Yes, and in the 3I there may be very many fully automated assembly plants just making deep space S&R drones, seeding local space with them, tens, maybe hundreds of millions of them, maybe billions, etc. Low tech, low power systems that just drift, passively scanning maybe 1AU, maybe 10AU, until needed

On 21/02/2016 11:24 AM, <xxxxxx@shadowgard.com> wrote:

On 16 Feb 2016 at 7:11, Greg Chalik wrote:

> My thinking was that all spaceships can have an emergency transmitter
> like IFF, and search vessels, probably robotic, can just traverse the
> space pinging away until they get a 'target'.

The sheer *size* of space renders that unworkable.

That plus speed of light limits.

Ignoring signal strength, it'd take 5 hours for the ping to go from
here to the (average) distance of Pluto, and another 5 hours to
return.

It'd take 7.2 years for the round trip over a parsec.

To give another idea of the scales involved, the distance from the
earth to the sun is 150 million km. That's one astronomical unit
(AU).

Pluto averages 39 AU from the sun. A parsec is a bit over 200,000 AU.

So if one AU is a meter, a parsec is more than 200 km.

Add in issues of speed-of-light lag and signal strength and it'd
taken *generations* to cover one hex with any reasonable number of
ships.

It'd be like looking for a person lost on an empty North america by
using people walking a search grid, yelling, and hoping to hear an
answer.

Let's try another analogy. The Us is about 3000 miles wide. Let's map
a subsector onto that (sideways). So a 10 parsec long by 8 parsec
wide subsector would be 3000 miles by 2400 miles.

One parsec would be 300 miles. and one AU would be about 8 *feet*.

And one inch would be about a million miles....

A misjumped ship can be up to 36 parsecs away from its starting
point. On the above scale that's almost 11,000 miles. Big enough that
the curvature of the earth starts affecting the analogy badly.

--
Leonard Erickson (aka shadow)
shadow at shadowgard dot com

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