Wednesday, July 18, 2012

Space Warfare XVII: A Blockade in SPAAACE !!!

 Orbital Combat

An expeditionary force, let us say, has set forth from Mars, heading toward Earth. Its mission is to establish and enforce a blockade of Earth - or of the rest of the Solar System, depending on how you look at it. Specifically, certain persons are to be embargoed, forbidden to travel from Earth. to any other planet, moon, or other astronomical body. Travel to good old Luna may or may not be included in the embargo, depending as much on operational as policy-objective considerations. (See below!)

Violators are subject to arrest. If they resist arrest they may be fired upon.

We will not, for this discussion, trouble ourselves with who 'certain persons' are, or why someone on Mars wants to keep them from leaving Earth. For our purpose, it is sufficient that

a) The relevant Earthside authorities have zero interest, or less than zero, in helping Mars bottle these certain persons up. A polite request would reach Earth a lot faster, easier, and cheaper than an expeditionary force. But a polite request, by itself, would be ignored.

b) Somebody on Mars (or at least in Mars space) has means and motive to issue more than a polite request. Namely send the expeditionary force.

c) Whoever this somebody is, their objective is to control outbound traffic from Earth, not eliminate it - especially not permanently. Slagging Earth, its launch sites, or orbital infrastructure are not objectives, or even acceptable outcomes. Slagging individual transport-class ships is dicey, depending on the circumstances. Military craft, however, are fair game.


Human interplanetary travel uses electric propulsion, on the general lines often discussed here. Main drive acceleration is in the milligee range, and the ships have either very large radiator fins or very large solar wings. Hardening these is a nonstarter, so deep-space ships are inherently vulnerable.

On the other hand, punching a few small holes in the wings will not cripple them, so the vulnerability should not be overstated. Spaceships won't sink, or become aerodynamically unflyable.


Delta v will be a constant preoccupation of commanders. This has been discussed here before, but it is almost impossible to overstate. The Martian expeditionary force probably take a slower orbit than civil transports, because transports can refuel at their destination. The expeditionary needs to reserve propellant for a (slow!) abort orbit back to Mars.

And while milligee drives preclude 'tactical' maneuver, at least some of your deep space ships likely have a few km/s of delta v for 'operational' orbit changes in Earth space. At a rate of about 1 km/s per day. By bringing along plenty of tankers for support, a few ships might have a couple of dozen km/s for operational movement.

Chemfuel spacecraft can have pretty much as much acceleration as you want, but unless they start out as mostly propellant drop tanks they will carry only 2-3 km/s of delta v. Which means that a 1 km/s burn is huge, a sizable chunk of your entire maneuver capacity.

Nuclear thermal propulsion is intermediate, but much closer to chemfuel. And for human missions much of the advantage may be lost due to shielding mass.

Just on a practical level, all of these constraints are a good reason to seek mutual understanding through dialogue. But of course you won't.


On the flip side, the technology of deep space travel makes 'distant blockade' a surprisingly viable concept. Departing ships spiral out for a week or more, their orbital speed (relative to Earth) gradually decreasing to a couple of km/s, before they finally pass escape velocity and break loose into solar orbit.

This gives ample time for ships in high Earth orbit to intercept would-be blockade runners, the interception taking place somewhere between geosynch and lunar distance. This sort of space chase is more than a bit odd to contemplate. Both prey and pursuer are circling Earth throughout the chase, which unfolds over a period of days due to their extremely sluggish acceleration.

But the scope for evasive maneuvers is extremely limited, since the blockade runner must keep spiraling outward if it is to proceed on its journey. One possible tactic is to feign a departure, either to draw the blockader into battle with a heavily armed ship, or as sheer bluff - forcing the blockader to expend its limited propellant, then 'reverse course' and spiral back inward toward low orbit. The ship performing the bluff has also expended propellant, but it can refuel at LEO, an option not available to the blockaders.

Such peculiar chases are complicated by the possibility of chemfuel (or nuke thermal) ships - or munitions - making far more abrupt orbit changes, leading to an engagement in a matter of days.

Earth-Moon travel is, or can be, entirely different, carried out using chemfuel or nuke thermal propulsion, blasting straight out of LEO into the lunar injection orbit. The challenge of intercepting Moon-bound ships is equally different, to the point that the blockader will either have to make separate provision for it (a ship positioned at the lunar L1 point, or in lunar orbit), or else not attempt to enforce the blockade with respect to Luna.

If blockade runners were pre-parked in lunar orbit - and the Earth-based defender had months to position them, while the blockader was en route from Mars - then the blockader must extend enforcement to lunar space. Otherwise the blockade might be evaded simply by going to lunar orbit first.



So far I have said nothing about weapons. The scenario as described does make one negative presumption: that lasers (or whatever beam weapons) have an effective range less than about 50-100,000 km - whatever turns out to the the distance from Earth at which departing electric ships reach escape velocity and transition from geocentric spirals to their solar transfer orbits.

Otherwise the prime intercept zone lies within direct zapping range of lasers in low orbit - or even on the ground. In that case the expeditionary force must either engage in a direct laser battle, or blockade from a higher orbit, outside the range of 'shore guns.' Intercepting blockade runners then becomes more difficult and propellant-costly, since they are already above Earth escape velocity on outbound solar orbits.

Kinetics, or missiles generally, have no 'range.' If they are on orbits below escape velocity they will orbit Earth (or Luna) indefinitely; if above escape velocity they will head out into the void on solar orbits. More relevant for missiles is flight time, which defines the target's window for engaging the missile or evading it.

Electric ships can, potentially, outrun any chemfuel or even nuke thermal missiles by running them out of delta v. But with milligee acceleration they can only do so if the flight time is in days. The drawn-out evasive maneuver will cut fairly deeply into reserve delta v, and leave the target far from its previous orbit, therefore probably off station.


I have also said nothing about the ships involved, save that they have the broad characteristics determined by their propulsion. It is by no means a given that either side has craft that fit our image of warships, especially if lasers or other beams are not an important factor. The expeditionary force must come closer, since its deep space craft must be able to deploy weapons in some way. But the Earth-based defender might well rely entirely on missile buses pre-positioned in patrol orbits, with its ships providing purely logistic support.



Finally, bear in mind that the scenario outlined - distant blockade - is pretty much the most favorable for an expeditionary space force. The blockader is not seeking to land anywhere in force, or even contest control of Earth's inner orbital space, only interdict outbound deep space traffic. It need not come close enough to Earth to be at risk of short-warning attack by surface-launched ASATs or surface-based lasers.

Discuss.





Related Links: Atomic Rockets, of course - especially, but not exclusively, the pages on space warfare.

And previously in the Space Warfare series on this blog:

I: The Gravity Well
II: Stealth Reconsidered
III: 'Warships' in Space
IV: Mobility
V: Laser Weapons
VI: Kinetics, Part 1
VII: Kinetics, Part 2 - The Killer Bus
VIII: Orbital Combat
IX: Could Everything We Know Be Wrong?
X: Moving Targets
XI: La Zona Fronteriza
XII: Surface Warfare
XIII: The Human Factor
XIV: Things As They Ought To Be
XV: Further Reflections on Laserstars
XVI: Origins and Scratch Forces

Also ... Battle of the Spherical War Cows: Purple v Green
Further Battles of the Spherical War Cows

Plus Space Fighters, Not Space Fighters, Reconsidered?

And, indulging in heresy - Give Peace a Chance




The image, as so often, comes via Atomic Rockets. Note that the engagement shown is much closer to the planet than the intercept zone discussed in the post.

126 comments:

Thucydides said...

Finally escaped from Battleship row!

While this is a very thought provoking exercise, I'm not entirely clear as to why the Martians are trying to blockade the Earth. Historical blockades were used to deny the enemy nation access to some strategic material or to overseas trade in order to put stress on the enemy economy.

As Tony pointed out in the past, Earth has the internal economy and resources to be the focus of human civilization for centuries to come, the Martians are more likely to suffer should their trade with Earth be cut off. Perhaps we need to change the back story a bit; the Martians are blockading Earth and are willing to suffer the economic effects in order to prevent the trade of McGuffinite between Earth to the Jovian moons.

This presents an even messier tactical and strategic situation; does the Earth want or need the McGuffinite enough to blast the blockade? Do the Jovians appear in force from deep space, and if so are they going to attack the blockade fleet or head to Mars?

To answer the narrower tactical situation, the Earthforce would probably adopt a field expedient solution of strap on chemical fuel boosters to clear their ships through the orbital zone, then drop them off while engageing the electric drive. Martian blockade ships would not have the delta V to run the blockade runners or warships down in the short term, so engagements would consist of trading zaps and (if close enough) missile shots as the Earthforce ships roar by. The mental image would be like something out of the 1500's with a gallass using its oars to slip past a bacalmed cog.

Earthforce ships and blockade runners can also move into place with a fresh escorting cloud of missiles or on board battery for each attempt, while the Martians will eventually be running out of missiles. If the Earthforce can move enough ships through the blockade, they can then attack the Martian logistical tail, or even move into a higher solar orbit, pick up speed and attack the Martians directly with a high speed flypast, unleashing SCoD's, warheads and penetration aids at a much higher speed than the Martian defenses may be able to deal with (and causing far more damage with every shot that does get through).

Daniel said...

If Mars is trying to keep some person(s) from leaving Earth, and the Earth government(s) aren't trying to blow the Martian fleet out of the sky, then that means that outgoing ships would need to be searched for the person(s) of interest, with shots being fired only if a ship tries to run instead of being searched. That means that the martian fleet will need lots of big troopships (unless robots have gotten good enough, in which case the troopships are either fewer in number or smaller) and transfer vehicles (possibly with some way of forcibly making an airlock) to deliver the espatiers to the stopped ships.

Add to that a cloud of missile pods to encourage ships that being searched is better than being shot, and you're good! Mind you, there'd need to be two types of missile pod: one for shooting the ships that are burning chemfuel or nukethermal to get past the blockade, and one to chase down any that either get past the first, or wait to start the hot engines until they're in amongst the blockaders.

First type will be based off of boost-stage ICBM interceptors. Outlasting these won't be an issue, because to escape, the blockade runner has to approach at least one launcher, maybe more (depending on how deep Mar's pocket's are...) making this engagement very quick and bright.

Second type would be a long-range bus. Initially launched via cannon/mass driver (probably just before/right as the other type launch, to give both a bit of a boost) the main bus would probably be a nukethermal with a couple chemfuel boosters. When the bus gets close enough, it'll launch its payload of chemfuel missiles.

Note: both types of missiles (head on and what the bus carries) would do well to have warheads of some sort. The head on missiles because head on collisions are hard and a proximity-fuzed warhead makes a 'close' hit count. The bus-launched missiles can use warheads because, unlike most space engagements where the participants are going at a fair clip relative to one another, these might not actually have the velocity to cause much damage by the time they catch up. So instead, build them like a modern air-to-air missile, except fit for navigating in space.

In conclusion, no need to have big, heavy, expensive, human carrying ships go chasing off after anyone doing a runner. If the blockaders have been broadcasting on all standard frequencies and sending messages through normal channels that There will be a blockade and the only ones with anything to fear are those carrying persons x, y, and z. Any not submitting to search will be shot., then the ones running don't need searching, and the ones not running do.

Craig A. Glesner said...

The one thing I didn't see mentioned and I would include in my Expeditionary Force is tenders chock full of fuel, arms and consumables. That would allow my EF to remain on station longer and maneuver more.

Michael W said...

Rather than a blockade, wouldn't it be simpler to establish "border agents" at possible destinations?

Anonymous said...

Hmm, "certain persons" sounds like the Mars coloniests are blockading their former commercial masters; so they are targeting a corporation or a group of corporations; that alone probably cuts down on the number of 'interested' nation-states. So the Martian blockade force knows that so long as they strickly target only those corporate ships, they don't have to worry too much about 'real' combat spacecraft.

The Martian ships will likely be large manned transports retrofitted with uprated electronics and weapons. The corporate 'warships' will likely also be retrofitted manned transports. Medium powered lasers with a fraction of a light-second range and missile weapons (kinetics) with a Delta-V of less than 10 kps are used on both sides; however, a dozen armed former merchantmen and a couple dozen logistics vessels would be stretched thin even if patroling at three-quarters the distance from Earth-to-Luna orbit. If they move to closer than 46,000 miles from Earth (twice the distance to GEO), they'll make Earth governments 'nervous'... Corporate ships will use every tactic discussed in the main post to evade the Martian blockade force; if the Martians brought small, agile, chemfueled 'customs' boats to catch and board corporate ships, they might get by with the occational 'dip' lower than twice GEO to intercept a stated target ship. This does seriously cut into the weapon's budget, but may make more political sense. Act like a legitamite government regulating a corporation (or group of them), and don't be too blatant about it and the Martians just might get away with it...for a while. Oh, and I'd only use missiles in extreme situations; for example, if a corporate armed merchantman fires on a custom's boat, it would have to deal with a salvo of Martian submunitions-carrying missiles. Shooting an unarmed customs boat will not garner sympathy, even if your ship then gets swiss-cheesed by a 'proper' warship.

Ferrell

Anonymous said...

Three other people posted while I was writting mine? Talk about eager to discuss the topic...

Ferrell

Brett said...

The Martians would be wise to declare a No-Fly Without Declaration of Cargo and Search Zone, and then put some robotic satellites with kinetic interceptors in a lower orbit (i.e. within range of the Laser Shore Guns). They would double as tripwires in case the Earth folk decide to start shooting back.

After that, it's mostly just making sure to match orbits with complying ships making their way outward. I don't think you could realistically bring enough fuel to handle all of that, but you won't need to if the Earth folk already have propellant depots in orbit (unless they're sending all the volatiles up from the surface, there's probably a captured asteroid they're using).

Locki said...

Sorry Rick can I ask for a bit more information?

Its not quite clear from the original post.

1. Is Earth actively trying to blow the martian blockage fleet out of the sky or will Earth meekly sit by whilst the Martians go about their business?

2. If Earth is strangely pacifist to such an overt act of aggression and breach of soveriegnty is there the equivilent of an "International Water perimeter?" Or can the Martian's choose to begin their blockade at point blank range. Eg a few 100m away from the earthside space station/elevator?

In succinct terms what acts by the Martians would consitute an act of war and invite massive reprisals? How aggressive can the martians afford to be. This feeds into a complex politico-miltiary equation about the relative balance of power (eg the US can still push harder than China because its stronger)

- Presumably destroying every ship WWII style will qualify as an act of war

=======

Technically, delta-V is going to be a total bitch for the blockading fleet. It almost has to be a one way, unmanned fleet in order to have any chance of running blockade runners down.

Plus if earth is actively supporting the (?) terrorists they effectively have unlimited delta-V and can just keep making unlimited dummy runs to the extra-planetry launch window until the blockade runners call it quits.

Really the only 2 tactics that makes sense from a delta-V point of view is to:

1. Attack in force and utterly trash Earth's space based asset and then directly control every orbital launch facility (disallowed by Rick) or

2. Blockade them at their ultimate destination where the Martians' will now presumably have a huge home delta-V advantage over the Earth terrorists (who've just used up most of their delta-V getting to their destination).

This tactic makes particularly good sense since there's really only so many spots you will want to travel to in the Solar System.

Its like trying to GPS tag Usain Bolt at the end of the marathon rather than trying to tag him in the 1st 100m.

Wait for the blockade runners to use up most of their delta-V

Jack Lusted said...

I wonder if analogies can be drawn between modern guided missile destroyers and typical plausible PMF spacecraft.

Both are not very armour and are compartmentalised. Destroyer probably a bit stronger hear but neither is relying on their hull to keep them safe.

Weapon systems are missiles supplemented with 'dumb' systems (lasers and ship guns being aim and shoot and can't really be jammed).

Large and sophisticated radars are used on modern destroyers and will likely be used in space allowing for tracking of a large amount of objects. ECM is also used on modern destroyers, though don't know how applicable that is in space.

Whilst PMF space warfare sometimes doesn't sound as exciting compared to battleships in space, I think it becomes a lot more exciting when you think of it as guided missile destroyers duking it out in space, with a few more interesting tactical options.

TOM said...

I think on the following : a colony becames a Nar Shadaa /or Somalia/ like place.
It produces lots of drugs, guns and smuggles them to lots of other colonies.
Maybe it even shelters pirates /ship hijackers/.

So they decide to blockade it, hoping it will be enough, invasion would be really expensive, although it can remain an option.


I would use magsailed ships, as they can provide practically unlimited delta-V.
I would use smaller assault boats to investigate the ships, and as
the space between the ships will be still large, it is a possibility, that the boats will need the escort and protection of assault gunboats.
Like the same named boat from TIE fighter, they could wield short range EMP weapons to paralyze their targets.

Bryan said...
This comment has been removed by the author.
Bryan said...

I think Mars has it, hands down. One big ship, full of computer-controlled "torpedoes" (AKA "combat wasps", at least in some space operas). Use a mass driver or the 'torpedoes' drive to insert them into lower orbits, main ship hangs out in higher orbit, and waits.

Any ship attempting to leave gets warnings to turn back ('please turn back, any attempt to cross the inner van allen belt will be met with lethal force').

Given low enough orbits, sufficient density, and sufficient acceleration, these 'torpedoes' should be able to intercept any outgoing electric-drive ship; despite the electric-ships superior delta-V.

Heck, you could replace torpedoes with high-power lasers in low orbits - with sufficient numbers, even your low-range laser scenario (50,000km) would be more than sufficient to destroy anything outgoing.

Capturing outcoming craft - that is something else...

TOM said...

I wouldnt stay low orbit until i want to start an invasion.
PDF lasers would eat my craft, and it is likely that they will have lasers for launch assist for example.

jollyreaper said...

Agreed with earlier poster, immigration agents should serve the purpose.

Funny enough, I was just sketching out a similar conflict, wanted to try out my hypersail idea in a real story. (Yes, Tony, I know the idea sucks and I suck for even thinking of it. Moving on.)

Ideological conflict: Human Identity Movement vs. Transhumans.

You don't discuss politics or religion in polite company and with a theocrat they're one and the same. The Human Identity movement rejects many forms of genetic engineering, body and mind modification, and establishes standards for what is and isn't human.

Of course, those who set the rules don't always live by them. Our main character is a captain who specializes in the discrete trade, that is providing transportation services that circumvent normal channels. "You're a smuggler." "No, I am a man of commerce."

He's beached with a broken ship and a flat bank account. He's approached by a high mucky-muck in the local government who needs to requisition his services. HI on this planet makes use of doodads that genetically test people to make sure they pass for human. You wear your doodad and it glows green, you're good. The other guy wears his doodad glowing green, good. But the handshake in this culture is to exchange doodads and see if they're still glowing green. You get red, this person has had work done.

His daughter has been compromised by a rival house with a retro-rival agent that causes her to fail her test. Her personal doodad has been modified into a falsie but she will fail anyone else's test. What's more, the compromise was from an illicit romantic dalliance that would be a scandal in and of itself.

So, she has to be taken offworld where a transhuman lab can reset everything back to normal. The fundamental hypocrisy, of course, being that they're going to fake her sign of genuine purity once more.

So, this is a wealthy system with a serious naval presence. Getting out will be tricky, especially since the rival house informs the navy about a blockade runner trying to get out.

So the story will be our captain, his partner, the girl and her chaperone/bodyguard aboard the good ship Hushful Slip, making a run out to interstellar space through a serious blockade.

Should make for a good yarn.

Brett said...

@Bryan
Capturing outcoming craft - that is something else...

That's been the main difficulty of the scenario since the beginning. It's not hard for the blockade fleet to shoot ships down, but they're not trying to stop all traffic from the planet - just grab certain people trying to leave it.

I think a bigger problem is likely the blockade fleet's survivability. Earthside military could send up weapons on chemically-fueled heavy lifter, and then use the area covered by the Laser Shore Guns to assemble and group for an assault. Or just launch up spacecraft that do nothing but launch missile buses at the Martian ships.

Rick said...

Frequent commenter Milo is having Blogger troubles, so he asked me to post this for him:

(I'll make my own comments after the Giants game.)

++++++++++

=Milo=


I have to say the scenario seems somewhat contrived - most blockades are about preventing trade or about bottling up military equipment, not about preventing a handful of poorly armed people from leaving. Unless Mars is using Earth as a prison planet, which I'm pretty sure they're not, because that would be silly.

However, as requested, I will play along and assume there is some explanation for this.

The first problem is that since you're trying to prevent the transport of people, rather than certain ships or bulk goods, and not even all people, it would be easy for one of the persons of interest to sneak out onboard one of the permitted ships. To prevent this, every outbound ship that isn't guaranteed to be totally robotic (no habitable module) will need to be stopped and searched. Even then, passenger transport with many people onboard would provide ample room for someone to blend in in disguise.

The large number of boardings that need to be performed during a single deployment mean it's highly impractical for the Martians to chase down ships for inspection. They will have to rely on ordering launching ships to match orbits with an inspection craft using their (the outbound ships') own delta-vee, under threat of being fired upon. There's another reason for this too - the difficulty of matching orbits in space and the damage that a collision at even "slow" space speeds can cause mean it's very dangerous to try to grapple with a ship that hasn't been intimidated into submission. Throwing some grappling hooks won't cut it here.

So the issue is to make sure the threat of being fired upon remains credible. A simple kinetic missile will likely suffice to shoot down civilian craft from a distance, without wasting delta-vee to chase them down. Armed craft, however, may have point defenses against such things, forcing you to get closer to engage them effectively - or if they can be engaged from a distance (perhaps due to superlasers of stupendous range), then you have a hammers-and-eggshells conflict, where the blockading ships are quite vulnerable against a sneak attack.

Since there will be so many boarding actions to ensure that targetted persons aren't being smuggled out, it would be important to have a good complement of close combat troops on your inspection ships.



Michael W:

"Rather than a blockade, wouldn't it be simpler to establish "border agents" at possible destinations?"

If those destinations are friendly to Mars, yes. If they are friendly to Earth, however, then it would be easier to blockade just Earth than to blockade every possible destination they might try to go to.

That said it is not clear why the Martians don't want these people to leave. If all they're concerned about is that the people can't come to Mars, then there are indeed much easier and safer ways to accomplish that.



Brett:

"The Martians would be wise to declare a No-Fly Without Declaration of Cargo and Search Zone,"

Problem is, even if people declare their cargo, they can be lying.

Tony said...

The image, as so often, comes via Atomic Rockets. Note that the engagement shown is much closer to the planet than the intercept zone discussed in the post.

Turns out the story being illustrated is about human-alien interstellar warfare. The action being illustrated is between an alien planetary defense fighter (the orange ship) and a human space-based fighter from an invasion fleet.

Interstingly enough, even forty years ago the author was astute enough to recognize that fighters were only really effective in orbital combat. The planetary defense fighters are boosted to operational altitude by chemical throw-aways, maneuver on space reaction drives to attack their targets, then return to the planet ballistically. The author makes an analogy to Me 163 Komets attacking B-17s in 1945. The space-based fighters are carried as parasites on battleships, and launched to intercept the planetary defense fighters before they can attack human fleet assets in on planetary approach or in high orbit. One gets the impression that the alien fighters are only a nuisance in the grand scheme of things, but enough of one to justify a symmetric counter.

Also, note the orange color of the alien fighter. In the story, it is stated that the alien fighters are usually painted black, to limit visual detection. (The thermodynamic problem with this was obviously not fully realised by the auther, but in a story with FTL and torch drives, what the heck.) The guy with the orange ship is an alien ace-of-aces, and his interaction in combat with the human protagonist fighter pilot (also an ace-fo-aces: "Common Denominator", get it?) makes the meat of the story.

Countercheck said...

I guess, one question I have is if the Earth transports are atmosphere capable or not. If not, then the passengers the Martians are trying to interdict will need to go into orbit some other way, possibly using an elevator, or some other sort of transfer station. If there are transfer stations, the Martians can simply land marines on them and conduct searches. If they need to chase down every launch from earth... then it gets really tricky, especially if Earth helps the targets by launching decoys.

Countercheck said...

I know the OP suggested that Mars isn't trying to challenge low Earth orbit, but if they can sneak infiltrators into those transfer stations, it might help them pinpoint targets. It's even possible an entire inspection crew could be infiltrated.

Cambias said...

Short analysis: the Martians will run out of propellant before Earth runs out of blockade runners.

More detailed: much depends on whether this is World War I or the Civil War. In other words, are the Martians trying to interdict all outbound traffic, or must they board and search every vehicle?

Because the first can simply be accomplished by hanging out in very high orbit and lasering the bejeezus out of anything on an escape trajectory. The Martians can keep that up until Earth gets sick of it (at which point Earth can either agree to Mars's demands or start launching warcraft to break the blockade).

But if the blockaders must rendezvous with outgoing traffic they're going to run out of gas very quickly -- especially if Earth is at all sensible and starts launching all kinds of crap which must be inspected.

Earth could also build and launch some bigass high-gee chemfuel vehicles whose sole purpose is to ram any incoming Martian fuel tankers.

The political status of the Moon is also important: if Earth can use the Moon as a base, they can build bigass buried lasers and clear a gap in the blockade. Conversely, if the Moon is neutral the Martians can buy fuel there and extend the blockade indefinitely.

setrain said...

About running out of fuel because of boarding every ship: Can't they commandeer a bit of fuel from every ship they board. It makes it more expensive and slower to leave Earth for everybody but not impossible.

Tony said...

Cambias:

"Short analysis: the Martians will run out of propellant before Earth runs out of blockade runners."

I'd have to agree with that, if they adopt a match orbits and board methodology. I think the only was to fruitfully mount a blockade would be to blast everything that tries to leave the Earth orbitals. But the political consequences of that are most likely unacceptable. Quite frankly, if you want to do board and search, the intercept at destination methodology is actually the one to choose, even if you have to establish and man 50 local blockades.

That's actually the blockade strategy used by the Union in the American Civil War. They didn't blockade Bermuda and Cuba -- it would have been logistically prohibitive and illegal anyway. They blcokaded COnfederate ports like Savannah, Charleston, and Wilmington.

Tony said...

setrain:

"About running out of fuel because of boarding every ship: Can't they commandeer a bit of fuel from every ship they board[?]"

And they're going to do that how? Refuelling at sea is a major cooperative effort, even today, using highly specialized refuelling vessels. I doubt space is going to be any different.

Thucydides said...

The point about enacting a search of outbound vehicles as an act of war is very valid (on the Bicentennial of the War of 1812 we should remember that British ships boarding American merchantmen to search for British deserters [and occasionally press ganging other crew members] was one of the causes of the war).

From a technical POV, the boarding parties would be carried in some sort of cutter with a high thrust, low ISP engine (chemical or NTR) so it can run down blockade runners, regardless of the propulsion system of the departing ships. Since there might be armed objection to this, the cutters would resemble Swift boats or some other form of armed cutter. Somewhere in high orbit are one or more tenders with interplanetary electric/lightsail/magsail type drives which brought the Swiftboats in the first place and provide the logistical support to keep this going.

OF course, the best way to render the blockade ineffective is for the persons of interest to simply stay on Earth and thumb their noses at the Martians; at some point the Martians will have crossed a cost/benefit boundary and will have to give up and go home. Looking at today's world, capturing someone in the PMF may not be enough to stop the terrorist attacks, insider trading or dance flash mobs the Martians fear; if enough people have been exposed to the memes of the movement/organization these persons of interest represent, then they are likely to spontaneously carry out the intended action regardless of the success or failure of the blockade. In some cases, the very act of the blockade and search for these people might trigger the events on Mars that the blockade was supposed to stop.

To turn the background ito a plausible PMF tale, the "blockade" isn't from an external power but is the MO of the Earth Customs and Immigration service, and is the last filter if screening from launch sites and transfer points has failed to turn up the persons of interest. Since outgoing (or incoming) spacecraft, are potentially lethal weapons with their high velocities, the Earth Space Guard cutters are designed as high thrust, low ISP "Swift boats" to intercept and capture spacecraft which are deviating from approved orbital paths, and have the thrust to actively push ships out of intersecting orbits as a last ditch defense if everything else fails. This design feature also allows the Swift boats to match orbits and deposit Customs agents on ships of interest.

Rick said...

Welcome to some new commenters!

And a bit of an apology to everyone for going *soooo* long between posts.


This discussion underlines the challenge of discussing space warfare in - excuse the pun - a vacuum. Your operations are very much bound up with your broader objectives.

A problem, especially with new technologies of warfare, that is hardly exclusive to space. IIRC, Imperial Germany did not set out to wage 'unrestricted' U-boat warfare, and certainly did not start out expecting to draw the US into the war.

preventing a handful of poorly armed people

Who said 'handful' or 'poorly armed'? That evasive phrase, 'certain persons', could easily mean espatiers or paramilitary colonial police.

That said, and while I was trying to keep options somewhat open, what I had most in mind approximates Ferrell's blockading their former commercial masters. If you are blocking access by officials or management of whatever specific sort, you're shifting a balance of power at their intended destination.

And whoever exactly 'certain persons' are, Mars in this scenario is implicitly asserting a right to regulate outbound (human) traffic from Earth, but is not seeking to eliminate it by simply blowing everything up.

Politically the blockade might be directed against a country or faction, or even against a global government, but where there is some kind of public opinion on Earth that the Martians don't want to antagonize by sheer indiscriminate destruction.

Historically, warfare has usually been 'limited' by factors of this sort. as well as the limitations of available weapons.


I will let things bubble along a bit more before addressing the operational and tactical issues.

But I'll note that the implications of disabling a ship can be very different depending on whather it is below or above Earth (or whatever planet's) escape velocity when the drive is wrecked.

If the disabled ship is above escape velocity, subsequent rescue of crew and passengers is probably a *lot* more difficult.

Brett said...

@Milo
Problem is, even if people declare their cargo, they can be lying.

Hence the "search" part. You're basically telling the Terrans that you're not trying to cut off their access to space - you're just trying to prevent several individuals from leaving the planet without being detained. The Earth folk sound less than helpful in the scenario, but they might be more willing to co-operate once they're in orbit if they know you're not planning to outright shoot down all their ships.

@Tony
And they're going to do that how? Refuelling at sea is a major cooperative effort, even today, using highly specialized refuelling vessels. I doubt space is going to be any different.

Unless the Earth folk are sending any and all propellant up from the planet's surface, I suspect that they'd have propellant depots in orbit around the Earth and Moon making fuel out of the volatiles on captured near-Earth asteroids (sort of like what Google's side-company is ultimately planning to do). It's not a stretch for the Martians to bring along a mobile facility for making fuel on site, or even to commandeer the Terran depots and fuel-making facilities.

Countercheck said...

Thanks for the welcome!

It might be possible to use kinetics to force non-compliant transports to use up enough dV dodging before they get out orbit that they can't make their target and have to abort.

Ray said...

Time could be the critical factor. Manhunts sometimes drag on for 5 or 10 years. How long can and will the Martians keep up such a costly operation? If the targets really do need to get off-planet quickly (why?), then time is against them instead. If exodus and intercepts take several days, time could certainly be a factor there too; time to prepare, psychological and fatigue effects.

Sounds like neither side really wants a slugging match. Deception could be the best bet for a clean getaway, and if that didn't work, then, depending upon their capabilities and those of the boarding parties, they might be able to take the boarding party hostage. Would the Martians fire on a ship containing their own personnel? Or could they conduct a follow-on boarding to do a hostage rescue safely?

Will have to find out what the differences and driving forces of the sides are. Civilians vs. military, or mercenaries vs police? Strict ROEs? Limited budgets? Equivalent equipment or markedly different capabilities?

TOM said...

Well i wondered, what can be the possibilities of smugglers, criminals in space?

IMHO they can rely on two things : human weakness, and compu security weakness.

They might be able smuggle drugs to hundreds of starports, they know the people that can be bribed.

Or they may hack up some satellites, so they can parachute their crates containing illegal stuff to some no man's land.

If a colony bacames a pirates home, than, to a planetary force, it might be easier to blockade that colony and hope, it will be enough to end the criminal activity.

A planet is more than able to blast away a blockade if it really wants to...

Tony : yes i agree about fighter speciality, well if lot of boarding action would be needed, that is also another good opportunity for them.

Locki said...

Tony said;

That's actually the blockade strategy used by the Union in the American Civil War. They didn't blockade Bermuda and Cuba -- it would have been logistically prohibitive and illegal anyway. They blcokaded COnfederate ports like Savannah, Charleston, and Wilmington.

Its also the "quarantine" strategy used by the USA against the Soviet's in the Cuban Missile Crisis.

If the US had dispatched all 15 carrier battle groups to blockade all of the USSR's ports there would have been a 100% chance of WW3.

Sensibly they just blockaded - errr I mean quarantined - Cuba and the chances of nuclear doom subsequently dropped to a mere 30% (as estimated by Secretary of Defence Robert McNamara).

If you cause each and every ship leaving earth orbit to slow down, waste deltaV and wait to be boarded and methodically searched from top to bottom you could doing billions of dollars of damage to the economy.

Imagine forcing each and every ship leaving the UK to slow down and be methodically boarded before they depart for Europe/Asia/Americas. It'd kill the economy of the UK in weeks and be essentially a declaration of war.

In any sensible setting forcing every departing ship to wait and be boarded equals a declaration of war.

However in the spirit of the game I'll ignore the politics of it now and just play with my solar electric drive tenders and NTR corvettes and try to come up with some sensible way of boarding every ship leaving a planet with 6 billion people onboard. Whilst being supplied by a logistics train stretching back across teh solar system.

Are we allowed to use inertialess drives? :)

TOM said...

Well, about Tony's previous post, sorry for being little OFF, but can normal visibility play a role in space?

There are IR sensors, but they can be jammed most easily, you can use any wavelength to do it, as they generate heat signs on the sensors.
Or am i very wrong?

Countercheck said...

Locki said;

If you cause each and every ship leaving earth orbit to slow down, waste deltaV and wait to be boarded and methodically searched from top to bottom you could doing billions of dollars of damage to the economy.

Imagine forcing each and every ship leaving the UK to slow down and be methodically boarded before they depart for Europe/Asia/Americas. It'd kill the economy of the UK in weeks and be essentially a declaration of war.

In any sensible setting forcing every departing ship to wait and be boarded equals a declaration of war.


The situations are not entirely analogous. I have trouble imagining a situation where a large scale planetary economy could be crippled by a blockade, without the existence of some sort of unobtanium necessary for prosperity that's only obtainable elsewhere in the solar system.

The more I think about it, the more I think the correct play is for the Martians to set up a customs station in high orbit and force Earther transports to rendezvous with them rather than expending the dV chasing them down. Use kinetics to force non-compliant ships back down out of orbit. And then keep them there for the week long inspection process... it's going to be hard to find a shielded cocoon jammed in a corner of the engine room.

TOM said...

My frame is the pirate colony, a small colony's economy will require trading, otherwise, economic depression will bring back the drug lords rule.

If the average ship is not so resistant, it can be more friendly to board it, then forcing it to dock on your station.

TOM said...
This comment has been removed by the author.
jollyreaper said...

Manhunts sometimes drag on for 5 or 10 years. How long can and will the Martians keep up such a costly operation?
--

I hear tell some Martians specialize in manhunting.

TOM said...

Sorry i mistyped it :

If the average ship is not so resistant, it can be more friendly to board it than forcing it to dock on your station.
And only do the latest one if you find anything suspicious.

Tony said...

1. WRT propellant confiscation, I was answering a suggestion that it could be taken directly from a detained interplanetary ship. I find that highly unlikely. As for capturing fuel depots, that seems to be one of those hard lines that one might not want to cross.

2. The whole problem with this blockade is that it is not "distant" on an interplanetary scale. It's a close (though not the closest) blockade, as if the US tried tocut off Continental trade by blockading Gibraltar, the English Channel, and the Norway-Shetlands-Orkneys gap with no local base or support. It would be logistically so expensive as to be totally impractical.

Blockading the Earth from high orbit, with your supplies coming interplanetary distances, while the Earth's supplies come from, well, Earth, is the same kind of deal. It's a neat conceptual construct, but it's just not practical in the real world.

Countercheck said...
This comment has been removed by the author.
Countercheck said...

@ TOM: It may be more friendly, but it costs YOU fuel, and your logistical tail will be a NIGHTMARE. Making them dock with you costs them fuel, and if you have to make good on the threat to box them in with kinetics, you're out a few ballbearings.

The whole blockade thing would become a lot easier if the Martians were acting with the support of an earth based group. If Earth's governments aren't unified, then it shouldn't be too difficult to find an ally on the ground, who could possibly sell you fuel, or perform inspections for you on the ground. If you can certify some launch sites as target free, then the pressure on Earth to break the blockade becomes greatly lessened... rather than fighting, critical shipping can move through mars friendly launch sites.

If, for example, the current NATO powers are the those hostile to Mars' demands, Russia and China would jump at the chance to 'certify' cargos past Martian inspection. They become a transportation hub, all those who are inconvenienced by the blockade but have no political stake can move their cargos, and the amount of shipping the Martians need to intercept is greatly reduced.

Previous comment deleted because I used you're instead of your.

Tony said...

Rick:

"(I'll make my own comments after the Giants game.)"

Los Gigantes, huh? Too bad about your boy Lincecum flaming out this year.

Anonymous said...

jollyreaper said:"I hear tell some Martians specialize in manhunting."

Funny.

From what I can tell from the main post, the Martians already have some idea of who they are looking for, so they have already narrowed the field; they only have to interdict ships owned/operated by one or few entities, plus a few suspicious runners. They don't have to board and inspect every ship leaving Earth orbit, just the ones on their list; also, it would just be the small chem fueled missile toting drones and customs boats that normally would expend significant amounts of fuel. I expect that the command ships would be accompanied by several tanker/support ships and that they would 'rotate' out on a regular schedule, shuttling back and forth between Earth and Mars orbit. This seems hidiously expensive, but better than a war with Earth, and the best way to acheive their goals. Which, by the way, sound more political than military.

Ferrell

Cambias said...

Note that outbound ships can't easily "heave to and prepare to be boarded." They're almost certainly NOT carrying much extra propellant, so "stopping them" and then releasing them is effectively the same as preventing them from leaving Earth in the first place. (The main difference is that some of the catch-and-release vehicles will have to take long complicated orbits to get home and may lose people to life-support failure along the way.)
I'm coming to like the idea of the Martians putting one ship in low orbit, announcing that EVERYTHING leaving Earth has to rendezvous with it for inspection, and failure to comply will be taken as proof of hostile intent. Saves the Martians their precious gas, and lets peaceable Earthlings go elsewhere in the Solar System with only minor inconvenience (relatively).
Of course, what it quickly turns into is a game of chicken: how many outbound ships will the Martians really blast to bits (only to have weeping mothers on the evening news telling the world the ships were loaded with kittens and rainbows)? How many ships will Earth be willing to lose?

Damien Sullivan said...

Interesting!

Perhaps more plausible scenarios:
Earth trying to blockade a rebellious colony.

Earth or another colony trying to block shipments between two other worlds, as with the Cuban missile crisis.

More willingness to shoot stuff down, perhaps, but still severe logistical constraints.

Delta-vee... can't electric drives plausibly get into the 1000 km/s range? Seems like that lets you make a lot of 10 km/s changes. Though whether that's "a lot" compared to traffic, well.

Locki said...

Countercheck said...


The situations are not entirely analogous. I have trouble imagining a situation where a large scale planetary economy could be crippled by a blockade, without the existence of some sort of unobtanium necessary for prosperity that's only obtainable elsewhere in the solar system.

======

This could turn into a terrible chicken and egg type argument.

But I kinda figured if the conditions were such that millions of humans left earth to establish a huge economy and sovereign nation state on Mars then some sort of McGuffinite made it economically feasible in the first place.

Mars didn't get strong enough to build giant inter-planetry nuclear reactors the size of Fukishima on space tourism alone.

Basically I just figured there had to be a vibrant interplanetry economy for whatever handwavium reason if we have solar battle fleets blockading each other in the first place.

So my analogy of blockading the UK is probably fair though not necessarily accurate.

I'm happy to be proved wrong though.

Countercheck said...

That's totally one interpretation, but I don't think it's required.

There could be McGuffinite, but it's not necessary that it be on other planets. Also, note, if it were, it would be being shipped back to Earth. The Martians have no interest in stopping return traffic, just outbound. Earth's massive population and industrial/agricultural capacity would will insulate it, for a time, from any economic shocks due to a skewed trade balance. If anything, I'd be more concerned about the economies of Earth's trading partners rather than Earth. It's a bit like if the Germans in WWII had used unrestricted submarine warfare to try to make America surrender rather than Britain.

What is the vibrant interplanetary economy going to look like? Transportation costs are still going to be ridiculously high, probably in the $1000s/kg range. Which means only wildly valuable cargoes will be transported... that would be people, unobtanium, goods incapable of being produced at the destination, and, depending on the state of encryption, possibly data. Information is high value and low mass, and if it is likely encryption could be broken in a reasonable time frame, transporting sensitive data physically might become useful again. Mail packets.

It's actually quite likely that, apart from people who actually need to be at the destination, most of these launches the Martians must intercept will be drones, thus reducing the probability of deaths due to botched interceptions. Probably the inspections could be carried out remotely too.

Rick said...

Maintaining the blockade is no doubt frightfully expensive.

But the Martians (presumably) believe that they can sustain it long enough that their Earth-based opponents will face even greater costs - either the political cost of letting Mars interdict their outbound traffic, or the political/military cost of forcing the blockade.

Setting up a 'customs station' in high Earth orbit could be viable, given the characteristics of electric drive. Remember that departing ships spiral out over a week or more. The propellant cost of circularizing for inspection is modest, probably less than 1 km/s.

If the Martians have spacefaring allies on Earth the exercise becomes a lot easier in logistics terms. It then becomes a delicate power-political dance: Is the interdictee ready to use force to prevent those allies from resupplying the Martians?

The interdictee may prefer to simply take on the Martians, and only have to deal with one enemy. It depends not just on the politics but on their force structure: How well equipped are they to fight in high orbit, beyond reach of surface-based weapons?

Thucydides' suggestion of blockade runners using strap-on boosters (or drop tanks and powerful OMS engines) is a nifty one, but regular interplanetary transports are ill-suited to this dodge. And the Martians may - probably do - believe that they can simply fire on departing military craft without antagonizing neutrals.

In any case, it seems to me that the interdictee has two basic options: Sit tight in hope that it can outlast the Martians, or take them on. If the first is not acceptable, then there will be a space battle in Earth's outer orbital space.


On a more terrestrial matter:

Too bad about your boy Lincecum flaming out this year.

Our boy Lincecum seems to be coming out of his slump. In any case, even with his awful first half of the season, the Giants are a couple of games up on LA.

(I have no Dodgers hate; over years of living on the outer fringe of SoCal I kinda sorta rooted for them over the years. [Good riddance to McCourt!] But rivalries are rivalries, and this one goes back most of a century.)

Anonymous said...

Well, depending if the Martians are going up against a small nation, a corporation, or just a group of induviduals, could determine the exact course of action that they take. The amount of care you need to take to not start a war could vary quite a bit. If they are just looking for a few private induviduals, a low orbit inspection station with some high orbit interceptors should surfice; government officials would require a massive high orbit blockade searching most departing ships with a much greater chance of a more serious conflict starting; searching specific ships for specific persons should fall somewhere in the middle. The amount of ratching-up-of conflict depends on if the Martians actually fire on any ships and who those ships belong to.

Ferrell

Tony said...

Rick:

"Our boy Lincecum seems to be coming out of his slump. In any case, even with his awful first half of the season, the Giants are a couple of games up on LA."

It wasn't actually intended as a dig. I'm a Rockies fan these days and, believe me, I know how much it sucks to have your key pitchers fall off the pace.

"(I have no Dodgers hate; over years of living on the outer fringe of SoCal I kinda sorta rooted for them over the years. [Good riddance to McCourt!] But rivalries are rivalries, and this one goes back most of a century.)"

You know, I grew up a Dodgers fan. But at the time (late Seventies through early Eighties) the big obstacles were the Reds and the Astros. The Giants were just that goofy team up in Frisco with the awful ballpark.

Anonymous said...

Rick:

Setting up a 'customs station' in high Earth orbit could be viable, given the characteristics of electric drive. Remember that departing ships spiral out over a week or more. The propellant cost of circularizing for inspection is modest, probably less than 1 km/s.

That would be the way to do it. Save your delta V and let the slow boats spiral up to you.

However, depending on who you are trying to stop, they may have a response. One of those slow transports might be loaded with commandoes/terrorists or short range missiles or just a big bomb. What does the blockade force do when they lose their customs station?

Ron

TOM said...

Well, there is always a chance, that somebody tries to play dirty...

Logistics and politics can enable different types of actions, for example destroying a would be blockade runner is more easy, board it with an assault boat carring remote controlled probes, and capture it if you dont find big piles of explosives, show the world, the ship hasnt carried top priotity aid for that poor african colony, then give back the confiscated ship for fuel has more political value.

longbeast said...

However, depending on who you are trying to stop, they may have a response. One of those slow transports might be loaded with commandoes/terrorists or short range missiles or just a big bomb. What does the blockade force do when they lose their customs station?


Being cautious and approaching your search targets from a distance doesn't have to cost the blockade fleet a lot of resources. Once you're in a high orbit, you can make quite huge altitude changes on small delta-V budgets, so you could have all the essential stuff in your fleet, like command ships and fuel barges, in a very high orbit, with little teams of smaller ships being sent down to the stop and search intercept orbit.

(This assumes that the earth ships aren't going to have any destinations outside the plane of the solar system. Some lunatic setting up hab stations in a solar orbit at 90 degrees to everybody else would complicate matters immensely.)


In that case, your "customs station" can be a swarm of robot ships/missiles that do a very cursory first inspection, followed by manned interceptors that match orbit shortly afterwards. Determined blockade forces could afford to lose loads of robots, and a few search teams to any crude improvised traps.

On the other hand, more sophisticated traps set up by a large and powerful military could be really scary to the blockade force. There's not much practical limit to what nasty things you can hide in a cargo ship.

Cambias said...

Why do we assume ANY of these spacecraft will be manned?

Countercheck said...

Why do we assume ANY of these spacecraft will be manned?

We know some of the Earth transports will be manned, because the scenario requires us to prevent people from leaving Earth.

I'd guess the Martian task force will have a human crew, if only because the minimum communication delay between Earth and Mars is about 4 minutes. While a sufficiently good AI could be making the split second shoot-don't shoot decisions without any human input (in fact, it's quite likely that will be the case - I've already heard about attempts to build computers that can perform decent ethical analysis, since human reaction times aren't sufficient to detonate a Hellfire in mid-flight when a child walks around a corner), having the computer make the decisions based on 10 minute old parameters may not be the most politically acute decision.

TOM said...

My first law of robotics would be : robot cant decide over human life except when it tries to save someone.

I dont trust the entire situation to AIs...


Otherwise i find it quite illogical, why would they try to keep someone from leaving Earth... Earth has the best hiding places.
If they want to keep someone from going somewhere, they should keep a blockade, to prevent someone from entering Earth.

Brett said...

You might want some human security teams to board the manned craft, if only to ease the comfort of the passengers of the ships being boarded. Other than that, the whole Martian fleet could be unmanned if the A.I.s are good enough.

TOM said...

" I've already heard about attempts to build computers that can perform decent ethical analysis, since human reaction times aren't sufficient to detonate a Hellfire in mid-flight when a child walks around a corner"

That will require pretty good compus... today they even have trouble with reading a text on a fuzzy background.
Human reaction time can be further shortened with wired reflexes.
/electric wires instead of slow nerves with chemical reactions/

Tony said...

Countercheck:

"human reaction times aren't sufficient to detonate a Hellfire in mid-flight when a child walks around a corner"

Since when? Laser guided bombs are sometimes directed into empty areas next to targets when non-combatants wander into the target area. A Hellfire, once it's motor burns out, is in effect just another type of laser guided bomb. I'm sure they've been guided off of targets from time to time when the tactical situation has changed after launch.

Skírnir said...

Hello again, interesting post. =)
Now I didn't read all of the 50+ comments, but a few things came to my mind:

Firstly, delta-V of chemfuel craft. These things don't need to be "mostly drop tanks" to exceed 2-3km/s delta-V. For a hydrogen/oxygen engine, you already get 5km/s for R=3, i.e. 2 tons of propellant per 1 ton of dry mass. Hydrogen tanks are bulky, but at these mass ratios they are manageable.
Of course, beyond that, you get diminishing returns. 6km/s for R=4 and so forth, and then the tanks start getting rather cumbersome.

As for the electric drive craft (or e-ships): you mentioned an accel value of 1km/day, that comes out at about 1 milli-G indeed. So the mass ratio can be very small, just on the order of 1.5, and that will be good for about 60-80km/s delta-v. So there's plenty of margin for operational maneuvers, and it's very easy to carry a sizable propellant reserve.

I also take it that LEO (up to what, maybe 400km?) is safe zone for Earth ships for some reason.
If all that is the case, as an outbound blockade runner I'd just couple my interplanetary e-ship with a chemfuel booster craft. You assemble the stuff in LEO, then ignite the booster and gather ~3-5km/s within five minutes. Then the e-ship separates and heads towards its destination, while the booster proceeds on a lunar capture trajectory.

The Martians can try to counter this by using their own chemfuel rockets to intercept the blockade runners. But unless they get a constant fuel resupply from their home base or wherever, they will eventually run out and Earth craft will not (as long as there are big orbitals reservoirs or hauling it up from the surface is cheap enough).
This is assuming that the Earth craft can fool the Martians into wasting their chemicals on decoys, or can reliably abort an attempt after the Martians have already committed to intercept.
Lots of variables here.

Countercheck said...

Tony:

I'm sure it does happen! I just remember reading somewhere about the difficulty of performing rapid ethical calculus, and that there were plans to TRY to augment it digitally. I mean, a Hellfire has a maximum flight time of about 16 seconds. If you're teleoperating a Reaper from the other side of the world, bouncing the signal off of a satellite, you might have a couple of seconds of com lag, and an onboard system might be more effective, if it could make the calculations.

This is entirely speculative, since I can't seem to find a source for this. I have no idea where I ran across the idea of trying to automatize shoot-don't-shoot decisions. But if the blockading fleet were to be entirely AI driven, then it would need to be able to make the call, unless it could be controlled by a ground station. There's an interesting thought - maybe a team could infiltrate Earth and set up a command centre on the surface, from which to direct orbital assets. You could have ELINT teams hunting the C&C team on the ground even as attempts are made to break the blockade. Now, that would make more sense if the com-lag were greater than the 10-20 minutes between Earth and Mars, but it could make for interesting fiction.

Tony said...

Countercheck:

"I'm sure it does happen! I just remember reading somewhere about the difficulty of performing rapid ethical calculus, and that there were plans to TRY to augment it digitally. I mean, a Hellfire has a maximum flight time of about 16 seconds. If you're teleoperating a Reaper from the other side of the world, bouncing the signal off of a satellite, you might have a couple of seconds of com lag, and an onboard system might be more effective, if it could make the calculations."

Even with humans, the decision to complete the engagement or dump the ordnance in a nearby field is based on some pretty stiff rules of engagement, of the better-safe-than-sorry nature. With that, one can make a decision fairly quickly -- if somebody that doesn't look like a target wanders into the kill zone, abort the engagement, then figure out how to reengage, or if you even can.

The trick is discriminating a non-combatant in a half second or less. What does one look like? What does a combatant look like, for that matter. That's the hard part -- target discrimination. Even well-trained humans screw it up from time to time. Above the level of simple calculation, if humans can't do it reliably, you can't expect computers to be able to, because the humans define the rules the computers are going to follow.

"This is entirely speculative, since I can't seem to find a source for this. I have no idea where I ran across the idea of trying to automatize shoot-don't-shoot decisions. But if the blockading fleet were to be entirely AI driven, then it would need to be able to make the call, unless it could be controlled by a ground station. There's an interesting thought - maybe a team could infiltrate Earth and set up a command centre on the surface, from which to direct orbital assets. You could have ELINT teams hunting the C&C team on the ground even as attempts are made to break the blockade. Now, that would make more sense if the com-lag were greater than the 10-20 minutes between Earth and Mars, but it could make for interesting fiction."

I think I'd try to stick with on-site, near-real-time control in a command ship.

Thucydides said...

For the blockade (whoever is manning that), the best choice of ships drive might be something along the lines of VASMIR, or more speculatively, a dusty plasma fission fragment rocket.

You get the high ISP needed to move around without using all your remass, and a "low gear" (changing the parameters of the VASMIR drive, adding some sort of remass to the exhaust stream of the fission fragment rocket) when you need to make a sudden move, either to intercept, or to attempt to dodge incoming fire (assuming the target ship isn't housing advanced military weapons on board, and a dodge is possible).

"Ethical calculus" is a bit of a slippery slope, what is seen as "ethical" might not be shared between the Martians and the Earth, and ethics has a tendency to evolve over time (or become field expedient, depending on the circumstances). Caedite eos! Novit enim Dominus qui sunt eius" was once considered to be the proper way to do things, after all...

Anonymous said...

Skirnir said:"The Martians can try to counter this by using their own chemfuel rockets to intercept the blockade runners. But unless they get a constant fuel resupply from their home base or wherever, they will eventually run out and Earth craft will not (as long as there are big orbitals reservoirs or hauling it up from the surface is cheap enough).
This is assuming that the Earth craft can fool the Martians into wasting their chemicals on decoys, or can reliably abort an attempt after the Martians have already committed to intercept.
Lots of variables here."

Yeah, that might work...the first time, or the Martians might not bother to intercept the departing ship with a chem-fueled customs boat and just put a missile into it, instead.

Ferrell

TOM said...

Well, missiles are also expandables, you can run out of them, it is a big question, what kind of supplies can you get?
Blockading an entire planet without allies, regular resupply is quite challenging...

Cambias said...

Note that the presence of factions on Earth which are either neutral or friendly to Mars also changes the situation dramatically. Blockade runners can register as neutrals, which makes the whole situation a diplomatic nightmare for the Martians. However, the Martians can buy fuel on the open market in Earth orbit, allowing them to be as profligate as they wish with propellant.

Countercheck said...

Tony:

I agree that the hard part is target discrimination. I disagree that humans will always be better at it than computers. While the human does indeed need to define the target parameters, she can take her time doing that in her fortified command bunker, and the computer will likely in future be able to carry out the commands more quickly and reliably. Just look at what Google is doing with the Google car. They've developed a good target discrimination system that can even predict the vectors of pedestrians, arguably more reliably than humans can. Now, I recognize there's a world of difference between a busy street and a combat zone, and the car's not discriminating between pedestrians and pedestrians with RPG-7s, but it's not out of the question that such technology could be developed in the next 10 years, let alone by the time we're deploying interplanetary battle-fleets.

As for the ground control team, I admit it's a bit goofy, but I bet a situation could be manufactured that would make it more reasonable, and it would be good story-grist.

Thucydides:
Ethical calculus might be the wrong term. RoE?

TOM said...

" They've developed a good target discrimination system that can even predict the vectors of pedestrians, arguably more reliably than humans can."

More reliably than drunken drivers that is sure, however is it proved, that this system is also so good, when it meets unexpected situations, like somebody runs across the street, where is no pedestrian crossing?
Harsh weather conditions like fog?
Theese are the real issues, not when everything going as it was planned.

Thucydides said...

Technically we are talking about the Rules of Engagement (RoEs), but they are derived from various factors including commander's intent, force protection, the situation on the ground and so on.

A form of ethical calculus is taking place here, you have to balance competing desires like perfect force protection (which would lead to pretty loose RoEs that involve lighting up any thing that is a potential threat) to insanely restrictive RoEs which are designed to minimize civilian casualties by eliminating the risk that anyone will be engaged in error. In the real world, there is a balance between these two extremes (and despite how things might seem to the uniinitiated or through news reports, RoEs are rarely that black and white).

The example Rick has given is full of ambiguity, and it would be hard to define a single set of RoEs that could encompass every possible situation. The Martians have to balance how badly they need to get these people vs the cost of maintaining a blockade vs the possibility they could be embroiled in a diplomatic incident based on the actions of their people to triggering open war.

Frankly, the more I think about this, the better solution would be to engage either the Earth authorities to find and arrest the persons of interest (for extradition to Mars) or, if the authorities are non cooperative, engage the services of private contractors who specialize in this sort of thing (depending on the sort of people you are looking for you might need bail bondsmen and bounty hunters or private security firms or start dealing with organized crime).

YMMV

Tony said...

Countercheck:

"I agree that the hard part is target discrimination. I disagree that humans will always be better at it than computers. While the human does indeed need to define the target parameters, she can take her time doing that in her fortified command bunker, and the computer will likely in future be able to carry out the commands more quickly and reliably."

Problem is, no human can pre-define every permutation. And as long as we rule out strong AI, if a human can't pre-define every permutation, you have to have humans in the real-time loop, or accept the computer making costly mistakes, either by action or inaction.

Humans can of course make the same kind of mistakes, but it's acceptable in humans where it's not in computers, by the logic that the human at least had the potential of reasoning things out in time, whether or not he actually did in practice. Putting computers in the human's place where the computer is not absolutely necessary will always be perceived as an unacceptable abdication of responsibility. That's especially true where war is concerned.

Tony said...

Thucydides:

"Frankly, the more I think about this, the better solution would be to engage either the Earth authorities to find and arrest the persons of interest (for extradition to Mars) or, if the authorities are non cooperative, engage the services of private contractors who specialize in this sort of thing (depending on the sort of people you are looking for you might need bail bondsmen and bounty hunters or private security firms or start dealing with organized crime)."

Remember, Rick has stated that the people in question could include substantial police or military forces. So the blockade is perforce necessary because the objects are bigger and tougher than private action could handle.

TOM said...

Still, the point remains, those persons wont leave Earth in such a situation unless they are forced to...
In all the Solar System, if someone can hide somewhere for decades, it is Earth.

Tony said...

TOM:

"Still, the point remains, those persons wont leave Earth in such a situation unless they are forced to...
In all the Solar System, if someone can hide somewhere for decades, it is Earth."


If a government wants to send a force of persons and equipment to a destination in order to carry out a mission, there's no question of hiding. There may be an amount of subterfuge in just who is going where, but they are leaving, and they are trying to get to a specific place.

Thucydides said...

While these arguments are all true, the fact that the Martians will be attempting to blockade the Earth and board ships "at sea" to enforce their laws is a pretty open invitation to war, as the British discovered in 1812.

There are going to be lots of "work arounds" involved here to minimize the risk of war on one side, and to ensure the mission is completed by the other. I have already mentioned using private agents to arrest the people in question, but if these people are hard targets in any sense of the word, I'd probably escalate to some serious criminal or terrorist organizations to disrupt the "enemy" . People who can afford to bring spacecraft from Mars for extended periods of time probably have the resources to interest the Russian Mafia, Colombian Narcos or the Al Qaeda to do the dirty work, and group of people who have to look over their shoulder all the time will not be as motivated to go to Mars and carry out the mission.

Going the other way, if there is an ideological component to what is being done, then there might be the possibility of "inspiring" actions at the target location by locals who have drunk the kool aide. Religious motivation has worked in the past, as well as adherence to an ideology like Marxism, so we know this works. For that matter, if the Earth's powers were really interested in doing the dirty on Mars, they would have planted sleeper cells there many years earlier.

For the would be story teller, we now have a deeply layered structure, with actions happening on Earth, in space and on Mars, and the outcome depending on many interrelated actions.

Locki said...

Tony said...

Even with humans, the decision to complete the engagement or dump the ordnance in a nearby field is based on some pretty stiff rules of engagement, of the better-safe-than-sorry nature. With that, one can make a decision fairly quickly -- if somebody that doesn't look like a target wanders into the kill zone, abort the engagement, then figure out how to reengage, or if you even can.

The trick is discriminating a non-combatant in a half second or less. What does one look like? What does a combatant look like, for that matter. That's the hard part -- target discrimination. Even well-trained humans screw it up from time to time. Above the level of simple calculation, if humans can't do it reliably, you can't expect computers to be able to, because the humans define the rules the computers are going to follow.


=======

I have to partially disagree here. Computers have proven themselves to be surprisingly adept at recognising objects/situations with imprescise (fuzzy) data where it was previously thought necessary to have an expert human. The main example I am thinking of is medical (pathological/histological) diagnosis. Facial recognition also falls under this category.

From my understanding ROE is decision making tree and quite rigidly protocol driven. Computers could be exceptional at target recognition in compliance with a rigid ROE. They never get bored, they never get distracted, they don't know if their tour is finishing in 2 weeks time, they haven't promised their child they'll be back in time for their 10th birthday and they don't know their colleague got killed in a similar situation 3 months ago. In short they are always objective.

I agree there will always need to be a human somewhere in the loop in order to deal with situations/scenarioes the programmers haven't envisaged. But 99% of the time, for the routine stuff, the computer is probably going to make the more accurate call. And a blockade is going to be a very long, very boring assignment for most of the time.




2. Best place for a blockade for humans.

The best place to search for humans would be at the tranfers point between the earth to space shuttles and the interplanetry spaceship. Since the scenarios seems to suggest earth is being pretty passive I'll ignore things like the nations of Earth blowing you out of orbit this is the critical space to control for any effective blockade to work.

At the point where the shuttle has to dock with the spaceship its manoeuvre options are limited. The two starships have to delicately adjust course in order to dock. The shuttle probably has precious little delta-V to evade.

If I could get away with it i would station my marines/drones right at the airlock between the shuttle and the spaceship.

I'd then cover this approach with a bunch of warships hanging just in laser range.Since lasers have a lethal range of 50,000km, delta-V is limited and the blockade is likely to be lengthy I'd just leave the kinetics at home.

This technique has two advantages:

1. It has the political advantage of inconveniencing the earth nations the least.

2. It is very delta-V efficient for the blockader since there is no pursuit or matching orbit shenanigans

TOM said...

I can agree with the objective and dont get bored, distracted stuff with compus, but personally, i dont see that they would be all so reliable with fuzzy data.
Our problem is text reading on various backgrounds, the programs needs correction and retraining every time they experience a new pattern.
I had the idea, instead of working with pixels, they should work with patterns, lines and curves like humans... they said it was tryed and it was too slow.
Of course i dont work at Pentagon, i guess others have much better stuff, so i can be biased, still i have my doubts that in fuzzy, not definite situations they are way better than humans...

Of course i dont deny that boring routine staff requires machines, battle situations arent fell into this category...

Then there is the issue of specialized vs general, a machine can use all its capacity to a dedicated task, like decide hostile or not hostile, that is their advantage, along with fast nerves that work with electricity instead of chem reactions...
Saving a kid s life by redirecting a bomb isnt an unethical compu job, but it is better not give up human control and decision if something is important.

Rick said...

My 'certain persons' riff was too clever by half. What I really intended from the outset was that Mars is challenging Earth's - or some Earth power's - control over habs elsewhere in the Solar System. They are doing so, in an immediate sense, by blocking movement of administrators who exercise that control or the troops/police that enforce it.

While these arguments are all true, the fact that the Martians will be attempting to blockade the Earth and board ships "at sea" to enforce their laws is a pretty open invitation to war, as the British discovered in 1812.

As they say in old New England, ay-yup. But the Martians may hope the other side will back down, and/or that if war does break out, it is in a more favorable environment, political and operational.

Hence blockade, instead of simply blasting ships. And hence also the location of blockade.

Inspection, etc., would be easiest at shuttle transfer in LEO. But if the blockade turns into a battle, the Martians don't want to fight in LEO, where their enemy can use surface-based weapons, horizon effects, etc.

High orbit is, tactically, much more like deep space. But the characteristics of electric drive are such that it is *almost* as good as low orbit for intercepting traffic.

In fact, in normal civil practice, crews and passengers probably use ferry craft to meet departing ships at high orbit, instead of spending an extra week or more twiddling thumbs during the spiral-out. (Not to mention the Van Allen belts.)


Politely ignored in this discussion is the problem of rendezvous, let alone formation flight, with nuclear-powered ships that have only shadow shields. A couple of km of air provides very effective radiation shielding. In space, no such luck, and prolonged exposure to unshielded reactors is bad news out to a remarkable distance.

Anonymous said...

I would expect that the shuttle/ferries would dock nose-first after first spiraling up into a leading position just slightly 'above' the IP ship, and then 'droping down' into docking position with the nuclear transport ship when the distances close up.

Again, if the amin/security people the Martians are interdicting are government types that is one thing, but if they are corporate contractors, then the rules should be a bit more lax as far as danger-of-starting-war-type-of-mistakes goes. Going after government officials of various off-world habs would be iffy, even if the Martians declared them 'corrupt'; going after corporate contractors they claim are corrupt or criminal might get them enough popular sympathy to get the blockade/inspection started. So long as they use some restraint, they might get away with it.

Ferrell

Anonymous said...

That should be 'admin'...

Ferrell

s337101 said...
This comment has been removed by the author.
Locki said...
This comment has been removed by the author.
Locki said...

- sorry. Posted from my work account. Reposted under my play account (s337101 is me of course)

TOM said...

I can agree with the objective and dont get bored, distracted stuff with compus, but personally, i dont see that they would be all so reliable with fuzzy data.

Our problem is text reading on various backgrounds, the programs needs correction and retraining every time they experience a new pattern.


======================

Computers are surprisingly good at interpretting lots of "fuzzy data". They are not good at handling unforseen situations. Its a subtle difference.

For example picking out specific faces in a crowd of randomly moving people in real time is possible. Its the sort of thing airports/immigration use all the time.

For even more impressive recognition software see some of the stuff casinos are using to keep out the card counters and cheats. I know someone who runs the security and they've been able to cutback on the humans patrolling the card tables massively since installing this gee-whiz piece of recognition software.

Or more mundanely, google drive can automatically recognise and tag any photo you ever uploaded.

A lot of data which we consider to be "fuzzy" (face recognition/histogical diagnosis) can be broken down and analysed quite easily with a mathematical formula.

At the very least the computers are going to be a really useful tool to help a human make his decision.

I suspect the computer will make some mistakes in target recognition/ROE but have a higher overall accuracy than a human for the other reasons I listed above (objectivity/boredom etc).

TOM said...

In sharp situations, we can rule out the boredom at least.

Of course, if compus handle most routine, people can have full capacity for the real important things.

Anonymous said...

Rick:

My 'certain persons' riff was too clever by half. What I really intended from the outset was that Mars is challenging Earth's - or some Earth power's - control over habs elsewhere in the Solar System. They are doing so, in an immediate sense, by blocking movement of administrators who exercise that control or the troops/police that enforce it.

If Mars is trying to stop Earth government officials and security forces from going to their colonies, then that is an act of war. Mars is basically securing the colonies independence or claiming them for the Greater Martian Empire. I would expect the shooting to start as soon as the Mars fleet is in range.

If Earth is balkanized, as it is today, the political situation would get interesting. Could other countries stand by and let Mars bully one country knowing that they might be next? What would the UN say and would anyone care?

Now if the administrators and security forces are from a corporation we have a different story. Hopefully for them, they have spent a lot of money on lobbying.

Ron

TOM said...

Or maybe simply the future Earth will be ruled by competing corprations.

Thucydides said...

Corporate officials are still citizens of various nations, so things like the relative power of their home nation, treaty rights, extradition treaties and international alliances all come into play. Since we can probably assume nations with interests in space are first rank Powers in the world, they have considerable resources and influence to protect their citizens. Just imagine trying to pull a Chinese or American corporate official from an airplane without a valid warrant and by people not recognized as a law enforcement authority.

We might also assume such people will be protected by various hard and soft systems, ranging from traveling with "clean" computers and under a false identity (although one that the customs computers would recognize as valid) to body doubles to corporate security or private bodyguards. The Martians might be tipped off about the imminent departure of Hugo Drax, but when they catch up to the ship, discover through DNA analysis it isn't him on board (or is it?, Hugo may have had a phony DNA profile planted many years ago to foil potential kidnappers...)

Geoffrey S H said...

I'm not sure if this would be relevant to the current conversation, but might different nations on Mars and factions there opposed to the blockade change this senario at all?

Cambias said...

There's a HUGE difference between "Mars blockading Earth" and "The North Mars Consortium blockading PanAfrica." Once there are neutrals on both planets, the whole thing turns into an espionage/smuggling scenario.

The PanAfricans ship their weapons or troops to the Free Marineris Republic, probably disguised as subjects of the Empire of North America.

North Mars doesn't sent warships to Earth orbit, it sends agents loaded with nanotech boosters and memory-metal weapons to the Pacific Combine, who then infiltrate PanAfrica and expose the smuggling scheme, blowing up the secret underground base and probably seducing an attractive PanAfrican double agent along the way.

Thucydides said...

But while this is all happening, does the Grand Dutchy of Muscovy support the North Martians in return for help against the Andean Empire and the Trans-Australian Alliance?

The more pieces on the chess board the more complex the formula becomes, but oddly the simple scenario is fraught with difficulties as well. Clearly there is no such thing as a "good war"

Byron said...

I haven't yet taken the time to read all of the comments, but I've thought about this before. Fundamentally, this is very simple. The blockader can make the various vessels attempting to transit come to them, saving delta-V. The blockader sends out a single "blockade missile" which rendezvous with the target vessel and possibly docks. It has some sort of warhead, either explosive or nuclear, and is fused such that any attempt to tamper with it causes it to go off. Probably doing so much as opening the airlock would set it off. The target vessel then comes in for inspection, and deviation would cause the target's destruction. The weapon could also be designed to disable the target, but then it would be the responsibility of the blockader to deal with the now-disabled ship. This means they need the capability to intercept and (probably) bring to a stop a full-size spacecraft. This is a significant requirement, though less strenuous then having to intercept each vessel attempting to transit. The majority of the blockading force only has to get to and from the target planet. The blockade missiles can be quite small, with correspondingly low remass requirements, and the inspection force is centralized for maximum efficiency. Only one inspection team is required, as you would know the schedule well before it occurs. Assuming that blockade procedures are codified, innocent vessels would probably notify the blockaders before they leave. Incoming vessels would obviously have their ETA known well in advance.

Byron said...

The biggest problem with a blockade is what Rick mentioned. A polite request is going to be much cheaper and cause less diplomatic fuss. There are two scenarios. The first is a case in which the planet being blockaded does not want the blockade. This means that the blockade forces will come into conflict with the planetary defenses. Even if the planet does not care about the person in question, they are likely to get touchy about their sovereignty. So the blockading force basically has to go to war, which is likely to consume the bulk of the forces involved. The blockade itself is minor compared to that.
I find it hard to conceive a scenario in which a power would conduct a selective blockade with the permission of the planet being blockaded, but I suppose it is possible. A more likely case is that the blockade is being conducted on a planet with a non-functional government, the sci-fi equivalent of a failed state. This also strikes me as the most likely case for the person of interest we are discussing. A terrorist leader, or some such, in the equivalent of Somalia, would be an ideal candidate for a blockade.
Another point that hasn't been raised is the simple fact that a power is unlikely to be searching all ships. Either the target is on the planet, and you can ignore all inbounds, or he's trying to go there, and you probably know where he's coming from.

Milo stated much of what I said earlier, and raised the point that blockades are generally not about a few people. They are about military equipment or some such. This is another case where it's unlikely that the blockade would have to be total. You would know approximately where the contraband was coming from, and probably when. This makes the blockade much easier.

Byron said...

Another thought is that a general blockade, or even a blockade against repeated cargo, doesn't have to be totally leakproof. During the Civil War, I believe the interception rate was something like 1 in 10. However, that was with specialized blockade runners, which were far more expensive to operate then conventional cargo vessels. Also, even said 10% attrition was not negligible. The penalties in space are similar. The blockade runner might need a couple km/s of chemfuel delta-V, which cuts deeply into payload. Or the blockaders might sit in the optimal transit zone, which forces the runners to use more expensive trajectories. In any case, it makes shipping more expensive, which might be the goal of the entire exercise.

Byron said...

The biggest problem with kinetic use during a blockade is that kinetics make very bad intimidation weapons. The target can pretend to cooperate until they're past, then go back to doing whatever it was you were asking them to stop doing. Not only that, you don't get them back once they're gone. Something with a warhead can come alongside and either dock or float nearby and blow up the target if it behaves suspiciously.

Locki:
There are any number of reasons you wouldn't need to board every vessel. First off, orbital mechanics are likely to make it difficult to conceal the destination of a vessel, which means that you can probably ignore a large fraction of the traffic. If the vessel is going from Earth to Mars, then by all means let your customs people deal with it. The same goes if it's headed for, say, Venus (or any other single destination), and you know that their customs people will hand the target over. This gets tricky if it's headed for, say Jupiter, and while Europa and Callisto are your friends, Ganymede is not. I do question the utility of a blockade in actually finding a single person or a small group of people who really don't want to be found. There are far too many ways to sneak past any reasonable inspection. It's far more likely that the blockade would be useful as a lever against the planetary government. "We'll keep inspecting all shipments until we get Space Osama."
Also, the traffic volume is unlikely to be as high as you would imagine. Given the drive tech, space travel is likely to be uncommon, so there might only be a few dozen flights per day.

The legal structure and blockade objectives are both critical. For instance, do you need these people alive? Or is the objective to make sure that they don't get off Earth, and who cares if we get the bodies? Is it allowable to just blow up a vessel that attempts to run the blockade? Most blockade-running tactics are vastly different from normal operations, so claiming "We used the chemfuel start for fun" is unlikely to fool anyone, which lends support to that idea. This of course assumes that blockades are seen as legitimate tactics by anyone that matters. If great powers regularly use blockades as means of influencing others, the entire thing becomes quite easy. Set up shop, and anyone who doesn't come in gets blown up. Everyone except the blockaded power (who presumably doesn't have the capability to interfere) agrees that this is normal and correct.
On the other hand, it may be a case where you can't simply blow up anyone who tries to run, and you have to chase them down and board them. That was, I believe, the situation WRT Iraqui oil tankers during the sanctions. They could only be boarded in international waters, and the boarding teams had to physically take control of the vessels. Not only that, they were not allowed to use explosives in breaching any defenses on the tanker. Thus it was a race between the boarding teams to cut their way in, and the tanker to get into someone's territorial waters. Something similar could happen in space. The blockader is not allowed to physically damage the target vessel (unless the target vessel shoots first, and with the obvious exception of cutting their way through the airlock) and must conduct searches in person.

Byron said...

The whole concept of a decoy blockade runner strikes me as little better then a decoy in a fleet action. The big problem is that the decoy would need to have the same mass and drive system as the real blockade runner. So the only real difference is the cargo. Unless the cargo is available in strictly limited indivisible quantities (and specific people are all that spring to mind for that) there is no reason not to load up multiple blockade runners with some of the cargo each, and set them off all at once. That way at least some of the cargo gets through. Even if the cargo has a specific critical piece, it's still a better idea to set off multiple blockade runners all at once then to try to run them out of propellant by sending them out one after another. When dealing with people, it's probably easiest to just disguise them aboard a liner or something of that nature.

Much of the discussion of computers controlling the ROE is pointless given the timescales involved. The only thing that will happen fast enough to require split-second decisions is close range weapons fire, which is pretty clear-cut. Other then that, the timescales are long enough for humans to be able to respond. In certain cases, light-lag could move that out of the realm of feasibility, but I'd imagine that those (like a chemfuel blockade runner) are clear-cut enough to be turned over to computers.

Cambias said...

We're not thinking about this correctly.

Two words: launch windows.

There won't be traffic in dribs and drabs, like ships going to and from Portsmouth in World War I. It'll be a Gaussian distribution of ships leaving right around the optimum launch window for a given celestial body.

The analogy is the Spanish Treasure Fleets or the British East India convoys. Everything heads out at once.

This means the blockaders get some advantages and some disadvantages. They can proclaim well in advance that no vehicles which haven't been inspected will be allowed to boost at the proper time. They don't have to hang around for a long siege. Heck, if they're blockading traffic heading for their homeworld, they can go along, inspect at leisure during a year-long voyage, and vaporize violators en route.

The disadvantage is that a big convoy is easier to escort than a bunch of ships lieaving piecemeal. Anyone inclined to challenge the blockade can do so with maximum force.

Byron said...

Cambias:
We're not thinking about this correctly.

Two words: launch windows.

Good point. That would considerably simplify things for a blockader. On the other hand, there are a few problems with claiming that launch windows would dictate all travel.
The first is that, depending on the cost of delta-V and the average delta-V available, the cost of flying off-window might be negligible.
The second is that blockade runners, by their very nature, will avoid normal launch windows. Of course, a launch window blockade might be the least powerful form of blockade. You just raise the price to get to a planet without ticking off all the inhabitants.

One thing that occured to me last night is that the blockader will probably have some warning of any attempts to run the blockade. If his optics are good enough, then he can probably see the attachment of chemfuel boosters. Even if he doesn't know when, he knows who.

Cambias said...

Byron:

True, although a launch outside the optimum window period might as well by trailing a big "BLOCKADE RUNNER" banner and thus is a prime target for intercept.

You're right, though, that this does imply the Martians should keep a presence in high Earth orbit to watch out for such things.

Byron said...

Cambias:
True, although a launch outside the optimum window period might as well by trailing a big "BLOCKADE RUNNER" banner and thus is a prime target for intercept.
I'm not so sure about that. If we're dealing with average delta-Vs at or above 30 km/s, the launch windows start to become less important. If you have a ship that can make Mars in three to five months, waiting a year between launches is probably not a good idea.

Tony said...

Byron:

"I'm not so sure about that. If we're dealing with average delta-Vs at or above 30 km/s, the launch windows start to become less important. If you have a ship that can make Mars in three to five months, waiting a year between launches is probably not a good idea."

Such a ship can only make Mars in three to five months if it launches through the good ol' 26 month synodic window. At a guess, it would take delts-vs of hundreds of kilometers a second to make off-synodic transits faster than on-synodic ones.

Byron said...

Tony:
Such a ship can only make Mars in three to five months if it launches through the good ol' 26 month synodic window. At a guess, it would take delts-vs of hundreds of kilometers a second to make off-synodic transits faster than on-synodic ones.
Not what I meant. Three to five months includes off-synodic windows. I'm just guessing, but space will get flatter as you get more delta-V. We generally do transits with a few km/s these days. Add an order of magnitude, and quite a lot would be possible. A one-tangent Earth-mars transfer would be 2 months and 14 days with 30 km/s delta-V. Off-window, that would increase significantly, but you're still looking at maybe six months in a worst-case scenario.

Ray said...

Another thought... just how much hassle are the innocents willing to put up with? How much cost are they willing to bear so that this foreign government can conduct their manhunt?

And how independent are the typical ships/crew? Are they like modern corporate passenger liners, or mostly like the classic fictional free-traders who spend a lot of time in space because they prefer not to be subject to government and authority?

Rick said...

Good points about launch windows and orbits.

I suspect that Tony is right about the impracticality of 'off-season' orbits, but it is difficult to test.

The problem is that there is a fairly simple approximation for Hohmann-like orbits, while torchships can use a flat-space approximation. But the orbits for demi-realistic electric ships pretty much need to be crunched out, meaning some fairly serious programming ...

Byron said...

Ray:
Another thought... just how much hassle are the innocents willing to put up with? How much cost are they willing to bear so that this foreign government can conduct their manhunt?

And how independent are the typical ships/crew? Are they like modern corporate passenger liners, or mostly like the classic fictional free-traders who spend a lot of time in space because they prefer not to be subject to government and authority?

Slightly confused here. If I read this right, you're suggesting that third party traders would avoid blockaded planets because of the hassle. This is actually what makes blockades effective instruments against a government you want to pressure into handing over the targets of the manhunt in question.
The independence of shippers is likely to be limited, because of the velocity at which their ships travel.

The problem is that there is a fairly simple approximation for Hohmann-like orbits, while torchships can use a flat-space approximation. But the orbits for demi-realistic electric ships pretty much need to be crunched out, meaning some fairly serious programming ...
Milo gave me an HTML thing that calculates one-tangent orbits for a given delta-V.

Anonymous said...

I'm thinking that launch-windows during the synod-period for a typical electric rocket would be a relitively short 'optimal' window, bracketed by two 'sub-optimal' windows, with the rest of the year being 'no-go' periods; during the off-years, there might be a single 'sub-optimal' window with the rest of the year 'no-go'; only the most robust of craft(meaning a standard propulsion module mated with a tiny hab and no cargo)could launch during 'sub-optimal' windows, and only these robust craft fitted with chem-fuel boosters would launch during 'no-go' periods and only under extreme emergencies, like astroid deflection.

Ferrell

Thucydides said...

While I am pretty math challenged when it comes to orbital calculations, I wonder if ships using momentum exchange (solar sails, mag sails, M2P2 and variations) don't have a big advantage here?

They have performance similar to electric PMF drives (current technology allows solar sails to accelerate at 1mm/s^2), but are capable of continuing to accelerate and otherwise make "powered" manoeuvres at any time during flight, while solar or nuclear electric drives are going to be limited by the amount of remass they carry. The take away here is a sail does not have to take a ballistic trajectory, and is probably less limited to launch windows than a powered ship.

Solar sails and their cousins also have pretty impressive performance once they spiral out of orbit; you can go Earth to Mars in 120 days on a fly by trajectory, so catching them might take quite a bit of doing. (OTOH their performance in orbit sucks, this leads me to think any ship using sails would have some drive system to rapidly boost into high orbit before deploying the sail; at which point the blockade ship is no longer able to assume they can match orbit using a ballistic trajectory).

Hopefully someone here can do the math and see if these are fair assumptions or not.

Tony said...

Thucydides:

To get the kind of performance you're talking about out of solar wind or sunlight, you're talking about sails made of unobtainium. Yes, you can make enough sail to carry, say, a hundred ton hab at demonstrated accelerations. The problem is that the sail couldn't support it's own weight, even at milligee accelerations.

Byron said...

Thucydides:

They have performance similar to electric PMF drives (current technology allows solar sails to accelerate at 1mm/s^2), but are capable of continuing to accelerate and otherwise make "powered" manoeuvres at any time during flight, while solar or nuclear electric drives are going to be limited by the amount of remass they carry. The take away here is a sail does not have to take a ballistic trajectory, and is probably less limited to launch windows than a powered ship.

That's an order of magnitude less acceleration then a milligee drive. 120 days from Earth to Mars is not terribly impressive. Also, momentum exchange is useless when hostile forces are nearby. The tether is easy to destroy.

Locki said...

Byron said...

I haven't yet taken the time to read all of the comments, but I've thought about this before. Fundamentally, this is very simple. The blockader can make the various vessels attempting to transit come to them, saving delta-V. The blockader sends out a single "blockade missile" which rendezvous with the target vessel and possibly docks. It has some sort of warhead, either explosive or nuclear, and is fused such that any attempt to tamper with it causes it to go off. Probably doing so much as opening the airlock would set it off. The target vessel then comes in for inspection, and deviation would cause the target's destruction. The weapon could also be designed to disable the target, but then it would be the responsibility of the blockader to deal with the now-disabled ship. This means they need the capability to intercept and (probably) bring to a stop a full-size spacecraft. This is a significant requirement, though less strenuous then having to intercept each vessel attempting to transit. The majority of the blockading force only has to get to and from the target planet. The blockade missiles can be quite small, with correspondingly low remass requirements, and the inspection force is centralized for maximum efficiency. Only one inspection team is required, as you would know the schedule well before it occurs. Assuming that blockade procedures are codified, innocent vessels would probably notify the blockaders before they leave. Incoming vessels would obviously have their ETA known well in advance.

I briefly thought of this myself but dismissed it fairly quickly for the following reasons

1. Your blockade missile must have enough delta-v to intercept then slow down and dock with the target.It's gonna be big. Real big. Why not just use your 50,000km lasers (Rick's tech) fire a scorching warning shot and tell them to rendezvous with you at the location of your boarding parties or you will turn up the heat (hahaha I crack myself up). Its essentially the same thing. And each laser is effectively an unlimited shot 50,000km "blockade missile."

2. The blockade missile will still look like a KKV until the point where it starts slowing down

3. Really attaching what is essentially a remote controlled limpet mine to every outgoing warship is an aggressive act of war.

Byron said...

Locki:
1. Your blockade missile must have enough delta-v to intercept then slow down and dock with the target.It's gonna be big. Real big. Why not just use your 50,000km lasers (Rick's tech) fire a scorching warning shot and tell them to rendezvous with you at the location of your boarding parties or you will turn up the heat (hahaha I crack myself up). Its essentially the same thing. And each laser is effectively an unlimited shot 50,000km "blockade missile."
Oops. Guess I missed the size implications for deep-space intercept. It might be possible to do the same thing with chemfuel in orbit, though, particularly if the missile can ride back. And the laser in question has a range of 1/6 ls. That's not a whole lot in this situation.

2. The blockade missile will still look like a KKV until the point where it starts slowing down
Not sure what the problem here is. You would tell them it's a blockade missile. If this tech is an accepted part of blockades, and blockades are an accepted part of warfare, nobody will care.
Also, I'm not sure how much it will look like a KKV. If the performance specs on your blockade missile are known, and the object launched matches those, nobody will worry. Sure, you could have a KKV disguised as a blockade missile, but why go to all the trouble? You have control of local space.

3. Really attaching what is essentially a remote controlled limpet mine to every outgoing warship is an aggressive act of war.
Warships? Who said anything about warships? A blockade itself is more or less an act of war. Nothing armed is going to be let through, assuming it wasn't destroyed when you set up the blockade and they challenged you.

Thucydides said...

Tony;

Not all sails are physical. Magsails, electrostatic sails and M2P2 all use the interaction of forces rather than thin sheets of reflective materials. Even with reflective sail technology, various proposals were made as far back as the 1970's for vastly improved sails, and modern material science shows things like Graphine and carbon nano tubes have potential ot be the "unobtanium" for high performance solar sails.

Byron

120 days is not too bad when you compare it to current technology, especially since you have used no fuel or remass in the process. Momentum exchange in this case is the momentum of solar photons or plasma being exchanged with the sail; tethers are a different form of momentum exchange than what I am talking about here.

Attacking an orbiting tether is another pretty serious act of war, since it is effectively like attacking an airport or seaport on Earth, plus it fills the sky with some pretty energetic debris, creating a navigation hazzard in orbit. If things have gotten that far we are now rapidly heading towards the various Space War scenarios discussed in multiple threads here.

Byron said...

Thucydides:
120 days is not too bad when you compare it to current technology, especially since you have used no fuel or remass in the process.
Current technology is not the benchmark here. The benchmark is milligee electric drives, as mentioned by Rick in the original post. I've heard claims that VASMIR should be able to do Mars in 39 days. I'm skeptical of the device, but 120 days is definitely on the long side for PMF.

Momentum exchange in this case is the momentum of solar photons or plasma being exchanged with the sail; tethers are a different form of momentum exchange than what I am talking about here.
I have never heard the term momentum exchange used to describe any form of sail.

Attacking an orbiting tether is another pretty serious act of war, since it is effectively like attacking an airport or seaport on Earth, plus it fills the sky with some pretty energetic debris, creating a navigation hazzard in orbit. If things have gotten that far we are now rapidly heading towards the various Space War scenarios discussed in multiple threads here.
And declaring that you're going to search all inbound or outbound spacecraft isn't an act of war? Nobody is going to acquiesce to a blockade that they could break. Ever. Either they would agree to whatever the blockader wanted through diplomatic means, or they would break the blockade.
Leaving that aside, the tether itself is vulnerable. It is fixed in space, and any vessel that attempts to use it has to come to it. Thus, the blockader leaves a vessel at the tether, and shoots at anyone who attempts to use it without permission.

s337101 said...
This comment has been removed by the author.
Locki said...

Byron said ...

Warships? Who said anything about warships? A blockade itself is more or less an act of war. Nothing armed is going to be let through, assuming it wasn't destroyed when you set up the blockade and they challenged you.

==============

My mistake. I meant starships. On any thread I tend to see the red mist and just think war.

I've been pretty much agreeing with you right from the start of this thread and saying this sort of blockade and search of all outgoing traffic amounts to a declaration of war and is a gross breach of a space nations sovereignty.

And realistically its much cheaper and less inconvenient for an ocean going ship to let itself be searched (so less likely to cause war) than it is for a starship with limited delta-V.
Only if there are failed states invovled(somalia) would this fly.

Jim Baerg said...

Hi: I recently got back into reading this blog & aside from this comment I've commented on the 'Sailing distant seas' post.

One relevant question for the blockaders & the blockade evaders is where is the propellant coming from for the electric drive interplanetary ships?

An article in a recent issue of Analog discussed the LCROSS results on the volatiles at the lunar poles & mentioned that as well as water, various nitrogen sulfur & organic compounds, mercury is quite abundant. So any lunar settlements using those volatile deposits for life support would be separating the mercury to keep from being poisoned & have it as a byproduct. Mercury is one fairly good propellant for electric drive ships, & cheap mercury from the lunar poles would probably be used by any interplanetary ships leaving the earth-moon system for elsewhere in the solar system.

I would expect interplanetary ships to leave from the L1 end of the lunar space elevator, & avoid the long spiral through the Van Allen belts.

What does this do for the political situation of the OP? Is there an independent lunar republic that is neutral in the dispute that leads to the blockade & quite willing to sell propellant to both sides?

Anonymous said...

Yes, but how does that work out when the blockade is against corporate ships and people rather than government ones? Would other corporations or government agencies be that bothered with a government (even an upstart one) searching NGO ships for specific individuals. If the Martians leave everybody else alone, then they avoid much of those issues.

Ferrell

Anonymous said...

I was replying to Locki, but Jim sneaked in while I was typing; good to hear from you again Jim.

Ferrell

Locki said...

Yes, but how does that work out when the blockade is against corporate ships and people rather than government ones? Would other corporations or government agencies be that bothered with a government (even an upstart one) searching NGO ships for specific individuals. If the Martians leave everybody else alone, then they avoid much of those issues.

Ferrell


I'm making this up as I go. But if a corporation or NGO has so much money that they can afford to build giant flying nuclear reactors and then launch them into space they probably have a LOT of government influence.

A company rich enough to build an inter-planetry spaceship will make Microsoft/Apple/Exxon-Mobile combined look like paupers.

You can bet the company will be lobbying their government hard about the infringment on their liberty.

Also the terrorist/search target(?) you are wanting to find is likely to be a wealthy citizen of some nation.

If the company doesn't kick up a fuss eventually the company officials will remember they are American/Chinese/etc citizens and lobby their government

Byron said...

Locki:
See how scary close we came to war during the Cuban missile crisis for example. And that was merely a "quarantine".
It was called a quarantine because the UN defines a blockade as an act of agression. Based on articles published about the legality of that action (school journal access wins again!) it appears that the quarantine was justified under the doctrine of self-defense, the fact that it was limited to the missiles, and a resolution of the OAS. An interesting comment made in realation to that was that the Latin American states did not view the quarantine as US intervention. Rather, they viewed it as the US stopping Soviet intervention. That, as much as anything, probably provided the legal backing.
The theory of the Pacific Blockade (or blockade without war) is basically the one I have been trying to construct:
PACIFIC BLOCKADE, a term invented by Hautefeuille, the
French writer on International Maritime Law, to describe a
blockade exercised by a great power for the purpose of bringing
pressure to bear on a weaker state without actual war. That it
is an act of violence, and therefore in the nature of war, is undeni-
able, seeing that it can only be employed as a measure of coercion
by maritime powers able to bring into action such vastly superior
forces to those the resisting state can dispose of that resistance
is out of the question. In this respect it is an act of war, and
any attempt to exercise it against a power strong enough to
resist would be a commencement of hostilities, and at once bring
into play the rights and duties affecting neutrals. On the other
hand, the object and justification of a pacific blockade being to
avoid war, that is general hostihties and disturbance of inter-
national traffic with the state against which the operation is
carried on, rights of war cannot consistently be exercised against
ships belonging to other states than those concerned. And yet,
if neutrals were not to be affected by it, the coercive effect of
such a blockade might be completely lost. Recent practice has
been to limit interference with them to the extent barely neces-
sary to carry out the purpose of the blockading powers.'

(11th edition of the Brittanica).
This pretty much describes what I was getting at. Quarantine (as in Cuba) is another option, which can also be compared to the interdiction of Iraqi oil smuggling pre-2003. I think that the situation Rick describes is closest to the quarantine. The problem is threefold. First, in the case of Cuba, there was a clear self-defense component. Second, it didn't actually go to the point where a Soviet ship carrying weapons ignored US orders, so its legality never was formally determined. Thirdly, no equivilent of nuclear weapons would be involved. If not for those, there would have been war in 1962. MAD, besides putting the entire human race in peril, gives everyone an excellent incentive to get along, if only grudgingly.

Only if there are failed states invovled(somalia) would this fly.
More or less. Or it could be a useful tool to apply pressure to a planet you have a problem with. "Hand over Space Osama, or we'll keep searching all outgoing ships for him." Never mind that he might not want to leave, and could probably sneak by if he did. The costs to the planet are a pretty effective lever. See above, with "harboring a terrorist" being the criminal act.

Byron said...

Jim:
An article in a recent issue of Analog discussed the LCROSS results on the volatiles at the lunar poles & mentioned that as well as water, various nitrogen sulfur & organic compounds, mercury is quite abundant. So any lunar settlements using those volatile deposits for life support would be separating the mercury to keep from being poisoned & have it as a byproduct. Mercury is one fairly good propellant for electric drive ships, & cheap mercury from the lunar poles would probably be used by any interplanetary ships leaving the earth-moon system for elsewhere in the solar system.
Mercury is only used in older types of electric thrusters. Apparently, it's difficult to work with, being both toxic, and hard to feed accurately.
The best data I could find suggested that mercury was present in about the same abundance as water by mass. The question is if that is enough. Given that, at a minimum, you'll need a kilogram of propellant for every kilogram of stuff you want to send out (probably considerably more), any setting with sufficient levels of space travel for war will probably require at least tens of thousands of tons every year. A lunar habitat will do its best to recycle water, so the mining will probably be on a scale of thousands of tons at most.

Ferrell:
Yes, but how does that work out when the blockade is against corporate ships and people rather than government ones? Would other corporations or government agencies be that bothered with a government (even an upstart one) searching NGO ships for specific individuals. If the Martians leave everybody else alone, then they avoid much of those issues.
Under current law, nobody is exempt from search during a blockade. I don't see why this would be any different.

Jim Baerg said...

Byron:
Even if mercury from the lunar poles is too scarce or otherwise not suitable as the propellant, any lunar material that is suitable will likely be cheaper than material brought up from earth. So argon, sodium or potassium extracted from lunar rocks would be likely electric drive propellants.

This still leaves the moon as the propellant source & crucial for the sucess or failure of any blockade.

Cambias said...

If the Martians are trying to limit their conflict to just "Space Exxon" rather than all of Earth, then "Space Exxon" simply has to ship everything via some third-party company. Or re-flag their ships through a Luna City shell company, so that boarding them becomes an act of war against the Lunar Republic, which is where the Martian blockaders get their fuel.

Thucydides said...

If you read upthread, I think the consensus from almost everyone is that creating or even threatening a blockade is pretty much a declaration of war.

Perhaps the only real change that the scenario has over ones with RBoDs vs SCoDs is the level of violence is kept ot a much more reasonable level, and in terms of plausibility, each side having only a limited number of ships with very limited capabilites is a much more realistic apprieciation of the parameters than filling the sky with multi thousand tonne ORION drive Dreadnaughts.

To that end, maybe the right historical model could be the various naval contests between South American navies in the late 1800's, such as Chile's various wars against Bolivia and Peru. The force to space ratio's were fairly small, each side had only a few major surface units and the overall war aims were limited (mostly due to the small amount of resources available).

Rick said...

I think the consensus from almost everyone is that creating or even threatening a blockade is pretty much a declaration of war.

And that was my expectation in writing the original post.

My intention was mainly to argue that that an attacker from deep space does not need to come down to low orbit and mix it up with surface defenses, but can blockade from high orbit. The defender must then either fight well away from the planet, or else accede to being blockaded.

Thucydides said...

While a blockade in relatively deep space is very much in the mode of Alfred Thayer Mahan (distant weather beaten ships), and very much in line with modern practice, I do wonder about the practicality of this.

Most historical blockades worked because the blockading power was much stronger than the blockaded power in terms of naval strength. A squadron or constellation of ships in high orbit at the end of a very long supply chain will find themselves very disadvantaged when the blockaded planet throws its resources into breaking the blockade. Even reversing the scenario and having EarthForce throwing a blockade around Mars still means the Martians can crank up missile production and continue to shoot at the EarthForce ships while the constellation commander needs to conserve his munitions expenditures until the next supply ship can arrive.

Another analogy might be the battles in the English Channel and the North sea between minelayers and minesweepers, with Motor Torpedo Boats buzzing around to escort the minelayers and minesweepers and attempting to disrupt the enemy ships from doing their tasks. Once again the ship classes are much more attuned to the PMF than massive fleets of dreadnaughts

Rick said...

As a practical matter, interplanetary battles seem radically improbably to me in the PMF, or for a long time after.

But given that we love to talk about them, I do so, to ground at least some of the exercise in plausibility. :>

Deep space electric craft have very minimal similarity to either battleships or torpedo boats - but at least in size and non-agility, that are *slightly* less unlike battleships than they are unlike torpedo boats.

(And yes, at some point I'll probably follow up with a discussion of a battle resulting from this blockade scenario.)

Anonymous said...

I think that due to the fact that spacecraft don't move like any terrestrial vehicle makes it difficult to make definitive comparisons. It's more like missile batteries floating on ocean currents past each other launching salvos. And that's still not very close. Maybe combat zepplins are a better analogy.

Ferrell

Rick said...

In a nutshell, yes!

Scott said...

Byron said...

Thucydides:
"120 days is not too bad when you compare it to current technology, especially since you have used no fuel or remass in the process."
Current technology is not the benchmark here. The benchmark is milligee electric drives, as mentioned by Rick in the original post. I've heard claims that VASMIR should be able to do Mars in 39 days. I'm skeptical of the device, but 120 days is definitely on the long side for PMF.

Let's dig out the old brachistochrone formulas. Earth-Mars distance is about 100,000,000km, and let's run a milligee drive. 73 days. Run that up to a centigee, .1m/s/s, and you're talking about a 23-day trip. It's almost longer to climb the beanstalk up to GEO (~12-14 days)

That 39 day number using a VASMIR drive is for a .05m/s/s acceleration! Five milligees.

Granted, those are closest approach numbers. Typical extreme distance is 225million km, which means a 49 day trip at 5 milligees.