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Re: Summary

At 12:09 AM 2/2/96, KellySt@aol.com wrote:
>From:	(Timothy van der Linden)
>I had to think it over a while, but thanks for reminding:
>>		* Suicide (explore and die before your time when supplies end)
>>		* One-way (Enough supplies are shipped to stay in target system >
>until natural death)
>>The ship need only be designed for a one time, one way flight.  This limits
>>the technical mission risk and requires less resources.
>Actually there may be an equal or bigger amount of resources. That depends
>on if the crew needs to be larger and if more appliances are needed.
>If instead of 1E9 kg of fuel you could bring extra crew and appliances that
>would probably make a "colonalization" more probable to succeed.

Colonization is infeasable anyway without fantastic reserves of people and
material.  It would take a lot less to return home.

>>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.

>>Round trip (Crew returns to Earth with ship at mission end.)
>>Simplest option, and one with little likely hood of public objection.
>I'm not sure what you mean with simplest, I think only the part after the
>comma is true.

Since the flight would be of a definate, ship survivable, length.  You
wouldn't have as much technical problem with equiping it to survive the
crews life span.  You wouldn't have to design the systems to function with
a declining and incapacitated crew.  You only have to make the life suport
systems good enough to last 20-40 years with a capable crew.

>>It obviously avoids the grisly public relations and crew morale problems of
>>a one way mission.
>Seems to me that you use this twice as a pro in this mission.

I ment then to cover differnt things, but I suppose it is redundant.

>>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.

Note that I'm assuming that the flight would have enough resources to
support the crew for most of their projected life expectancy.  Obviously
this wouldn't be a factor in a flight where the crew is expected to kill
themselves at the end of the mission

>>Pick up and return by follow on flight
>>High risk and more complicated.  Multiple ship types, and concerns that the
>>first ship might be left stranded.
>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?

>>Crew constructs equipment for return flight
>>This option come up with light/microwave sail craft, beamed power craft,
>>and fuel launcher craft.  The crew would  construct automated duplicates of
>>the systems that launched the ship from Sol space.
>>Would establish launcher facilities in both star systems.  Which could
>>allowing faster two way flights with specialized fast light ships.
>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.

>>The crew might get back faster with their ship using the constructed
>>launcher systems for assistance.
>>If they can't build the equipment, they don't get home.
>>The construction phase may require so many resources that the first flight
>>is devoted just to infrastructure construction.  With little or no
>>exploration being done in the first mission.  This obviously would cool
>>public interest and slow down the return of productive information.
>Again, 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.
>Although a power-array may require less different parts than a colony, the
>size it much bigger and it uses the same type of machinery that is required
>to build a colony.

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

>Another con is that less time is available for research, unless robots are a

?? I said that in that statement?

>>Multi-step.  (Ship proceeds to other target star after completion of first
>>mission, in first starsystem.)
>>Technical feasibility is low since wear and tear on the ship would
>>accumulate, dramatically increasing the likelihood of a catastrophic
>>Because of the extremely long flight times with likely technology, the
>>mission would take so long as to be undesirable.  At some point the ship
>>would be superseded by newer faster ships sent straight out from earth,
>>decades after its launch.
>Not even undesirable long, but probably too long. Also the conditions should
>be the same as a one-way mission and it needs much more energy
>>Multi-generation Succeeding generations of crew continue the mission
>>The follow on generation(s) in the ship will have no allegiance or
>>commitment to the mission or its originators (they, never agreed to
>When children grow up in a certain environment, they may like it there. So
>it may be very likely that they will 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

>>The follow on generations would have no hands-on experience with the
>>exploration systems they would be expected to use.  Or for that matter, any
>>experience with planets and starsystems.
>The could be trained just like the initial crew was, the ships computers
>will have a large amount of knowledge and learning tools.

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.

>>               technical                 political          Desirability
>>             Risk    Feasibility     risk     Feasibility
>>One-way      med-low  Medium         Ex-high    Nil          Low
>>Round trip   medium   medium         low        High         high
>>Pick-up      Med-high medium         medium     medium       medium
>>Construct ret high    med-high       medium     medium       medium
>>Multi-step   Ex-High. med-low        low        Medium       medium
>>Multi-gen    Ex-high  Low            high       medium       low
>>Hibernation  high     Low            medium     medium       low
>The feasability of a round trip probably depends on the creation of a power
>source at TC. I think that if that power source can be created, a colony for
>a one-way mission can be build also. That makes the political feasability
>much higher. Maybe even higher than a two way mission. I would find it more
>exciting to know there people building on a new civilazation than on a back
>and forth mission. If the colony could prosper its (political & scientific)
>value is much higher than a two way mission.

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.

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.  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).  That would be a political
problem.  You would NOT be building a new civilization.  Your at best
seting up a minimally self maintaining base in a harsh and isolated
environment.  It would have neather the resources of personal or equipment
to do much more than that.

>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.

>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.

>>Mission purpose
>>Colonization of planets or moons
>>Isolation from resources.  Ores, energy and raw materials are far harder to
>>access on a planet than in space.
>If the death-trap could be overcome be medical care, it may be more pleasant
>to live on a new (fresh) planet than in a space station.

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.

>>propulsion systems
>>Fusion feed from internal fuel sources.
>>Staged fusion ship
>I think you shouldn't look at staging the "classical" way. Why not add
>hundreds of the same kind of engines and throw them away when not needed any
>more. Making many engines of the same type is probably cheaper than a few
>that differ in size. Another advantage is that when one becomes defect it's
>not a big deal (unless it is an error that each engine has).
>In fact this is just a ship with say 1000 stages.

That is "classical" staging?

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


>>Can be destroyed to create tremendous amounts of energy.  Releases over a
>>hundred times as much power per pound of fuel as a fusion reaction.
>>Unfortunately, though it releases more power, this power is harder to
>>directly use to power the ship.
>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.

>>It is however far more dangerous to
>>handle.  If we could synthesize the thousands of tons of antimatter this
>>would take.  It would have the potential of exploding with a force of
>>hundreds of millions of H-bombs.
>This explosion can only happen if there is an equal amount of matter nearby.
>I think it may be possible to keep the anti-matter far enough away (in a
>large torus for example) Of course even when a minor amount of anti-matter
>is "spilled" the ship is likely not to reach its final goal (but does not
>have to explode). So while your argument is not completly right, the idea
>is. But of course when a major engine of the ship stops working indefinately
>this may also be the case.

The ship would be a nearby source of mass.  A leak might not explode all
the fuel in a intermix, but a tiny amount would still go off like a H-bomb.

>>Future tech
>>The engineering and science we have now and assume we will have in the
>>future will change.  Fusion, fission, relativity, quantum mechanics, and a
>>host of other basics of current physics; all were discovered within the
>>last hundred years.  We can conservatively expect physics to have changed
>>far more in the next hundred years, then it did in the last hundred years.
>>What technologies that age will have on hand are impossible to guess.  They
>>could have matter conversion, hyperlight drives, new understandings of
>>inertia and kinetic energy, or all those and far more.  Any of these would
>>dramatically effect our ability to travel between the stars.  So even
>>though we can't come up with any practical ideas for exploring the stars
>>now, we can be sure our descendants will find it far easier than we
>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.

>A possible disavantage for a two way trip is that the crew has to live a
>long time in a ship. If it is a disadvantage depends on the size of the
>ship, if this is a disadvantage for a one way mission depends on the
>possibility to extend the ship when at TC.

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.



Kelly Starks                       Internet: kgstar@most.fw.hac.com
Sr. Systems Engineer
Magnavox Electronic Systems Company
(Magnavox URL: http://www.fw.hac.com/external.html)