrestial concept and use of towed arrays started with sonar. Why? Because the towed array is able to get further away from the localized interference and noise pollution being put forth by the scanning ship. Towed sonars started with ships, but they are also found on helo's and even submarines. The cable concept works because it's being done in a fluidic environment. If the ship stops, the array will also quickly stop (and often start to sink somewhat because of the additional weight from the cable - while underway they have no issue with maintaining relative depth).
In space you have no fluid to bleed off movement. So putting any object at the end of a cable (and the longer it gets the more pronounced the effect gets) means the object can get whipped around at great speeds with any sort of movement done by the ship it's attached to. The only way to stabilize the movement is to equip it with thrusters to offset some of the effects. Even deploying the array would require thrusters to get it to it's deployed position. Simply ejecting it won't work since you are in zero gravity. and spooling out cable won't work because there is no gravity to "pull" the cable out of the spool.
This is a navalized concept that doesn't translate well into space, similar to small-craft "dogfights", which would look nothing like their aerial forefathers.
I'd also argue against the starship "tow cable" concept. If you have ever towed another car without power (or steering or brakes) you will have discovered Newtonian physics in a very painful, and hopefully inexpensive way - objects in motion tend to stay in motion. Probably a better example of the very bad idea is a tetherball. Ever hit a tetherball? It goes in the opposite direction of how you hit it, but it doesn't magically stop on it's own. No, once you impart energy to it, it will continue to move around until all that energy is gone. Pulling a starship on a cable CAN work, at least to start. But say you are pulling it between planets. At the 50% mark you have to do a turnover maneuver and begin deceleration. While it might be possible to do the turnover with a long cable so that the tug ship is able to maneuver around the pulled ship, at some point the pulled ship has to turn - and physics is an unforgiving bitch when it comes to objects at the end of a cable. That towed ship is going to start drifting, and without thrusters on it, the tug ship will be unable to stop it.
The most practical (and safest) way to "tow" anything would be to physically attach one ship to the other and then boost as a single entity. The Shuttle used to do it all the time with the ISS, at the end of its stay, to give the station more altitude. In this instance space is quite forgiving. Assuming you do let someone use the cable, the negative piloting DM would be substantial. The book has a -4 DM when it comes to unstreamlined ships entering the atmo to land. This is rather harsh considering if you have gravitics you can simply float down to the ground. With no strong crosswinds to deal with there is virtually no risk. So towing a ship by a cable under Newtonian physics rules should be vastly more complicated.
As long as things are consistent and are within a logical framework I'm cool with it. Concepts like jump drives, collapsed matter hull materials, meson guns, etc... all are ok in my book. Just make the interaction and baseline consistent and avoid having to do handwavium all the time to make things fit. Or, for all this cable nonsense, if we go to a reactionless drive universe these problems would go away. But we are in a reaction-based universe, so they stick with us and we have to figure out ways to more or less work within the limitations.
Condottiere
Emperor Mongoose
I vaguely remembered that I thought experimented this before.
It was basically to get around the extended array rules, though you'd have to drift, and the cable ensured both secure communications and that the pod wouldn't get lost, and could be reeled in.
It was basically to get around the extended array rules, though you'd have to drift, and the cable ensured both secure communications and that the pod wouldn't get lost, and could be reeled in.
Rick
Mongoose
The very first thing that I thought of was the Schlock Mercenary "Very Dangerous Array" - a deployed series of missiles with enhanced sensor packages that act as enhanced sensor array drones and missiles.
Could you make the drone small enough to fit into a missile warhead, I wonder? :twisted:
Could you make the drone small enough to fit into a missile warhead, I wonder? :twisted:
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Anonymous
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phavoc said:
Why not? Put a weight or thruster on the end and eject it sideways from a launcher while you're drifting. Depending on available technology, it's possible that you may have to recover your towed array before changing course.
phavoc said:
It would work. a very basic sensor system isn't that big. and you can scale engines reactors down to fit the need.
introducing the "Oka: Suicide drone
( off the top of my head design)3 ton non gravity hull, standard configuration, budget priced.
.3 ton reaction drive
.5 tons fuel
drone control system
basic sensors
.1 ton reactor
warhead 1 nuclear mine
options emissions absorption grid and stealth hull.
launch the drone it loiters or advances ahead of ship, if it detects an enemy ship it reports in...if ordered to attack it screams in at max thrust and rams the target or extra mayhem launch a dozen of them.
Moppy said:
How do you account for the fact that the ship can move under thrust, but the platform would not? And a weight doesn't do anything in zero-G. Unless you plan on physically ejecting it to give you some opposite thrust.
A thruster could work so long as it's strong enough to move the combined mass.
But in general cables are a bad idea in zero-G and a vacuum.
Condottiere
Emperor Mongoose
I don't think anyone's taken the position that it's an optimal solution.
In the absence of the tractor beam, and if big enough clamps aren't around, possibly the only way to tow stuff in deep space.
In the absence of the tractor beam, and if big enough clamps aren't around, possibly the only way to tow stuff in deep space.
Got that part trying to figure out exactly how to compensate for those drawbacks.phavoc said:
What I am assuming
1) no major maneuver, or vector change while deployed. straight line constant acceleration ( with upper limit due to cable stress limits)
1a) best used during straight line cruise, or drift modes,..
2) some means to dampen/control vibration, or momentum based oscillations, and prevent collision during recovery
3) cable serves as data/power transfer, as well as part of antenna array
4) not intended as replacement for drones but as an add-on or part of another system.
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Anonymous
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phavoc said:
My thought proces was that a mass on the end simplifies launcher design. It probably wont matter for a custom designed system, but if you are throwing a homemade cable out of a free trader, you can get in a vaccsuit and literaly throw it and the mass will help it straighten out.
I have already said why towed arrays probably wont be used much when you have drones, but we're kind of forced to consider cables in a towed array thread. Otherwise every ship is a carrier and we can rename the thread.
As for being under thrust, one assumes that a patrolling warship probably isn't under thrust for stealth reasons. Certainly in megatraveller, it matters.
I dunno, a patrolling ship would be under thrust most of the time. A towed array would only be used for passive scanning. And, granted, a ship that is drifting would have a smaller active signature. But if you are just drifting you can't cover as much ground.
Generally speaking a ship on a regular patrol wouldn't be going silent a lot if there was no active or perceived threat. You do it when you have a suspicion, or sometimes just for training.
Now a ship specifically lpoking for intruders or is actively monitoring a location, they would be prime candidates for this.
If you want to keep the cable concept, I suggest adding in a little future tech. Make the cable some sort of carbon polymer or whatever that when an electric charge is added it 'locks' it as a solid, which at least for towing would solve a lot of your cable problems. When you want to reel it I you just remove the charge. It would work easily enough for towing it (or pushing it), but lateral deployments might be too much, especially if you are wanting this thing kilometers from your ship.
Still a fan of dtones to do this task though.
Generally speaking a ship on a regular patrol wouldn't be going silent a lot if there was no active or perceived threat. You do it when you have a suspicion, or sometimes just for training.
Now a ship specifically lpoking for intruders or is actively monitoring a location, they would be prime candidates for this.
If you want to keep the cable concept, I suggest adding in a little future tech. Make the cable some sort of carbon polymer or whatever that when an electric charge is added it 'locks' it as a solid, which at least for towing would solve a lot of your cable problems. When you want to reel it I you just remove the charge. It would work easily enough for towing it (or pushing it), but lateral deployments might be too much, especially if you are wanting this thing kilometers from your ship.
Still a fan of dtones to do this task though.
