From: Eugen Leitl (eugen@leitl.org)
Date: Tue Sep 10 2002 - 11:41:36 MDT
On Tue, 10 Sep 2002 CurtAdams@aol.com wrote:
> You're a little sloppy with your attributions. Most of this is mine,
> to which he was replying.
I know that, he knows that, you know that. The original piece was lost
upstream in the inbox. I personally blame the tetanus vaccine.
> >My guesstimate is a few kg for the payload. The sail could be a few tons.
>
> That's a complete guess from where the sun doesn't shine. The non-water
No, it was a guesstimate, and a conservative one at that.
> part of the human brain is about 0.15 kg and it's vastly insufficient. We
Actually, we're talking about large-scale structures built by a hard
vacuum form of gray goo on steroids. It doesn't take a lot more of
information to create an insect than to create a procaryonte. The
effective seed itself is thus minimally few ten cubic micron sized, not
considered redundant encoding for radiation hardening. The rest of it is
navigation, hull, power plant and reaction mass. Consider it a capsid, a
delivery vehicle. If you remove the transport vector, and put it gently
down on the surface of a well-insolated carbonaceous rock, the perfectly
fertile seed for the future large scale machinery is probably barely
visible with the naked eye.
Besides, it doesn't matter whether the seed is the size of a poppy seed,
an acorn, a coconut, or a truck. In fact, a larger sail is a target less
easy to miss, and allows you to package lots of fancy stuff into it.
> couldn't even figure out what it would take to recreate civilization and it
We don't want to recreate a civilization. (At least not yet). We want to
create a bootstrap bridgehead, a cosmic mitt for subsequent baseballs
whirled thisaway, which requires orders of magnitude of an animal genome
to encode, if done efficiently. You can of course include complete
civilization seeds, in the volume of a grapefruit or less.
> would certainly be enormous - gigatons of equipment and people, minimally.
People are bitvectors. Gigatons is cheap, if your equipment is
autopoietic. Image: you can grow a forest the size of a continent starting
with a single acorn.
> How much more efficient could nanotech be? We don't know.
It doesn't matter. It's at least as efficient as biology, and most likely
one or two (perhaps even three, but now my other name *is* pujol) orders
of magnitude more efficient (in terms of functionality concentration).
> Like I said - propellant, not data, for space operations. It's big and things
> move very fast.
That's the whole point of using photons for propellant. You leave your
power plant at home, your propulsion is completely passive.
> The problem is that even with excellent focus your fluxes have to
> cover an enormous area - solar system size. You can't keep it focused
> on a little sail at 10,000 AU.
Solar system is few lighthours across. This is also roughly the aperture
size of our instrument. We have to track the sail for few lightmonths. We
have the complete power of a star at our disposal. While this is possible
that we can't achieve enough flux on a ~10 km sized object (which is
sailing the gradient towards strongest flux, so we don't have to track
that precisely) I don't think this is likely. I can't crunch it for you,
though. Input from other armchair space conquistadores is solicited.
> Actually you do need corrections at 0.9 c 5-fold mass increase at that point.
> Not night-and-day, but not trivial either.
Not to shabby, considered whether this has been pulled from (ewww). 5-fold
is coolio, if you don't like it, use 0.8 c, then.
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