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Reasons Against Super Fast Scifi Space Travel


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1. Good realistic alternatives exist. Don't want your bones to turn to mush? Separate vessel with a kilometer long tether and rotate 1 RPM with thrusters for 1g gravity. Granted I know this IS an engineering issue and lots of rad shielding is a given. Yet for people in space to be a common thing then everything they operate will need to be man-rated anyway.

2. Semi-fast fast travel can be done via Project Orion. Just pull in the  rotating tethers before you start blasting the bombs out the back. It really is good enough.

3. Really fast space travel is is plot breaking. I have no problem with instant FTL, but once there if you can zip around warping at lightspeed that has some dangerous implications. It would make any idea of space combat as we know it obsolete, and render ship to ship combat obsolete as well. So mucj for scifi...not everyday a trope kills another trope LOL.

4. Power required for 1g or any good thrust constant acceleration is massive. When in doubt, the lower power option *cough* Project Orion, is simply waiting for you and available to use.

 

 

 

 

Edited by Spacescifi
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We should estimate the distance at which we can register a "standard" 1 Mt X-ray flash by modern X-ray telescopes.

(I have no idea about the X-ray telescopes sensitivity, so don't expect it from me).

Then, if the distance is comparable to interstellar distances, "we" should have a look if such X-ray flashes actually happen around.
If they do, we can estimate an average frequency of collisions of alien interstellar ships with interstellar stones.

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20 minutes ago, kerbiloid said:

We should estimate the distance at which we can register a "standard" 1 Mt X-ray flash by modern X-ray telescopes.

(I have no idea about the X-ray telescopes sensitivity, so don't expect it from me).

Then, if the distance is comparable to interstellar distances, "we" should have a look if such X-ray flashes actually happen around.
If they do, we can estimate an average frequency of collisions of alien interstellar ships with interstellar stones.

You jest but if we could build an Orion drive then aliens could too. How far away could you see one of those operating (for given thrust-class levels)? Which of our telescopes would be ideal?

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Chandra would be a good bet I would think. The Wikipedia article is light on performance data but does mention that Chandra was able to detect X ray emissions from Pluto. Admittedly, that doesn't tell you much on its own.

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Orion is very marginal as an starship, yes you could build something the size of half an death star, there the other half was an pusher plate and use hundreds of megaton charges who would give decent isp. 
Interplanetary orion make the solar system an playground so would any very marginal interstellar drives. 

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The pro for fast travel in sci-fi is that it spares you the time skips.

The contra is that it's a big can of worldbuilding worms.

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3 hours ago, Spacescifi said:

3. Really fast space travel is is plot breaking. I have no problem with instant FTL, but once there if you can zip around warping at lightspeed that has some dangerous implications. It would make any idea of space combat as we know it obsolete, and render ship to ship combat obsolete as well. So mucj for scifi...not everyday a trope kills another trope LOL.

Leaving aside the slightly snarky point that scifi doesn't have to include space battles, I would argue that it just means you need a different plot.  Okay, any space navy style fleet battles might be out (always assuming that your setting doesn't allow for some method of preventing enemy combatants zipping around at lightspeed) but that still leaves plenty of scope for war stories.

Why are your protagonists fighting? Presumably there's some point to it over and above blowing up enemy ships for the heck of it, some valuable real estate to attack or defend, whether that be a planet, an O'Neill cylinder, a Ringworld, a General Systems Vehicle, or whatever. Something that the enemy wants to take intact, such that slamming relativistic projectiles into it would do enough damage to make the whole exercise rather pointless. That, right there, gives you some useful constraints. It keeps combat vessel speeds within reason (just because they can zip around at lightspeed, it doesn't mean they have to, especially if accidentally annihilating your prized mission objective is a serious risk). More to the point, neither side can make use of their OTT maximum velocities to simply avoid combat - the attackers want to secure their objective and the defenders need to stop them.

Or consider a planet. Sure the attacking force can zip in at lightspeed and maybe avoid any defenses whilst doing so but, if they want to put boots on the ground and take that planet away from the enemy, then they have to establish some sort of presence there , whether that be sufficient orbital weaponry to cow the populace into surrender*, or sending in the drop troopers to secure a beachhead. In either case you're back to reasonable speeds for space battles if you want them. You just end up with a setting where all the fighting takes place in orbital space rather than deep space.

 

* edit - I include this as an example only - lets not get sidetracked into guerilla warfare and whether a threat from orbit would actually cow the populace particularly effectively.

 

Edited by KSK
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27 minutes ago, KSK said:

Leaving aside the slightly snarky point that scifi doesn't have to include space battles, I would argue that it just means you need a different plot.  Okay, any space navy style fleet battles might be out (always assuming that your setting doesn't allow for some method of preventing enemy combatants zipping around at lightspeed) but that still leaves plenty of scope for war stories.

Why are your protagonists fighting? Presumably there's some point to it over and above blowing up enemy ships for the heck of it, some valuable real estate to attack or defend, whether that be a planet, an O'Neill cylinder, a Ringworld, a General Systems Vehicle, or whatever. Something that the enemy wants to take intact, such that slamming relativistic projectiles into it would do enough damage to make the whole exercise rather pointless. That, right there, gives you some useful constraints. It keeps combat vessel speeds within reason (just because they can zip around at lightspeed, it doesn't mean they have to, especially if accidentally annihilating your prized mission objective is a serious risk). More to the point, neither side can make use of their OTT maximum velocities to simply avoid combat - the attackers want to secure their objective and the defenders need to stop them.

Or consider a planet. Sure the attacking force can zip in at lightspeed and maybe avoid any defenses whilst doing so but, if they want to put boots on the ground and take that planet away from the enemy, then they have to establish some sort of presence there , whether that be sufficient orbital weaponry to cow the populace into surrender*, or sending in the drop troopers to secure a beachhead. In either case you're back to reasonable speeds for space battles if you want them. You just end up with a setting where all the fighting takes place in orbital space rather than deep space.

 

* edit - I include this as an example only - lets not get sidetracked into guerilla warfare and whether a threat from orbit would actually cow the populace particularly effectively.

 

It is also possible to excuse things with the cost and technology level. So light speed projectile weapons, while theoretically feasible, either are impossible to build fire control systems for or are too expensive.

I am not sure if Star Wars counts in this discussion, but for example, hyper space tracking does not result in hyper space ramming becoming the main tactic in space battles because starships are expensive (don't want to spend quadrillions in Earth money for one attack) and an FCS for a hyper space weapon doesn't exist. Hyper space tracking itself existed back during the Empire days but was not widespread because of its cost, if I recall correctly. The only reason it happened in Episode 8 is because the enemy ship was in visual range and right there in front of the ramming ship.

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32 minutes ago, SunlitZelkova said:

Hyper space tracking itself existed back during the Empire days but was not widespread because of its cost, if I recall correctly.

Hyper Space tracking was mentioned in Rogue one, with the implications it was being researched, but not yet available. I also wouldn't be able to understand how cost is a concern if the Empire can afford to build two freaken Death Stars, but can't afford to find the Rebels who always run via hyperspace. Intelligence wins wars!

 

The simplest reason super fast space travel exists is the same reason editing exists. No one cares about unimportant events occurring that isn't impactful of the plot. Sure it can be a useful plot mechanic itself (relativity is a fun thing to play around) but because it's so inherently unusual it has to be explained through exposition, which again impacts the telling of the plot. Depending on the story you want to tell, getting bogged down in how realistic something is can muddle the underlying message and themes.

An Orion Drive could be used, but the difference between some fancy/magic FTL travel and the Orion Driver is hilarious in terms of their impact on the plot. With FTL you can do whatever the hell you can dream of. With an Orion drive you just took a 1 way trip down the proverbial galactic block to your closest neighbor, which really limits storytelling potential.

Sure FTL is more fiction than science, but including more science doesn't make every story better. 

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3 hours ago, magnemoe said:

Orion is very marginal as an starship, yes you could build something the size of half an death star, there the other half was an pusher plate and use hundreds of megaton charges who would give decent isp. 
Interplanetary orion make the solar system an playground so would any very marginal interstellar drives. 

 

I will level with all of you.

Orbital dynamics and all the stuff regarding newtonian movement goes out the window when you can lightspeed around a solar system.

All the knowledge..wonderful knowledge by the way...means NOTHING and cannot be used that has been gained.

I cannot abide by that.

48 minutes ago, MKI said:

Hyper Space tracking was mentioned in Rogue one, with the implications it was being researched, but not yet available. I also wouldn't be able to understand how cost is a concern if the Empire can afford to build two freaken Death Stars, but can't afford to find the Rebels who always run via hyperspace. Intelligence wins wars!

 

The simplest reason super fast space travel exists is the same reason editing exists. No one cares about unimportant events occurring that isn't impactful of the plot. Sure it can be a useful plot mechanic itself (relativity is a fun thing to play around) but because it's so inherently unusual it has to be explained through exposition, which again impacts the telling of the plot. Depending on the story you want to tell, getting bogged down in how realistic something is can muddle the underlying message and themes.

An Orion Drive could be used, but the difference between some fancy/magic FTL travel and the Orion Driver is hilarious in terms of their impact on the plot. With FTL you can do whatever the hell you can dream of. With an Orion drive you just took a 1 way trip down the proverbial galactic block to your closest neighbor, which really limits storytelling potential.

Sure FTL is more fiction than science, but including more science doesn't make every story bette

 

Made me laugh about the cost comment.

I agree fiction requires just that.

I just prefer some fast FTL but normal intersystem travel times. 

2 hours ago, KSK said:

Leaving aside the slightly snarky point that scifi doesn't have to include space battles, I would argue that it just means you need a different plot.  Okay, any space navy style fleet battles might be out (always assuming that your setting doesn't allow for some method of preventing enemy combatants zipping around at lightspeed) but that still leaves plenty of scope for war stories.

Why are your protagonists fighting? Presumably there's some point to it over and above blowing up enemy ships for the heck of it, some valuable real estate to attack or defend, whether that be a planet, an O'Neill cylinder, a Ringworld, a General Systems Vehicle, or whatever. Something that the enemy wants to take intact, such that slamming relativistic projectiles into it would do enough damage to make the whole exercise rather pointless. That, right there, gives you some useful constraints. It keeps combat vessel speeds within reason (just because they can zip around at lightspeed, it doesn't mean they have to, especially if accidentally annihilating your prized mission objective is a serious risk). More to the point, neither side can make use of their OTT maximum velocities to simply avoid combat - the attackers want to secure their objective and the defenders need to stop them.

Or consider a planet. Sure the attacking force can zip in at lightspeed and maybe avoid any defenses whilst doing so but, if they want to put boots on the ground and take that planet away from the enemy, then they have to establish some sort of presence there , whether that be sufficient orbital weaponry to cow the populace into surrender*, or sending in the drop troopers to secure a beachhead. In either case you're back to reasonable speeds for space battles if you want them. You just end up with a setting where all the fighting takes place in orbital space rather than deep space.

 

* edit - I include this as an example only - lets not get sidetracked into guerilla warfare and whether a threat from orbit would actually cow the populace particularly effectively.

 

 

Who said I was writing a war story?

However...it is not a utopian scifi universe by any means.

So the threat of being blown out of the sky is still real.

 

Space war really is kind of nonsense. A very special kind requiring very specific circumstances.

Generally speaking, planetary invasion is NOT fun for the conquerors.

 

You either make a wasteland or the defeated create one via scorched earth policy like on Babylon 5.

 

https://m.youtube.com/watch?v=MXkIuVLnsFE

Edited by Spacescifi
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1 hour ago, MKI said:

Hyper Space tracking was mentioned in Rogue one, with the implications it was being researched, but not yet available. I also wouldn't be able to understand how cost is a concern if the Empire can afford to build two freaken Death Stars, but can't afford to find the Rebels who always run via hyperspace. Intelligence wins wars!

Probably because they were building the two Death Stars. For example, there was a design for a TIE Fighter with shields and a hyper drive that could have surpassed the performance of the X-Wing, but the Death Star ate all of the funding and so it was never built.

41 minutes ago, Spacescifi said:

Space war really is kind of nonsense. A very special kind requiring very specific circumstances

I think if a civilization has reached the point where it can build interstellar spacecraft capable of FTL speeds, war should be unnecessary to its people.

Edited by SunlitZelkova
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14 minutes ago, SunlitZelkova said:

Probably because they were building the two Death Stars. For example, there was a design for a TIE Fighter with shields and a hyper drive that could have surpassed the performance of the X-Wing, but the Death Star ate all of the funding and so it was never built.

I think if a civilization has reached the point where it can build interstellar spacecraft capable of FTL speeds, war should be unnecessary to its people.

It is not ever never necessary on Earth unless one wants something bad enough.

 

Yet with space travel this good, the cost of going exterminatus on a planet is a lot higher than just say...building space habs.

The one place space war actually makes sense to me  is attacks on space shipping and piracy.

In other words, space trade wars. Motivated by a desire for profit and probably greed too.

 

Solely between the ships among the stars.

 

Planets pay for it. Ships bring it. If they can survive.

Edited by Spacescifi
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5 hours ago, SunlitZelkova said:

Probably because they were building the two Death Stars. For example, there was a design for a TIE Fighter with shields and a hyper drive that could have surpassed the performance of the X-Wing, but the Death Star ate all of the funding and so it was never built.

The Tie Defender? This was built, just later as it exists in SW Squadrons, which is a cannon game.

Its very possible Palps was too busy focusing on the big guns rather than focusing on what would of been more tactically important technologies. Then again, the traditional Empire only lasted a few decades, and didn't exactly have the best tactics overall. :wink: 

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22 hours ago, magnemoe said:

Orion is very marginal as an starship, yes you could build something the size of half an death star, there the other half was an pusher plate and use hundreds of megaton charges who would give decent isp. 
Interplanetary orion make the solar system an playground so would any very marginal interstellar drives. 

I've always heard of things like "max delta-v = 30Mm/s (.1c), but never heard of anybody explaining how that would fit into the rocket equation.  Granted, a lot of that is because pusher plates don't really use the rocket equation at all: they use the blast to transfer the energy into momentum on the pusher plate, and that is what drives the ship (surprisingly efficiently, and scales up with the mass of the plate).  Still, 30Mm/s is a *lot* of delta-v (and presumably means you will be doing .05c if you want to slow down when you get there.  Of course, .05c means you need a lot less shielding from all the interstellar spacedust hitting you at relativistic speeds).

For intra-solar system travel, the Orion is pretty extreme but doable.

On 4/15/2021 at 2:09 PM, sevenperforce said:

You jest but if we could build an Orion drive then aliens could too. How far away could you see one of those operating (for given thrust-class levels)? Which of our telescopes would be ideal?

Whatever "the aliens" used to get here would require some pretty extreme technology.  Even if their tech was anything we could possibly create (such as the Orion), they would be likely be operating on timescales of thousands or millions of years.  Such an alien "invasion" might not contain any members of the species/culture/whatever who built it but would be just a delivery pod for the "de-terraforming" equipment and lifeforms (assuming the "equipment" is some sort of self-replicating nanotech, the differences would be academic).  Perhaps the plot may involve tripping some sort of 'don't wipeout inhabited planets' code in the pod, or maybe it sees Earth as "extra vermin infested" and attacks harder.

Remember, sending Earth's human population back to the dark ages requires somewhere between 1950s to 1960s tech.  And it could be done well under an hour once you reach Earth orbit.  Making a starfaring alien enemy that wouldn't simply crush humanity (presumably the same way we've been wiping out most of Earth's various species*) while happily modifying Earth (as well as Venus and Mars) to meet their needs is fairly tricky.  Space warfare has been possible for over 50 years, with much of that time largely assuming it would escalate into "global thermonuclear war".  Starting a spacewar has always been the province of 007-type villains, not something a rational type would do (the rationality of starting a terrestrial-based war is beyond the scope of this forum, but no "modern" war has been "necessary" thanks to "insufficient technology" (while this might require some circular definitions, I'm sure there are recent examples that fit, and involve nations with higher available tech than most counterexamples)).

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14 minutes ago, wumpus said:
On 4/15/2021 at 2:09 PM, sevenperforce said:

You jest but if we could build an Orion drive then aliens could too. How far away could you see one of those operating (for given thrust-class levels)? Which of our telescopes would be ideal?

Whatever "the aliens" used to get here would require some pretty extreme technology.  Even if their tech was anything we could possibly create (such as the Orion), they would be likely be operating on timescales of thousands or millions of years.  Such an alien "invasion" might not contain any members of the species/culture/whatever who built it but would be just a delivery pod for the "de-terraforming" equipment and lifeforms (assuming the "equipment" is some sort of self-replicating nanotech, the differences would be academic). 

Oh, I'm not talking about aliens getting here. I mean if aliens were using Orion drives to zip around in their own respective solar systems. Thermonuclear weapons are momentarily brighter than a star and produce distinct x-ray signatures, though of course total luminosity is not comparable to that of a star.

But suppose there were aliens on some of the planets or moons in the Alpha Centauri system. Suppose further that they were spacefaring and had graduated to Orion Drive vehicles to use for moving stuff around their system. Would any of our telescopes be able to pick up the characteristic pop-pop-pop-pop-pop of an Orion Drive? Or would the energy output be just noise against the background of the star system?

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5 minutes ago, sevenperforce said:

Oh, I'm not talking about aliens getting here. I mean if aliens were using Orion drives to zip around in their own respective solar systems. Thermonuclear weapons are momentarily brighter than a star and produce distinct x-ray signatures, though of course total luminosity is not comparable to that of a star.

But suppose there were aliens on some of the planets or moons in the Alpha Centauri system. Suppose further that they were spacefaring and had graduated to Orion Drive vehicles to use for moving stuff around their system. Would any of our telescopes be able to pick up the characteristic pop-pop-pop-pop-pop of an Orion Drive? Or would the energy output be just noise against the background of the star system?

Good question.  I'd assume it would take a long time to detect such a thing.  Detecting planets seems to require observing minute occultations of stars via said planets, so I can't image how we would see an Orion.  Perhaps we could detect a fission-based Orion, as any fusion reaction would be lost in the noise of the fusion from the nearby star.  Why aliens would be using fission during the timeframe where we were just able to observe them would come down to "because the plot required it" regardless of how statistically unlikely.

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6 hours ago, sevenperforce said:

Oh, I'm not talking about aliens getting here. I mean if aliens were using Orion drives to zip around in their own respective solar systems. Thermonuclear weapons are momentarily brighter than a star and produce distinct x-ray signatures, though of course total luminosity is not comparable to that of a star.

But suppose there were aliens on some of the planets or moons in the Alpha Centauri system. Suppose further that they were spacefaring and had graduated to Orion Drive vehicles to use for moving stuff around their system. Would any of our telescopes be able to pick up the characteristic pop-pop-pop-pop-pop of an Orion Drive? Or would the energy output be just noise against the background of the star system?

 

Remember the Oort cloud...and that every solar system may have one.

 

Which can kill spaceships on the way in.

Orion is doable but far from most optimal.

 

Fun KSK post re-quoted:

 

So what exactly did happen to the enemy flagship, Captain?"
"Uh - we picked up a short duration, high intensity radiation source on the edge of the Oort cloud, Admiral. As far as we can tell, they hit a magnitude eleven object on the way in. Feel a bit sorry for the blighters to tell the truth."
"At least it was quick."
"Aye, sir."

 

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10 hours ago, wumpus said:

I've always heard of things like "max delta-v = 30Mm/s (.1c), but never heard of anybody explaining how that would fit into the rocket equation.  Granted, a lot of that is because pusher plates don't really use the rocket equation at all: they use the blast to transfer the energy into momentum on the pusher plate, and that is what drives the ship (surprisingly efficiently, and scales up with the mass of the plate).  Still, 30Mm/s is a *lot* of delta-v (and presumably means you will be doing .05c if you want to slow down when you get there.  Of course, .05c means you need a lot less shielding from all the interstellar spacedust hitting you at relativistic speeds).

It anyway follows the Meshchersky's equations, just discretly.

Optimistic estimation said that if they can focus most part of energy, then theoretical upper limit  of ISP of nukes is ~200 000 s (i.e.ISP*g ~2 000 km/s), and fusion pellets are ~ 400 000 s (ISP*g ~4 000 km/s).

https://translate.google.com/translate?hl=&sl=ru&tl=en&u=http%3A%2F%2Fgo2starss.narod.ru%2Fpub%2FE028_WJ.html

(see "INTERNAL BALLISTICS TYARD")

Though, it's an estimation for magnetic pulse post-Orion, not for the mechanical one.
Though, the mechanical one was proposed just for Saturn.

3 hours ago, Spacescifi said:

Remember the Oort cloud...and that every solar system may have one.

We even don't know if the ours does. It's still just a mathematical abstraction.

And even if so, the distances between the Oort objects are in tenths of AU.

Edited by kerbiloid
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5 hours ago, Spacescifi said:

Fun KSK post re-quoted:

 

So what exactly did happen to the enemy flagship, Captain?"
"Uh - we picked up a short duration, high intensity radiation source on the edge of the Oort cloud, Admiral. As far as we can tell, they hit a magnitude eleven object on the way in. Feel a bit sorry for the blighters to tell the truth."
"At least it was quick."
"Aye, sir."

 

I think you missed the point of @KSKs post.

'death by space rock' is a really lame way to kill off a character. "

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8 hours ago, Shpaget said:

I think you missed the point of @KSKs post.

'death by space rock' is a really lame way to kill off a character. "

 

Maybe...bit not of it is hilarious.

 

I would make it so if I went that route.

 

How many times do the lamest things win wars?

 

Russian winter beat both Hitler and Napeleon.

A litte over a hundred years between them. Same russian winter.

Edited by Spacescifi
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Completely different things.

In war, logistics is one of the most important things and failing to establish a robust supply chain to the front line will inevitably cause a defeat in any conflict that lasts more than a few weeks or even days. Even if the attacking army manages to conquer a new territory, they will not hold it unless the supplies start coming rather quickly.

Having a fictional story grind to a halt out of a blue is lazy writing. I can see this particular scenario used as a part of a background setup, or as a one small event in a much bigger chain of events, either as a brief explanation of previous events or as a comic relief.

Plot should develop naturally as a result of character actions and reasonably logical natural events. In comparison, deus ex machina is can be jarring, break immersion and overall is just lame and stinks of lack of imagination.

All that being said, space rocks are not very common. The main asteroid belt is so empty that space probes which pass through it don't even consider its existence, and it's jam-packed compared to Oort cloud emptiness. Heck even the existence of Oort cloud itself is debated, as pointed out by kerbiloid.

Asteroid belts in movies where spaceships have to carefully and slowly navigate between giant rocks that constantly grind and bump against each other are not realistic.

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On 4/16/2021 at 12:20 AM, SunlitZelkova said:

because starships are expensive (don't want to spend quadrillions in Earth money for one attack)

But not too expensive to put them into battle. Including single-seat FTL-enabled ships.

Simply put, there is no excuse for them not lightspeed-ramming a Star Destroyer, let alone a Death Star, with a snubfighter all the time. SW opened up the mother of all cans of worms just for one pretty visual that had little storytelling value - the ramming scene as well as the Supremacy itself are a late addition (that TLJ went with the first draft is an oft-repeated lie), Holdo used to be an actual FO sympathizer as a senator for Cantonica the Casino Planet, the covert seat of Snoke's power and the location of his throne room, ensuring that the main characters converge on the same location rather than some of them spend time on an inconsequential side story. Sounds like a better movie, does it not?

/rant

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