
What future space combat would really look like - dikarel
http://forums.spacebattles.com/showthread.php?t=131056
======
amalcon
There are three fundamental problems I see here:

1) Why put humans on warships at all? Algorithms are probably better at it.
Computers would obviously do the heavy lifting anyway (calculating burn
times). An algorithm knows no fear, shows no mercy, and does not flee or
surrender unless programmed to do so. The only thing left is target selection,
and it doesn't seem worth bringing a human along just for that.

2) If you don't need to put humans on warships, then you quickly realize you
don't need a warship at all. Just send a bunch of missiles from wherever the
warship would have launched. It's harder to take them all out at once with a
"mine" or something. You also get to build more missiles if you don't need to
build the warship. Sure, you might attach a collective nuclear rocket
"booster" to many missiles to build that initial velocity. There's no need for
that rocket to be anything more than an engine temporarily attached to the
missiles. It's also not really required to begin with.

3) If you're sending lots of missiles, there's no reason for them to be any
larger than the smallest size permitted by design and manufacturing
practicalities. For something that amounts to a liquid-fueled rocket, that
smallest size is preposterously small. A liquid-fueled rocket can be fit into
an object the size of a soda can with current technology. This makes the
notion of point defense completely laughable: divert ten thousand missiles out
of one hundred thousand, and you've reduced the incoming energy by 10%.

~~~
zeteo
> Why put humans on warships at all?

The whole idea of the article is to explore what's possible with current
technology, and general-purpose AI is not part of that. Guided missiles are
routinely defeated by counter-measures even when the flight only takes
minutes.

~~~
amalcon
How would having humans a few light-seconds away from the missiles be able to
help with that?

~~~
zeteo
Eh? My point was that humans on board can improvise (remember Apollo 13) and
carry out their objectives even in the presence of a forewarned and
intelligent opponent.

~~~
srl
The real reason, of course, is that war is just so much cooler when people are
dying. Sources: G. Carlin.

Honestly, though, I fully expect AI to advance sufficiently in the next 20
years that a 10s delay is sufficiently small, and the AI can handle anything
likely to occur in under 20s on its own.

~~~
zeteo
>I fully expect AI to advance sufficiently in the next 20 years

Yes, people have been expecting AI to become human-like within 20 years for
the past 6 decades.

[http://en.wikipedia.org/wiki/History_of_artificial_intellige...](http://en.wikipedia.org/wiki/History_of_artificial_intelligence#Dartmouth_Conference_1956:_the_birth_of_AI)

("Researchers expressed an intense optimism in private and in print,
predicting that a fully intelligent machine would be built in less than 20
years")

~~~
tuppy
Huh, why do you require human-like AI to control a bunch of high-velocity
objects, calculate intercepts, and release other high-velocity objects on
those intercepts?

The only human-level decision that needs to be made is simply confirming the
object is a target and should be attacked.

~~~
zeteo
Most people haven't served in the military, but have you ever played a war
game? Deciding where to move the weapons platforms and which objects are
targets for what is the very essence of fighting a successful battle.

~~~
davedx
Have you ever played against the AI in Starcraft or other countless video
games with AI?

------
jasonkester
I think Banks' _The Algabraist_ got it about right.

In fact, that whole book is crammed full of good "things we currently believe
to be true about physics extrapolated as far as theoretically possible" ideas:

    
    
      "How do you navigate this thing?"
      "Point."
      "Point?"
      "Yes, point.  It's all about having enough power.
       Fiddling around with calculations about DeltaV is really
       just a sign that you don't have enough power."

~~~
arethuza
"It's all about having enough power."

That really does sound like the name of a Culture GSV.

[Correction - No Culture ship would be quite so lacking in gravitas, so I
suspect a more likely name would be "Fiddling around with calculations about
DeltaV"].

~~~
jdowner
I would say there is a good chance that a GSV would have no gravitas and that
a GCU would have very little gravitas indeed.

------
johngalt
The author underestimates guns while overestimating "kinetic missiles". Speed
imparts a lot of energy, but it wont transmit all of that energy to the
target. You'll have a <missile diameter> hole in the ship.

Your ships are closing at 1000km/s and your cloud of missiles have a 10km/s
Delta? A cloud of slugs would be almost the same, and you could put up a lot
more of them. Of course a hybrid approach is likely, with shrapnel filled
missiles. Better to impact like a shotgun than a needle.

Edit: Also gets it wrong on point defense. If you have enough energy weapons
to mount an effective defense you'd make yourself such a large/vulnerable
target that you'd be impossible to miss. Once again putting a cloud of slugs
in the path of an inbound missile would be easier and more effective. With the
speeds/distances involved all of the missiles would be approaching from a very
narrow cone, and a small deflection would mean a miss.

~~~
electromagnetic
Railguns are worthy of note, but would likely only be worthy of PD weapons.
The problem with guns is that your target moves. With the exception of
missiles, every fraction of the speed of light slower your weapon is, the
bigger chance you take of missing. With a round fired at .1C over 300,000KM (1
light second) you need to account for about 11 seconds of lead on your target.
That's 11 seconds that they don't change their course enough for you to miss.
Compare this to a laser where it's 1 second of lead.

> With the speeds/distances involved all of the missiles would be approaching
> from a very narrow cone, and a small deflection would mean a miss.

Not necessarily. Unless space battle becomes solely a chasing game (which
would favour the defender as if you know you're a runner the majority of your
PD's will be aimed out your ass). A missile can sit for any amount of time
after being dropped before firing. This means you can distribute a missile or
approach from opposing angles. If your ship uses turrets for PD then you know
it cant easily shoot two different angles at once. If you're fighting well
within your missiles ranges (because fighting at maximum range gives too much
time for PD's) then it'll be very easy to launch your missiles around your
target in a flank attack.

------
ohyes
Space combat seems pointless to me.

What exactly would they be fighting over?

Presumably you want to reach space for resources, so asteroids, planets and
moons with minerals, stuff like that. You might also want
planets/asteroids/moons that are 'good' for colonization (easily terra formed
or already life sustaining).

You probably wouldn't see many fights where you are firing at the resource
itself. No one with the money to fire at earth, will actually fire at earth,
because it is more valuable as an inhabitable planet. If each side can
obliterate whatever is being fought over, you basically have an instant MAD
scenario.

Similar with moons/asteroids. I'm not going to fire a massive kinetic weapon
at a moon or asteroid (and blow it to pieces) if my objective is obtain that
object to profit from it. More likely I'll pay people very well to infiltrate
and sabotage it, repeatedly. I wouldn't even bother trying to invade.

Why not an invasion force? Well, you could send an invasion force, but that
would be fairly pointless. It is easy to defend an entrenched position that
your enemy does not want to shoot at (sabotaging just the defenses might be
too obvious, and i think would have too high a possibility of failure). On top
of this they can use massive force to repel you, and you cannot (you don't
want to obliterate your objective). So an invasion fleet is probably not
likely.

A far more likely scenario would be to simply drive your competitor out of
business. If they keep getting sabotaged, it becomes unprofitable for them to
operate (it becomes a 'cursed' outpost, wages go up, you have to make
repairs). Then you can easily take their stuff (or buy it on the cheap when
they are going out of business).

This gets you into interesting things, you would end up with extensive
background and history checks, genetic tests to prove that you really are who
you say you are, mental/psychological screening, mind-reading, brainwashing,
complex hacking of the computers that do background checks, genetic 'doping'
to make a person pass as someone else, brainwashing.

Your competitors will also likely try to assassinate you if they every figure
out that you are the one ordering the destruction of their outposts (it should
be easy to figure out, as there will be few entities with resources to profit
from this).

~~~
sliverstorm
You can argue this over in your head a lot, but it's really quite simple in my
mind.

If we assume space travel becomes relatively easy (that is to say it is used
for more than initial colonization) there will be interstellar commerce. If
there is unprotected commerce, there will be pirates. Any time there are
pirates, protection will develop. Let us call these peace-keepers the Navy.

If you engage in commerce and you have a powerful Navy, you can influence or
even control commerce.

Do you see where I'm going? Most wars are about resources. Commerce is about
resources. Anywhere you have commerce, you are liable to develop conflict.

~~~
brazzy
Read TFA, it argues pretty convincingly that there will not be pirates because
A) you can't hide in space and B) Any ship is a WMD, so governments will do
_anything_ to keep them out of the hands of criminals, and protection rackets
would be a far more profitable use for them than raiding commerce.

~~~
electromagnetic
Pirates are generally noted as coming after privateers. Privateers had plenty
of places to hide. Notably privateers with letters of marque against Spanish
shipping had British, French and Dutch ports to hide in.

Piracy developed when the pirates could appear easily as privateers. If you
didn't piss of your host nation, then you were free to loot the ships you
wanted. Then pirates gained enough money and power that they could start their
own micronations. Note that privateer ships were often enlisted by the
military during wars, so it's safe to assume an assault on a pirate haven was
out of the question for the military. Especially when pirate controlled
settlements were often cleared by privateers issued letters of marque on
condition of clearing the settlement.

I don't see how governments will keep ships out of the hands of criminals when
governments show little desire to exploit space, where as corporations do.
Corporations will grow very quickly in space, governments won't. Governments
are likely to spread via colonies rather than commerce or expansion.

The guy doesn't argue convincingly that there won't be pirates, because his
argument should have meant pirates wouldn't have existed in the 1700's. The
Spanish knew where the pirates and privateers were running to, but they were
well enough armed that you wanted superior numbers. So it was a matter of
attacking a solitary ship with more fire power before it could reach a safe
port.

Even though Port Royal and Tortuga were known as lawless ports, there was
plenty of law there. The Spanish weren't about to invade a port with cannons
on its battlements and dozens of privateer and pirate ships docked. Many of
these pirate ships were better crewed and equipped than their respective
nations military ships. Stede Bonnet had a sloop with 120 men and 16 guns. He
was captured when he only had 50 men and was beached in a harbour. Notably the
military brought 2 of the same tonnage ship, notably 8 gun vessels which
Bonnet's ship had originally been at the start of his life of crime. [Edit:
IIRC Rhett had 130 men on his two ships and simply outlasted Stede whose crew
surrendered - Stede wanted to blow his ship up rather than surrender]

~~~
weavejester
I'm not sure you've understood the poster's arguments.

The worst a pirate captain could do with a single ship in the 1700s was to
sink a few merchant ships.

The worst a pirate captain could do with a spaceship is to destroy an entire
continent.

In the 1700s, a pirate captain could hide his ship from government navies, and
take merchant ships by surprise.

The location of a spaceship is public knowledge; it cannot take anyone by
surprise, and the authorities know exactly where it is.

You can see how there might be a _little_ bit of a difference? There's a
considerable incentive for any planet-side government to make sure pirate
spaceships don't exist, and there's nowhere the pirate can hide.

~~~
Udo
This idea that you can't hide in space betrays a lack of imagination. As a
rule, ships will operate near objects such as planets, asteroids or nebulae.
These objects provide plenty of opportunity for cover and ambushes. There is
also the possibility of minefields and other unmanned devices that can easily
be shielded from detection. And those are just the things we can realistically
grasp with our _current_ technological understanding.

The other point that a rogue ship can wage war against an entire planet is
correct, but it's also misleading because the assumption only works if the
planet has no defense systems appropriate to the threat. The other argument
that ships will be highly regulated because they're dangerous, powerful, and
profitable is probably correct but at the same time it's important to remember
that being outlawed per se doesn't stop anything. We should know better,
because we tried this with drugs, terrorism and copyright violations - all of
which are still going on despite the massive amount of resources employed to
eradicate them.

~~~
electromagnetic
Don't forget that motor vehicles are well regulated, dangerous, powerful and
profitable. It still doesn't mean dad won't hand the keys to his 17 year old
kid and said kid won't try doing 160 and take out a hotel lobby.

We wilfully put aeroplanes in the hands of thousands of pilots. It doesn't
stop them coming to work drunk, or falling asleep at the wheel, or heck
snapping.

The reason governments won't strictly regulate space ships will be the same
reason governments don't strictly regulate driving. It costs too much.

~~~
weavejester
There's just a _slight_ difference between taking out a hotel lobby, and
removing an entire continent filled with billions of people off the map.

------
quanticle
This essay isn't all that realistic. I found this one [1] to have a far more
realistic view of what space war would look like.

Tl;dr: it's much cheaper and _much_ more effective to lob comets at your
enemy's homeworld than it is to fight with ships.

[1] <http://www.gwern.net/Colder%20Wars>

~~~
makmanalp
Ender's game spoiler alert! Hope it doesn't ruin it for anyone _else_...
(grumble.)

Anyway, how the heck does one lob a comet? If throwing one was so easy, why
wouldn't they just throw it right back at you?

~~~
patio11
Physics. Attacker gets arbitrary mass (reactant, etc) and time to accelerate.
Defender needs same mass/time to decelerate... after discovering the attack.

Note that you could literally prep an attack for millennia which would be
discovered a matter of hours prior to ending a civilization.

Physics makes for sucky narratives. Good thing it also makes for a vast, dead,
boring universe.

~~~
Tichy
I don't think you would try to slow down approaching meteorites to zero speed,
only deflect them a little so that they miss the planet. The further away you
catch it, the less energy it takes (I assume, didn't do the maths).

~~~
quanticle
It depends on the momentum of the asteroid. If I've accelerated an asteroid up
to .5 _c_ , then even if you discover the attack years ahead of time you might
still not have the energy to deflect the asteroid by enough to save your
planet.

You also have to remember that the attacker can launch multiple simultaneous
asteroids. You might have enough nukes to deflect one asteroid. Do you have
enough to deflect ten? A hundred?

~~~
russell
If you can accelerate an asteroid up to .5c, you have harnessed energy
resources to power the earth for a gazillion years. You would be so rich that
you dont need to be a warlord. You could become ... a banker.

Actually, at .5c from the Kuiper belt, the warning time is only 30 hours or so
and the momentum is such that deflection is impossible. I'm too lazy to do the
math but the collision would be spectacular.

------
ew
It was definitely an interesting read, however, I feel that fundamentally, for
humans to reach the point where space combat is even feasible we will have
solved so many more important problems that there won't be a need for fighting
in the cosmos. Earth, in general, is at peace. We are largely struggling
against terrorism, radical groups, and internal genocide rather than full
scale, nation-on-nation wars.

No two democracies have gone to war, ever, and that's an important indicator
of our future. Don't get me wrong, we have A TON of human rights, poverty, and
equality problems, but things are rapidly improving directly proportional to
our technical capabilities.

By the time we can even construct two ships capable of having a realistic
fight in space we're more likely to send them exploring rather than duke it
out. All current governments even capable of dreaming of getting in to space
work together on the problem, sharing resources and knowledge.

To recap, we'll never go to war in space. I also doubt any other intelligent
life with the capabilities to do so will need to attack us because they've
solved any problems requiring them to do so.

~~~
philwelch
> No two democracies have gone to war, ever

That stirs up a whole new thing, detailed here:
<http://users.rcn.com/mwhite28/demowar.htm>

~~~
ew
That was almost as good a read as the main post :)

------
stcredzero
Against space piracy:

 _First, it requires that FTL ships be cheap enough that criminals can acquire
them. This is another area in which the analogy between the age of sail and
the space age breaks down. Sailing ships were skill-intensive but materially
cheap. You had to have people with the right skills, but once you did all you
needed was wood, rope, and cloth. But spacecraft are going to follow a post-
industrial revolution paradigm of being materially expensive as well as skill-
intensive. They are likely to require sophisticated, precision-manufactured
components and expensive fuels like helium 3, fissionables, or antimatter.
Imagine Captain Jack Sparrow commanding a nuclear-powered aircraft carrier and
you’ll get an idea of the kind of difference we’re talking about._

If technological trends continue, the degree of technology available to the
average citizen and the average criminal will continue to increase. As an
individual, I have access to more media distribution than Queen Elizabeth
could even imagine. As an individual, I can build a device like a CNC machine
or a 3D printer from off the shelf parts.

Skillfully crafted wood, rope, and cloth would seem like miracle items to
someone from the stone age. A CNC laser cutter would represent miraculous
technological savvy and princely embodied wealth to someone from the 1400's.
The equivalent to an Orion ship might well be within the rech of rogue
elements of the late 21st century.

That said, space piracy probably won't happen, or at least won't resemble
piracy from old movies in the least, but the technology being out of reach
won't be the reason why.

~~~
electromagnetic
Agreed. Piracy denotes the theft of goods or money. When you can print goods,
money is worthless. Your soul resources become matter and energy, and most
matter is easy to come by.

Piracy would likely extend solely to the theft of energy resources. Similarly,
so would war but on a bigger scale.

Piracy of goods would only extend to things not easily replicable by the
present technology, or not easily replicable on many colonies. Even then,
you're looking more at the theft of raw materials or for material value.
Piracy would likely resemble robbing armoured vans today than any kind of
piracy we've seen before, but they'd likely be trying to get precious metals
or power like uranium.

~~~
nl
_most matter is easy to come by_

Endless wars over oil, rare earth metals in Africa and the ever increasing
price of iron ore would tend to indicate you might be wrong about that.

Just because a single 3D printer won't use much won't magically make resource
constraints disappear.

~~~
JonnieCache
I guess he's imagining some cheap way to rearrange subatomic particles.

~~~
electromagnetic
The logical steps in 3D printing is to increase the number of molecules the
printer can print with. There's almost an infinite number of molecules you
have to deal with, so it's a very logical step that once 3D printing becomes a
commercial endeavour then there'll be quick steps made towards an atomic
printer.

91 regularly occurring natural elements is a much shorter order than tens of
thousands of common molecules. Considering there are over forty simple
hydrocarbons and molecular printers start looking bulky, granted you might
only ever use a maximum of 5 hydrocarbons, but that day you need a 6th you'll
be cursing your shitty base model printer.

------
brmj
Here's a thought I've had in the past after encountering a document of this
type: Stealth in space is trivial is what you are trying to keep hidden
doesn't need to accelerate, support human life or do anything much that
generates significant heat, especially if it can stay far away from what it is
hiding from. Space is big and hard to hide things in, but it is full of all
kinds of smallish debris in the vicinity of a solar system. If you have
something of about the right size, orbit, albedo, radar reflectivity and
temperature, it ought to be hard to distinguish it from a stray bit of rock or
ice too small for anyone to have paid attention to it in the past.

Bearing this in mind, suppose that you built a small, camouflaged satellite
which would just sit there at ambient temperature until it received
instructions, upon which it would point itself at a given patch of sky, do the
finest bits of the aiming using its own passive sensors and then fire a
nuclear bomb-pumped x-ray laser at whatever has the misfortune to be there.
With something like this, one could probably swat any reasonable craft out of
the sky before it had time to respond. You could perhaps also use such things
offensively by putting them on orbits that will take them within their
effective range of whatever you want them to shoot, though they would stand
out a bit more that way.

The only real countermeasure to these I can think of would be to move your
spacecraft rapidly back and forth at all times, which is probably infeasible
given the amount of reaction mass it would take.

I'm not sure what the implications of all of this are, but I suspect they
would be interesting.

------
Tloewald
It's an interesting topic for discussion, but the writer makes lots of
"realistic" assumptions whil ignoring many others. Assuming this level of
"realism" -- I.e. no unforeseen technologies -- we basically don't get
enormously high delta-v for most kinds of useful ship, so the very high
sustained accelerations (e.g. 4G) aren't going to happen. The discussion of
perfect intelligence is good but fails to mention that most plausible
spacecraft would be detectable at enormous ranges even with their engines OFF.
Clearly almost everything will be automated and networked.

I think the writer starts out with the a priori assumption that there will be
spaceships with a crew at one end and an engine at the other and works from
there. I suspect you'll just have a swarm of networked drones. Why put so many
eggs in one basket?

(We're already seeing this approach being experimented with on nuclear hunter
killer subs, where firing at an enemy gives away your position, and giving
your position away gets you killed -- the US Navy has been working on
submarines tha launch drone firing platforms.)

------
cletus
If you're interested in "realistic" (meaning: no FTL) space battles read
Alastair Reynolds' _Redemption Ark_ (and read _Revelation Space_ and _Chasm
City_ before that).

It includes a chase between star systems that goes on for years and "close"
(ie within a few light-seconds) combat that involves a lot of interpolation of
enemy position, movement and actions.

Personally I still have serious doubts about the viability of _any_ kind of
prolonged manned presence in space. Its simply too expensive and the distances
involved in interstellar travel are so vast that even perfect mass to energy
transformation would make the process prohibitive in terms of cost and time.

But it's fun to muse about.

~~~
baddox
I assumed that most of the proposed space battles in question would be between
human factions relatively close together (certainly within the Solar system).

------
gerggerg
Why would space war ships be manned when we're already flying unmanned
vehicles on earth? I think we've touched on a reality of intelligent species
coexisting in the universe. Space war would consist of staying hidden and
probably nothing else.

Plus, certainly people would be fighting over the planets or the technology
(or maybe the amulet of Endor) so simply throwing comets and obliterating
things wouldn't make much sense except maybe defensively or to help with a
gennocide.

Terrestrial battles to take over usable land would probably continue to be the
name of the game. Followed with setting up tonnes of drones and sensors for
defense.

~~~
InclinedPlane
Speed of light delay could be critical in space battles, especially when you
consider that it goes both ways (sensor readings -> brain : decision making ->
control signal). The real question is how smart you can make computers, if you
can't make them as smart as a human then you need to have a meat-brain
somewhere in the middle of the battle. If you can make them that smart then
that opens up a whole host of questions on sentience and ethics.

Edit: Keep in mind that your manned "ship" might still be thousands or
millions of kilometers away from the enemy and controlling a vast array of
computerized drones. But when weapons are zipping around at 10s, 100s, or even
1000s of km/s the scope of the battlefield changes dramatically. You can be
remotely operating missiles that are farther away than the moon is from the
Earth and still be in the thick of it.

~~~
gerggerg
I don't know if as smart as would be valuable against as low powered as. A
computer would make decisions instantly, take much less resources, would die
less easily, wouldn't get bored, wouldn't forget it's mission, would feel no
sympathy, could travel farther, could stay in operation longer, could
tactically self destruct without hesitation, would take no salary.

But that being said, I honestly can't think of a reason to ever have a space
battle. You either want to blow up a planet or not. If so, you do it from an
large distance with a humongous rock. If not, you land on the planet, or fly
around their atmosphere and kill them the old fashioned way.

Maybe defensively you chase down an attacker to prevent future attacks? But
then all you have is guided missiles and the speed of their ships. Not really
a battle.

What I guess I'm saying is I can't ever see there being an attack position
other than lets wait until there are no rocks in-between us and them.

~~~
InclinedPlane
We already have nuclear weapons on Earth, yet wars still happen. Space is big,
incredibly so. And once there are people and industrial infrastructure
sprinkled throughout it armed conflicts will probably be inevitable.

------
j_baker
I admit to skimming this, but there are a couple of things I see wrong with
this.

1\. You can see a spaceship from the next solar system for sure. But it would
take years for you to see it.

2\. I doubt the future of combat will involve humans. I envision giant fleets
of spaceships that are too big for humans to control. Thus, I forsee space
combat as being driven by complex algorithms.

~~~
Avshalom
As to 1: It would take years for the light to get there, it would also take
several MORE years for the ship to actually get there. The important take away
is distance can't be used to hide, there is no "Oh they won't notice us we're
still outside the orbit of Pluto."

~~~
talmand
How can that be? Space is big, we cannot even properly comprehend how big it
is. I'm talking just in our immediate vicinity. If I took, say, three of the
world's largest ships, put them together to form one ship and then placed it
in a random spot somewhere within the orbit of Pluto; how long would it take
you to find it? Keep in mind I'm not talking within the orbital plane, I'm
saying within the sphere of the solar system.

Unless someone is watching 100% of the sky for even the slightest miniscule
changes, I imagine you could get mighty close (granted, close is Pluto)
without being detected.

Isn't most of the information we have about newly discovered far away objects
is how they interacted with other known far away objects?

But, of course, there's the given that if we've advanced far enough to engage
in space combat then we've likely created technology to help in detection.

~~~
Avshalom
It's two things basically:

-You can do a full survey in about 5 hours with one telescope these days.

-Ships are very bright, don't look anything like stars and CCDs are very sensitive.

<http://www.projectrho.com/rocket/spacewardetect.php> has a good break down.

~~~
dalke
I've been trying to get a sense of how effective these scans are. Asteroid
2005 YU55 was discovered 28 December 2005. It's about 400m in width, which is
the length of the biggest vessel we have. When it was discovered, it was 0.8AU
from the Earth, and its orbit is inside that of Mars.

This tells me that 6 years ago we did not know all of the +300m asteroids
within the orbit of Mars. How much better are we now? I read the page you
linked to, but that didn't list actual numbers based on asteroid searches.

There's an estimated 4,000,000 asteroids in the solar system of size 300m or
larger. I sincerely doubt that a telescope survey of 5 hours finds 1 million+
asteroids each night, otherwise that number would be pinned down a lot better.
(It can't find all 4 million because at 5 hours there's still substantial
portions of the sky unseen.)

~~~
cschneid
Asteroids don't pump out waste heat. Things get a lot more obvious when heat
differentials are big.

~~~
dalke
I was commenting on Talmand's scenario; take "three of the world's largest
ships, put them together to form one ship and then placed it in a random spot
somewhere within the orbit of Pluto; how long would it take you to find it?"

Using the formula in the "Refrigeration" section of the page linked to by
Avshalom, the "maximum range a ship running silent with engines shut down"
(assuming diameter = 500 m and temperature = 290K is about 500 million km, or
about 3.3 AU. That's well within the orbital radius of Jupiter.

That's assuming the _entire_ _asteroid_ is at 290K. Pluto averages about 40 AU
out, given a 0.056% chance that a room-temperature asteroid would be
detectable.

I'm also uncertain about the reasoning in the page linked to by Avshalom. I
think that assumes a 3K background, and I think you also think there's a big
heat differential. However, the average temperature of the moon is something
like -25C, and if an asteroid were closer to the sun, then the difference in
surface temperature between an internally heated vs. sun heated asteroid is
well within the errors in measuring the physical properties of the asteroid.

You can even work it out for yourself, using the equation at
[http://en.wikipedia.org/wiki/Standard_asteroid_physical_char...](http://en.wikipedia.org/wiki/Standard_asteroid_physical_characteristics#Temperature_measurements_and_regular_temperature_variations)
. I worked it out to:

    
    
      166C at Mercury orbit: http://www.google.com/search?&q=(((1-0.1)+*+(3.827E26+watts)+%2F+(0.9+*+Stefan-Boltzmann+constant+*+16+*+pi+*+(0.3+*+150000000+km)**2)))+**+(1%2F4)
    
      90C at Venus orbit: http://www.google.com/search?q=(((1-0.1)+*+(3.827E26+watts)+%2F+(0.9+*+Stefan-Boltzmann+constant+*+16+*+pi+*+(0.6+*+150000000+km)**2)))+**+(1%2F4)
    
      5C at Earth orbit: http://www.google.com/search?q=(((1-0.1)+*+(3.827E26+watts)+%2F+(0.9+*+Stefan-Boltzmann+constant+*+16+*+pi+*+(1.0+*+150000000+km)**2)))+**+(1%2F4)
    

(The values for albedo and emissivity are not well known, so there is a wide
error range in this calculation.)

Still, that's enough to show that the heat differentials inside of the Earth's
orbit are not that big.

~~~
Nick_C
You are using averages where the min and max are extremely wide apart. For
example, the Moon is not actually at -25C, it is either +130C or -110C (or
transiting between). We know the time when those temps occur, so we can look
for other objects not at those temps at that time. Same goes for the other
objects.

~~~
dalke
I am definitely using averages because if you have an ship which is 300+
meters across then you can leave the top few meters for insulation, so the
surface of your ship has the expected extreme temperature ranges.

I should restate what I said: instead of "that's assuming the entire asteroid
is at 290K", I mean, "except the insulation layer", which you need anyway to
keep the near-surface area livable.

If you need 20 meters for that, then your living volume is 21 million cubic
meters, or a reduction of about 20%.

That's not to say that there's no contribution. More that I believe the
calculations from that linked-to page ignore the difficulties of
differentiating between the internal heat (cooled through black-body
radiation) from surface heat from the sun.

For example, from Stefan-Boltman, cooling goes as T * * 4, which means if you
have a cooling radiator on the sun-side which is at 150C, or 20C above
"normal", then it's about 6 times more effective than a -90C radiator on the
cold side. I suspect it's easier to stop the 20C delta on the cold side than
the warm side.

------
dustingetz
my takeaway: there will be no space battles, because whichever side has more
money will always have vastly superior weapons, and they will take what they
want. violence will happen in key strategic plays, like political
assassinations. it's not like today's earth-combat where we're all mostly
equal and everyone has time to launch their nukes and we all die. this is all
assuming that one side doesn't simply exterminate the other like a termite
infestation.

------
51Cards
Still only part way through and though I don't entirely agree with all the
conclusions the thought experiment is proving to be fun.

This however is my favourite point so far as I had never really thought about
it this way when watching popularized SciFi.

 _Another thing about motion in space is that changing your ship’s orientation
does nothing to your speed and vector unless it is accompanied by firing your
main engine, because there is no friction. This means that all those space
dogfights where one fighter gets behind the other and the other one has to try
and shake it like in air combat are very unrealistic. There’s no
comprehensible reason why the pursued pilot can’t just turn his fighter around
and blast the bugger._

Buck Rogers in the 25th Century TV series has just been ruined for me. Wait,
no, it still had Wilma Deering, so all is not lost.

~~~
TeMPOraL
AFAIR they did that maneuver on Battlestar Galactica a few times. But still,
it's a good point.

~~~
Qz
Babylon 5 did this a lot as well.

------
philwelch
I don't think space combat is even going to happen. Any combatant with the
necessary wealth and technology to develop any space-combat capability is
going to have significant terrestrial interests and nuclear weapons already,
at which point they're already subject to MAD and won't engage in direct
combat anyway. At the very minimum, you would need economically and
politically independent Moon/Mars colonies, and even they would be so
dependent upon Earth trade that they would either not want to start a war or,
even if they did, would have Earthbound allies who are significantly more
vulnerable than they are, and no less essential to their survival.

The closest we'll ever get is probably the development of ASAT weapons, and
even those aren't likely to see much use.

~~~
rbanffy
> Any combatant with the necessary wealth and technology to develop any space-
> combat capability is going to have significant terrestrial interests

Imagine a colony that long ago severed its ties with Earth (or whatever other
terrestrial body they started from). Living off comets and asteroids seems
entirely feasible and it's a much harder to attack/easier to defend set up.

~~~
philwelch
Complete economic isolation from the earth seems very unlikely, at the very
least because it wouldn't actually benefit anyone.

~~~
rbanffy
If the outer solar system dwellers become self-sufficient, they would have no
need to go down the gravity well of the Sun to have commerce with earthlings.
The further out those colonies are, the lesser their contact with Earth will
be. If they live off the Oort cloud, the would be about one light year away
from Earth and it's very hard to imagine a shared culture with such a
communication lag.

~~~
philwelch
Why, exactly, would people dwell in the Oort cloud? The idea of having an
isolated, self-sufficient colony in the Oort cloud seems like an even poorer
version of North Korea, except you'd have to ship all the people out there.

There's no good analogy with colonialism on Earth, because most of that
involved getting very very rich by trading with the mother country, and if
there's anything to be won, economically, from the moon or the astroid belt or
even the Oort cloud, it'll be from Earth trade. As far out as the Oort cloud,
you'd be better off sending robots than human colonists for the very same
reasons you point out.

~~~
rbanffy
What if the people want the exile? Provided fabrication technology is advanced
enough to provide for material comfort, what is the difference between living
on a planetary surface or living on a very comfortable habitat? What if you
don't like Earth laws?

That same fabrication technology would negate the traditional colonial model.
There would be very little need to move physical goods between worlds.

Imagine having a million times more space and material resources than you
currently have on Earth now. While the mass on the Oort cloud is a fraction of
the mass of the Earth, it's still a lot of stuff.

~~~
philwelch
Alright, let's go with that scenario for the sake of argument. What would be
the casus belli?

If it's something like rare elements available only in the Oort cloud, the
traditional colonial model would apply and the overwhelming interest in the
Oort cloud would be in those very rare elements and not as some sort of
refuge. Your Oort cloud pilgrims would have to be fiercely protective of their
rare elements and to have gotten there first before the rare-element
prospectors. The Oort cloud would have to be not big enough to satisfy both
groups of people, and the Oort pilgrims would have to be stubborn enough not
to move their replicator-colony to the Kuiper belt or elsewhere.

At that point, you can start to reasonably speculate: you have clear
objectives on both sides at the very least. It becomes very hard to predict
what would happen because we've stipulated so many counterfactuals that
everything we know would be obsolete. Logistics, which has dictated almost
every war in human history, would look totally different due to the
fabrication technology, though limits to propulsion technology and the vast
distances involved would cause other issues. The Oort pilgrims would have the
advantage of locality--they could see and respond to any movements from the
inner solar system within months while delaying or hiding their defensive
actions until the last minute. But the fabrication technology would render
pretty much anything expendable, and it might be feasible to turn maybe a few
hundred Kuiper belt objects into a swarm of self-guiding missiles or something
while the Oort pilgrims wouldn't have enough raw materials to really hurt,
say, Earth.

------
yock
On the subject of privateers, why is the author so insistent on the danger of
crashing ships into planets? What does the math look like when space craft
like he describes hits the upper reaches of our atmosphere? At those speeds,
could a space craft _really_ penetrate far enough to cause terrestrial damage?

~~~
rw
An example: Project Thor / "Rods from God":
<http://en.wikipedia.org/wiki/Kinetic_bombardment>

~~~
yock
The linked article seems to mention re-entry friction as a problem yet-to-be-
solved:

 _The system would also have to cope with atmospheric heating from re-entry,
which could melt the weapon._

Then there's the question of whether or not heat is truly the most immediate
issue. NASA and USAF had to actually fly an airplace near and past the speed
of sound to see how the properties of the atmosphere changed when compressed.
Is it logical to hypothesize that similar changes may be encountered as speed
continues to increase?

~~~
sp332
I don't think melting is that big a deal. It's still the same amount of mass,
only now it's _molten_ steel instead of steel rods.

~~~
andrewflnr
It'll start breaking into little blobs, though, which will have less and less
power.

~~~
sp332
It doesn't matter. As long as each "blob" is heavy enough to resist deflection
by the wind, the same total mass will impact at about the same speed. The only
downside I can see is that the blobs might hit at slightly different times,
which would reduce the instantaneous force on the target. But I think it would
transfer the same total energy.

~~~
PotatoEngineer
The same total energy would be transferred, but it would be spread out over a
larger area. If the area is sufficiently large, then all you've done is raise
the temperature of Germany by one degree for a while.

(Still, there are plenty of configurations that make good kinetic-kill weapons
with a manageable amount of re-entry heat. Think large rods with good amounts
of mass and small cross-sections. This is an engineering problem, not a show-
stopper.)

~~~
dalke
Figuring Germany at 357021 sq. km, and "1 degree" to raise the equivalent of a
meter of water by 1 Kelvin, gives 1.5E18 J.

If I did my math right, that's the energy in a 400 megaton bomb, or 17 kg of
antimatter. The US nuclear arsenal is about 2500 Mt.

I don't think you'll be able to distribute that much energy so uniformly.
Almost certainly you'll end up with all of it dumped into the surface, with
people, land, and cities burned to a crisp. Only a few people in mines or deep
valleys might survive.

------
Splines
As mentioned in the post, David Weber's _Honor Harrington_ series operates
very much like this. I've read a few of them and enjoyed it. Nuances in space
combat in his stories tend to be important.

[http://en.wikipedia.org/wiki/David_Weber#Honor_Harrington_se...](http://en.wikipedia.org/wiki/David_Weber#Honor_Harrington_series)

Also, it's worth watching this scene from Mass Effect 2. It's amusing :)

<http://www.youtube.com/watch?v=7GqqDCe4Yrs>

~~~
dalke
Assuming a ship of 500 m in length, and weighing 10,000,000 tons (100 times
heavier than the largest aircraft carrier), the firing of a 20kg shell at 1.3%
of the speed of light requires a momentum transfer of 0.008 m/s from the ship.
Assuming constant acceleration, the firing requires a shell acceleration of
1.5E10 g, which is done in 130 microseconds.

A velocity change of 0.008 m/s in 130 microseconds means the ship itself has
an average acceleration of about 60m/s/s or about 6 g. However, this assumes
the entire ship is rigidly coupled to the firing system. If held together by
normal structural forces, which propagate at best at multiples of the speed of
sound, then no more than 1/2 meter of other structure can be involved. It's
more likely the equipment itself will have 100s of g of stress.

The acceleration requires 1.5E14 Joules, or 35 kT of TNT, which is what the
clip said.

------
JDulin
A fascinating read and good outline for what space battles require, but not a
predication of what future space combat will look like. By limiting the
discussion to only technology that we could build today, the exact scenarios
in here will never play out.

Large scale space combat will play out only when humans can build these
weapons cheaply, and have an incentive to build them at all. That is decades
from now. By the time a human society decides to construct the ridiculously
expensive space warships and defenses the author talks about, we will have
much more advanced technology (that is probably a lot cheaper to.)

------
elmindreda
My favourite space combat scene is the one on the way to Home in _Protector_.

~~~
pavel_lishin
I also enjoyed Niven/Pournelle's descriptions in Mote in God's Eye - to
paraphrase, space combat is incredibly boring except for brief flashes of
terror.

~~~
talmand
I really liked Lucas' treatment of space combat with capital ships in Episode
III. You line up next to each other and start blasting, just like they did
back in the good old days of pirates on wooden sailing ships. Of course this
is incredibly stupid and immensely destructive to both ships but it makes for
awesome explosions.

But I think doing this within range of a planet's gravity well isn't too
intelligent. Lose power and down you go.

I always appreciated the space battles in the X-Wing series of computer games.
That's the way I see it, large capital ships with single-man fighters buzzing
around them. But since we have semi-automated drones with human pilots on the
other side of the world with a satellite link, I would have to assume those
single-man fighters would be unmanned.

But Niven/Pournelle's idea of space combat is most likely what we would get.

~~~
pavel_lishin
> But I think doing this within range of a planet's gravity well isn't too
> intelligent. Lose power and down you go.

Sure, if you're dumb enough to park yourself in a decaying orbit.

~~~
talmand
I believe it is well established in Star Wars canon that the drivers of the
capital ships don't always seem to be the brightest guys in the fleet.

------
Avshalom
<http://www.projectrho.com/rocket/spacewarintro.php> for all your back of the
envelope needs.

~~~
gwern
I think <http://www.projectrho.com/rocket/> is by the same guy as OP, actually
- the forum post made many points I recognized from Project Rho.

~~~
nyrath
Well, that turns out not to be the case. I'm the author of the Project Rho
site, and I did not write the essay on the Spacebattles forum. But I agree
with all the points the poster made, he just wrote the article more succinctly
than I did in my website. ;)

------
doku
Those monitoring platforms if they emit any signals they can be detected and
destroyed. During the early days of Iraq war, Iraq had a GPS disruption device
that floods the wavelength with their own GPS signals. The first thing US did
was to send a missile that use disruptor's own signal to track it down and
destroy it. Establishing enemy's fog of war would be first priority.

It is very unlikely battle's will occur in open space if both sides knows each
other's capability. The side with slight disadvantage will seek to level the
playing field by heading towards asteroid field or unmonitored planets.

Once they arrived at the planet, one strategy for the orbital battle field is
to go into an extreme elliptical orbit. The more skilled pilot will be able to
calculate the opponent's possible orbit and tries to outwit his opponent. As
the pilot approach the perigee of the orbit, the cinematographic tense scene
panes to the pilot's face as the ship slows to the escape velocity in the
upper atmosphere. Only to escape tattered and draught, and approaching the
enemy hidden by the planet horizon.

------
stcredzero
This whole thing about "stealth will be impossible, because everyone will have
dispersed observation platforms," seems very handwavy to me. If detection is
so easy across vast distances, then ultimately observation platforms shouldn't
be able to survive _unless they have stealth_. Otherwise, no matter how cheap
you can make your observation platform, you can make something else that will
destroy it for much less.

I imagine space warfare to be a complex "cold war" of vast distances, with
robot missile and detection ships tightly beaming waste heat and information
in carefully chosen directions. There will be complex games of deception and
counter-deception. It will be a matter of tricking the enemy into critical
errors about what you know and don't know about the disposition of their
forces.

The situation where everybody is using torchships, and everybody knows where
everybody is at all times is similar to the Surface to Air Missile dominated
era of aerial warfare of the 70's. There will be tremendous incentives to
someone to develop workable stealth of some form.

~~~
MatthewPhillips
A destroyed observation platform is just as useful for defense as a working
one :) I'll replace my cheap observation platforms after I've disposed of the
threat that just gave itself away.

~~~
stcredzero
It will be a losing battle if the resource that destroyed your platform is
cheaper than your platform. And while your're "disposing of the threat that
just gave it self away," you're actually falling into my trap, for I've only
sent that drone to get you to maneuver and give your other forces away, so my
other disposable stealth drones can spin-up to high-energy missile mode and
blow them up as well.

See, you can't just handwave stealth in space away. If you think you can, you
just haven't thought it through quite enough.

~~~
MatthewPhillips
I see what you're getting at, but I wouldn't call that "using stealth". Surely
the demolition of one observation platform isn't going to raise an eyebrow. If
I'm defending a solar system I have tens of thousands of observation platforms
that get taken out by asteroids and comets from time to time.

Trying to create a diversion isn't really effective at the scale of a solar
system (or greater). While I might send a small fleet at your drones, you
still have to get at me from _somewhere_ , and that probably involves
destroying more drones. But why bother? Getting to my base at the center of
the solar system is going to take you more than a few minutes, I'm going to
figure out where you're really coming from.

It makes more sense to use drones for reconnaissance, and then just go at your
opponent with a bigger fleet.

~~~
stcredzero
_I see what you're getting at, but I wouldn't call that "using stealth".
Surely the demolition of one observation platform isn't going to raise an
eyebrow._

You're forgetting that holes in your observation cloud open windows through
which my drones can beam waste heat. Of course I wouldn't be trying to destroy
just one drone. The point is not so much to divert, as to cause you to reveal
your resources and to give mine more opportunities to use stealth.

Also, the scenario here is not the invasion of a solar system. I thought it
was the control of a particular resource like an asteroid. But if you want to
play "invasion of the solar system" then I'm game.

 _It makes more sense to use drones for reconnaissance, and then just go at
your opponent with a bigger fleet._

Only up to a certain point. If you create a tremendous concentration of
resources and industrial output such as an awesome battleship, you might have
something that can beat any individual craft in a 1 on 1 battle, but you've
also created an opportunity to hurt your side _a lot_ with only a very small
expenditure on my part. This is especially true with stealth.

------
orenmazor
I think Hamilton nailed it when he talked about kinetic weapons and 'wasps'
(aka small bots that can move in ways a human occupied ship can't)

~~~
jermy
Indeed - in this particular series (The Night's Dawn Trilogy) space warfare
was conducted at very long range by kinetic drones, fired from spherical
ships.

------
majmun
I imagine, that this space warfare as described in article will only be
preceding the real war. once this unmanned missiles are exhausted . if
invading force has won. it will try to land on the resource that it is fought
for, (planet, moon, asteroid, space station). and once they are landed it will
be more classical warfare. (so don't worry there will still be blood). so this
is very much like trench warfare.

All this is valid for current technology . and same species war (humans vs
humans) , but war between aliens and humans will most likely be war between
Von Neumann probes. if you lose you got terraformed or planetXformed. all will
be very quick and precalculated. so if you are not prepared in advance for all
possible situations. you will probably lose. (or not be able to terraform).
pretty much all you can do to protect you r self from alien Von Neumann probes
is find it first in space or early stages of development and try to reverse
engineer it.

------
meric
"there's no stealth in space, but there most certainly is stealth in an
atmosphere."

It would allow for ambushes, and fake-ambushes.

A lone-ship running from a fleet, carrying a local governor, running past an
uninhabited planet, away from a chasing enemy fleet. The lone-ship passes
right next to the planet and keeps going. The enemy fleet follows. When the
fleet is passing next to the planet, will there be an ambush waiting? Will
missiles hidden in the moon orbiting the planet emerge and fire in a cloud of
<"thunder" replacement>?

The algorithm deems the chance of an ambush springing from the planet
atmosphere as "possible", and the fleet retreats.

~~~
pavel_lishin
Unless you need to make a gravity-assisted course correction, why would you
follow in the path of a ship? Ambushes aside, they can drop all sorts of
things behind them that you don't want to run into.

~~~
meric
Well my point stands, ambushes can be held in atmosphere.

Let's say enemy fleet regularly uses the planet to make a "gravity-assisted
course correction"...

------
learc83
Do any other hacker news readers check out spacebattles.com? I'm glad to see
it on the front page, I've been a member there since '01

------
zmj
What's the difference between a spaceship and a missile once you remove the
human passengers and pilots?

~~~
nyrath
Not much. The main difference between a missile and a robot controlled
spacecraft is that the latter has more propellant. The spacecraft presumably
is intended to return while the missile is just has to arrive at the target.
The spacecraft will have roughly 4x the propellant [1] propellant to enter
mothership to target trajectory [2] propellant to slow to combat speed at
target [3] propellant to enter home to mothership trajectory [4] propellant to
slow to a stop at mothership. A missile only needs [1].

------
electromagnetic
The OPs problem here is that in the attempt to change the analogy from naval
combat to aerial warfare is that he fails to grasp the medium again.

Space is big, space is empty. FTA this means everything is easily trackable,
not only are thrusters visible from across the solar system (except perhaps if
you're headed directly for someone, but the thrust required there would be
insane), but even every object in the solar system is glowing in infrared
energy and thats background objects, not to mention you've strapped nuclear
power plants, life support and whatever other heat producing apparatus onto
your ship to make it glow even brighter.

The problem with being visible from a distance means it favours those who can
hide. Basically, it favours mines. It's simple strap a laser onto a small
rock, bury capacitors inside it and have them charged by solar panels. Why?
Because the aim is to one-shot your target somewhere important. The mine is
disposable, if it one shots the target you might get lucky enough to use it
twice. If not you'll have dozens of others waiting. You've got 3 targets:
Power supply (nuclear reactor/capacitor bank/whatever), main engine (you
cripple their thrust and they're a sitting duck) and control centre (heck,
you're likely able to nail all habitable space in one shot as a space ship is
more likely to have a vastly expanded cockpit rather than a whole ship of
habitable space)

The other problem with space combat is heat. Before you'd even fire a missile
or a bullet, you're going to be aiming infrared lasers on your targets from
light minutes away. If a ship is habitated then you only need to get it to the
point where the life support can't shift enough heat to keep the air
temperature below 40C. In uncrewed ships you're talking hot enough to make
processors malfunction, which isn't considerably hotter than people can
tolerate. These might cope better as cooling can be dedicated to very small
areas.

The problem with space is that objects can get very hot, very fast and unless
you bring a lot of material to heat sink and dump, you've got problems.

Space will be a war predominated with mines and heat. There are currently
about 25,000 objects in space. If only 1% of these are ship-killer mines,
would you attack Earth? Well, you'd need more than 250 ships, assuming you're
able to kill all the mines in a very short time before they can refire.

Want to attack a mining base in the asteroid field? Find the rock without the
massive laser hiding in it! Furthermore, try to wage an effective assault when
you're pulverizing everything within a million kilometers of you, and still
have the weapons/energy/heat sink capability to fight your target that has a
massive rock of shielding and heat sinking, versus your ship.

What about launching asteroids or comets at your target? Well 1 if it's viable
to nudge an asteroid from hitting earth, then it's viable to nudge the
asteroid your in so that it's missed.

~~~
saulrh
Mines are just as detectable as anything else. Problem: how does your mine
know when to go off? If it has sensors, it has electronics; if it has
electronics, those electronics are running at something above 3 Kelvin; if
you're running anywhere above 3 Kelvin, you can be seen against the cosmic
background.

Also, asteroids are incredibly vulnerable, because they can't move. You don't
even need to get into range; just boost up another rock and nudge it into a
collision trajectory.

~~~
electromagnetic
I don't disagree, but remember the number of asteroids over 100km is around
200. The number of asteroids over 1km is between 700,000 and 1.7 million. That
means the very big asteroids are between 0.0003% and 0.0001% of the objects in
the asteroid belt. Given that the smallest known Aten asteroid is ~5m in
diameter, then it's an easy conjecture that the asteroid belt is likely to
have tens if not hundreds of million asteroids <1km in diameter.

They're going to have enough mass that blasting them is going to be
impractical. It's going to be a waste attacking a mining asteroid if you're
dumping hundreds of munitions at every nearby rock.

> If it has sensors, it has electronics; if it has electronics, those
> electronics are running at something above 3 Kelvin; if you're running
> anywhere above 3 Kelvin, you can be seen against the cosmic background.

This is very true, however given the variation in albedo's of asteroids and
meteoroids then there's going to be a wide range of 'normal' temperatures for
asteroids. With enough processing power you could assume that people would
eventually start calculating asteroid albedo vs distance from sun vs apparent
temperature. If you've got a light rock that's hot as all hell, then you might
be best to shoot it just in case. Probably not likely for civilians at least,
even the military might not want to be running too much processing power as
they'd have greater heat sinking issues to worry about.

The real thing that will determine how hard or easy to find mines will be is
human mining. How much dirt and debris are we going to be producing, or even
purposefully producing. If we're mining bigger asteroids are we going to
require ships to land, or simply dump payloads into orbit for ships to snag.
If we're doing the latter, then we're talking about hundreds of objects
running well above background levels. How much rock are we going to strip off
an asteroid and leave nearby?

If piracy or warfare becomes real, then mining companies will likely want to
limit the approach vectors for incoming ships. What better way than dumping
copious amounts of junk in your orbit. Given that a cubic meter of silica
weighs around 2500kg, then you're not likely to crash your ship into it at any
speed. Put thousands of these in orbit, and people are only going to approach
from the clear paths.

Again, all these rocks would be hotter than background, and you only have to
mine 1% for it to be a solid defence. Making someone take 100 shots in 1-hit
wins warfare is a very effective defence.

------
kevinalexbrown
What if you launch a surprise attack by launching a missile at relativistic
speeds?

~~~
rbanffy
Unless you are talking about yet to be invented explosives, at relativistic
speeds you may as well launch a rock. The explosive power of your warhead will
probably be irrelevant when compared to the kinetic energy of the projectile.

But, fairly enough, launching anything at relativistic speeds requires yet to
be invented propulsion systems that will require energies much larger than any
explosive we know today.

For maximum efficiency, you could launch a lump of antimatter at relativistic
speeds. That should take care of the details.

------
whyme
hmmm... so the author is using today's understanding of technology to
substantiate future outcomes. No can do - I say!

------
berntb
Would it be feasible to use a nuclear device as a shotgun?

That is, most of the kinetic energy of the bomb is directed (like discussions
for the bombs in the Orion project). The bomb would be optimised to send
tungsten bullets off at X km/s.

Then put that as the payload of a missile.

Edit: Fragmentation bombs was discussed in the second page of the article.
Hmm... this would need a very _tight_ spread of the heavy pellets, which is
probably not possible with a nuclear weapon?

Edit 2: Add a 2nd level of explosive drive to the fragments? They disperse a
bit (to make them hard targets) but know where the target will be and when.
More like submunitions, I guess.

Edit 3: Rail guns to send (small) kinetic missiles at a high initial speed?
These could potentially run in stealth mode for quite some time, before doing
final course corrections.

------
maeon3
Information and stealth are the biggest assets in space war so maybe that is
why we dont see aliens chit chatting all over. A species wins a war by making
the enemy think it has won, while hiding out at a new home base to build up
weapons.I see earth as an extension and continuation of that war. We don't
know where our allies are, So that when they discover our position and
interrogate us they won't find the rest of the hive. the winners of war will
be the species that hides the best.

