Condottiere
Emperor Mongoose
I tend to think that jump flashes scale with the amount of energy that jump drives input.
Navy Logistics
- Thread starter Sageryne
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Terry Mixon
Emperor Mongoose
Could be. All I know for sure is that there is no maximum detection range. It might take a while at lightspeed for the flash to announce the arrival of a fleet, but it will be revealed.
Possibly on departure, but what about arrival?
It can be detected, whether it is revealed or not is a formidable sensor check (with maybe up to DM+4 for very large vessels). According to MGT2 High Guard it also only tells you the size of the ship to the nearest 10,000 tons, so a scout or Free Trader would read the same as a 5000 ton close escort or a 3000 ton Destroyer. A 5000 Ton ship could carry a Type J in a bay, release it as soon as jump was completed, drift off unseen and leave the scout as a credible source of the jump flash (and as a picket ship)
Arkathan
Emperor Mongoose
IIRC, both.
Terry Mixon
Emperor Mongoose
But it will reveal a fleet vs a couple of ships. Like I said, all I was doing was pointing out that Oort Cloud refueling for an aggressor fleet isn’t necessarily a slam dunk.
Condottiere
Emperor Mongoose
In theory, starships coast to their destination.
So you would have an energy discharge on entering jumpspace, and creating a rift on the other end would be detectable as gravity waves, scaling to mass of starship.
So you would have an energy discharge on entering jumpspace, and creating a rift on the other end would be detectable as gravity waves, scaling to mass of starship.
On the other hand, it would be impossible to guard more than a tiny fraction of the Oort cloud, and we're talking at least months of realspace travel to intercept, or a week to get there via Jump. Sol's Oort cloud is estimated to start around 2000 AU and to extend out to 200,000 AU. 1AU is about 8 light minutes, so at 2000AU it takes light about 16,000 minutes to travel. That's 266 hours, or around 11 days. A ship jumping in to the inner Oort would only be detected by anyone in the inner system a week or two after it arrived there. And that's the same for a report by a sensor or patrol that somehow happened to be at the spot they jumped into.
The distances are too vast to be able to react, even by elements stationed in the Oort unless those elements are quite close to the arrival, and if so those elements are on their own.
(On the other hand, just because someone jumps into the Oort cloud, it doesn't mean they're that close to an iceball. It could easily take THEM weeks to travel to one. But that still means they're likely to be able to get there, refuel, and jump out before the defenders can detect them and send anyone to where they were a couple of weeks ago...
Terry Mixon
Emperor Mongoose
As I said earlier, an in-system jump would get a reaction force in a week. They’d have to refuel unless they had enough for another jump, but it wouldn’t be months. I should design some QRF (quick, relatively speaking) ships for just that purpose.
The other parts of your response are well considered.
A week AFTER they were aware of the arrival of the intruders, which is going to be a week or two after they arrive.
And once they arrive where the intruders WERE, maybe two to three weeks ago, they're unlikely to still be there. Either they arrived close to a fuel source and have already refueled and left, or they had to travel in realspace to get to it and the intercepting force will need to follow. If they had to spend two weeks to get to that location, so will the pursuers unless those have a significant G edge.
However, there is a slim chance that the defenders might be able to guess which of the thousands of possible objects the invaders had headed to, and if they are lucky, and it was far enough from the entry point, that an interception might occur.
Being able to do an immediate second jump might help, if the intruders did have to head to an object several weeks distant. The fuel situation for the pursuit ships wouldn't be super critical otherwise since they're still in system and other ships could be sent to recover them if absolutely necessary (or even send a tanker with them on the initial jump).
It's important to stress that these distances are at different orders of magnitude than even outer system worlds. You need Jump to get there faster than radio.
But the intruders also need to deal with those distances too - objects are estimated to be separated by 50 million km or so (call it roughly a day's thrust as that's just an average), and not all of them may be suitable for refuelling. Days or weeks of thrusting to get there, then time to gather and crack the ice in temperatures close to absolute zero. But the odds are there's a big enough chunk of pure enough water ice or solid Hydrogen within a day or two, which they can turn into unrefined fuel within a few days and refined fuel with a few days more at most. Call it a week and you're probably close.
So under most circumstances, by the time anyone in the system can detect the arrival, they've been gone for days already.
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Terry Mixon
Emperor Mongoose
That assumes that Oort Cloud refueling is fast, which I submit that it is not. Objects are far apart and one must search for many icy bodies to make it work. Those then need to be melted and processed. For a J4 fleet, that is a lot of fuel. I wish we knew how long such a task takes, but I also submit that two to three weeks might still have them refueling from such a sketchy source.
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Terry Mixon
Emperor Mongoose
And as an exercise, I created a QRF destroyer to respond to fleet arrivals. They would no doubt also have light and heavy cruisers to harass the refueling operations. With stealth jump capability, the enemy won't see them jump out, and most likely won't see them arrive either.
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Condottiere
Emperor Mongoose
The locals are or likely to know the locations of remote iceballs, and would presumably have a doorbell camera installed in orbit.
They would need trillions of them, and that doorbell chime is heard several weeks after the visitors arrive.
I stress again that we are talking about distances that are light WEEKS distant. And that's only the inner Oort. If the intruders choose to jump to the middle of the belt it's light months.
The average separation of Oort Cloud objects is estimated to be around 50 million km, with the average size of one being a few kilometers. And billions of them in the 20 km diameter range.
You could probably cover the dwarf planets - you'd probably be able to get away with mere thousands of sentrys - but the distances still defeat you unless you actually station shooting defenses there. Nothing is going to be able to respond quickly enough. Other Oort dwarf planets are also light days or weeks away.
I stress again that we are talking about distances that are light WEEKS distant. And that's only the inner Oort. If the intruders choose to jump to the middle of the belt it's light months.
The average separation of Oort Cloud objects is estimated to be around 50 million km, with the average size of one being a few kilometers. And billions of them in the 20 km diameter range.
You could probably cover the dwarf planets - you'd probably be able to get away with mere thousands of sentrys - but the distances still defeat you unless you actually station shooting defenses there. Nothing is going to be able to respond quickly enough. Other Oort dwarf planets are also light days or weeks away.
Condottiere
Emperor Mongoose
If refuelling is an issue, that would tend to limit coverage needed.
It's also a hint of something happening in a particular area, to which greater attention can be given
Light speed should ensure some margin of warning time, during which you could send a courier(s) for hep from the neighbours.
It's also a hint of something happening in a particular area, to which greater attention can be given
Light speed should ensure some margin of warning time, during which you could send a courier(s) for hep from the neighbours.
Maybe. If we're getting up towards millions of monitoring stations and thousands of armed bases that can respond in time you begin to approach the density required for the inner cloud.
You might be able to justify such a network at a major hub system in YTU, but I'm not sure that scans for the size of naval budgets we've seen in Chartered Space.
But the cold hard facts are that getting from those bases to locations even a few light hours away is going to take more time than the intruders probably need to refuel, at an exorbitant amount of cost and effort to maintain. And it's only the inner Oort I've been discussing. Multiply the times by 10 for the middle and 100 for the outer. The volume that needs to be covered increases exponentially too.
One last consideration, which is a Chartered Space thing - that far out your Thruster plates don't really work. You'll need reaction drives to get around once you jump in, which may be enough to rule out Oort refueling as a serious tactic in the first place.
MasterGwydion
Emperor Mongoose
Time doesn't matter. Once the fleet has spent a week or two moving, the intercepting fleet wouldn't even be able to detect them on sensors from so far away. They would for all intents and purposes, just be gone.
Edit - Even including the penalty for being too far out from the star.
Scaling things back to closer ice sources... it's still going to be tricky to cover an outer system asteroid belt (which is likely to have a high ice percentage).
For argument's sake and simplicity, let's say there's a belt at "close gas giant" range - around 600 million km further out (4AU). Even 6G takes over two days to travel that distance. The belt would be about 25AU in circumference.
Detection is now a matter of half an hour, not weeks, and intercepting forces can be dispatched to arrive mere days after they arrive. If there are interceptors based in that belt zone they may be closer and be able to arrive much quicker, although space travel can be deceptive there because of acceleration and deceleration. It takes 6G nearly a day to travel only 100 million km, for example.
If you had 25 rapid response stations in such a belt separated by 1AU, they could provide about 18h to intercept cover using 6G SDBs and fighters. I think that might get you there, although it depends a lot on how rapidly they can turn ice into jump fuel. But it is at least practical to look at.
For argument's sake and simplicity, let's say there's a belt at "close gas giant" range - around 600 million km further out (4AU). Even 6G takes over two days to travel that distance. The belt would be about 25AU in circumference.
Detection is now a matter of half an hour, not weeks, and intercepting forces can be dispatched to arrive mere days after they arrive. If there are interceptors based in that belt zone they may be closer and be able to arrive much quicker, although space travel can be deceptive there because of acceleration and deceleration. It takes 6G nearly a day to travel only 100 million km, for example.
If you had 25 rapid response stations in such a belt separated by 1AU, they could provide about 18h to intercept cover using 6G SDBs and fighters. I think that might get you there, although it depends a lot on how rapidly they can turn ice into jump fuel. But it is at least practical to look at.
Maybe we can short cut all this somewhat. What published sources do we have for extensive tanker type craft in the Imperial Navy orders of battle?
If there are none then it is clear that is not how the IN operates.
On the other hand we do know that IN vessels carry sufficient 50 ton support craft (at least in the MGT2 designs) to make refuelling operations possible such that they can skim or uplift from planetary sources to refuel in under a day. We also know that refined fuel is not really necessary if you have decent engineers and astrogators and a properly maintained ship (something I assert is a given for IN).
In order to guarantee hampering a fleet jumping in from refuelling defending forced need to have sufficient force at every possibly refuelling site i.e. every planet with free water (regardless of whether the planetary government permits refuelling since an invader is unlikely to care about that), eery gas giant, the asteroid belt and possibly the Oort cloud. You don't have time to wait for the enemy to appear before dispatching ships as they have at most a day to get there.
Each of those deployed defensive fleets are out of support of the rest. So each have to be sufficient of themselves to defeat the entire enemy fleet. The invading fleet attacks at a point and time of its choosing and can defeat the home fleet in detail.
All this assumes that the enemy fleet is even bothered about making its primary mission objective securing a route of retreat rather than engaging and defeating the home fleet and presumably conquering the system. Unless the fleet where trying to island hop deep into enemy space without securing the systems en-route I cannot see a good reason to do that. It would make more sense to nibble away at the edges, secure them and then use those as jumping off points for subsequent legs.
It seems a distinctly sub-optimal strategy to me and runs against normal expeditionary warfare. I know it is Spaaaace, but that seems a poor excuse to throw common sense out of the window. You secure your lines of retreat, but you don't make that your primary mission objective. If you are jumping in for the purpose of establishing a refuelling depot then you defeat the home fleet first. If retreat is necessary you can achieve that by not jumping to your full extent to get into system.
If all your 50-ton craft are just refuelling cutters you can ensure they are filled before you enter enemy territory. You might just squeak a Jump-1 out of them without even having to send them off, but you can most likely get Jump-1 with a single refuelling trip. Using the fast cutter from the Small Craft Catalogue will speed up the round trip. Using a dedicated 50-ton cargo shuttle with Fuel/Cargo Containers will improve your tankage above the baseline 30 tons. If you were desperate you could even drain the flight tanks of the support vessels if it would just give you enough for a desperate hop away.
I thought fleet combat was supposed to more like submarine warfare than surface fleet actions. Diesel submarines packs didn't have tankers following them around. They had tankers deployed into random bits of the ocean where they went to refuel.
A simple MO might be jump a 5000 ton tanker into the asteroid belt. Deploy an on-board 200-ton seeker ship and have it conduct normal operations (seeking permission to prospect and refuel) and then have it either conduct mining operations or at worst jump out again. Meanwhile the tanker goes silent running and hides in the asteroid belt. As far as the system sensors are concerned a 5000-ton or less ship jumped in, some time later a ship of the correct size entered transponder range and behaved entirely reasonably and if unwelcome flew out to the 100D limit and jumped out. This could be done several times over the course of a few weeks and get lost in normal system traffic.
Frankly with droid labour you could hollow out enough space in an unprofitable rock asteroid to build a substantial fuel depot right under the systems nose with little chance of detection. Even with relatively small numbers of cheap robots this might only take weeks. A long plan might have you build a small hangar and a small craft with refining capacity snuck in. A few mining probes could then be deployed to gather ice from nearby asteroids and over time a stockpile could be built up. This activity might take years of effort to do stealthily, but real life cold war activities have been no less inventive or successful.
If there are none then it is clear that is not how the IN operates.
On the other hand we do know that IN vessels carry sufficient 50 ton support craft (at least in the MGT2 designs) to make refuelling operations possible such that they can skim or uplift from planetary sources to refuel in under a day. We also know that refined fuel is not really necessary if you have decent engineers and astrogators and a properly maintained ship (something I assert is a given for IN).
In order to guarantee hampering a fleet jumping in from refuelling defending forced need to have sufficient force at every possibly refuelling site i.e. every planet with free water (regardless of whether the planetary government permits refuelling since an invader is unlikely to care about that), eery gas giant, the asteroid belt and possibly the Oort cloud. You don't have time to wait for the enemy to appear before dispatching ships as they have at most a day to get there.
Each of those deployed defensive fleets are out of support of the rest. So each have to be sufficient of themselves to defeat the entire enemy fleet. The invading fleet attacks at a point and time of its choosing and can defeat the home fleet in detail.
All this assumes that the enemy fleet is even bothered about making its primary mission objective securing a route of retreat rather than engaging and defeating the home fleet and presumably conquering the system. Unless the fleet where trying to island hop deep into enemy space without securing the systems en-route I cannot see a good reason to do that. It would make more sense to nibble away at the edges, secure them and then use those as jumping off points for subsequent legs.
It seems a distinctly sub-optimal strategy to me and runs against normal expeditionary warfare. I know it is Spaaaace, but that seems a poor excuse to throw common sense out of the window. You secure your lines of retreat, but you don't make that your primary mission objective. If you are jumping in for the purpose of establishing a refuelling depot then you defeat the home fleet first. If retreat is necessary you can achieve that by not jumping to your full extent to get into system.
If all your 50-ton craft are just refuelling cutters you can ensure they are filled before you enter enemy territory. You might just squeak a Jump-1 out of them without even having to send them off, but you can most likely get Jump-1 with a single refuelling trip. Using the fast cutter from the Small Craft Catalogue will speed up the round trip. Using a dedicated 50-ton cargo shuttle with Fuel/Cargo Containers will improve your tankage above the baseline 30 tons. If you were desperate you could even drain the flight tanks of the support vessels if it would just give you enough for a desperate hop away.
I thought fleet combat was supposed to more like submarine warfare than surface fleet actions. Diesel submarines packs didn't have tankers following them around. They had tankers deployed into random bits of the ocean where they went to refuel.
A simple MO might be jump a 5000 ton tanker into the asteroid belt. Deploy an on-board 200-ton seeker ship and have it conduct normal operations (seeking permission to prospect and refuel) and then have it either conduct mining operations or at worst jump out again. Meanwhile the tanker goes silent running and hides in the asteroid belt. As far as the system sensors are concerned a 5000-ton or less ship jumped in, some time later a ship of the correct size entered transponder range and behaved entirely reasonably and if unwelcome flew out to the 100D limit and jumped out. This could be done several times over the course of a few weeks and get lost in normal system traffic.
Frankly with droid labour you could hollow out enough space in an unprofitable rock asteroid to build a substantial fuel depot right under the systems nose with little chance of detection. Even with relatively small numbers of cheap robots this might only take weeks. A long plan might have you build a small hangar and a small craft with refining capacity snuck in. A few mining probes could then be deployed to gather ice from nearby asteroids and over time a stockpile could be built up. This activity might take years of effort to do stealthily, but real life cold war activities have been no less inventive or successful.
Sigtrygg
Emperor Mongoose
I intend to invade system A.
Pre-invasion use "merchant ships" with rather impressive but hidden passive sensors to gather as much data as possible.
Step 1 - use stealth jump scouts to jump into the oort cloud (by the way the Oort cloud may be a lot larger than so far mentioned, current research suggests Sol's oort cloud is as much as 3 light years distant, as Rinku mentioned)
Their job is to locate a comets, or better yet several comets.
Step 2 - use a stealth jump refinery/tender/station ship to jump to the comets and manufacture fuel and drop tanks.
Step 3 - battlefleet jumps to support station, launches drones towards the target world that will arrive in one week going very fast - these are active sensor drones and noise makers. Battlefleet refuels and uses drop tanks to jump insystem. Support staion stealth jumps to back up comet.
Step 4 - drones arrive and start active sensor scans, conduct EW, battlefleet arrives and receives data from drones.
Fight.
Retreat is to station to refuel, repair and rearm.
One last thing added in edit - my invasion force has to be a minimum of three times the tonnage/spinal mounts of the defenders, if the defender has a TL advantage double this for each TL difference.
Pre-invasion use "merchant ships" with rather impressive but hidden passive sensors to gather as much data as possible.
Step 1 - use stealth jump scouts to jump into the oort cloud (by the way the Oort cloud may be a lot larger than so far mentioned, current research suggests Sol's oort cloud is as much as 3 light years distant, as Rinku mentioned)
Their job is to locate a comets, or better yet several comets.
Step 2 - use a stealth jump refinery/tender/station ship to jump to the comets and manufacture fuel and drop tanks.
Step 3 - battlefleet jumps to support station, launches drones towards the target world that will arrive in one week going very fast - these are active sensor drones and noise makers. Battlefleet refuels and uses drop tanks to jump insystem. Support staion stealth jumps to back up comet.
Step 4 - drones arrive and start active sensor scans, conduct EW, battlefleet arrives and receives data from drones.
Fight.
Retreat is to station to refuel, repair and rearm.
One last thing added in edit - my invasion force has to be a minimum of three times the tonnage/spinal mounts of the defenders, if the defender has a TL advantage double this for each TL difference.
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