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Re: Re: Summary

Also to Kelly
> >I'm just saying that there is a limit to the amount of information that
> >be transmitted inteligably over interstellar distences even is your
> >with all the usable spectrum.  Obviously the local star(s) will drown out
> >most of the frequency bands, given that earth scopes will be looking
> >at it.  So we will eiather have to make due with that stars quiet bands,
> >incredible amounts of power (you really want to out shout a star?), and
use a
> >lot of low bouad and error correction to make up for interfearence.
> There indeed will be a limit but is that limit really to small? These
> SETI-programs seem to scan many bands, and their telescopes are pointed
> directly at the stars. I assume they have made some calculations about
> Signal to Noise ratio. I am not saying that it is easy but we were more or
> less assuming we could use a beam to propell the starship. If we are not
> able to propell a starship with it we certainly could use it as a
> transmitter for information.

I wasn't assuming we would be using a propulsion beam, much less build one in
the target systems.  You've pretty wel convinced me that, that isn't

SETI wasn't expecting to download the output of a couple hundred researchers
and all there raw data.  I know bandwidth is a problem on the hubble and the
other remote platforms (they use data filtering to skim out the desired
parts, and everyone prays they selected the right parts) so I assume the
problem would also exist for a starship.


> >A simple system like a fuel launcher that only has to work for a couple
> >months every few deacdes should be able to be automated once its set up.
> >making redundant copies will assure acceptable relyability.  Also the
> >thing eveyone does when entering the system is repair the fuel launcher.
> In this conclusion you say that it could work automatically for a few
> or so. Could we really trust such a big machinery to keep on working for
> several months (if not a year)? Because when it doesn't, that means we are
> doomed. Besides that I can recall some one saying that an Earth-based
> launcher would be better than a ship-based launcher because of the amount
> people needed to operate it (and because of the weight that the ship
> need to carry, but that isn't discussed here).

Sure, we have a lot of big mechanical systems experience and the launcher is
very simple and has very few moving parts.  The complex part would be the
minning and construction parts, and the crews will be around to supervise


> >> On a multi-gen ship there will also be a scientific crew, they are
> >> explorers. If then need some practical experience, they will have all
> >> time they need. Simulators for shuttles and vehicles could do a great
> >> helping them.
> >
> >You can't simulate exploring planets in the confines of a vitual reality
> >simulator, nor can you learn everything about fliying high performance
> >aircraft without flying them.  None of which can be done completly in a
> > In a multi-gen crew.  Nothing about exploration, not even seeing a real
> >or horizon would be familure to them.
> Indeed they would not have experience walking through the landscape etc.
> they could learn fast enough. A multi-gen ship would not need to examine
> star-system within a small period. If they wanted they could take a few
> generations. They would be excellent objective observers since they
> know very well what Earth was like. Flying aircrafts perfectly isn't
> necessary, as long as the flight and landing is reasonable smooth that is
> enough.

Thats like giving a navy TomCat fighter and mission to someone whos never
been out of doors, much less in and aircraft, but has played the sim game a
lot.  (The landings should be especiaslly --- colorfull.)

> >> It's a big risk trusting your live to a automated system on which you
> >> have no control. A single programming error can shut down the power
> >> and there would be no one to turn it on again.
> >
> >Compared to the dangers of a colony, thats trivial.
> At least one has the idea that it can do something about it when living in
> space colony. And why should a space colony be so significantly more
> dangerous than a 5 year flight in space?

Because a space colony is a 50-100 year flight through space.  Same life
support needs and risks, just for 10-20 times longer, and with and
increasingly old and wornout crew and ship.

> >I agree that hibernation is risky technically and unsafe.  But that
> >effect its political risk.  Politics is about impressions, not realities.
> The media would certainly point at all possible difficulties, certainly
> obvious ones.

Not if they liked the program.  Media generally don't ask many hard questions
of things they agree with.  Look at how little media investigation there has
been on global warming and greenhouse theories.  They are every bit as easy
to investigate, yet that seldom is done.  Certainly my experience at NASA
confirms that.

> >> So, do you know how to solve it without having a big industry at the
> >> end of the trip?
> >
> >You could save the light high tech parts of the stages (fuel processors,
> >power systems, etc) and throw away the heavy structure and tanks.  That
> >allow you to rebuild the heavy stuff in the starsystem from local ores,
> >refit it with the salvaged parts of the old stages.
> I wonder if any part at a rocket engine can be regarded as not hi-tech. And
> if it is, it still takes quite a while to rebuild and assemble all the
> parts. You don't want several parts to break down while you are on your way
> back.

I was thinking the pumps and fuel processors, and high energy power systejms
wouldn't weigh as much as the propulsion dishes, tanks, and reinforcing
structure.  Those heavy parts would be easier to rebuild in systems from
local ores.

You can design systems to function for a while with failures.  With a staged
system you'ld just need to transfer fuel to the remaining working boosters.

> >However you should note that staging quickly requiers a HUGE ship.  You
> >quickly might need to mine a starsystem for fuel.
> It's the use of fusion-fuel that causes this, staging is a result of using
> fusion fuel. (Just a minor difference)

Or any fuel without a much higher power to weight ratio.

> >> How where you going to use that heat then?  Does it matter that 
> >> much if you are first tranforming the heat into electricity?
> >
> >The Bussard reactors, and the fuels they use; don't produce radiation,
> >or the rest.  The power comes out as charged fast moving particals.  Those
> >particals can be run past a magnetic feild for almost perfect conversion
> >the fuels power to electricity (with virtually no thermal load) or
> >as a reaction mass.
> I really wonder how this works, does the LIT-page about this, cover that

Don't remember.  I'm sure I've discused it a few times and went into some
details on my old web page.