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Re: Space Geography

From: Tom B <kaladorn@g...>
Date: Fri, 23 Sep 2011 02:16:26 -0400
Subject: Re: Space Geography

Roger replied to me:

> "Orbital inclination" is the term you're after here.

TomB: Yes. I wasn't sure what that inclination was relative too so I
avoided the term.

> Inclination of orbital plane relative to the ecliptic, which is what
> described in 2), isn't the same thing as eccentricity.

TomB: I meant eccentric in the sense of 'not conforming to the common
versus mathematically eccentric orbits. Sort of how you might describe
eccentric Englishman. :0)

> But all the planets' planes are within 7 degrees of Earth's orbit, and
> all except Mercury within about 3.5 degrees. To a first approximation,
> the smaller the body, the more inclined its orbit is likely to be -
> Pluto's at 17 degrees, Pallas at 34, Eris at 44.

TomB: That gives me a reasonably idea for Earth's system. What I'm sort
wondering is if this sort of data is readily available from an online
of any sort. (By readily, I also mean 'without mind bending math tools
apply to the data').

> >Would that sort of approach help? Does background clutter matter?
> With realistic sensors, yes, but to a limited extent - remembering how
> sparse real-life asteroid fields are, unless you're willing to bury
> ship in a comet and wait for several years, it _is_ going to be

TomB: I'm not talking about hiding behind planets or comets, although
sorts of things are valid. I'm talking about using background radiation
the systems of your galaxy and perhaps from bodies in your system to
it harder to pick you out.

TomB: Further assumptions:
1) FTL is Hyper
2) FTL system entry is 100D or some other lengthy distance away at
3) FTL exit can be detected reliably close in, less reliable further out
4) FTL exit can preserve speed, but exit vector direction can be chosen
5) Any stealth approach would preclude much braking until you had gotten
close as needed, therefore zero-zero intercepts with a body are not
You want near distance passes at reasonable speeds for engagement. Or
recce with no engagement and a drift out.
6) Hull camouflage that can replicate the pattern of what is behind you
some or all spectra is feasible but perhaps subtly off perfect
7) Heat signature can be masked if not thrusting or firing but only
for a limited
time (hours, days, maybe a week max)

TomB: In assessing what a ship can pick out vs. the background, there
be questions of:
a) sensor transducer capability
b) sensor array capability (assume you are not just using one sensor)
c) sensor system data synthesis capacity
d) rate the system can scan a volume of space (may not be all that fast)
e) computer processing power backing up the sensors
f) how detection changes if the crew are not on alert (are they running
full deep scan or not)
g) ship's own desire to remain hidden or not

TomB: How fast would you have to come in ballistic to close from 100D
without detection if your hull stealth and thermal masking only lasted
days? Is it a practical speed? Does a masked hull stand a chance of not
being picked up by a sweep by a typical sensor array? Lots of
to make, but important to understand if you want to understand how a
would play out. What is and is not possible will govern strategy and

Only solitary men know the full joys of friendship. Others have their
family; but to a solitary and an exile, his friends are everything.
-- Willa Cather (1873 - 1947)Solitudinem fecerunt, pacem appelunt
-- Publius Cornelius Tacitus (from the book Agricola, attributed to a
speech from Calgacus)

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