Then Klaus Teufel brought this up:
Yesterday 11:23 PM
Let's crunch some numbers.
Jupiter has an area of 52 billion square kilometers. A fast streamlined ship, let's say it makes Mach 5. If refueling takes 6 hours as I suggested the SDB can intercept ships passing within 36000 km. That gives an area of 400 million square kilometers or .7% of the planet's area. That means you need at least 130 SDBs to cover a gas giant. That's for an intercept by one SBD which is a tall order for the SDB if the opposing task force has any kind of admiral in command. The tenders will either have defenses or escorts (hey, fighters might be a good idea after all!)
If the SDBs are any good at all we're talking 200 Mcr each, that means you need 26 billion credits for minimum coverage. If you use ten times the number to have a flotilla covering the gas giant completely that 260 billion credits. Ten ships probably won't be enough. Remember the name of the game is High Guard. The rest of the squadron will be hovering nearby ready to call the wrath of GHU down on your flotilla. Now 260 billion credits is also a lot to spend on a last ditch scorched earth strategy. Maybe if you spent that money on your main fleet the bad guys wouldn't win in the first place? Most planets haven't got many trillions to spend on defense. Likewise most sector navies don't want to spend that much on every planet.
So how do you defend your gas giant?
In a word: nukes.
Read Special Supplement 4: Missiles. Mines are perfectly allowable in that system and fairly cheap. In space even an unguided piece of explosive will hit anything within 2500 miles. So they must still have some kind of short range guidance and propulsion. Buy a bunch of them. Stick them under balloons. They have an intercept area of 20 million square kilometers and you need 2600 to cover a gas giant. At the cost of even 100,000 cr. you could buy a few thousand for the cost of a single SDB. Seed the gas giant with them. Use your SDBs to maintain and control them as needed. When the bad guys show up watch hilarity ensue.
Even if your ship is moving mach 1 to refuel you cover 24,000 kilometers in the six hours I established for refueling. That means you cut across the engagement areas of at least ten nukes. Even that relatively expensive option is probably 10 Mcr or less. Again you can afford 10 times or more the number of turrets as SDBs.There will probably be more. Instead of a single mine laying under a balloon imagine a remote controlled triple turret with three launchers.
May I point that nukes are bad in space but they are absolutely terrifying in an atmosphere. In space nuclear weapons mainly damage through x-rays melting your hull. Atmospheres add blast effects to that. This is happening to a tanker or tender the owner probably try to save money on. The tanker is probably moving at several mach. It will not respond well to huge blasts being set off around it.
I always assumed the High Guard concerned themselves with incoming attacks while their comrades were refueling. It seems they need to worry about what is below as well as above. Refueling might be a matter of clearing a region of the gas giant and confining your refueling operations there. But by then you've restricted your area of operations and then the SDBs have a great chance to find you and raise merry hell.
I said it before but Traveller is about making difficult decisions. Personally I'd chicken out and refuel at the nearest Europa type moon. Quick thaw an area with nukes or lasers and fill them up.
Except you could mine Europa too.