Infinite Acceleration Would Be More Secure Than I Thought....

[Spacescifi]

For years I was frustrated over the fact that the ideal space drive... something that allowed for high thrust constant acceleration, would also be a terribly powerful weapon.

I thought it would be absurd for any planetary authority in their right mind to allow hundreds of vessels to come and go as they please that are capable of THAT.

Until now... turns out the answer was obvious all along.

Let's go extreme... and presume all common space drives can accelerate virtually indefinitely (so long it's powered), even for missiles.

That does not mean big heavy ships are obsolete. What it means is that fleets of fighter craft that escort it are the ONLY thing that will save it in battle.

Space fighters with particle beams and missiles of their own could intercept and destroy incoming missiles... just spamming missiles would not ensure a definite win even if you could.

 

The idea of big ships with big guns is frankly... unnecessary.  Looks cool but it's a bad idea unless you're attacking a nearly stationary target. Even then fighters and missiles could do the same job with less risk to the main vessel they escott.

Since if fighter drones can outrun a large manned vessel, they will simply overwhelm it before it can use it's big gun effectively against them.

I do not see any real area for large vessels with powerful long range guns where fighters in this setting could not supercede them.

Especially in the OP setting where high thrust acceleration is virtually infinite.

 

Do you?

 

[wumpus]

Infinite acceleration (of a rocket) implies emission of infinite momentum in the other direction (conservation of momentum and such).

If you want to read how that works in a story, try L. E. Modesitt Jr. at least the early sci-fi stuff.  Mostly Ecolitan, maybe Timegod.  He moved on to mostly fantasy and mostly moved on from the terrorist/war crime apologia (it is a lot easier to accurately justify ramming a planet at nearly light speed when an all-knowing author is feeding you information).

[Spacescifi]

36 minutes ago, wumpus said:

Infinite acceleration (of a rocket) implies emission of infinite momentum in the other direction (conservation of momentum and such).

If you want to read how that works in a story, try L. E. Modesitt Jr. at least the early sci-fi stuff.  Mostly Ecolitan, maybe Timegod.  He moved on to mostly fantasy and mostly moved on from the terrorist/war crime apologia (it is a lot easier to accurately justify ramming a planet at nearly light speed when an all-knowing author is feeding you information).

 

If light emitted from the drive could be modified to be high pressure rather than low pressure, then thrust generated from pushing a reflective nozzle could be on par with a rocket... but unlike a rocket it would not be subject to the tyranny of the rocket equation since it would not rely on exhausting propellant.... only power.

Edited August 25, 2022 by Spacescifi

[Shpaget]

Why would you bother with their small fighters when you can just mount an engine to the nearest rock and rearrange their tectonic plates?

[DeadJohn]

3 hours ago, Spacescifi said:

presume all common space drives can accelerate virtually indefinitely (so long it's powered), even for missiles.

3 hours ago, Spacescifi said:

Space fighters with particle beams and missiles of their own could intercept and destroy incoming missiles

Such a missile seems undetectable if launched from far enough away. Aim at a planet, accelerate, reach light speed, and defensive fighters wouldn't realize the lightspeed missile was approaching until after it passed.  Any particle beams fired at the missile would never catch up to it.

Your scenario would require fighters with faster-than-light radar to detect the approaching missile, or faster-than-light particle beams to catch up to the missile, plus a top missile speed somewhat less than the radar and particle beam.

Then the arms race continues as your enemy fires an undetectable infinite energy particle beam instead of a missile at your planet, or fries everyone with a focused FTL radar.

[Spacescifi]

1 hour ago, Shpaget said:

Why would you bother with their small fighters when you can just mount an engine to the nearest rock and rearrange their tectonic plates?

 

Because satelites would notice and send word for reenforcements.

25 minutes ago, DeadJohn said:

Such a missile seems undetectable if launched from far enough away. Aim at a planet, accelerate, reach light speed, and defensive fighters wouldn't realize the lightspeed missile was approaching until after it passed.  Any particle beams fired at the missile would never catch up to it.

Your scenario would require fighters with faster-than-light radar to detect the approaching missile, or faster-than-light particle beams to catch up to the missile, plus a top missile speed somewhat less than the radar and particle beam.

Then the arms race continues as your enemy fires an undetectable infinite energy particle beam instead of a missile at your planet, or fries everyone with a focused FTL radar.

 

You do not need FTL weapons.

 

All you need is FTL portal radio... instant communication channel. And of course FTL methods that drop you some distance away far enough from a planet that you could not just FTL warp ram them.

 

With early warning satelites orbiting around the solar system the very strength of RVK's would become it's weakness.

 

It too is more susceptible to damage, and thanks to insta-comms every fleet and big gun in the solar system will be raining fire down ahead of it.

 

Only takes one hit to blow it up at that speed.... and if you have long range partice beam from orbital defense stations that can hit a light second out reliably... you would scatter them out so that you could buy a planet a few extra seconds as it's last line of defense.

Assuming fighters and missiles do not kill it first.

It is important to note that when traveling at uber high speed it is quite possible to miss your target.

 

Especially if dodging fire at the same time.

Edited August 25, 2022 by Spacescifi

[DeadJohn]

1 hour ago, Spacescifi said:

It is important to note that when traveling at uber high speed it is quite possible to miss your target.

The missile is targeting a planet - huge target with a predictable orbit that can't evade. Meanwhile, the defensive systems have to hit the small high speed unexpected missile. The defenses are vastly more likely to miss the incoming missile than the missile is to miss a planet.

In an unrestrained interplanetary war with infinite-energy tech, planets will be toast if the best defense is to shoot things. There's a reason why so much science fiction includes force field tech.

[Spacescifi]

19 minutes ago, DeadJohn said:

The missile is targeting a planet - huge target with a predictable orbit that can't evade. Meanwhile, the defensive systems have to hit the small high speed unexpected missile. The defenses are vastly more likely to miss the incoming missile than the missile is to miss a planet.

In an unrestrained interplanetary war with infinite-energy tech, planets will be toast if the best defense is to shoot things. There's a reason why so much science fiction includes force field tech.

Outsider webcomic has spaceships that can cruise at 30g for 100 hours max, and particle beam cannon that can hit a lightsecond out.

 

Not infinite.... but close enough.

 

I made much the same point you did in a discussion.

The main reason why planets are not toast is that enemy spacecraft are blown up or chased away usually before they ever get in range of a planet... since the main aliens of the story... space amazon elves basically, specialize in uber fast ships with uber long range blaster beam cannons.

Usually outnumbered and still win often. Just cannot keep killing faster than their enemy can churn out replacements.

[kerbiloid]

A Doomsday Orion with Sundial warhead burns everything in ~1 000 km radius, and is just 20 m in size.

[Spacescifi]

35 minutes ago, kerbiloid said:

A Doomsday Orion with Sundial warhead burns everything in ~1 000 km radius, and is just 20 m in size.

In vacuum I doubt it. It's all radiation without the air blast.

 

Granted, if you detonated every sundial on an orion all at once you get more range, even then, I am not sure it vaporizes everything within 1000 km in vaccuum... that is more than the distance to space from Earth!

[kerbiloid]

42 minutes ago, Spacescifi said:

In vacuum I doubt it. It's all radiation without the air blast.

It explodes at 150 km altitude and heats air below with X-rays.

[wumpus]

On 8/25/2022 at 1:03 PM, Spacescifi said:

 

If light emitted from the drive could be modified to be high pressure rather than low pressure, then thrust generated from pushing a reflective nozzle could be on par with a rocket... but unlike a rocket it would not be subject to the tyranny of the rocket equation since it would not rely on exhausting propellant.... only power.

Pressure is irrelevant, there is no conservation of pressure.  Momentum is the key, and is pretty much set for each photon.  And since the energy =hc/λ and momentum = h/λ, it shouldn't matter what wavelength you are emitting, you get the same (tiny) momentum per Joule of energy.  And while this might maximize the Isp of your starship, the energy efficiency isn't going to enough to make it a good choice.

[Spacescifi]

20 hours ago, DeadJohn said:

The missile is targeting a planet - huge target with a predictable orbit that can't evade. Meanwhile, the defensive systems have to hit the small high speed unexpected missile. The defenses are vastly more likely to miss the incoming missile than the missile is to miss a planet.

In an unrestrained interplanetary war with infinite-energy tech, planets will be toast if the best defense is to shoot things. There's a reason why so much science fiction includes force field tech.

 

Actually I recall reading that at near light speeds, hydrogen atoms, though rare, when they hit an object going that fast they shower it with deadly radiation.

Meaning that destroying a missile could actualky be easy.

 

Just make an atomic cannon and fire bursts of hydrogen atoms at near light speed.

 

Either the missiles electronics would fry, leaving unable to maneuver away from attacks, or... enough radiation could be used to blow it up outright.

 

Light speed is not the speed limit, it's lower than even that if you do not want to be showered in deadly hard radiation.

[Spacescifi]

5 minutes ago, wumpus said:

Pressure is irrelevant, there is no conservation of pressure.  Momentum is the key, and is pretty much set for each photon.  And since the energy =hc/λ and momentum = h/λ, it shouldn't matter what wavelength you are emitting, you get the same (tiny) momentum per Joule of energy.  And while this might maximize the Isp of your starship, the energy efficiency isn't going to enough to make it a good choice.

 

I see. I just assumed more pressure would provide more thrust because I can feel light when it flashes on me, and the pressure is quite weak

I just though that if the pressure the light emitted was on par with a rocket engine, the momentum from rocket level pressure ray exhaust would be increased as it exits the nozzle.

 

I am not saying shine out a high pressure ray and expect high thrust.

 

I thought that speed of light ray exhaust with the pressure of rockets would increase the momentum of the nozzle as it exits it.

 

In other words, I was thinking that high pressure light speed exhaust would have more energy than low pressure light speed exhaust, so therefore it should produce rocket level thrust.

 

Are you saying that even if we made a high pressure ray that blew out high pressure rays of light on par with a chemical rocket, it would oddly STILL only give poor thrust?

 

That seems... paradoxical... high enough thrust to kick up dust and blow a man away, but not high enough to transfer enough momentum to provide better thrust for the ship?

I guess in a way to have greater pressure, high pressure rays would need 'imaginary mass', behaving as if they have more energy than a normal photon.

[Spacescifi]

Perhaps if I just say the that the drive emits 'hyper-repulsive' photons, that way the momentum would be increased and also thrust at the same time... unless you're going to tell me that hyper-repulsive emitted photons should move at FTL or a higher top speed than light... but I only wanted them to have to light speed exhaust.

Edited August 26, 2022 by Spacescifi