> All I know is that there are 47,000 asteroids out there without us having
> done very much polluting as yet.

How  many ships do you envision in a commercially active high-population system?

500?

1000?

2000?

5000?

If we're already tracking 47k asteroids, another 5000 IR beacons with
lights and transponders does not seem particularly challenging.

And ships ARE IR beacons, by default. They will be significantly
warmer than the backgrounds of space, unless lots of special effort is
taken.

> So what happens after a system has been exposed to 3,000 years of
> spacefaring civilization?

After 3000 years, presumably, this is all pretty well worked out science.

> Salvage sounds good, but realistically in space salvage is quite expensive,
> not like on surface where ships just get towed to India and hakced appart by
> illiterate workers.

You're conflating two different things.

Spotting and plotting a derelict is one task.

Intercepting it and towing it somewhere for refit is another.

Spotting and plotting is relatively simple.

Whether anybody has the resources and interest to go out, chase it
down, stop it, and bring it back is a different question.

> I wonder if anyone has tried to produce a formula for calculating amount of
> artificial objects in system based on length of habbitation, size of
> populations, number of habbitats, TLs, etc.

Eh.  You seem to be changing (sort of) the dimensions of the question.
The original issue was keeping track of *ships*, and the primary
concern was ships jumping in-system.  Not so much keeping track of
every nut, bolt, and teddy bear* that ends up in space, lost or
discarded.

> The same problem exists for submarine detection in the littoral which is
> very congested under the surface, and that is even without the man-made
> junk. I'm not aware any nation ahs a full coastal sensor array in place.

Apples and oranges.  Water itself is a tricky medium to find things
in, and your scale is off by several orders of magnitude.

You also seem to be thinking of this in terms of item (say, a sub)
finding another item.  System traffic control is not a single-point
entity.  It will have to be a big, distributed, redundant network.

The Sol system is about 13 light-hours across.  Put a layer of sensor
bouys 15 light minutes above  and 15 minutes below the ecliptic.
Assume each buoy has an observation sphere of 60 light-minutes radi,
that's 28 sensor buoys to give you eyes above and eyes below, with
lots of overlap.   Not an insurmountable task or expense.  It's broad
field IR cameras, computers and comm gear.

Most expensive part of the system will be a couple of 3G tenders and
spare buoys and parts.

(I mean, I came up with this after 15 minutes of noodling around.
3000 years of space travel allows plenty of time to refine the
system.)

If you are worried about people popping in further out, build some
specialized broad-field units and point them toward the rim.

It will be a substantial network of sensor buoys, stations, system
defense and revenue ships.  While it may be possible to use an
asteroid to mask a ships location from one perspective, if there are a
dozen of those sensor buoys, it will be very challenging to hide from
ALL of them at the same time.   If there is a concern with ships
hiding in the asteroid belt, there will be extra sensors, above and
below the ecliptic,

Likewise, even if you can successfully *hide* once in-system, being
hidden limits what you can *do*.  And once your ship comes out of
hiding, it is likely to be spotted and plotted again.

> If you want to discuss Soviet doctrine further, contact me off the list.

And at that point, you're conflating me with someone else.

*B5 reference.

--

"Any sufficiently advanced parody is indistinguishable from a genuine
kook." -Alan Morgan