Physically plausible explanation for missile based space combat?

[GTOM]

If their making random course corrections there's also a source of power and an exhaust emission. You mention traveling fast but unless they're traveling extremely fast crossing a distance like a light second is going to take on the order of hours. Plenty of time to shoot down with long range beam weapons or simply fly away if you're in a ship.

I proposed tether propulsion for the first part, if there are 100m long nanotube cables, the missiles can be (almost) anywhere in a 100m circle. (Connect them and rotate them around each other, pull the cables, or let them loose)
But i don't deny, with deep space conditions, on similar tech level, detection is the easier thing.
(For my other, FTL setting, the alienware missiles will have another upgrade, if they are destroyed, they emit a strong directed X-pulse, so they hit back. i think i name the magitech material pulsarium. )
Although i don't rule out some stealth attack part in orbit (launch magitech drone from landing cargo shuttle in order to hack PDF satellite).
Or people rebel on liberated in Red Army style planet when third partys fleet comes. When occupy force fleet turn sensors toward coming fleet, attack them in the back with missiles (boost them on other side of planet, and contain their heat with some liquid helium for a time)

 

[Ryan_m_b]

I proposed tether propulsion for the first part, if there are 100m long nanotube cables, the missiles can be (almost) anywhere in a 100m circle. (Connect them and rotate them around each other, pull the cables, or let them loose)

Assuming they weren't observed deploying the enemy could just shoot in the middle of that 100m and sever the tether, sending either ship/missile flying off. To reconnect/correct the course they'd have to power up.

But i don't deny, with deep space conditions, on similar tech level, detection is the easier thing.

It is the most different aspect of space compared to other forms of human experience, line of site is essentially infinite which changes a lot of strategy and tactics.

(For my other, FTL setting, the alienware missiles will have another upgrade, if they are destroyed, they emit a strong directed X-pulse, so they hit back. i think i name the magitech material pulsarium. )

http://www.alienware.co.uk/?ST=alienware&dgc=ST&cid=41141&lid=1069630&acd=239715600820560&ven1=s51xsHpOB&ven2=e have moved onto missiles in your setting eh? Guess gaming isn't that lucrative in the future

Although i don't rule out some stealth attack part in orbit (launch magitech drone from landing cargo shuttle in order to hack PDF satellite).
Or people rebel on liberated in Red Army style planet when third partys fleet comes. When occupy force fleet turn sensors toward coming fleet, attack them in the back with missiles (boost them on other side of planet, and contain their heat with some liquid helium for a time)

Stealth in orbit may be possible, I'm not hugely convinced that heat dumps would last very long (moving heat around takes energy which costs heat so you're constantly expending increasing amounts of energy to contain an increasing amount of heat).

Still a big thing that we've not touched on is subterfuge. You might be able to sneak weapons close to a fleet, for example: hiding a nuke aboard a trading ship that travels nearby then sabotages its own systems and sends out an SOS.

 

[GTOM]

Assuming they weren't observed deploying the enemy could just shoot in the middle of that 100m and sever the tether, sending either ship/missile flying off. To reconnect/correct the course they'd have to power up.

Other setups are also possible, like connect three, and they don't even know the radius of the circle.

It is the most different aspect of space compared to other forms of human experience, line of site is essentially infinite which changes a lot of strategy and tactics.

I have compared it to chess, you can see whole board.

Stealth in orbit may be possible, I'm not hugely convinced that heat dumps would last very long (moving heat around takes energy which costs heat so you're constantly expending increasing amounts of energy to contain an increasing amount of heat).

Yes, doing it for long time surely isn't realistic.

Still a big thing that we've not touched on is subterfuge. You might be able to sneak weapons close to a fleet, for example: hiding a nuke aboard a trading ship that travels nearby then sabotages its own systems and sends out an SOS.

Yes, such things will be really important in my story.

 

[Artribution]

Unless you're pretty close to the enemy I don't see how any of that matters.

Found a description of what some shaped-charge applications could look like:

Back in the 1960's, rocket scientist came up with the infamous "Orion Drive." This was basically a firecracker under a tin can. Except the tin can is a spacecraft , and the firecracker is a nuclear warhead.

Anyway, they realized that about 90% of the nuclear energy of an unmodified nuclear device would be wasted. The blast is radiated isotropically, only a small amount actually hits the pusher-plate and does useful work. So they tried to figure out how to channel all the blast in the desired direction. A nuclear shaped charge.

Remember that in the vacuum of space, most of the energy of a nuclear warhead is in the form of x-rays. The nuclear device is encased in a radiation case of x-ray opaque material (uranium) with a hole in the top. This forces the x-rays to exit only from the hole. Whereupon they run full tilt into a large mass of beryllium oxide (channel filler).

The beryllium transforms the nuclear fury of x-rays into a nuclear fury of heat. Perched on top of the beryllium is the propellant: a thick plate of tungsten. The nuclear fury of heat turns the tungsten plate into a star-core-hot spindle-shaped-plume of ionized tungsten plasma. The x-ray opaque material and the beryllium oxide also vaporize a few microseconds later, but that's OK, their job is done.

The tungsten plasma jet hits square on the Orion drive pusher plate, said plate is designed to be large enough to catch all of the plasma. With the reference design of nuclear pulse unit, the plume is confined to a cone of about 22.5 degrees. About 85% of the nuclear device's energy is directed into the desired direction, which I think you'd agree is a vast improvement over 10%.

About this time the representatives of the military (who were funding this project) noticed that if you could make the plume a little faster and with a narrower cone, it would no longer be a propulsion system component. It would be a nuclear directed energy weapon. Thus was born project Casaba-Howitzer.

Details are scarce since the project is still classified after all these years. Tungsten has an atomic number (Z) of 74. When the tungsten plate is vaporized, the resulting plasma jet has a relatively low velocity and diverges at a wide angle (22.5 degrees). Now, if you replace the tungsten with a material with a low Z, the plasma jet will instead have a high velocity at a narrow angle ("high velocity" meaning "a recognizable fraction of the speed of light"). The jet angle also grows narrower as the thickness of the plate is reduced. This is undesirable for a propulsion system component (because it will destroy the pusher plate), but just perfect for a weapon (because it will destroy the enemy ship).

The report below suggests that the practical minimum half angle the jet can be focused to is 5.7° (0.1 radians).

They would also be perfect as an anti-ballistic missile defence. One hit by a Casaba Howitzer and a Soviet ICBM would be instantly vaporized. Which is why project Casaba-Howitzer's name came up a few times in the 1983 Strategic Defense Initiative.

Casaba Howitzers fired from orbit at ground targets on Terra would be inefficient, which is not the same as "does no damage." A nuclear warhead fired at a ground target would do far more damage, but the Casaba Howitzer bolt is instantaneous, non-interceptable, and would still do massive damage to an aircraft carrier.

Scott Lowther has done some research into a 1960's design for an Orion-drive battleship. It was to be armed with naval gun turrets, minuteman missiles with city-killing 20 megatons warheads, and Casaba-Howitzer weapons. It appears that the Casaba-Howitzer charges would be from subkiloton to several kilotons in yield, be launched on pancake booster rockets until they were far enough from the battleship to prevent damage (several hundred yards), whereupon they would explode and skewer the hapless target with a spear of nuclear flame. The battleship would probably carry a stockpile of Casaba-Howitzer weapons in the low hundreds.

Mr. Lowther estimates that each Casaba-Howitzer round would have a yield "up to a few kilotons" and could deliver close to 50% of that energy in the spear of nuclear flame. Three kilotons is 1.256 × 10¹³ joules, 50% of that is 6.276 × 10¹² joules per bolt.

This is thirty-five times as powerful as a GBU-43/B Massive Ordnance Air Blast bomb, the second most powerful non-nuclear weapon ever designed. Per bolt.

Get a copy of the report for more details, including a reconstruction of a Casaba-Howitzer charge.

What is the mass and volume of a Casaba-Howitzer charge? Apparently this also is still classified. An Orion Drive nuclear pulse unit would be about 1,150 kg, have a blast yield of about 29 kilotons, and be a cylinder with a radius of 0.4 meters and a height of 0.87 meters. The volume would therefore be about 0.4 cubic meters. As previously mentioned a Casaba-Howitzer charge would have a yield ranging from sub-kiloton to a few kilotons, so presumably it would be smaller and of lower mass than a pulse unit.

http://www.projectrho.com/public_html/rocket/spacegunconvent.php​

There are some other applications there, very interesting reading.

MIRVs separating presumably requires some form of power, that means there's a source of heat on the missile that can be detected. If their making random course corrections there's also a source of power and an exhaust emission.

Yeah, there'd be an exhaust emission, but you're saying your sensors could detect and accurately measure the tiny plume of expellant gas from a 25-centimeter MIRV's RCS thrusters from a light-second away? Seems incredible. Even if you could scan the entire sky with that much accuracy, and you fired your laser as soon as you measured it, by the time your laser reached the position you plotted, the MIRV could simply have made another random minor adjustment, and this is assuming you have a rapid-fire laser that could keep up the firing rate. And the missile could use other launch systems (railgun etc.) that wouldn't produce any exhaust capable of being tracked.

edit: fixed some numbers given above

 

[GTOM]

Found a description of what some shaped-charge applications could look like:

http://www.projectrho.com/public_html/rocket/spacegunconvent.php​

There are some other applications there, very interesting reading.

I am skeptical about that, on other threads, they mentioned, they could achieve some directivity, but not much.
Anyway we are at the point, that the missile itself should spit directed beams, than i like more the laser fighter thing, it can't expend that much energy, but more able to focus on radiators, hot lasercannons.

Otherwise, i had the following thoughts : yes, the ship propulsion require much more power than the cannon, but an entire 50 ton propulsion system takes that heat.
In case of a laser, the surface of the mirror, or the focusing lenses has to take pretty much heat (if i remember correctly that xaser focuses with a Be prism)
Hannibal's method of cracking rocks in the Alps was heat them up, then cool them rapidly.
So, present day high power lasers has pretty low rate of fire, hours, i guess it can be helped, but in the future probably their rate of fire will be still low. That at least gives more time to beam rockets to get close enough to do serious damage.

Maybe big battleships should have some bomb-pulsed system, that has enermous power in order to counter PDF cannons, but has a really low rate of fire, so a big battleship isn't really good against squadrons of smaller ships, it needs escort.

Yeah, there'd be an exhaust emission, but you're saying your sensors could detect and accurately measure the tiny plume of expellant gas from a 25-centimeter MIRV's RCS thrusters from a light-second away? Seems incredible. Even if you could scan the entire sky with that much accuracy, and you fired your laser as soon as you measured it, by the time your laser reached the position you plotted, the MIRV could simply have made another random minor adjustment, and this is assuming you have a rapid-fire laser that could keep up the firing rate. And the missile could use other launch systems (railgun etc.) that wouldn't produce any exhaust capable of being tracked.

edit: fixed some numbers given above

I have read about the sensitivity of James Webb's IR cam. If tenth of it is true, they shouldn't have any problem detecting a speeding rocket from light seconds.

 

[GTOM]

I had another idea (for the later, operatic setting)
Send swarms of micromissiles about a cm cross section. Even with a nrad spread, from a long distance, much of the energy is wasted.
They form a hive mind for flare rejection and things like that.
(It is rare to employ such things against fighters for cost reasons, but they rather throwing EMP bombs to confuse them in terminal phase, so they can be dodged.)

Well it shouldn't be the only instance of using some kind of micro or nano weapons, although cost issues can prevent make a ground war entirely with theese stuff.

 

[GTOM]

It's worth noting as well that there are other forms of beam weapon that couldn't be so easily reflected, for example: particle beams, FELs and X-Ray lasers. In regards to the idea of swarming missiles sure: if you can deploy in such numerical strength then you'll win. But working with the assumptions I mentioned in the previous paragraph an attacker would need to launch 5 missiles at the defender to be sure of a win, and that's if they have only one point defence laser. If they have 10 you need to launch 41.

About the X-FEL thing :

"Rigorous derivation from Maxwell's equations gives the divisor of 2 and the proportionality constant. In an X-ray FEL the typical undulator wavelength of 1 cm is transformed to X-ray wavelengths on the order of 1 nm by {\displaystyle \gamma }https://wikimedia.org/api/rest_v1/media/math/render/svg/a223c880b0ce3da8f64ee33c4f0010beee400b1a ≈ 2000, i.e. the electrons have to travel with the speed of 0.9999998c."

Doesnt that mean, that the process is very inefficient due to the big relativistic mass?

 

[Noisy Rhysling]

One reason for using missiles would be "because you can". A mixed weapon arsenal gives you more options than just one system. Missiles could be used as a threat to herd the enemy toward a specific location. They could also be used to lay mines, those would be waiting for the enemy to come at you from a specific direction. Send the missiles out to an intermediate location and redirect them when you're sure of the enemy's course. They would also require less power from the ship's systems, especially if they're "fire-and-forget" types. Missiles could be fired at more than one enemy, or more enemies than can be covered by the lasers. They would also be useful against non-ship targets, such as surface installations. Our terrestrial warships carry a mixed bag of systems to enable them to counter more threats.

 

[Noisy Rhysling]

Oh, and one way to give the reader information without preaching would be to have senior officers instructing midshipmen. Q&A sessions about their studies, or hands-on training sessions. (My wife would call this "Hogwarts in space.")

 

[GTOM]

One reason for using missiles would be "because you can". A mixed weapon arsenal gives you more options than just one system. Missiles could be used as a threat to herd the enemy toward a specific location. They could also be used to lay mines, those would be waiting for the enemy to come at you from a specific direction. Send the missiles out to an intermediate location and redirect them when you're sure of the enemy's course. They would also require less power from the ship's systems, especially if they're "fire-and-forget" types. Missiles could be fired at more than one enemy, or more enemies than can be covered by the lasers. They would also be useful against non-ship targets, such as surface installations. Our terrestrial warships carry a mixed bag of systems to enable them to counter more threats.

Good ideas. Although most combat will be in the asteroid belt, they can solve bombardment by moving things to the opposite side (unless attack from two opposite direction a bit GO like style), dig deep the reactor.
I think missiles can be most useful, when there is a fuel producing asteroid, they can build masses of missiles very cheap, and enemy ships has to come close to capture the place. (Usually no big ones come close until fast agile fighters sorrounded and scanned the entire place.)
Information handle is a good question, i usually narrate that, and try to avoid too big infoblocks.

 

[Noisy Rhysling]

Remember that in the real asteroid belt the rocks are space widely apart. I was told that on average you can't see one from the other with a Mk. 1, Mod. 0 eyeball.

 

[GTOM]

Remember that in the real asteroid belt the rocks are space widely apart. I was told that on average you can't see one from the other with a Mk. 1, Mod. 0 eyeball.

i know but if the target is something ön or around an asteroid they still offer cover.

 

[Noisy Rhysling]

i know but if the target is something ön or around an asteroid they still offer cover.

Yep, but in general you couldn't count on them for cover even inside the Belt.

That could be a "teaching moment" for the mids.

"Okay, you lot, calculate the most effective coverage of Ceres with our missiles. Explain your choice." Something along those lines.