Cheap Mass Produced Space Missiles Probably Won't Look Like An Earth Missile...

[Spacescifi]

Imagine an inflated ball made of fabric and wire mesh, with explosives and a rocket engine inside.

Is this cheaper to make and lighter weight than your standard hard shelled missile? Possibly... once you start mass production. And since it will weigh less it can reach higher speeds faster than hard shell heavier missiles.

Granted, expensive longer range engine missiles you may opt for a more durable body frame, but if all you are doing is the space equivalent of a drive by, you may as well launch a swarm of cheap missiles once within a reasonable strike distance.

Thoughts?

[kerbiloid]

Spoiler

 

 

[steve9728]

Welcome to Zhuhai Airshow hahaha

[razark]

What purpose do the fabric and wire mesh serve?  Why is it inflated, rather than just an empty structure in the desired shape?  Why is there even a structure of any sort?

For a space-exclusive missile, all you need are propulsion, warhead, guidance, and something to hold those parts together.  Anything beyond that is just decoration if you don't have to consider it being useful (such as armor to prevent point defense systems from shooting it down (which fabric and wire mesh would seem to be rather lacking in that quality)).  If the missile is being launched from space into a planetary environment, it would need some sort of atmospheric protection (again, not something you're going to wrap in canvas and chicken wire).

The only reason sci-fi missiles look like missiles we're used to seeing is because we're used to seeing missiles that look like missiles we're used to seeing.

 

Also, your question boils down to: "Imagine <X>. Is it better than <Y>?", where <Y> is also an imagined item.  So, the answer is never going to be anything other than "Yes", because I can always imagine a better imaginary item than another imaginary item.

Further, we don't really know what thing produced for use only in space is going to be like, since almost every thing we have ever created is a thing that has been created to be used not in space.  We simply do not have a frame of reference to compare (see the fact that there's an inflated ball of materials that has no reason to exist in your original question).

And "Possibly... once you start mass production."
Just... no.  If it's cheaper to make, it's going to be cheaper to make a one-off than worrying about the economy of scale.  Designing a hard shell, producing it, and then fitting the payload into it is going to always be more expensive than building the payload and covering it in paper mache, no matter how many you make.

[KSK]

I imagine a space missile would look much like an atmospheric missile, only without a casing. Off the top of my head, I think you’d need the following for a space missile

Motor, propellant, maneuvering thrusters, warhead, guidance package.

Again, off the top of my head, I’d put the propellant tanks in the middle, have the guidance system, warhead and one set of maneuvering thrusters on a boom sticking out in one direction, and have the motor and other set of the thrusters on a second boom pointing in the other direction. Keep the whole thing as axially symmetric as possible.

Reasoning. Keep heavy stuff (likely propellant) near the centre of mass and put the thrusters on a decent lever arm from the COM.

Stretch the propellant tank a bit and the whole thing starts to look like a classic rocket shape.

Edit. Thinking about this a bit more, I can think of valid reasons to give the missile a casing.  It could make handling and storage easier, a thermal protection system might be helpful if you’re operating near a star, and depending what motor you’re using, having a radiating surface to dissipate waste heat might be necessary.

I might be starting from a completely wrong set of assumptions here but it wouldn’t actually surprise me of a spaceborne missile would end up looking like an atmospheric missile but with RCS nozzles where the fins would go.

 

 

 

 

Edited June 10, 2023 by KSK

[Shpaget]

Do you really think that a bit of metal tubing is a significant factor in the total cost of modern missiles? Come on dude, a ten second google search will tell you that they cost hundreds of thousands of dollars for even the smallest ones.

As for inflatable shells, I would imagine that you'd like your missiles to be capable of steering without folding, and accelerating at a decent rate without collapsing on themselves.

[magnemoe]

One thing you definitely want with an in space missile is an ability to restart engine, or being multi staged. this because you first burn for intercept and then close do an second burn to course correct or compensate for an moving target then close.  Yes at close range this is not needed but here guns are probably more effective. 

Guided missiles on earth uses fins to aim and unless ballistic they need to burn until they hit, none is true in space. 
Because if the velocities in space I think most will lack explosives as they have more kinetic energy than tnt anyway. 
Agree with an case for handling but missiles often come in pre-packed launch tubes anyway. 
 

[SunlitZelkova]

10 hours ago, KSK said:

I imagine a space missile would look much like an atmospheric missile, only without a casing. Off the top of my head, I think you’d need the following for a space missile

Motor, propellant, maneuvering thrusters, warhead, guidance package.

Again, off the top of my head, I’d put the propellant tanks in the middle, have the guidance system, warhead and one set of maneuvering thrusters on a boom sticking out in one direction, and have the motor and other set of the thrusters on a second boom pointing in the other direction. Keep the whole thing as axially symmetric as possible.

Reasoning. Keep heavy stuff (likely propellant) near the centre of mass and put the thrusters on a decent lever arm from the COM.

Stretch the propellant tank a bit and the whole thing starts to look like a classic rocket shape.

Edit. Thinking about this a bit more, I can think of valid reasons to give the missile a casing.  It could make handling and storage easier, a thermal protection system might be helpful if you’re operating near a star, and depending what motor you’re using, having a radiating surface to dissipate waste heat might be necessary.

I might be starting from a completely wrong set of assumptions here but it wouldn’t actually surprise me of a spaceborne missile would end up looking like an atmospheric missile but with RCS nozzles where the fins would go.

 

 

 

 

You never know. Soviet AShMs had armor to deflect or lessen the damage of CIWS fire, so a shell might be worthwhile even in space.

[KSK]

The pre-packed launch tubes would work too.

I admit that I started with ‘missile = small, fast, and manoeuvrable’ and  just went from there. I didn’t give much thought to actual use cases for missiles in space combat.

[DDE]

7 hours ago, magnemoe said:

Guided missiles on earth uses fins to aim and unless ballistic they need to burn until they hit

They generally don't AFAIK. Even the smallest ones have a ballistic cruise stage where they still have enough impulse to maneuver after their target.

Anyway, this is the usual artwork of a Soviet Kaskad space missile

And this is probably the actual Shchit-2

The central array is best understood as a combination microthruster block and warhead. The whole thing is spin-stabilized and probably heat-seeking.

[kerbiloid]

7 hours ago, DDE said:

"Крыльчатка механизма стабилизации" = "stabilization control impeller"

It has an impeller to screw into the space aether!

[tater]

Depending on the ability of typical space vehicles to maneuver, and the closure rate of missiles, I'd expect them to be fragmentation warheads. Disperse 1000s (millions?) of projectiles  such that a portion of that cloud is guaranteed to intersect the target, even if it is trying to be evasive.

[kerbiloid]

9 hours ago, tater said:

I'd expect them to be fragmentation warheads.

Directional fragmentation warhead.

Spoiler

 

This one was omnidirectional because the metal things are solid fuel charges of the main thruster, separated on explosion and turned into shrapnel for free.

Spoiler

The first one is seeking, while the second one is defensive, it's shot at the target which is homing at the protected object itself.

[tater]

1 hour ago, kerbiloid said:

Directional fragmentation warhead.

Yeah, all you need is a disk of fragments. Relative KE does all the rest.

[Hannu2]

I think that shape of space missile is determined by radar or other detection technology. I would guess that missiles will never be practical weapons in combat between spaceships because they are easy to see in empty space. It is also very difficult to predict what kind of radars or other detectors are possible when there will be space wars.

[Spacescifi]

16 hours ago, tater said:

Depending on the ability of typical space vehicles to maneuver, and the closure rate of missiles, I'd expect them to be fragmentation warheads. Disperse 1000s (millions?) of projectiles  such that a portion of that cloud is guaranteed to intersect the target, even if it is trying to be evasive.

Realistically how much a spacecraft manuevers and how fast depends on the the power limits of the propulsion system and how much fuel/propellant is available for it.

Because of this, quanity is roughly as good as quality in space war, since given the extreme velocities involved and the total lack of scifi forcefield bubbles to protect spaceships from attack., a bunch of less expensive weaponry will easily wreck the most expensive space vehicles and infrastructure we can make.

In real life, space infrastructure would be the target of space wars, since barring safe torchdrive SSTOs, you need it to even make a beachhead in space colonization or even for ISRU. In such a case, I honestly think swarms of small spacecraft with nuclear or plasma drives, slow though they be, would dominate space war. Since they are the one thing you do not need space infrastructure to put them into orbit. It may take months or years, but once the swarm arrives it's space station or moon base target is as good as dead, unless it has good enough defenses, but offense is much easier than defense in space so the odds are against defense really.

 

3 hours ago, Hannu2 said:

I think that shape of space missile is determined by radar or other detection technology. I would guess that missiles will never be practical weapons in combat between spaceships because they are easy to see in empty space. It is also very difficult to predict what kind of radars or other detectors are possible when there will be space wars.

In scifi spaceships often have near or unlimited delta V while missiles are always limited.

If such were true, then spaceships could evade most hostile encounters by simply avoiding or evading them altogether

Battles would only be forced around space or orbital infrastucture spacecraft are seking to protect.

One thing scifi often gets wrong about torchdrive spaceship battles is that it would be more about space jousting and drive bys than anything else.

If a fleet is going to strike your moon base or your orbiting station the safest way is to fly fast while doing a drive by, since the slower they fly the more time the base or the orbiting station has to destroy them.

Which means, amusingly enough, that instead of being pounded on by a fleet hovering above you, it will zoom past while blasting you, and then take probably hours to retroburn to make another pass and do it all over again!

Edited June 12, 2023 by Spacescifi

[kerbiloid]

In Casaba we trust.

Spoiler

And in recombinational X-ray lasers.
http://www.projectrho.com/public_html/rocket/images/spacegunconvent/weapspace11.jpg

[Terwin]

I think that Guidance(if any) is the most expensive part of any missile, followed by propulsion then payload and finally casing(except for nukes, as the payload is probably most expensive for those).

The long/narrow profile helps minimize the target area for defensive fire, and a bit of armor that doubles as fragmentation or penetration material is also likely to be useful.

I would not be surprised if the most practical space missile turned out to look like a finless normal missile, possibly with a more exposed motor to enable better gimble, and rcs ports.

[magnemoe]

5 hours ago, Spacescifi said:

In scifi spaceships often have near or unlimited delta V while missiles are always limited.

If such were true, then spaceships could evade most hostile encounters by simply avoiding or evading them altogether

Battles would only be forced around space or orbital infrastucture spacecraft are seking to protect.

One thing scifi often gets wrong about torchdrive spaceship battles is that it would be more about space jousting and drive bys than anything else.

If a fleet is going to strike your moon base or your orbiting station the safest way is to fly fast while doing a drive by, since the slower they fly the more time the base or the orbiting station has to destroy them.

Which means, amusingly enough, that instead of being pounded on by a fleet hovering above you, it will zoom past while blasting you, and then take probably hours to retroburn to make another pass and do it all over again!

This is pretty realistic, as in realistic good engines like orion pulse nuclear or fusion concepts are large, this is also true in real life as missiles has shorter range but is faster than fighter jets. 
But in space this will have more of an effect, as you are not putting an orion engine on an missile but your are limited to chemical or nuclear thermal, on the other hand range is technically infinite, its just that the enemy ship might burst out of the salvo you fired at it. Obviously stationary targets like an base can not move but they can use mass as armor so they require an larger missile but one you can launch much farther out as it can not escape just intercept or tank it. You also has anti missile missiles who would be much smaller versions of the anti ship missiles as the relevant missiles are coming for you anyway so you only need range to do followup shots for the ones you missed. 

[StrandedonEarth]

12 hours ago, Spacescifi said:

One thing scifi often gets wrong about torchdrive spaceship battles is that it would be more about space jousting and drive bys than anything else.

If anything, what sci-fi gets wrong is the relative velocities in space. Any attack or "joust" in space is going to happen at relative velocities of at least 1 Mm/h, if not multiple tens of Mm/h. It's easier to just release a cloud of lead marbles in the path of oncoming wessels. Defense against ships will be easy, just shower them with gravel. The simplest offence is attacking with a rubble pile.

The ultimate outcome of a space battle is that space gets filled with high-speed debris and no-one can use it safely.

[darthgently]

Space defensive weapons need to leave was little debris as possible.  More along the lines of focused tactical EMP and such.  Offensive uses would obviously best be avoided.  But ppl being ppl...

Edited June 13, 2023 by darthgently

[Nuke]

i like the expanse strategy of shooting through drive cones with railguns. otherwise their consumption of ammunition for both missiles and pdcs seems like it would be prohibitively expensive.  both in terms of mass expendature to move it about, performance lost for your ship, and in direct cost. the only thing missiles really seem to have going for them is extreme range and the ability to lay dormant and drift for years. 

On 6/10/2023 at 2:20 PM, DDE said:

They generally don't AFAIK. Even the smallest ones have a ballistic cruise stage where they still have enough impulse to maneuver after their target.

Anyway, this is the usual artwork of a Soviet Kaskad space missile

And this is probably the actual Shchit-2

The central array is best understood as a combination microthruster block and warhead. The whole thing is spin-stabilized and probably heat-seeking.

ive seen features like that on spin stabilized asat weapons. get the missile up to closing speed with the main thruster, a ring of lateral thrust srbs is a lot more reliable than a liquid fueled engine. the thing i find facinating is that they sync the thruster firing with the rotation angle and they can nudge the thing in any angle. this one looks like its taking it to a new level, the charges all seem to be aligned through the same point along the center axis, which i bet is the cg of the missile (probibly after burning its main thruster). once consumed the casings probibly make excellent shrapnel with some explosive fittings. 

not sure what the red thing is. looks to spindly to be a thruster. antenna perhaps. but i suspect they use a compressed gas to spin up the missile prior to launching. "impeller" makes since if thats the case. 

[darthgently]

12 hours ago, Nuke said:

but i suspect they use a compressed gas to spin up the missile prior to launching. "impeller" makes since if thats the case. 

Zooming in, the "blades" are classic impellor type for capture of a tangential high velocity stream

[wumpus]

17 hours ago, StrandedonEarth said:

If anything, what sci-fi gets wrong is the relative velocities in space. Any attack or "joust" in space is going to happen at relative velocities of at least 1 Mm/h, if not multiple tens of Mm/h. It's easier to just release a cloud of lead marbles in the path of oncoming wessels. Defense against ships will be easy, just shower them with gravel. The simplest offence is attacking with a rubble pile.

The ultimate outcome of a space battle is that space gets filled with high-speed debris and no-one can use it safely.

 

16 hours ago, darthgently said:

Space defensive weapons need to leave was little debris as possible.  More along the lines of focused tactical EMP and such.  Offensive uses would obviously best be avoided.  But ppl being ppl...

"Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space." Douglas Adams

You really can't fill up space.  You'd have a hard enough time filling up the elliptic.  You can have issues with space junk in Earth orbit, and certainly any debris crossing GSO would be bad.  But those are just tiny portions of space that humans care about.  In general, any debris field will rotate and expand around the Sun until it might not exist.  Compare to the asteroid belt.  As far as I know, no craft has ever needed to take evasive action in the asteroid belt and that is almost certainly the canonical example of "space debris field".  Also look at the "space metro map": the map only cares about delta-v, because you are unlikely to ever use the same route twice between the planets.  There really is nowhere for "space pirates" to lay in wait, with the possible exception of a weird orbit that will just happen to line up with an optimal launch window between planets the next orbit or two (and even then, it is a one-shot event.  You'll have to move on to be in position for the next good launch window.  And if there *are* space pirates, you probably aren't going to wait until the window opens up, especially if it increases the chances of a lost vessel.

To answer the original question (why, why do I do this?), it depends.  If avoiding RADAR detection is key, then they will look like current atmospheric missiles.  If not, expect spherical tanks, possibly with multiple stages of large/medium/small tanks (hint:  think of the rocket equation).  I've assumed some sort of stealth, but thinking about it a bit more it should be trivial to cover any likely battlefield (like the solar system) with enough sensors to watch for missiles firing their engines.

[darthgently]

52 minutes ago, wumpus said:

 

"Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space." Douglas Adams

You really can't fill up space.  You'd have a hard enough time filling up the elliptic.  You can have issues with space junk in Earth orbit, and certainly any debris crossing GSO would be bad.  But those are just tiny portions of space that humans care about.  In general, any debris field will rotate and expand around the Sun until it might not exist.  Compare to the asteroid belt.  As far as I know, no craft has ever needed to take evasive action in the asteroid belt and that is almost certainly the canonical example of "space debris field".  Also look at the "space metro map": the map only cares about delta-v, because you are unlikely to ever use the same route twice between the planets.  There really is nowhere for "space pirates" to lay in wait, with the possible exception of a weird orbit that will just happen to line up with an optimal launch window between planets the next orbit or two (and even then, it is a one-shot event.  You'll have to move on to be in position for the next good launch window.  And if there *are* space pirates, you probably aren't going to wait until the window opens up, especially if it increases the chances of a lost vessel.

To answer the original question (why, why do I do this?), it depends.  If avoiding RADAR detection is key, then they will look like current atmospheric missiles.  If not, expect spherical tanks, possibly with multiple stages of large/medium/small tanks (hint:  think of the rocket equation).  I've assumed some sort of stealth, but thinking about it a bit more it should be trivial to cover any likely battlefield (like the solar system) with enough sensors to watch for missiles firing their engines.

The problem with the "space is big" answer is that any created debris will occupy an orbit that intersects the orbit it was in prior to becoming debris generally speaking.  The initial orbit now has debris that will periodically intersect with it.  So craft collision debris is not randomly distributed, but tends to end up in orbits that intersect previously planned orbits.   This is, as you note, far more of a deal around a planet where certain altitudes and inclinations are prime sat real estate.  But, ideally, one wouldn't want unnecessary debris intersecting the paths of Earth's Lagrange 1 and 2 points either, for example