Thursday, November 4, 2010

Space Patrols

We now return you to your regularly scheduled blog.

The discussion thread about 'temperate and indecisive conflicts' veered, among other things, into a discussion of patrol missions in space. [Oops, wrong thread - the discussion arose on the 'Industrial Scale of Space' thread.] My first reaction was that (so long as you aren't dealing with an interstellar setting) there is no place in space for wartime patrol missions. But the matter might be more complicated, and for story purposes probably should be.

According to The Free Dictionary, patrol is The act of moving about an area especially by an authorized and trained person or group, for purposes of observation, inspection, or security. This fits my own sense of the word, and is in fact a bit broader, 'security' including SSBN patrols, which are not observing or inspecting anything, just waiting for a launch order if it comes.

In a reductionist way you could say that all military spacecraft are on patrol, since they are all on orbit, and if they are orbiting a planet they have a very regular 'patrol area.' But this is not what most of us have in mind. We picture a patrol making a sweep through an area, looking for anything unusual, ready to engage any enemy they encounter, or report it and shadow it if they cannot engage it.

Back in the rocketpunk era it was plausible that, say, Earth might send a patrol past Ceres to see if the Martians had established a secret base there. But (alas!) telescopes 'patrolling' from Earth orbit can easily observe the large scale logistics traffic involved in establishing a base; watch it depart Mars and track it to Ceres. If you want a closer look you can send a robotic spy probe. If you engage in 'reconnaissance in force' by attacking Ceres, that is a task force, not a patrol.

In an all out interplanetary war there may be plenty of uncertainty on both sides, but very little of it can be resolved by sending out patrols.

But of course all-out war is not the context in which the Space Patrol became familiar. I associate it with Heinlein's Patrol; apparently the 1950s TV series had an independent origin (unlike Tom Corbett, who was Heinlein's unacknowledged literary child).

The rocketpunk-era Patrol, which in turn gave us Starfleet, was placed in the distinctly midcentury future setting of a Federation. This is as zeerust as monorails. But plausible patrolling is not confined to Federation settings. It can justified in practically any situation but all out war.

Orbital patrol in Earth orbital space will surely be the first space patrol, and could be imagined in this century. It might initially be a general emergency response force, because travel times in Earth orbital space are short enough for classical rescue missions. On the interplanetary scale, with travel times of weeks or more likely months, rescue is rarely possible. But eventually power players will want some kind of police presence or flag showing in deep space.

As so often in these discussions, I picture a complex and ambiguous environment in which policing, diplomacy, and sometimes low level conflict blur together. To take again our Earth-Mars-Ceres example, there are kinds of reconnaissance that cannot be carried out by robots (short of high level AIs). If Ceres closes its airlocks to liberty parties from a visiting Earth patrol ship, that conveys some important intelligence information.

The ships that perform these missions will be fairly large (and expensive). They must carry a hab pod providing prolonged life support for a significant crew: at least a commander and staff, SWAT team of espatiers, and some support for both.

Let us say a crew of 25 - which is cutting the human presence very fine. Now we can venture a mass estimate. Allow 100 tons for the hab compartment plus 25 tons for crew and stores plus 75 tons other payload, for a total payload of 200 tons. Let the drive bus be 200 tons for the drive, including radiators, and 100 tons for tankage, keel, and sundry equipment.

Our patrol ship with a crew of 25 thus has a dry mass of 475 tons, mass fully equipped 500 tons, plus 500 tons propellant for a full load departure mass of 1000 tons. Cost by my usual rule of thumb is equivalent to $500 million, perhaps $1 billion after milspecking, expensive compared to military planes, cheaper than major naval combatants.

This is no small ship. If the propellant is liquid hydrogen the tanks have a volume of about 7000 cubic meters, equivalent to a 7000 ton submarine. The payload section is about two thirds the mass of the ISS and of roughly comparable size, though the hab is probably spun giving the prolonged missions.

Armament is necessarily modest. The 75 tons of additional payload allowance probably must include a ferry craft for the espatiers and an escort gunship or two, plus their service pod, leaving perhaps 15-20 tons each for kinetics and a laser installation. The laser might be good for 20 megawatts beam power, with plug power from the 200 megawatt drive engine.

This ship is no laser star, but the laser is respectable. Assuming a modest 5 meter main mirror and a near IR wavelength of 1000 nanometers, at a range of 1000 km it can burn through Super Nano Carbon Stuff at rather more than 1 centimeter of per second. Its armament is also rather 'balanced.' My model shows that this laser can just defeat a wave of about 1000 target seekers, each with a mass of 20 kg, closing at 10 km/s - thus a total mass of 20 tons, comparable to its kinetics payload allowance.

Deploying troops, or personnel in general, is impressively expensive: About three fourths of the payload and cost of a billion dollar ship goes to support and equip a crew of 25, with perhaps a dozen espatiers. For comparison the USS Makin Island (LHD-8) displaces 41,000 tons full load, carries a crew of 1200 plus 1700 Marines, and costs about $1.8. So by my model it costs about as much to deploy one espatier as 80 marines.

And this ship is about the minimum patrol package, so standing interplanetary patrol is a costly and somewhat granular business, something not everyone can afford.


Apparently this cover is from the current reissue of Heinlein's Space Cadet.


Tony said...

I was maybe a little bit hasty earlier in saying that patrolling was of no value. It does have the value of giving you immediate reaction capability in a crisis. And in an environment where transit times are weeks or months, that can be important. IOW, while there may well be no physical horizon to patrol beyond, there is a time horizon.

However...a patrol vessel for that purpose could not be a relatively fragile assemblage of modules and cargo. This ship is going to have to fight it out with whoever else has a patrol vessel on-station -- as well as any local forces that might exist -- then dominate the local space until reinforcements arrive. So it's either got to be analogous to a pre-WWI overseas station cruiser, or the operator has to accept abandoning the hab and interplanetary drive (perhaps permanently) in order for the rest to be able to fire and maneuver effectively.

Anonymous said...

I don't think that "space patrols" would be like navy, or even air force patrols. It would be more like a giant figure-8 in the sky. Only with weapons and spy-gear...I do think that the 'patrol ship' would have extensive spin-hab and payload sections, but I think that the weapons mounted on the ship would be mostly point-defence, while the ship would also carry drones that mount the offensive weapopns (missiles and/or lasers)and be controlled from the ship. I also think that 'partols' would be more like convoy escorts (or raiders), 'show-the-flag' type, area security (like orbit), but I don't think you're going to send a billion dollar spacecraft from orbit 'A' to orbit 'B' and back again, just on the off chance that they would run into an enemy 'craft. It would be more like the bomber-interceptor type of combat. Deverting a 'show-the-flag' patrol to a hot-spot would be the exception rather than the norm. The only reasons I can see that you'd have these ships on a 'patrol' like Rick has discribed, is to keep close to convoys, unfriendly folk, or as mobile intelligence-gathering platforms. The customs/law-enforcement/anti-piracy/counter-terrorisim mission for your espatiers would be secondary. I further think that 'patrol ships' could be more like a mobile space station that are sent to orbit a planet or moon for short amount of time, and then off to the next target.

So...'space patrols' aren't going to be like 18th century sailing navy patrols, or even modern-day SSBN patrols. If you could send railroads on combat patrols, 'space patrols' would be like that...


Elukka said...

Shameless plug: I happened to design a paramilitary patrol/interceptor ship recently. Well, not really a coincidence as it was inspired by a previous discussion here. It'll manage an interplanetary flight but I imagine it's made more for smaller operational areas, say a gas giant's moon system.

Open-cycle gas core NTR engines, thrust around 1 g (or nearly 3 with LOX injection at the cost of some isp), delta-v 30 km/s. Propellant is methane. There's a secondary chemical engine for operation near other craft as the main engines do have radioactive exhaust.

It has a fairly big 140 tonne hab module and a turreted laser. Total mass is about 2200 tonnes. Besides going with a high-thrust engine, I find it surprisingly similar to the craft Rick described!

...Almost forgot the pictures.

Geoffrey S H said...


We need more designs and pictures like that...

One quibble: are you sure your heat radiators are big enough?

Elukka said...

The hab's got a wraparound radiator and the engines get rid of the brunt of their waste heat by the way they work but... no, they're probably still not enough. I did a terrible thing and sorta threw on radiators that I thought looked good instead of running the numbers. :P
(I did mathify the rest of the design though)

Clay said...

We already have space patrols, and we call them spy-sats.

I just don't see this scenario. The cost, the mass, the vulnerability of a single mirror as our primary means of offense and defense.

So your laser can burn 1000 incoming big projectiles? Big deal. This has always struck me as the major flaw in single laser configurations--the assumption that the enemy won't just buckshot you to death.

Imagine this patrol ship up against so robot ships using auto-canon to blast out clouds of shrapnel heading your way from beyond your laser's range and riding into your projected path of travel.

Sure, they miss a lot, but they have hundreds of thousands of projectiles zipping towards you too. How do you track a cloud? How do you blast it? Can you paint that much space with your laser before overheating?

All it takes is for the shrapnel to rip apart your mirror, or radiators, or sensors, or whatever.

And then boom...

Here comes the slow nuke to turn your patrol ship into a flash of light that no longer exists.

More realistic are lots of robot patrols--cheap and expendable. They swarm. They spy. They report. And eventually they fail and self-destruct. No muss. No fuss.

Plus they're cheap and easy. NASA could build these today if it wanted.

Sorry. I just don't see this scenario as very plausible.

Clay said...

Hey--I just had a weird idea for these drone ships.

Do you think it would be possible to design them to cannibalize themselves for ammunition.

In other words, they'd lock onto a target, fire their basic store of ammunition, and if the target wasn't destroyed, the drones would be built in such a way that they could begin consuming their parts for ammo until the drone was nothing but the basic power unit, firing computer, attitude determination and control system (ADCS), and the rail gun.

Everything else. The shell. Primary thrusters. Etc... Fired down range. I wonder how much you could scavenge if you had no intention of bringing it home again.

Geoffrey S H said...


I usually treat them as "wings" for aesthetic purposes- I make them are wide as long as the main body and the double. Alot, I know, but it allows for poetential increases in power-requirements. The design essentially is "future proofed".


It meant for inspection, not main-line combat work. As far as kinetics vs lasers are concerned, the "battle of the spherical war cows" in the atomic erockets webtie providesd a good list of arguments for and against lasers.

Geoffrey S H said...

*sp "then" not "the"

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


Well, these patrol ships are obviously meant for combat to some extent if we are arming them. My argument is that arming them, and indeed sending them, is pointless.

Patrol ships can't outfight the drones cost effectively, nor can they out-patrol the drones either from a cost-effective standpoint.

And I've read the arguments regarding space battle here and elsewhere, but I think they bear repeating in this context.

There just isn't a scenario where dispatching isolated patrol ships with limited weaponry for long-range reconnaissance makes any sense unless you are actively trying to get attacked in order to justify going to war (a la American PT boats harassing Japanese warships pre Pearl Harbor)

Byron said...

My overall view on this is that any sort of presence patrol will be in the form of a station, not individual ships. It's far cheaper in remass, and you get more ship for your money, as you don't need deep-space endurance. There might be a few ships for flag-showing patrols, but those would be very rare.
Yes, but there are two major problems with that. First, the fact that you spend as much time coming back as you did going out. Second, the fact that you are only "on station" for 1% of the time. Yes, you can stop at the target, but the mass penalties for that sort of thing are rather severe.

The ship looks impressive. Do you have any more numbers?

Clay, a single big laser will tend to be more powerful than several small ones. It has a longer effective range, and thus starts burning things sooner. I do agree that a few defense lasers would be helpful, but the main offensive laser will likely be a single unit.
As for attacking lasers, I'm in favor of sand clouds.
The point of armament is to provide the ship with some sort of chance against an enemy. If they can't outfight drones (which I won't take as a given) they still will do better with guns than without guns.

If anyone's interested in ship design, I've recently made a spreadsheet that automates a lot of it. It was originally for Rocketverse but it's pretty adaptable. If you want a copy, I'll find a way to get it to you. I also have a Newtonian space battle tracker that works with it.

Cambias said...

I think patrolling in space is a waste of time. You're wasting energy and reaction mass putting your ship in one particular orbit -- thereby pretty much guaranteeing no enemy will be encountered in that orbit.

The life-support cost is tremendous -- not just in launched mass but also radiation exposure and the "opportunity cost" of having those crewmen on a trajectory to point A rather than any other point. Given the capabilities of modern drones I can't imagine any spacefaring power which would send out humans to snoop around potential threats.

Instead of a patrol ship, I'd envision something like a frontier fort -- a base from which missions can be launched, with telescopes to monitor that whole part of the Solar System, hardened defenses, long-term self-sufficiency, etc.

One can imagine "forts" like that in key locations around the system -- Saturn orbit, possibly the Jovian trojans, etc.

Cambias said...

By the way, Clay, this is off-topic, but do you have any reference to the use of PT boats to harass Japanese warships before WWII?

Byron said...

The only reason to send manned ships is for "courtesy visits" and that's a pretty flimsy excuse. If your intel people are reasonably competent, they'll have agents aboard cargo ships going there. I somewhat agree with the "fort" theory, but I'd go farther and make it a full base, with facilities for crew and family, moderate repairs, etc.

Thucydides said...

Patrolling will reduce the time horizon for the force which engages in it, which is really the point, I think.

Arguments that the patrol vessel is vulnerable are somewhat moot, since if the vessel is attacked, then it is an unambiguous signal that hostilities have commenced (unless the owning Power is willing to tolerate the loss for political or military reasons of their own).

I would argue that a patrol vessel on the lines Rick has described would be a two part vessel. The Hab would be an independent space vehicle in its own right, while the major portion of the ship (keel, engines, radiator main assembly, Liniac and mirror) are also an independent vessel. Once the decision is made to land a shore party (or liberty party for that matter), the hab undocks and trundles off while the weapons platform remains in the High Guard position.

For Elukka, who seems to have a flare for this sort of thing, the main platform would look somewhat like a paper airplane, with large triangular radiators along the truss. The engine is at the wide end (radiators corresponding to where most of the heat generation is) and the mirror is in the nose, perhaps in a "thimble" turret at this scale. Tankage, KKV's etc. are in the spaces between the "wings", and the hab is hanging off one of the hard points. Depending on the scale (and given the description), the hab might resemble a pair of spare tires hanging from a medium length girder bridge (counter rotating so they do not impart momentum to the carrier vessel). If you really want to take the "paper airplane" analogy seriously, then there are three fins and most of the other hardware is attached to the truss on the "top" of the paper airplane.

The big advantage of this design is the carrier need not go with a manned hab, and indeed the hab could be the control station for a constellation of these vehicles, making it adaptable for everything from patrolling to being the nucleus of a constellation or task force.

Byron said...

It wouldn't reduce the time horizon by enough to matter in most cases. Not if the opponent was smart. If you're basically going there, swinging through the system, and leaving, the time in the system is going to be minimal compared to transit time. It's like sending "patrols" to, say, Deigo Garcia from the US by steaming a ship all the way around the world, and not stopping there, just sailing close by once, and leaving. Oh, and the ship can't turn around once it's past. Response time might be less if you have two, but no matter what, they'll wait until you've passed to make trouble.
If you choose to stop in orbit, that's slightly different, but unless you only want occasional visits, it makes a lot more sense to build a permanent base. You only have to ship supplies, and your crews will be a lot happier. Plus, the ships you have won't have to carry stuff like spin habs, as the missions aren't that long.

Tony said...

I think some people are not understanding what a patrol is in the context of near and medium term interplanetary spaceflight. The bojective will not be to go there and come back, or go to several places and pass through each without stopping. The objective will be to go and stay for the suration of the mission (months or years), so that if anything happens somebody will be on-hand to handle it. The patrol area is not a large volume of space. It's the tactically relevant volume of space around a point of interest, like a planet or an asteroid. So yes, there are some affinities with the fortress analogy and the spy sat analogy, but only some.

The patrol ship needs to do three things:

1. Go to the patrol area,

2. Remain on station, and

3. Fight if and when the time comes to fight.

Notice that these three requirements would best be met by three different spacecraft. But since we don't have three different spacecraft, we'll make do with three different modules:

1. Interplanetary propulsion,

2. Habitation, and

3. Combat.

The interplanetary module takes the hab and the combat modules to the patrol area. The hab is lived in and the combat module manned while on patrol station. If shooting starts, the combat module detaches from the hab and goes to work.

Note that the combat module need not be monolithic. It could be augemtned by orbital or even self propelled sensor and weapon platforms. The reason for its existence -- and the existence of the whole patrol ship complex -- is to place humans in the loop in tactical time. It doesn't exist to be a tripwire, or to be here one day but gone the next. It exists to be avaialble to fight and to actually fight when called on to do so.

Milo said...

I'll note that I am only against deep space patrols. Ships in orbit around an enemy planet (or a partially enemy planet, such as a multi-faction world or a friendly world that's under invasion, or a potentially enemy planet, that you suspect but aren't sure is planning something nefarious) can reasonably make use of some patrol tropes, although it's not quite the same.

One issue with "patrolling" this close to an enemy planet, without access to stealth, is that the enemy is unlikely to let you unless you show up in enough force to strongarm their defenses. If relations are merely strained rather than actively hostile, though, then a show-the-flag mission is viable.


"I was maybe a little bit hasty earlier in saying that patrolling was of no value. It does have the value of giving you immediate reaction capability in a crisis."

Only if you know in advance where the crisis is going to turn up.

The extreme difficulty of changing course in space means that you cannot hang around in a trouble spot and be ready to give chase if something comes up. The mere size of space means that there isn't going to be any narrow region of space you can keep an eye on to keep most trouble under wraps, unless that region is in orbit around a planet.


"This has always struck me as the major flaw in single laser configurations--the assumption that the enemy won't just buckshot you to death."

I think there is practically no point defense that can help against buckshot. Even a small amount of armor, however, can.


"My overall view on this is that any sort of presence patrol will be in the form of a station, not individual ships."

A fleet of ships can be in several places at once, which is useful when you're trying to keep an eye on an entire planet. I don't think a patrol craft benefits that much from being large, except in as far as that it gives you more room for crew amenities to endure the long boredom.

Byron said...

Milo, you misunderstand what I meant. I was trying to say that a long-term patrol won't be carried out by ships on rotation from a home base at a different planet. Instead, a base will be constructed in the system, and ships will be more-or-less permanently assigned there while the crews rotate.
The problem is that to be capable of carrying a crew on an interplanetary voyage, a patrol craft will have to be large. My stations solve that, as they only have to deal with the normal crew under peacetime conditions for a month or two at most. If you need to move it back home for a refit or something send a skeleton crew.

Tony said...


"Only if you know in advance where the crisis is going to turn up.

The extreme difficulty of changing course in space means that you cannot hang around in a trouble spot and be ready to give chase if something comes up. The mere size of space means that there isn't going to be any narrow region of space you can keep an eye on to keep most trouble under wraps, unless that region is in orbit around a planet."

The whole point of patroling is that you don't know when or where the crisis is going to be, so you maintain a presence where you have an interest, ready to react when one does.

Also, the size of space and the difficulty in changing direction dictates precisely that you can only focus on well-defined regions of interest. The only such well-defined regions are those within tactically relevant distance of a point of interest, like a planet or an asteroid. Anyplace else has little if any strategic value and just ain't worth fighting over -- not that anybody would go there in the first place.

About the only situation in which you might get combat away from natural bodies is if two powers launch comparable warships through the same window at the same destination, and either one or both ofthem had enough spare delta-v to maneuver into combat, fight it out, and still make any necessary orbital correctios and orbital insertions at the destination.

Clay said...


Ahhh, but that small amount of armor isn't so small given mass constraints. Even a little--and we don't know ahead of time how "little" it gets to be because we don't know what the scenario will be--can radically reduce the overall amount of Delta-v available, or else run up the price tag.

And there's a Catch-22 with up-armoring your ship. Once you do a little, and the price goes up, then you feel the need to protect it even more since now that ship represents a bigger investment. And so on and so forth.

And yes, I know a big laser is theoretically better than several small ones, but it also puts all your eggs in one basket. Again, you don't need to destroy big-gun patrol ships with buckshot, you just need to screw up their mirror or mess up their radiators, etc...

That's the problem with space warships. They're like flying aircraft carriers in modern war. Theoretically useful, but too vulnerable to justify the expense.

In this case, we either have real warships or automated spysats. Why build a ship that isn't powerful enough to really fight, only to take a look at stuff that can be observed at far less cost by automated spysats.

Even if there is trouble, the patrol vessel isn't really a warship. It will quickly get overwhelmed, and it won't take much to do it.

I didn't mean to imply that US PT boats really tried that; I was just trying to come up with a hypothetical to make clear what I meant about using patrol vessels as bait. Sorry for the confusion. It does read a little too literal. I would edit it to put in a marker if I could.

Mr. Blue said...

Don't forget one very important role for Patrol Ships: Deep Space Search and Rescue. Think of it as an analog to today's Coast Guard cutters.

So, the espatiers would be have a good levening of Paraescue types to effect rescues inside damaged ships. Add a pretty good trama center onboard ship.

The ship would need to be armed, but it would not really be used for classic warship to warship combat. You would mostly use the laser to vaporize or move any potentially hazardous debris. That laser would also come in handy if you needed to slag a fleeing smuggler or rouge missle.

Milo said...

Mr. Blue:

"Don't forget one very important role for Patrol Ships: Deep Space Search and Rescue."

That is more a police role than a military role (unless you're searching and rescuing downed soldiers, that is). Anyway, you aren't going to fly circles around deep space to check for shipwrecks. You're going to wait at home until you receive a distress call, then dispatch to the location of the emergency. Either that or you're escorting some convoy, in which case it's just one ship in a convoy lending a hand to another - you're no more on patrol than the rest of your convoy is.

Anonymous said...

Elukka: your ship is great! as an interceptor or convoy escort, it looks like a good compromise between cost and mission demands. I could see it being used very handlly as a customs inforcer or as an asteroid deflector, as well as other missions. As a secondary armed spacecraft, this is what I imagined a "real" space fighter would be like. Your ship would be perfect for an independent colony or minor power.


Rick said...

Welcome to a new commenter, and thanks to Elukka for the outstanding design and graphics. What is it modeled in?

I will split my responses to points into mainly technical and mainly strategic.


I've come to be doubtful that armor is worth the mass penalty. Any kinetic strike that saturates a decent laser defense will probably overkill the target, while a laser will zero in on vulnerable points rather than just zap away at armor.

For the same reason, military craft might not look much different overall from civil ships, apart from the actual weapon mounts.

The advantage of range (and more zapping intensity at any given range) justifies a single main mirror, I think. Tanks have one main gun, and they are much more subject to being engaged from an unexpected bearing.

I like the idea of being able to detach sections. There are some mass penalties, but mostly pretty minor ones. One constraint, in my presumed tech, is that the laser draws electric power from the main drive, so is necessarily connected to it.

For interplanetary missions the distinction between 'ship' and 'station' is quite blurred. Attach a drive bus to a station and it becomes a ship; remove the drive bus from a ship and its hab becomes a station.


The ship I outlined is not intended for 'combat patrols.' In an all-out shooting war the patrol ships may as well be mothballed for the most part.

They are intended for missions more comparable to those of coast guard cutters, Victorian gunboats, and Teddy Roosevelt era 'peace cruisers.' Basically wherever a polite request and a 20 MW laser will get more compliance than the polite request by itself would.

So the armament is not primarily to engage peers but to provide a clear dominance over jury-rigged or other light armament.

Whether there is a valid mission for these ships is a valid question. To be strictly realistic, there probably won't be anything beyond Earth orbital space but research stations, and an extremely minimal military/police presence comparable to Antarctica today.

But if you are going to assume a future Solar System filled with all sorts of activities, power players are going to want intermediate coercive options between sternly worded protests and interplanetary kinetic/nuclear strikes.

Mr. Blue said...

Milo said: "That is more a police role than a military role …"

Exactly. The biggest reason to have a ship patrolling is a law enforcement role. Protecting settlers from pirates and keeping an eye out for off planet smugglers or errant debris is a pretty worthy role.

“Anyway, you aren't going to fly circles around deep space to check for shipwrecks. You're going to wait at home until you receive a distress call, then dispatch to the location of the emergency.”

If by deep space you mean the MMBV (Miles and Miles of Bloody Vacuum) between planets, you’re right. However, you would want to patrol where the people are- planetary systems or the ‘belt.

Raymond said...


Very nice model there. Keep 'em coming.

Tony, Rick:

I'm with you in terms of mission parameters. Having even modest forces available at potential trouble spots can be invaluable if trouble actually happens. Response times of minutes or hours instead of weeks or months can make all the difference.

Perhaps, though, the word "patrol" conjures up too many visions of continual movement for many people here. Maybe "deployment" would be a better general term, if only to reduce confusion and assumptions?


The problem with your stations is that they're fundamentally an escalation. They'd be suited to supporting forces in a given theater where large-scale open hostilities were expected to break out. They'd be an overinvestment for most hotspots.


A small amount of armor, enough to stop sand or micrometeors or other particulate threats, would likely be standard on combat lasers anyways (the shutters as mentioned in the Spherical War Cows threads). And the efficacy of buckshot depends on penetration, effective laser range, delta-v available to the target in the buckshot's flight time, and probably something else I'm missing. It isn't a surefire countermeasure.

Tony (again):

You may have combat away from natural bodies if one side attempts a deep-space interception of an incoming constellation precisely to keep the combat (with its various shrapnel) away from vulnerable space assets. But that wouldn't really be a patrol, so we can probably discount that scenario for this discussion.

Milo said...


"Tanks have one main gun, and they are much more subject to being engaged from an unexpected bearing."

Tanks are not really large enough to justify fitting more than one main gun. The reason tanks are so much smaller than battleships is that they have to move through relatively rough and cramped environments (compared to the open sea), and have to worry about roads and bridges being able to support their weight.

"For interplanetary missions the distinction between 'ship' and 'station' is quite blurred. Attach a drive bus to a station and it becomes a ship; remove the drive bus from a ship and its hab becomes a station."

I've spoken in the past for single-use ships that are designed to make one trip and then be set down for use as a stationary habitat upon arriving at their destination.

Although I was talking about peaceful colonization, and I was landing the ships rather than using them as orbital stations. But I wouldn't be surprised if you found military applications for this kind of approach, although there's the obvious issue that you'll want to get your stuff back if the war ends.

Fuel constraints, though, mean that even a ship that has fully functioning engines will spend a lot of its time coasting in a single orbit (hopefully a tactically advantageous one).

Mr. Blue:

"However, you would want to patrol where the people are- planetary systems or the ‘belt."

I have already conceded planetary systems as a location where patrol-like situations can occur, although if the planet in question is friendly to you, then this is not so much of a "patrol" since you're pretty much parked at your homebase until trouble arises.

If your police job actually calls for you to constantly intercept, board, and search other ships, then you might have a case. Again, though, you'll be knowing exactly which ship you're planning to board before you make any kind of burn to leave your parking orbit.

The asteroid belt, though, is not a good place to try to patrol. It's large. Moving from Ceres to Vesta is not going to be particularly easier than moving from Ceres to Mars - at least if you're not interested in waiting a few millenia for a proper Hohmann window. If people have any interests in the asteroid belt, they will be clustered around a few asteroids and the rest will be ignored.


"You may have combat away from natural bodies if one side attempts a deep-space interception of an incoming constellation precisely to keep the combat (with its various shrapnel) away from vulnerable space assets."

Yes, I think that's the most likely source of deep space battles. (Given the size of space, two forces just coincidentially running into each other in transit is quite unlikely.)

Mr. Blue said...

Milo said: “The asteroid belt, though, is not a good place to try to patrol. It's large. Moving from Ceres to Vesta is not going to be particularly easier than moving from Ceres to Mars - at least if you're not interested in waiting a few millenia for a proper Hohmann window. If people have any interests in the asteroid belt, they will be clustered around a few asteroids and the rest will be ignored.”

Think Coast Guard. They don’t patrol the entire ocean- just the territorial waters of their country, and then mostly the shipping lanes. A potential Space Patrol Cutter would likewise stay close to the normal shipping routes between major asteroids- that is, if there is any particular interest in the belt. A planetary system such as Jupiter or Saturn would be a more likely location.

One advantage to a cutter is that is allows an authority both enforce laws (mining claims, disputes between settlements, ect) and provide a valuable service (search and rescue), but in a way with less of a militaristic flavor.

Of course, that’s only if there is an authority willing to spend the time, money, and effort to maintain this presence (always the caveat here).

Geoffrey S H said...

Why hve a seperate hab section?
Mass penalties would rersult from giving it a seperate engine- meaning the propulsion unit would have to be upscaled, likely making things too expensive.

Keep them all in one, keeping the propulsion unit within a managable and cost effective size. If that means that the design is impracticle, then i gues that means that patrol craft are not very cost effective or useful at all.


You have any larger combat craft, both manned and unmanned on the way, or any freight stuff? Would be interesting to seeyour ideas...

Geoffrey S H said...

...not to mention that the propulsion unit would not probably be able to get out of range, given tht there is no such thng as range inspace, and would not b able to change its cvourse- the combat module would be on the same flight path and therefore the propulsion module would eventually come within "range" of any combatant. It would have to be protected in some way from even the weakest of hostiles and thus might have armor, etc, driving up the mass penalties yet further.

I'm sorry, but I don't see how having seperate modules would make this concept any more workable.

Thucydides said...

Separation of modules provides a certain flexibility to perform different missions and tasks (the hab module can be replaced by another fuel tank if you want to fly the carrier/laser bus as part of a combat constellation, for example, or each part can be upgraded as needed rather than taking the entire unit out for a refit).

As well, approaching a colony, hab or other object of interest with the manned hab is less threatening than moving in with the entire assembly (especially the armed part) even though leaving the armed transit/laser bus in High Guard is actually more threatening...moving around and docking near or on large space structures like habs, colonies or momentum tethers will also be much easier if the carrier/laser bus is left behind. A colony made of a lot of small habs and other units clustered around a massive momentum tether would be much harder to approach with a huge spacecraft.

This is also an interesting inversion of the "aircraft carrier in Space" trope; the "Galactica" is the 40m diameter hab module while the "Viper" is the 300m weapons/bus assembly. Hot pilot Apollo is sitting beside Col Tighe at the console wondering "what is that aftershave he's wearing [and how is he tweaking the life support system to produce that awful stuff anyway]?

Tony said...


"Perhaps, though, the word "patrol" conjures up too many visions of continual movement for many people here. Maybe "deployment" would be a better general term, if only to reduce confusion and assumptions?"

There are all kinds of patrols -- ambush patrols, security patrols, reconaissance patrols, contact patrols... Just because most people tend to think security patrol when they hear the word "patrol", that doesn't mean other patrols stop being patrols.

What we're talking about here is just a security patrol with a very narrowly defined patrol area and a built in reaction force.

Byron said...

Armor would be useful for dealing with the buckshot problem. There is no way that a ship could intercept all of it, and it is possible to armor against it. Also, I seriously doubt lasers will be that accurate. Just because a telescope can resolve details of a certain size doesn't mean it has that sort of pointing accuracy. The same applies to lasers.

On a strategic level, there are very few interesting places in the solar system. Earth, Mars, Jupiter, Saturn, maybe Ceres and another couple of asteroids. It's very easy to put a small garrison at all of those. For another example, Rocketverse really only has three major planets. And yes, each moon system is close enough together to be patrolled from a single base.

What I'm proposing is not overkill. I'm suggesting stationing a small station with a couple of corvettes at a place I have interests that isn't unified. The base supports them, and probably any merchant trade as well. It's a lot of what your and Saber's bases on 5-2 do. I can see detachable habs somewhat replacing the station, but it still seems easier to not have to worry about interplanetary equipment for your combat ships. Plus, the presence is there constantly. And why is leaving a station in orbit more provocative than keeping a ship there all the time?

Thucydides said...

I have to agree that armour is not going to be a priority, or even possible for most of the ship. Since there is a crewed hab, that will be the armoured citadel to protect the crew and most of the electronics from radiation and micrometeor erosion while in flight.

A few other sections of the ship will be built with lots of extra strength in order to deal with flight stress or for other reasons (the Liniac and optical train for the laser will be encased in its own truss within the keel truss to remain aligned and isolated from shock and vibration coming from the rest of the ship.), but for the most part, the performance gains from reducing mass will be far greater than the gains from armouring the entire structure.

Thinking along those lines, the ship might be designed to use water as remass, since it not a deep cyrogen and relieves the design of huge heavily insulated tanks, cyrocoolers and so on. Water is pretty easily available from almost anywhere in the solar system, so the crew should be able to gain access to it without a lot of difficulty.

Rick said...

As noted above, nearly all of the Solar System, including nearly all of the asteroid belt, is nothing but miles and miles and miles of miles.

Human factors are a huge constraint here because the long travel times, and the dicey question of minimum crew and hab size for missions so prolonged that they are more 'tour of duty' than 'deployment.'

Which actually has more than just military implications.

Raymond said...


Dammit, I knew you were going to say something like that. I should've left in my caveat about the multiplicity of patrol types. (Lesson for the day: always include the caveat.) Yes, I know there are a lot of different patrols. I think Rick may be right, however, in that the duration is long enough to change the nature of the deployment somewhat. Is a mission lasting the better part of a year still a patrol?

Byron - a few things:

- Having a cruiser offshore during a potential crisis and having a permanent or semi-permanent garrison are very different animals, politically. The former is more suited to transient or temporary concerns, the latter can be viewed as an occupation. A corvette can be dispatched to a trouble spot in a fraction of the time required to establish a station and its supply lines. If you have the political muscle and the forces to spare to maintain bases in every major planetary system and most of the minor ones, with accompanying supply lines, then you're probably The Empire and outside the scope of this discussion (wherein we assume that the populated solar system is much larger than your routine political reach).

- If we include small and/or scattered settlements in the asteroid belt, the list of possible trouble spots is much larger than the one you give. Also, gas giant moon systems are large enough that travel time can still be measured in days. Having warcraft with weapon travel times in hours (or seconds) can still be a major advantage. Perhaps you'd have a station in the Jovian system, but you could still be well-served by sending a patrol to Europa if a crisis looms.

- If the interplanetary drive pylon and hab section detaches from the shorter-ranged combat portion, couldn't we call the hab/propulsion module a station? How about if we attach multiple combat sub-craft? (Maybe that's a carrier...)

- There are also some advantages to keeping the higher-level maintenance and refit capability closer to home, and rotating the whole machine to and from its intended deployment. A permanent station would require a larger maintenance contingent and accompanying facilities, which are harder to support further away. A corvette on patrol can be brought back afterwards, and have the more involved refit operations performed well away from potential enemy forces.


I'm not talking about armoring the whole craft. A faceplate would likely suffice for combat operations. The shutters on lasers, however, would likely be quite thin - just enough to protect from micrometeors and very small fragments - and would be basically required to keep the mirror in good enough shape for combat. I have yet to hear a good technical argument on how grains of sand or small buckshot-like shrapnel would have much more penetrative power than the kind of particulate threats faced by mere transit, and thus why such a weapon would really work that well against a sensible mirror design.

Brian said...

Hey guys, off topic, however, the blog writer did mention Heinlein in this blog entry...what is with the lack of availability of Heinlein books in electronic format?? Peanut Press only has 3, Amazon Kindle has 3 or 4 it looks like, Sony ebook catalog seems to be the best with 9. If I want to read it on my Palm m515, my options are quite limited; it seems the better ways are to buy it on paper or borrow it on paper from the public library... :-( I read a lot of books on my Palm m515, most of which I got for free (because they are too old to be copyrighted) from Project Gutenberg. :-)

Byron said...

I know that a corvette is faster than setting up a station. What I'm saying is that likely crisis spots will have permanent bases established before the crisis occurs. It's a lot faster to go from the base to the trouble spot than the home planet.
And I'm mostly referring to keeping stations in areas with lots of different factions in close proximity. Generally, those tend to be where crises occur, and also it's easier to get basing rights there.
And if there's a crisis on Europa, I'll move ships from my Jovian station there. It's a lot faster than moving them from earth, and I can supply them much more easily.
The carrier concept works, but it still has to get there in a crisis, and move back and forth in peacetime.
I'm not suggesting complete refits being conducted at these stations. Minor work would be done here, and for overhauls, they'd be sent back. Again, it's cheaper to do on site.

Raymond said...


There are these horrible, nasty things called "torrents" in the parlance of the rogues and villains populating the seedier areas of the net. I couldn't possibly recommend searching through them, even though they have of late expanded their thievery of the estates of dead authors into the once-sacred realm of the written word, and may be able to supply you with the filthy trash you seek.

Raymond said...


Carrier, station-with-engine, not seeing a lot of difference. Launching craft from your Jovian station to provide presence around Europa? Sounds exactly like a patrol to me. Nobody said you had to launch all your patrols from your home base.

There's also the level of investment - having one or two tours' worth of patrols for a given crisis window costs a lot less than setting up a long-term base, and said crisis window may not be long enough to justify the commitment you're advocating.

Not that you'll never set up a long-term base, just that it's a different level of force allocation. Having bases everywhere assumes you have enough available forces to be everywhere, which may not necessarily be the case.

Byron said...

However, crises tend to cluster. This will be even more the case in space. Nobody really proposes more than isolated mining colonies in the belt, which leaves the various planets. Most people can probably maintain a deployment or two at the planets they have interests in. It's not a cure-all, but it's better for a lot of situations.
And I never claimed that Jupiter to Europa wasn't a patrol. It's just a far more limited one. I've been advocating against regular interplanetary patrols, which Thucydides started.

Milo said...


"What I'm saying is that likely crisis spots will have permanent bases established before the crisis occurs."

If it's economically affordable and politically acceptable to maintain permanent bases in all these locations. Neither is a guarantee.

"And I'm mostly referring to keeping stations in areas with lots of different factions in close proximity. Generally, those tend to be where crises occur, and also it's easier to get basing rights there."

That's nice for gas giant systems, not so much for, say, Mars.

Tony said...


"Dammit, I knew you were going to say something like that. I should've left in my caveat about the multiplicity of patrol types. (Lesson for the day: always include the caveat.) Yes, I know there are a lot of different patrols. I think Rick may be right, however, in that the duration is long enough to change the nature of the deployment somewhat. Is a mission lasting the better part of a year still a patrol?"

Well...let's all recognize that people in the future doing this kind of thing will call it whatever they wish to call it. So whatever terminology we use here will strictly for our purposes. I just don't think patrol is all that bad a word for sitting on station for months or years, providing security, and reacting to whatever comes up. We don't need to find a better or more precisely descriptive term. We just need to recognize where and how such missions will likely be conducted, and go form there.

If our host Rick, who could be doing something else -- probably more productive and cardiologically safe -- wants to use "patrol" as a naming convention, I'm not really interested in arguing over it. It's close enough.

Citizen Joe said...

I also think that the Coast Guard model is the better example. Patrolling may involve search and rescue, plus safety inspections, customs inspections, space hazard mapping/clearing. But this really only applies to 'deep' space. If you're talking about orbital space patrols, there isn't much need for a manned presence. The patrol ships would be out there performing duties that would make space commerce safer/more affordable. i.e. Your merchant vessel could go with less armament (mass) if it knew that the path was cleared ahead of time by a patrol vessel.

Rick said...

I have no problem with using the word patrol for long duration missions. It might then acquire secondary connotations in the space service, such as 'tour of duty.'

The ambiguity of 'ship' versus 'station' has some interesting implications. Base facilities can be repositioned in the time scale of shifting policy concerns, from Ceres in the 2270s to Jupiter after the collapse of the Athens Accord in 2293, returning to Mars space in 2312-13 and assigned to administrative patrol.

But there is a Really Important consideration that I left out, hab radiation shielding. You can get away with nothing but a storm celler for a few months, but if you are going to live in space for years you need to spend most of it behind plenty of shielding.

This favors big habs for any prolonged stay, since hab volume increases faster than surface to be shielded. I believe that large habs will also be better for other human factors - you are still cooped in a can, but a bigger can with more variety, including more people.

These big habs can be fitted with a drive bus, so they are mobile, though probably sluggish, but you will certainly want much smaller fast transports. And you won't have many of the big habs, because they are big, and therefore expensive.

But as noted the Solar System has only a few zones of real interest - basically the planetary space and moon systems of the major planets, plus whatever handful of smaller bodies turns out to be of special interest. So half a dozen 'regional' base stations pretty much will cover everything.

Milo said...

"But there is a Really Important consideration that I left out, hab radiation shielding. You can get away with nothing but a storm cellar for a few months, but if you are going to live in space for years you need to spend most of it behind plenty of shielding."

On the other hand, you need considerably less shielding if you plan to stay inside a magnetosphere than if you plan to travel through interplanetary space.

But then again, does anywhere except Earth even have enough of a magnetosphere to protect against radiation (without causing more radiation than it stops, like Jupiter's)? And practically, if you aren't worried about needing to ever move your base, you're going to be much more liberal with piling on lots of mass, even if it's only a minor benefit.

tkinias said...

Just thinking a bit about the question of bases vs. “patrols”. Let’s say you’ve got a point of interest that’s a one year round trip from Earth (or Starbase One or whatever). Let’s say, also, that two years is the maximum acceptable deployment length for your crews. That means that a crew must spend half its deployment in transit. There are AFAICT basically two ways to tackle the problem: (1) keep the combat vessels on station and swap out the crews annually, using transports to move the crews there and home; and (2) swap out the combat vessels themselves annually. Having stationary bases is essentially a variant on (1).

Option (1) lets you get by with half as many hulls—assuming the spacecraft never need yard maintenance. If they need to go into the yard every few years anyway, the savings in hulls is much reduced. Offsetting the savings in hull numbers might be a diminution in crew effectiveness, what with starting over with a new crew (or one that hasn't done its job for at least a year) annually. And that’s not to mention the possibility that transports might not be considered safe conveyance out to remote stations.

Option (2) may, in some circumstances, be a reasonable tradeoff. And “six months out, twelve on station, six back” could be considered to be something rather like a “patrol” of sorts, no?

Rick said...

If you are using transports to swap the crews out and back, you also need to count the cost of the transports. How much this adds depends basically on how much of the cost of the warships goes to their specifically military features.

For example, the patrol ships I described in this post are basically just moderately armed transport types themselves, so keeping them on station and rotating crews aboard regular transports might not save that much. If you were supporting a laser star on station it would be a different matter.

Thucydides said...

It seems to me that given the size of nuclear or fusion engines, fuel and remass tanks the size of nuclear submarines, radiator assemblies, etc. you are already talking about a huge ship. At this point, you should have enough room for a Liniac or Surfatron to power the proverbial laser of stupendous range, and plenty of space on the truss to mount lots of hard points for KKV busses, 10m main mirror assemblies, relay mirrors, target drones and whatever else you desire.

The interplanetary craft is already a laserstar or kineticstar. A manned module is needed to provide the man in the loop capability to control the weapons once you are near a planetary orbit or similarly "cluttered" space (industrial hab cluster or massive momentum transfer device) where clear shots are difficult, and to do the up close and personal inspection visits. The minimum size for this is about 40m diameter so the crew inside isn't being distressed by the Coriolis force, although radiation shielding and human factors might require a much larger hab. An alternative unitary design would resemble an umbrella, with hab modules on the ends of long booms projecting from the central truss and the whole thing rotating slowly around the long axis for gravity.

So we don't really have a patrol craft at all, but a cruiser capable of relatively independent action, and a unit capable of being networked with similar units to become the basis of a constellation.

Milo said...


"It seems to me that given the size of nuclear or fusion engines, fuel and remass tanks the size of nuclear submarines, radiator assemblies, etc. you are already talking about a huge ship."

We have no idea how large fusion engines are going to be, given that we haven't built any yet.

Even for old-fashioned fission stuff, the fact that we're in space at all means we've probably managed to improve on the efficiency of current designs. But by how much... who can say?

Thucydides said...

We have some idea of what a fusion engine *might* look like, by scaling things like the laser ignition facility or ITER. Even the EMC2 IEC design is estimated to be built around a 5 m diameter sphere so we have a sort of upper and lower estimate.

Even a small, IEC based design will need various control equipment, the magnetic nozzle for thrust and the cooling apparatus leading to the radiators, so you will be looking at something the size of a bungalow on the end of the truss. The obvious payoff is there is far greater potential ISP with a fusion design. If you want to use fission, an NTR tops out at @ 1200 seconds (with a realistic figure of 800 seconds), and to go well above that you would need to develop large and complex "nuclear light bulbs" using gas core reactors, which will probably be just as big as the IEC.

KraKon said...


KraKon said...


Anonymous said...

I think the main difference between 'ship' classes and 'station' classes will be function and capability, rather than a hard-and-fast division. If modular designs prevail, then it may well be that future spacecraft could fill both functions at different times during its service life...
Oh, and speaking of modular; different types of propulsion would probably be used for different mission profiles.


Rick said...

Yes. I don't think modularity is a be all and end all, but it works well in the space environment. In particular the distinction between payload and drive bus seems fairly fundamental. One drive bus can boost many different payloads, and a payload in an orbital mission doesn't need a deep space bus.

Most prospective high ISP drives are electric. (There are exceptions, such as classical Orion that just boots you along.) Any electric drive that can push a fair sized ship on fast orbits can provide a lot of plug power for a laser.

So it is plausible that you could have even commercial drive buses fitted with the needed connection and switching gear, the 'plug,' and have laser pods available for wartime service, allowing any big ship to function as a laser star.

By our expectations such a cobble should be no match for a real warship, but I am not sure that the analogy to current era war vehicles really holds up. Lasers don't zap enemy ships, they zap enemy lasers. (Or incoming kinetics, and if the kinetics get through they'll blast you to Hellenbach.)

So only the laser pod really has to stand up to a fight. The drive bus that carries it is more like a locomotive hauling a railroad gun than the hull of a battleship.

Milo said...


"If modular designs prevail, then it may well be that future spacecraft could fill both functions at different times during its service life..."

Today, it is common for permanently moored ships to serve some useful function.


"allowing any big ship to function as a laser star."

While any ship will have ample energy for a laser, that doesn't mean that the laser equipment itself won't be expensive. Also remember to count the necessary secondary components: turrets, firing ports, sensors, fire-link computers.

"So only the laser pod really has to stand up to a fight."

Destroying an enemy ship's engines will set the enemy back by a sizable amount of money, and the ship is incapable of making any maneuvers. While this will not immediately affect your fight, losing strategic mobility is a serious blow to the enemy in a larger campaign.

If this happens in deep space (that is, in transit), then the crippled ship will be unable to come to a stop at its destination, and is doomed to ring-out.

Furthermore, remember that the laser is being powered by the electric plants in the ship's engines. So...

Rick said...

Permanently moored naval hulks, and the railroads' similar use of old passenger cars, was my inspiration. At first I pictured old ships being used as interim stations. Then I realized that stations could be built where your industry is and simply flown out to their duty location.

Elukka said...

Thanks for the kind words and sorry I took so long to respond.

Here are some more numbers, copied from my design document. Many of the figures are (hopefully at least slightly educated) guesses, though I did the math on the propulsion system. I can't vouch for it all adding up though! And I'm still not sure how to calculate thrust power.


Mass Distribution (metric tonnes)
1 100 t – methane (CH4) tank (loaded)
220 t – liquid oxygen (LOX) tank (loaded)
640 t – NTR engine pods, total
15 t – secondary propulsion & reaction control system
140 t – habitat & life support
70 t – weaponry

Propellant mass: 1300 t
Total mass: 2 185 t

25.7 MN (acceleration 1.2 g) – gas core nuclear thermal
60 MN (acceleration 2.8 g) – with LOX injection

Exhaust velocity
65 km/s – gas core nuclear thermal rockets
44 km/s – gas core NTR with LOX injection
3,8 km/s – chemical rocket (CH4/LOX)

Propellant mass flow
425 kg/s

30.6 km/s


Thucydides - Your ideas remind me of the Human Outer Planet Exploration (HOPE) designs. There are some nice renders of those craft around, but I don't remember where. Google image search will probably find them. I might end up doing something with the concept some time.

Ferrell - Those kinds of missions are pretty much what I had in mind for it - anything you need a fast ship, and optionally weapons, for. I don't really think my interceptor classification for it is a very good fit, but I failed to come up with anything better.
...Hm. Perhaps there could be a dedicated combat variant of the design, though.

Rick - It's modeled in Google Sketchup (still the only 3D modeler I can wrap my head around), and rendered in Kerkythea.

Geoff - I have a bunch of other ships, but most of them are either still only in my head or old and terrible :P I modeled a really quick and dirty Orion-powered freight barge a while back though, but I'm not sure it'll ever end up finished.

Oh, and there's also this significantly more finished and slightly less recent another pic)

Elukka said...

Well, I mangled that up somehow. Last paragraph is supposed to be:

Oh, and there's also this significantly more finished and slightly less recent missile corvette. (another pic)

Nyrath the nearly wise said...

There are some images of HOPE here
Human Outer Planet Exploration

Nyrath the nearly wise said...

Elukka, you should experiment with the free 3D modeling program Blender. It is not that much more difficult than Sketchup.

sample of my blender stuff

Elukka said...

Hey, it's you! I'd just like to note that most of what I know about spaceflight and ship design is thanks to your site.

Byron said...

I'm not sure what version of blender you're using, but I've used both it and sketchup, and it's a lot harder to learn blender. I only know how to use it for video editing.

And I second Elukka's comment. It probably applies to most of us here.

Nyrath the nearly wise said...

Why, thank you. I'm glad you found my site useful.

People who want retro-SF asteroid patrols might be satisfied with patrols around Saturn's rings. The delta vees and synodic periods are much more reasonable.

Ring Raders

It still relies upon many shaky assumptions, but there is it.

Byron said...

And what of all this speculation doesn't rest on shaky assumptions. It's a lot less of a jump to Saturn than to orbit, in many ways.

Elukka said...

Blender is my eternal nemesis. Every once in a while I download the newest version, try to grasp it, look up a tutorial or two and get nowhere.

I'd love to learn it somehow, I just don't know how - I'm painfully aware of Sketchup's limitations.

Byron said...

There's always option three. I've done my stuff in Autodesk Inventor. Still, that's not exactly in the same category. But I've tried Blender, too. All I ever did was use it to edit my video.

Elukka said...

Nyrath, I have a story (mostly in my head) maybe-kinda-sorta in the works inspired by Ring Raiders. It's not Saturn, though, (which gives me some convenient freedoms) but it is a society that's grown around a gas giant's atmospheric mining colony.

Geoffrey S H said...


I think its pretty much each to his own with programs for modelling...I find sketchup brilliant, but couldn't get my head roud blender either.

I have some models on the go, but they are on the very end of the plausible midfuture, and have nothing in the way of support struts or detail yet... my computer can't take much detail on the screen unfortunetly.

Geoffrey S H said...

Whoops! Misread the comments here, thought Byron said blender was easier for him.

In the case then I agree on the difficulties of blender... does blender allow more details? Always wondered that...

Elukka said...

Well, Blender is way more powerful than Sketchup... I don't know the specifics, but my understanding is there's very little you can't do in Blender, while there's plenty you can't do in Sketchup.

It'd certainly be worth learning.

Geoffrey S H said...

Time, time, time...

As interesting as building models is, and learning numbers of a rocketpunk setting, university work comes first.

Now if some stuff on sketch-up I could do on blender in more detail and (crucially) in LESS TIME, then I might think of learning it.

Details such as greeblies, etc....

P.s: Elukka,Is that corvette of any particular nationality? Just curious.

Elukka said...

Not really, no, unless a completely fictional nation counts.

It's not a coincidence that I modeled it after visiting a Sovremenny class destroyer, however. :p

Thucydides said...

Jerry Pournelle pointed out the drawbacks of belters and their pesky torchships (there is really no need to be limited to the belt, or anywhere in the Solar System with that kind of technology), but did suggest that if you had NERVA style ships, the moons of Jupiter would be quite easily colonized, with plenty of opportunities to run patrols, regular shipping etc.

Saturn is even better, since we not only have lots of moons, plenty or water, nitrogen and hydrocarbons for remass but also the Rings themselves as a setting for whatever we want to do.

Rick said...

Elukka - the ship you posted originally looked rather Russian to me, but the corvette not so much. In fact the big projecting missile tubes (?) put me in mind of the USN 'dynamite cruiser' of the 1890s.

Elukka said...

I think a gas giant is a great setting not only due to the things you mentioned, but also because they look really cool, (especially if they have rings) and their surrounding space is reasonably small. It's a nice change from Galactic Empires when you can actually often see the place you're going to.

And there is, of course, still the possibility of longer interplanetary expeditions.

Rick - The habitat module of the first ship does borrow from the Soyuz. The dynamite cruiser is interesting... And that's a cool ship class name, in a very retro way. (oh, and yes, they're missile tubes)

Milo said...

"when you can actually often see the place you're going to"

That's an interesting point. I see the moon much more often than I see any foreign nation, but I would have a much easier time visiting the latter than the former :)

And seeing an inhabited world in the sky is always inspiring.

Thucydides said...

i hadn't thought of the dynamite cruiser when I saw the model, rather ex Soviet frigates and cruisers with batteries of missiles on the deck to support their main mission: attack and destroy carrier battle groups. Even the rather outlandish Soviet "Lun" class ekranoplan mounted multiple anti ship missiles on the upper fuselage. (As an aside, the dynamite gun used a compressed air charge to lob dynamite shells at the target, since dynamite shells were considered somewhat unstable and prone to detonate prematurely if subjected to the shock of a regular artillery piece)

This is interesting, since it represents a sort of middle ground between carrying missiles internally somewhat like a torpedo (or missile in a VLS cell), or strapping them on the outside of the ship somewhat like a fighter plane's missile. Of course very large ships might carry KKV's in a magazine and launch them out of a turret.

Given the space environment is pretty hard on equipment, I suspect that missiles/torpedoes/KKV's or whatever your kinetic weapon is classed as will have to be carried in some sort of protected enclosure, and so need a launch tube or turret to be expelled from the vehicle.

For ships which rotate about their long axis for centrifugal "gravity", weapons might be mounted in pods on the ends of booms to utilize some of the spin energy to cleanly separate from the vessel and get a bit of initial boost before lighting off the booster. in the more general case, I would favour the use of VLS cells in order to ripple or salvo the weapons in a mass launch to overwhelm enemy lasers, Kirklin mines or KKV's.

Since patrol vessels as described in the opening page are essentially light cruisers (capable of independent action), then they will need to carry their kinetic battery in such a manner, or risk being swarmed by enemy weapons.

francisdrake said...

This is a really interesting thread, combining the space opera stuff 'space patrol' with reality (or at least posibility)!

I am thrilled by the amount of profound discussion, but I think taking current or past naval strategies as a blueprint for spacewar is too far fetched.

WWII was not Napoleonic armies with Stukas (if you pardon me that drastic comparision) and an interplanetary conflict will not be like Guadalcanal in space.

I even doubt if 'war' is the right name, and that a 'warship' would be the method to wage war in space.

Assuming an interplanetary scenario were different factions will not settle for a political solution (which would be the preferrable solution by far!) they will seek to imply their will on the opponent.

They will look for adequate methods to 'project their power' onto the adversary. I don't think a patrol ship, alone in hostile space, months away from any reinforcement, with very limited deltaV, is an adequate measure.

If you want somebody to subject to your will, you must be able to give him bad times, which are so bad that he settles for the lesser of two evils and does what you want.

These threats could be
- disrupting his economical base,
- inflict pain on him, or
- take his life.

And the cost of these threats should not exceed whatever you intend to gain in the end. Cost includes here the cost of lifes, which some seem willing to spend, as long as it is not their own lifes ...

Based on the above I would see the patrol task, meaning 'gather intelligence', as a purely robotic mission. Robots are relatively cheap, as there is no need for a life support system, not even for a return flight.

The 'show the flag' part I would rather leave to merchant vessels. Transporting goods over the vastness of space will be a pretty impressive job on its own. Being present with a regular flight schedule, providing valuable merchandise and transport options will by far exceed the presence of any muscle-packed patrol ship painted in red-white-blue (or any other color of your liking :)

If a conflict arises, and if settling this conflict by military measures is chosen as the appropriate measure (that is pretty big IF) it would be about time to send your fleet of death and destruction to the enemy.

This has to be a pretty impressive strike, to saturate his defenses and inflict heavy damage on his base or planet. Again this is not a job for a single patrol vessel lingering around. I even doubt if this strike fleet has to be manned at all. The task is to fly to the target and hit it hard. Robots could do that pretty good, especially if they do not have to slow down and can hit the target with orbital speed.

Sorry to say, but out of all these scenarios I do not see any task for a manned space patrol. I agree it does make great stories for a space opera, but I don't expect it to be seen around the solar system anytime in the future.

francisdrake said...

Ahh, sorry, double post!
How can I delete that?

Rick said...

I got rid of the duplicate.

I agree with much of your main point; these craft have little or no role if major powers come to blows in space.

Essentially these are police craft. The alternative of simply putting the police presence aboard transport ships (conceptually, even if not an actual SWAT team) is fine so long as you own the transport ships.

I'm picturing an era when commercial transports have become the rule, so the patrol authority (or authorities) can't simply piggyback on them.

All that said, it is pretty much space opera with an illusion of realism.

francisdrake said...

Rick, thanks for deleting the double post!

I imagine a short range patrol (around the homebase or planet) would make sense, but this would rather be a kind of 'coast guard'. It could inspect incoming vessels. If necessary reinforcements would be at close range.

For long range operations I could imagine purchasing space on a commercial vessel. Like on a Spacing Guild-vessel in Frank Herberts 'Dune'. If we consider the interplanetary routes to be something like a railroad that could be an option.

Rick said...

That is an interesting concept! You need the interplanetary operator to be 'above the battle' (or pulling strings), in any case willing to provide space to all comers including paramilitary craft.

You might want to drop by the 'First Stage' discussion thread, because I am about to take your username in vain. :-)

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mike said...

Hi, First time poster, long time reader (I used Springsharp and the aircraft spreadsheet for Nationstates).

I've been following your space-warfare posts, and I've got a few comments.

For the patrol craft, design really depends on the geopolitical situation. Are we talking about multiple earth nations with a presence in space keeping a wary eye on each other, or corporations trying to keep their indentured servants in line? Only very wealthy nations would be able to afford anything commensurate to a purpose built ship of war/patrol, and I can imagine having one of these in orbit around you being extremely demoralizing. I don't see any purpose for them to be deployed to friendly space... if it's friendly, your inspection crews can ride in small runabouts, and live on a base, and they needn't be armed because you'll have remote weapon platforms controlled by either ground or space bases. The only place where they'd be useful is orbiting and threatening a potentially hostile population. Where there's room for a kinetic payload, there's room for nukes. If you think of it less as a police/inspection platform and more of a mobile intimidation platform with the legs to change orbit (or even run home), it makes sense. For myself, I'd like to see it with a larger payload capacity, so it could deploy a constellation of observation/kill satellites over its target.