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Re: Re: Summary

>>>Lower information return to Earth due to limited baud rates of interstellar
>>Assuming we are able to create 1E18 Watts I think that bandwidth is minor
>Power gets you range, not bandwidth.  Since you only have the ability to
>use the avalible spectrum once.  I do worry about bandwidth.

I assumed these bands where unusable because of interstellar noise, but
since that does not seem to be the case, I ask you which interstellar bands
are not usable and why? I cannot believe that the bandwith is too small, if
necessary we may be able to build X-ray transmitters.

>>>Technically more challenging.  Getting a ship to the target starsystem is
>>>hard enough.  Getting it back would make it harder.  But this must be
>>>traded off against the added complexity of a ship capable of supporting its
>>>crew for the rest of their lives.
>>Indeed, but if we are not able to build a small colony during a one-way
>>mission than the chances are small that we are able to build a complete
>>power array for a two-way mission. So this means that all power for the
>>return mission has to come Earth.
>No, that would only be true if you asumed a beamed power ship, which I
>don't.  Besides, if you do have a beamed power system that can power the
>ship all the way into another star system (which seems questionable),
>useing that system again to get the ship out wouldn't add any complexity.
>Upgrading all the ship systems for an indefinate stay would add complexity.

It would have been easier if you wrote what kind of propulsion you assumed.
Since you are not assuming a beamed power ship, I assume you use a fusion
powered ship so distances are less than 6 ly. This limits the amount of
possible stars even more, I would see that as a cerious disadvantage.


>>Also politically less preferable, because the project will take longer and
>>probably twice the effort.
>Thats a possibility.  It certianly would be politically less likely to be
>funded allong its entire history.  But given that expenses would be spread
>out over a longer time it might cost less over a given period of time.
>I'm surprized you objected to this section thou, since its the only option
>(i.e. assured routine supply flight) that woulkd allow a colony mission?

I'm just being consequent.


>>>Crew constructs equipment for return flight

>>This assumes that either people stay behind to control and repair the
>>launcher or that we have AI that is smart enough to keep the thing working
>>!! This is something we have not discussed before as far as I know !!
>Sure we have.  Months ago.

Then what was the conclusion, I can't remember it?

Saying that it only has to work for 20 years, is not enough since the pro
was that it had to make a two way trip easier.

>It wouldn't take the same equipment as a colony, nor would it nessisarily
>be a power array.

If you are planning on building a big mirror, I think you need a lot of
machinery and crew to operate it. To build anything like a mirror of several
kilmetres, you need ore-extracters, refineries, transporters etc. The amount
in which they are needed exceeds by far that what is needed for building a
colony. The mirror may look easy to build but I'm sure that almost
everything you need for a colony you also need for building a mirror. The
only thing you would not need is a farm.


>>>Multi-generation Succeeding generations of crew continue the mission

>There environment wont be that of explorers, but as ship crew.  The
>mission, exploring and returning info to earth, would interfear with that.
>The history of utopian or riligious colonies in the U.S. suggestes that
>children and gradchildren don't followe int the focused extreams of the

We are not talking about religious groups. These groups often have the
tendency to cling to an utopia. Often they use stringent rules based on the
belief of the leader, everyone trying to disobey is punished. On an explorer
ship people can have a more democratic way of living.
Also not everybody needs to be an explorer, there are people that need to do
other jobs as well.

>No, the initial crew could be trained on earth and the solar system, by
>people who operated the systems in a real environment.  That wouldn't be
>possible on the ship.  Especially when the origional, experienced crew grew
>old and died.

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 the
time they need. Simulators for shuttles and vehicles could do a great job
helping them.

>I disagree that a two way mission depends on a beamed power system, nor am
>I assuming were going to Tau Ceti.  Given that we've been at this for over
>a year and a half and still havent figured out any way to get there, I'm
>not optimistic.

It would be nice if you wrote that somewhere in this draft though.

>Ignoring that I don't follow your assumption that it would make a one way
>mission more practical or feasable.  A power system would only need to keep
>working for a few years until the ship gets to the drive cut off point.

It's a big risk trusting your live to a automated system on which you would
have no control. A single programming error can shut down the power source
and there would be no one to turn it on again.

>A self sustaining colony would need to keep working for generations, and
>require huge amounts of people.  Even if a colony was buildable, that
>doesn't nessisarily make it politically feasable.  Your still sending
>people out to a desolate area for no real proactical benifit (other than
>scientific, which doesn't require a colony).

With colony I don't necessary mean a planet based one, a scientific mission
that would really "get into" the planets would need much more than 10 years,
so they would like a place to live also.

>>Multi-step, Multi-gen and hibernation ships all have the same condition(=a
>>working ship for >40 years) as a one-way mission so I think they should have
>>the same political feasability.
>The difference in political terms, is that it would seem likely that a
>hibernation system would get the crew back alive (assuming everthing
>worked).  The others condem them to die in space.

You are constantly saying most things will break down within 25 to 35 years.
If the largest part of the crew is in hybernation, they will have an even
harder job to get things fixed in time. So if I want to follow that,
hibernation is even doomed more than a one-way mission. And of course this
assumes that hibernation will work, I personally would see a bigger
possibility of an anti-matter drive than for hibernation.

>>The difference between constrution-return and round-trip are not clear since
>>we haven't defined how(=what energy source) the round-trip makes its return.
>>So its not clear how the differences in feasability are explained.
>Rount trip could use a fusion powered ship that mines fuel in the system.
>Possibly with a fuel launcher construction option.

Of course we need to know if the fuel we need can be found and mined easely.
Although hydrogen will be present, it may not be as concentrated as we like.


>Not likely.  We have no reason to asume we'ld find any earth like planets
>in neighboring star systems.  Especiall ones that are so earth like as to
>be comfortable.  (I.E. an Earth like world that was no cooler or wetter
>than the Sahara or warmer than the antarctic in winter, would still be
>remarkable.)  Certainly if you sticking to the L.I.T. Tau C. flight idea,
>by definition their were no even vaugly earth like worlds spotted there.

Then why are we going, one of the main LIT objectives was that there was a
strong evidence of life in the system we would explore.

When there is life it will almost certainly have some acceptable temperature.


>>A problem with staging is that you throw away your ship, this makes a
>>two-way mission much harder!

So, do you know how to solve it without having a big industry at the remote
end of the trip?

>>This is not certain, the ideas I stated some time ago are only a few and
>>were considered as most preferred though less easy methods. There does not
>>have to be a real difference between a fusion or an anti-matter powered
>>ship. Both can be used as heat-energy sources to accelerate reaction mass.
>True, but I wasn't expectin to use the fusion power to heat a rockets
>reation mass.  That would threaten to melt the ship quickly.

How where you going to use that heat then? Does it matter that much if you
are first tranforming the heat into electricity?

>>FTL is a principle that has been withstanding many experiments to unprove
>>it. Chances are small that FTL will become possible in the next century (if
>>at all).
>Small but not impossible.  It seems ftl is possible, but we know of no way
>to do it with any realistic physical system, much less a buildable one.
>But then we would have said that about space travel a couple of cventuries
>ago. It definatly requires some new physics (as opposed to engineering)
>tricks.  Then again, without it star travel beyond the nearest stars will
>never be practical.

Why does it seem that ftl is possible, I've never seen a serious article
that stated to have found a way to make a signal travel faster than the
speed of light. Even not in tunneling!


>I don't follow that last bit.  Presumably a one way flight could construct
>a larger space platform for living quarters.  But if they could construct
>anything that extensive, they could build a way to get home.  So presumably
>eiather way they are stuck in the ship.  Just for a lot longer if they
>aren't coming home.

Indeed they could, but maybe they would not want to stay any longer in a
small ship. Of course this depends on the duration of the trip.