# Does size matter in space

#### Elijah Talbot

Summary: I am writing a story that features space warfare. I was wondering does a big ship perform better than smaller vessels?

I'm just a writer (well wanting to be one with my poor grammar) so I don't know much about engineering or space at all.

So space is massive, so battles in space will be fought with the combatants being hundreds of thousands of kilometres apart. Which means the spacecraft must have a good targeting system and weapons that can reach the enemy ship in a short period of time.

What I think makes sense is big ships (Like 3km to 15km long) in space warfare will do better than smaller ships. Simply because of the big ships will have better armour and weapons. The other thing to note is the ships would be faster since they would have giant engines. I'm no wizard, that is what I think makes a lot of sense because it's space. There is nothing to slow down massive objects. Mercury is orbiting around the sun at the 170,505 km/h. Big ships will take a good beating since they have a bigger mass, etc. Am I wrong, or am I missing some details?

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#### scottdave

Homework Helper
Gold Member
Massive ships should be able to withstand more damage and remain operational. But don't expect them to be as agile as less massive ones. The larger ships have massive engines, because they need them.
Newton's 2nd law: Acceleration = Force / Mass. So more mass means more force is required to achieve the same acceleration.

#### phinds

Gold Member
The other thing to note is the ships would be faster since they would have giant engines.
VERY bad analysis. The size of the engine is irrelevant. What matters is the size/power of the engine relative to the size/mass of the ship. It is very easy to imagine a small ship with much greater acceleration ability than a larger one.

Just think of a SAM missile compared to an airliner.

#### essenmein

Summary: I am writing a story that features space warfare. I was wondering does a big ship perform better than smaller vessels?

I'm just a writer (well wanting to be one with my poor grammar) so I don't know much about engineering or space at all.

So space is massive, so battles in space will be fought with the combatants being hundreds of thousands of kilometres apart. Which means the spacecraft must have a good targeting system and weapons that can reach the enemy ship in a short period of time.

What I think makes sense is big ships (Like 3km to 15km long) in space warfare will do better than smaller ships. Simply because of the big ships will have better armour and weapons. The other thing to note is the ships would be faster since they would have giant engines. I'm no wizard, that is what I think makes a lot of sense because it's space. There is nothing to slow down massive objects. Mercury is orbiting around the sun at the 170,505 km/h. Big ships will take a good beating since they have a bigger mass, etc. Am I wrong, or am I missing some details?
How do you define "better performance"?

Bigger ship probably has bigger guns.
Bigger ship probable has more armor
Bigger ship is a bigger target to hit, ie easier for the smaller ship to hit.

Smaller ship might be able to maneuver close enough to the larger ship to render its larger guns useless.
Smaller ship might be agile enough to make being hit by larger guns hard.

Larger ship would be less maneuverable.

Smaller ship would be harder to detect, ie might be able to sneak up on the larger ship.

#### MikeeMiracle

I think the ultimate question is what are you trying to achieve? To carry more people on board you need a bigger ship. It depends what the purpose of the craft is.

Sometimes smaller is better. An army of ants can take out small mammals that are many times their individual size due to their sheer numberical advantage. If the engines fail on 1 of 1000 ships then only 1 ship is out of action. If the engines fail on the big ships thats many more people/resources stranded.

#### some bloke

Another thing to consider is the damage output of the weapons you're planning to use. By the time such ships can be built, you can bet that someone had long ago developed the means to blow them up. Whilst a large ship would have more ammo, larger guns etc, if the small ship has 2-3 torpedoes which can each rip through a large ship, then it's ability to evade the large ship should let it slip through and deal the damage.

That said, I wouldn't expect to be able to bring down a (seafaring) battleship in a dinghy with a torpedo. I would expect a lot of anti-small-ship weapons, including a hold full of fighters to go out and engage with the small ships directly.

#### Rive

I am writing a story that features space warfare. I was wondering does a big ship perform better than smaller vessels?
As a sci-fi writer it is just one of those things you have to decide for yourself when you set up your world. Some worlds prefer big (Star Wars: 1-10km in length, BSG: 1-2km), some plays with very big (The Culture: 10-200km) ships, but almost every variations has smaller ships attached anyway.

Just don't forget to make up some strong technobabble behind the story for support.

#### Tghu Verd

I am writing a story that features space warfare. I was wondering does a big ship perform better than smaller vessels?
Not wanting to seem impolite, @Elijah Talbot, but have you read a lot of space battle sci-f? Because you seem to be launching into a topic in which you have little knowledge, and being sci-fi, readers will pick that apart in reviews. But that aside, a few questions:

- Do your ships travel FTL? That dramatically changes how warfare occurs.
- if they are relativistic, then light speed can introduce a real sense of drama, kind of like submarine hunts in WWII, because the ships are always at the mercy of delayed communications.
- How are they powered? Do they need supply dumps or will you use handwavium so they can travel forever?
- Have you crafted a hierarchy of vessels? Typically, large vessels have smaller ones to support them, they don't tend to just travel by themselves.
- What weapons are in use? Current physics ones like lasers, torpedoes, rail-guns? Or exotic tech like gravity waves, hypercannons, time bullets?
- What defenses have been iterated for each type of weapon?
-Is there artificial gravity? Crews in zee gee behave very differently to crews with gravity.
- Is there inertia suppression? This can allow much higher speeds if you want?
- Where are the ships built? Most sci-fi ignores the economics of warfare, but it adds realism when resources are constrained. You can also use shipyards as plot pivot points because they are vulnerable fixed assets that need to be protected.
- What about crew? Is the ship a 'traditional' vessel with a large human crew to keep it all running, or is it crewed by robots and AI, with no or few humans?
- if traditional, where do the sailors come from? How are they trained? Not having enough can be an interesting source of plot tension, esp. as the undermanned ship goes into battle against the fully crewed vessel. It's a Rocky plot in space.

Basically, there's a lot more to work through than just "how big are the ships" and the size should be a function of the story, not an attribute that you then elaborate the story around, because doing that will lead to plot holes pretty quickly.

#### Elijah Talbot

Thanks everyone for your replies and feedback, it made me learn the basics of science. I will do my best to reply to each one of them if I have the time.

How do you define "better performance"?
I define “better performance” as if a ship is in a one on one battle with another of the same class (Like battlecruisers, for example). Now, this sounds vague which it is and is a fault on my part because I did not go into detail about it. Now to determine which is better factors have to come into play like armour, weapons, etc. Therefore, I believe bigger ships will perform better because of the reasons I listed before. The biggest drawback is its size, bigger will give you bigger guns, but you are a target. Now, ship classes do play in a role, for example, a battleship will destroy a transport ship regardless of size.

Smaller ship would be harder to detect, ie might be able to sneak up on the larger ship.
I do not think so. Now space is big, and it is dark, so sight will not be reliable. Therefore, to detect ships, you must use different methods like radar, thermal and radiation detection. Of course, radar detects objects using radio waves, thermal will detect the heat of the ship, and radiation detection detects radiation (duh). Because the engines of the spaceships will spew a metric ton of radiation and heat.

- Do your ships travel FTL? That dramatically changes how warfare occurs.
- if they are relativistic, then light speed can introduce a real sense of drama, kind of like submarine hunts in WWII, because the ships are always at the mercy of delayed communications.
- How are they powered? Do they need supply dumps or will you use handwavium so they can travel forever?
- Have you crafted a hierarchy of vessels? Typically, large vessels have smaller ones to support them, they don't tend to just travel by themselves.
- What weapons are in use? Current physics ones like lasers, torpedoes, rail-guns? Or exotic tech like gravity waves, hypercannons, time bullets?
- What defenses have been iterated for each type of weapon?
-Is there artificial gravity? Crews in zee gee behave very differently to crews with gravity.
- Is there inertia suppression? This can allow much higher speeds if you want?
- Where are the ships built? Most sci-fi ignores the economics of warfare, but it adds realism when resources are constrained. You can also use shipyards as plot pivot points because they are vulnerable fixed assets that need to be protected.
- What about crew? Is the ship a 'traditional' vessel with a large human crew to keep it all running, or is it crewed by robots and AI, with no or few humans?
- if traditional, where do the sailors come from? How are they trained? Not having enough can be an interesting source of plot tension, esp. as the undermanned ship goes into battle against the fully crewed vessel. It's a Rocky plot in space.

Basically, there's a lot more to work through than just "how big are the ships" and the size should be a function of the story, not an attribute that you then elaborate the story around, because doing that will lead to plot holes pretty quickly.
This comment is big, and I like it. I will answer them the best I can.

Q1: Yes. Long story short to achieve this you would need a device (We will call it fast mode) to be implemented into your ship. The size of this device ranges from 30 meters to 200 meters. That is because fast mode needs a lot of energy for it to work. There are drawbacks like when using fast mode you will be detected.

Q2: Yes, they are relative. Which will guarantee to create drama.

Q3: Basically handwavium but with a long limit. The story does not require it.

Q4: Yes, I have. It took time since space warfare is going to be so different to naval warfare. Now large ships are good going against one ship. But against a fleet is borderline stupidity, these ships cost money and a lot of crew to maintain it.

Q5: There are but not limited to: Cannons (cheap weapons), lasers, torpedoes, rail guns, anti-matter weapons (yes, it defies physics), etc. Each weapon has its own uses and is situational. For example, if a ship is behind another ship, you would use a rail gun to hit the first ship and let the derby hit the other ship.

Q6: Things like matter shields, heat resistant materials, etc. I am working on it.

Q7: There is artificial gravity since I am planning to make a film then a book it is there because it’s cost effective.

Q8: I have not heard of interial-suppression before. I looked it up, and it made me rethink many of the technologies I thought of.

Q9: Most ships are built in solar systems that are designated in the construction of spaceships. These locations are highly valuable and would be the first areas to attack if you are planning to invade a galaxy. To get these resources, they would first mine a planet within the solar system. Once a ship is done (which will take a few years) the crew from all over the galaxy will be transported to that ship.

Q10: It would require a large crew. Which will create problems that I will get into later on.

Q11: Now, for the point of the story, sailors typically from all across the galaxy with training that varies. This is what will create the tension in the plot, the logistical nightmare of running a galactic army. The point of the story is to show the disorganisation, the carnage and casualties of taking over solar systems and running these giant space ships. A ship is as good as its crew, and if the crew have different forms of training, then there will be problems.

The point of this thread is to see if big ships are going to perform better then smaller ones in a one on one battle. I want to see what happens if the ship functions perfectly (good crew, supplied, etc.) in a battle. The biggest problem I see with the functionality of big ships is the Acceleration = Force / Mass.

#### Tghu Verd

The point of this thread is to see if big ships are going to perform better then smaller ones in a one on one battle.
Well, if you believe Jay Allan's interminable Blood on the Stars series, which is basically a series of space fleets beating each other to slag, book upon book of it, bigger is definitely better.

(As an aside, the first book in the series, Duel in the Dark, was outstanding. Unfortunately, it's been boilerplate ever since and it's only because I was suckered into Book 2 on the basis of Book 1 being awesome that I've slogged my way through the rest. God I do hope it ends soon, though. I'm down to reading a dozen pages at a time because it's become so tedious!)

Q7: There is artificial gravity
OK, so once you have antigrav, all sorts of consequences occur. Check out Bobby Adair's Freedoms Fire series for a good take on that, because antigrav should render kinetic weapons moot - you just repel them away from you - and even EM weapons can be diverted if you've a big enough gravity well. Then there's the ability to create gravity bombs. Most authors fail in their imagination on this front, because they just see the 'hold things in place' aspect without realizing that you can manipulate gravity, you can weaponize it.

since I am planning to make a film then a book it is there because it’s cost effective.
Good to have aspirations! Look forward to seeing it.

#### essenmein

OK, so once you have antigrav, all sorts of consequences occur. Check out Bobby Adair's Freedoms Fire series for a good take on that, because antigrav should render kinetic weapons moot - you just repel them away from you - and even EM weapons can be diverted if you've a big enough gravity well. Then there's the ability to create gravity bombs. Most authors fail in their imagination on this front, because they just see the 'hold things in place' aspect without realizing that you can manipulate gravity, you can weaponize it.
I've been mulling over this a lot. If you have AG (artificial gravity), this would provide the "inertial damping", these AG systems keep the ships in one piece, controlling for a static 1G down is the easy part, they have to over come 1000's of G's as the ships maneuver, this keeps them from tearing themselves apart as a result.

Now AG as a mass driver "shield" is something I've been pondering, but the question that pops in my head, and maybe that is the "fiction" part of scifi, how can you have gravity fields that hold people down in some parts of the ship, repel with large effective "negative mass" in all directions on the exterior and also overcome directional acceleration from the ships engines?

#### Tghu Verd

maybe that is the "fiction" part of scifi
"Yes, but how does it work?" Paul asked the Professor.

The Prof adopted what Paul's friend John called his 'smug face' and started to explain. "As you would know if you'd been paying attention in my GR class, Paul, gravity propagates in waves. My anti-gravity plates take advantage of that, using destructive and constructive interference to manipulate the local field very precisely."

He waved over to the middle of the room, at what looked like cheap bathroom floor tiles to Paul. They seemed unlikely enough as artificial gravity devices, but the 'other thing' was just wrong.

The closest tile was a shiny white and had a tennis ball floating about six centimeters above it, circling lazily. The next one looked like it had not been cleaned in forever, and the slight green bulge in the center was familiar, but not enough to immediately place. The air above this one seemed to waver, like a heat shimmer, and Paul thought the bulge was a tennis ball sliced in two and placed there, but the shape was not quite right and that didn't make any sense anyway, so he figured it was just his brain taking the floating tennis ball and and associating the color similarity of the bulge to that.

Further away was the 'other thing', which was entirely strange. An oily toadstool about a meter tall rose from the floor, only when Paul concentrated on it, it was not exactly oily and if he squinted, he could occasionally make out what looked like other views of the lab, swirling in and out of focus and at strange angles, like the view through a poorly ground lens.

The Prof puffed up and launched into what Paul just knew was going to be a patronizing spiel.

"So, the first plate cancels Earth's gravity exactly, putting the tennis ball in free fall in a zone from immediately above the plate to sixty centimeters high. It stays there for hours, until air currents nudge it out to the edge of the zone, and then it falls down, of course."

Of course. As if Paul couldn't have worked that out by himself. He knew he wasn't a genius like the Prof, but he wasn't a dullard either. That the Prof treated all his students as dullards was not consolation, Paul was emotionally skewered by each incident of the Prof's intellectual bullying, and more so when it was not buffered by being part of a group under fire.

"Truly, canceling out the stochastic signal is the hardest part of this tile, as even minute random field effects will disturb the anti-gravity effect. I built a swarm of picolayer MOSFET processors with quantum dot interferometers that read even relic gravitational waves and produce what is essentially a real-time counter frequency to negate them. Those relic waves are so annoying, not small enough that I can ignore them, and not large enough that I can use them, but I've patented the processor and the NSA bought a bunch of them as encryption busters, so all's well that ends well."

Paul suppressed a groan. Besides intellectual bullying, the Prof was an habitual boaster. Actually, beyond a boaster. He thrived on one upping everyone and everything, even if, as Paul suspected in this instance, it meant throwing confidentially agreements out the window. The Prof did not seem to care about that, just as long as he could name drop his latest triumph. Paul often hoped that such behavior would get the Prof into trouble, but his prolific genius was such that his indiscretions were viewed with some kind humor, as if those being name dropped were secretly pleased that the renowned Professor Samuel Clements Silver had deigned to mention them. He mentally shook his thoughts away, as the Prof had recommenced his lecture.

"So, as I was saying, to cancel Earth's gravity locally, the processors instantaneously calculate the changing quadrupole moment to determine the gravitational radiation and then generate a locally destructive frequency. Big as Earth is, it's a tiny amount of energy, about two hundred joules per second, and once you've got the wave heights, that is very straightforward to overcome.

"The second tile is actually a gravity amplifier. Be very careful with that one, it's generating a forty gee field between the surface of the tile and six centimeters above it. Squashed that tennis ball flat, as you can see, and would do catastrophic damage to your body if you were stupid enough to go near it."

Paul sighed. That was so like the Prof. He didn't believe in safety warnings or cordons to protect people. If they're stupid enough not to be paying attention, well it's their stupid fault if they hurt themselves he'd been heard to say often enough. The Uni's OHS Rep had tried to explain that each mishap in the Prof's class cost them dearly in payouts and insurance premiums, but then the Prof would just license some other new gadget which would more than cover the expense and the Dean would shrug as if to say, 'What can you do?'

"Gravity amplification is actually much harder to achieve than zero gravity, as the processors need to create and maintain a constructive cascade of wave forms that are self-referential, as a shaped field. My original picolayer architecture was not quite fast enough, so I had to extend it with a look ahead cache that applies a Monte Carlo to future events and builds a probability distribution seven nanoseconds out. As the eigenstates superposition collapses, the look ahead refines the Monte Carlo using an 'informed observer' algorithm and that is correct enough of the time to beat the odds and maintain the cascade."

The Prof looked off into the distance.

"You know, Paul, that informed observer algorithm was actually the hardest thing I've ever done." His face darkened. "I even had to ask that damned blowhard Phillips for help with the entanglement math. He's been crowing about it ever since, the idiot, talks as if he'd invented quanta momentum theory when he knows full well that I brought the concept to him pretty much fully completed. I mean, really, all he had to solve was a trivial calculation, tricky mind, but trivial. That's the last time I ask him for help with anything, let me tell you."

Paul kept the smile from his face. He'd heard all this before, but the truth was that Phillips wasn't crowing about helping. He was actually still reeling from how the Prof had unified Quantum Mechanics with General Relativity, in his spare time, for an unrelated project, and not even gotten why it was a big deal! Phillips knew that calculating a twelve dimensional, time-dependent, observer-less Hamilton space was a fantastic effort of its own, but in context, it was as if Einstein had asked him to tabulate his tax return. No, Phillips was not undermining the Prof at all, but the Prof was nothing if not self-absorbed. And perhaps just a little loopy.

"Anyway, let's not talk about that again. Old ground, Paul, and you know me. Forgive and forget."

Paul could not back a snort at that, and the Prof looked at him sharply. To deflect what was likely to be a severe dressing down, Paul pointed at the toadstool.

"And what's that one Professor Silver?"

It was clear that Silver was not fully buying the distraction, and Paul suspected he would be working off some demerit points very soon, but the Prof's nature for exposition overcame his nasty demeanor.

"That, Paul, is my crowing achievement. The toadstool as you so loathsomely put it, is a curved space time manifesting as an outward facing spherical manifold. I'm thinking I'll have to call it an anti-black hole so the punters can somewhat understand it, plus that's going to get Miss Rogers over in the astrophysics department in a tizz because it's clearly not anything to do with a black hole and you know how pedantic she is."

The Prof giggled, a bully knowing a weakness in a victim. "You should see how she blows up when I call Pluto a planet. Makes me laugh every time. My God, you'd have thought she'd know I'm just doing it to wind her up by now, but the woman has zero self control."

Paul knew that last part to be true enough. Jenny Rogers had once fallen for the Prof, even though it was against the University fraternization policy, and Paul was honest enough to admit to himself that he could see why. The bully and shameless self promoter came in a package of movie star good looks, and was loaded to boot. Forbes had put him in the Top 10 list of wealthy individuals last year, based on a succession of patents and gadgets licensed off for ridiculous sums. Watching the floating tennis ball, Paul just knew that next year his name would be even higher on the list. Jeff Bezos was getting rich selling and shipping all the Prof's stuff to the masses, but the man himself was fast catching up with each passing day.

"So, the toadstool. It is a collection of plates configured to create a two dimensional gravity bubble that almost entirely encompasses the collective. I say almost because the prototype has power and control cables coming up through the bottom, hence the toadstool shape, but I am working on a self-contained unit. Bloody thing required yet another new processor, because the field interactions are so complex. Rather than try to predict the future to create and maintain a cascade, I cheated a little and developed an heuristic that tags a place holder on each gravity wave as it passes, encoded in the polarization, and which the next in line processor uses to calculate the wave height they need to generate to exactly shape the gravity effect. That processor tags its gravitation wave, and so on, a closed loop system that uses a forward equivalent class model to keep the gravity field in check. That reduced the algorithm load enough that a custom germanium-on-sulfur chipset, overclocked and using inline DRAM, could just keep up. Actually, I can overclock them considerably because the processor takes the thermal energy and uses it to cycle-pump the incoming gravitational wave, which actually incrementally cools the processor down to a fraction of a Kelvin. It's like a troupe of Maxwell's demons are having a gravitational wave party and getting drunk on stolen heat."

Paul knew about Maxwell's famous demon of course, but he just couldn't picture how the Prof managed to violate the second law of thermodynamics. He thought it might just be a metaphor, until the Prof continued.

"My first batch of processors actually cooled themselves to death, got right down to absolute zero, which stopped them working as you'd likely imagine, and in that instant between one Planck time period and the next, ka-boom! Turns out that you can harness zero point energy, though that first try was pretty frightening. I'd unwittingly created an entropy instability that instantiated the equivalent of three kilograms of TNT from the quantum foam. I have to admit, I was not expecting that."

Paul knew that nobody had been. It was a miracle that the Prof's explosion hadn't killed anyone, but his habit of working odd hours was fortuitous in that he had started his experiment at four in the morning, then immediately gone to get a coffee from the vending machine down the hall, thinking the device would need a few minutes to 'warm up'. So nobody was around when the Prof had not only proven the existence of zero point energy, but harnessed it, and then gone on to figure out that time had to be quantized. Until now, the Prof hadn't disclosed what it was that he was working on that could explode in such a manner, and the Uni's lawyers had forced him to sign even more stringent damage waivers on the basis that his silence put an undue risk on their insurance policy. Scuttlebutt was that the Prof had laughed all the way through that meeting, calling them a a "bunch of indolent Blacktone's". Apparently, they'd ignored that until one of them later thought to look up what the Prof might have meant, and realized he'd insulted them all and they'd been too ignorant to realize it.

But of course, the Prof had keep shtum and since nothing had exploded since, the excitement had passed. Paul focused back on the toadstool - no way was he going to call it an anti-black hole, he'd side with Rogers on that one - as the Prof continued his explanation.

"As you can see, it does marvelous things to photons, reflecting them in unpredictable ways, but generally creating curved paths 'front' to 'back' if you take that reference to mean the angle of the incident light hitting the gravity interface being perpendicular. The stochastic signal actually injects just enough uncertainty that the light rays can be jostled out of the field, and I call that the Hawking's Hair Effect, because while it's not at all like what he predicted, the opportunity to honor one of the great's was just too good to pass up."

They were both silent for a moment, a mutual recognition that invoking Hawking's name warranted recognition of his passing.

"So, Paul. To get back to your original question. It works because of gravitational waves, and as you'd no doubt know if you paid any attention last semester when we dissected the properties of self-propagating transverse oscillating waves of electric and magnetic fields, once you can detect a wave, it's only a matter of time before you can manipulate a wave. And once you can manipulate a wave, well, wondrous things can happen. In this case, more wondrous than radio and television, at least I think so. I've been thinking of a few things that my anti-gravity plates can do, which is why I asked you here, actually. I need a new lab assistant, and I think your combination of keenness and constrained intellect will be just the ticket."

The Prof slapped Paul on the back, as if they were sharing a joke rather than him engaging in blatant workplace abuse. For a second Paul was tempted to show the Prof that while he might have a 'constrained intellect', he had fast and furious fists honed by almost two decades of Karate. But looking about the lab, and realizing how revolutionary the Prof's latest invention would be, he sucked up all the resentment and anger, and focused creating on a good outcome for himself, Paul McKenzie. That outcome would be fame and wealth, necessarily scavenged from the reflected brilliance of the Prof and not earned entirely by his own efforts. But Paul knew he could live with that. A few years suffering as the Prof's dogsbody? What was that against decades to live whatever life he pleased?

"Prof, that's fantastic," Paul enthused. "Honestly, I could not think of anything that I would enjoy more!"

It was a lie of course, but Paul's mother had always said that God forgave a lie told to spare someone's feelings. The only problem was, as Paul told the lie, he just wasn't quite sure who's feelings he was sparing.

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#### GTOM

Due to square cube law, bigger ships can maintain smaller acceleration/lesser manueverability provided that they have similar engine structure as the smaller one.
Orbital ships dont need long range life support and ion thrusters (generally high exhaust speed/low thrust drives)
While it can be possible to build big ships with high acceleration but they are expensive and i doubt they are truely useful, they cant dodge neither lasers, neither a barrage of missiles.

Manueverability can have a bigger role at orbital ships (being able to take off, change course fast, maybe they could dodge a few missiles, provided that the lasers damaged them)

I would say there are three different types of combat : high closing speed high range (like attack a convoy and have time to speed up) high range low speed (siege of a celestial with ships) low speed low range (low orbit combat)
Fighters arent good for deep space attack due to short ranbe (either compared to frigates or missiles) but they can be good for orbital combat, defence in deep space.

Homework Helper

#### GTOM

concocted ships that can ?
Small ships at extreme range might.
But the point was that a big ship can hardly dodge any kind of attack.

#### essenmein

Small ships at extreme range might.
But the point was that a big ship can hardly dodge any kind of attack.
The problem is any ship dodging lasers, how would you detect its approach and therefore know that you have to dodge?

IMO larger combat ships would employ much the same type of ideas we do today, fighter jets can barely "dodge" a missile, so an aircraft carrier has no chance. So to defend these types of vessels they developed Close In Weapon Systems (CIWS) or variations of it, ie basically point defense cannons to take out high speed close targets, whether thats a missile, a plane or an artillery shell.

#### GTOM

The problem is any ship dodging lasers, how would you detect its approach and therefore know that you have to dodge?

IMO larger combat ships would employ much the same type of ideas we do today, fighter jets can barely "dodge" a missile, so an aircraft carrier has no chance. So to defend these types of vessels they developed Close In Weapon Systems (CIWS) or variations of it, ie basically point defense cannons to take out high speed close targets, whether thats a missile, a plane or an artillery shell.
Theoretically a small ship can keep changing course to avoid hit with lasers at extreme range. Or in SF, might have FTL sense.
But i also think it is not the main reason to give big acceleration to small orbital ships.
Main reasons are: dodge missiles damaged by lasers
probably they are attacked by unguided/improvised weapons of rebels
if they can take out a radar, they might get out of the sight of a small missile
fast course change in order to fulfill missions
take off

#### essenmein

Theoretically a small ship can keep changing course to avoid hit with lasers at extreme range.
Maybe its my interpretation of the words, but to me "dodging" is the active act of avoidance, ie watch the thing coming and get out of its way, evasive maneuvering is more passive, done when expecting something might hit you, but there is no feed back, ie you are not detecting something and getting out of its way, you fly a pattern that you don't think the attacking weapon system can track. Classic example is flight paths of WW2 bombers over Europe, changing altitude and direction at prescribed times based on knowledge of how the german AA Flak targeting systems worked, but not as a result of detecting individual incoming projectiles.

#### Tghu Verd

Small ships at extreme range might.
Beam divergence means that a laser beam at extreme range, which I agree is a term open to interpretation, will be splashing a large area. For example, a beam with 1 mRad divergence fired 15,000 km away will be 15 km wide at that point. You'd need a lot of power in the beam to damage a ship hardened against lasers, so at extreme range jinking to avoid lasers is just not necessary.

"Does size matter in space"

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