[Spaceships] How should a large station... duck?

[David Johnston2]

Originally Posted by DataPacRat

Would it help if the star this cylinder orbits was deep enough in a nebula to make it infeasible to pick out the cylinder from afar?-

I feel like pointing out something obvious. If the enemy can pick out the cylinder from that kind of range, then the people who built the cylinder can definitely see the kind of energy expenditure it takes to accelerate a missile to relativistic speeds; something which would be much more obvious.

[AlexanderHowl]

Well, a far enough starting point (like a light-year) and a slow enough acceleration (no more than 0.01g) might go undetected with the proper design, but it would be unlikely to get above 0.05c in a realistic setting. Anyway, destroying such a treasure would be beyond insanity, as it is a prize beyond compare. If it is a TL12 civilization, its productive capacity would be phenomenal (a SM+33 nanofactory could produce $3 quintillion worth of products per hour), and it could produce a SM+15 battleship every second with enough materials.

[(E)]

What about using the robotic miners as tugs?

[Donny Brook]

Place it in mutual orbit with a tethered counterweight. To dodge, reel out more tether.

[Fred Brackin]

I don't see the difficulty. The scaling of Spaceships that allows you to build a sM+34 object just by moving your decimal point far to the right will let you build an engine to propel it too.

[Agemegos]

Originally Posted by Fred Brackin

I don't see the difficulty. The scaling of Spaceships that allows you to build a sM+34 object just by moving your decimal point far to the right will let you build an engine to propel it too.

I think the problem is that as your orbital habitat gets bigger the distance that it has to move in order to dodge gets bigger, but the time you have to dodge in doesn't get any longer, so you need higher velocities and therefore greater acceleration. A habitat that is SM+34 is about a million metres across. If it gets, say, 100 seconds to dodge in it must apply 200 m/s² to dodging, which is about twenty gee. Whereas as ship of, say, SM+13 only needs to dodge by 300 metres in the same time: 0.006 gee is sufficient.

Give an SM+13 ship half a gee of acceleration to dodge with and then it can dodge in 11 seconds. An SM+34 habitat with half a gee needs 633 seconds.

Originally Posted by Anthony

At 0.99c, in the reference frame of the target, it takes light 500s to cross 1 AU, and it takes the impactor 495s, so you have only 5s warning. This generally makes detection not very viable. However, the impactor has the same problem: you probably don't know the target's position with more accuracy than 'orbiting that planet', so if you've got 5 km/s delta-v available for course correction, you need to know the target's position something like 1,250s before impact, which means you need to be able to detect the target (and distinguish it from possible decoys) at 250AU.

It's an orbiting habitat the size of a minor planet, with no drives. With a bit of public-source intelligence it ought to be possible to predict its position for a year in advance with a precision better than one kilometre.

[John_A_Tallon]

Originally Posted by Donny Brook

Place it in mutual orbit with a tethered counterweight. To dodge, reel out more tether.

That's very clever. I like it.

[Ulzgoroth]

Originally Posted by Donny Brook

Place it in mutual orbit with a tethered counterweight. To dodge, reel out more tether.

If you can manage a really big megastructure, you can one-up that by having a counterweight-and-cable system that wraps around the star and lets you adjust your orbital radius. Over lengthy projectile flight times that should let your orbital period be unpredictable so they basically have to search the entire orbit for you during the approach.

(If you don't mind being unsubtle, putting a big opaque cloud of satellite/statite objects around the system so the attacker can't see anything until they get very close is a possibility, but it sounds like security-through-obscurity is wanted here and being a blatant astronomical anomaly might hurt that.)

[Fred Brackin]

Originally Posted by Ulzgoroth

(If you don't mind being unsubtle, putting a big opaque cloud of satellite/statite objects around the

Put those things around the megastructure you're trying to hide. Then make the shielding items out of very transparent glass or plastic and fill them witha m ix of hydrogen with a little helium and maybe some traces of methane and/or ammonia.

From a few light years away you might look like a gas giant. :)

[DataPacRat]

Originally Posted by (E)

What about using the robotic miners as tugs?

Scale issues. A SM+12 robo-miner/tug is around the size of one of the Pyramids; the station is around the size of the entirety of Egypt.


In case it might affect anyone's thought processes, I'm planning for the plot to be set a long time after this station was built, after several pre-industrial civilizations have risen and fallen internally. I want to heavily lean on the tropes of exploring the unknown, at several scales: not knowing what will be found inside the station, outside the station, and possibly even within the main characters if I can manage that level of subtlety. If I can get away with it, a more physics-compliant version of Dungeon Crawl Classics.