Re: starship-design: RE: New Starship Classes

[Kelly St <KellySt@aol.com>]

In a message dated 4/20/98 7:12:45 PM, you wrote:

>Chris,
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>
>
>Gee, we've already covered most of those points! Sorry, but I suppose it is
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>unrealistic of me to expect everyone to go and read all of the archives when
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>they join the group...<G>
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>
>
>You raised quite a few points, some of which I will save for the actual
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>description of Pathfinder and Caravan. What I will do is summarize briefly
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>as best as I can remember some of the earlier "discussions" about your
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>questions.
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>
>
>> -----Original Message-----
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>> From: Christoph Kulmann [mailto:guderiak@hotmail.com]
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>> Sent: Sunday, April 19, 1998 12:15 PM
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>> To: lparker@cacaphony.net
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>> Cc: starship-design@lists.uoregon.edu
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>> Subject: New Starship Classes
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>>
>
>>
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>> It's a good idea, but I strongly disagree with your proposed
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>> crew of 10  - 20 specialists.
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>> First of all, even a relatively small ship would still need
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>> decades for
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>> a two-way mission to a neighbouring star system.
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>
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>I am making different assumptions as to propulsion systems. I am assuming
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>constant acceleration at 10 m/sec (1G). Such a trip will take only
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>marginally longer than the difference in light years (in real-time) and
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>considerably less in ship board time.

I've been woundering about this.  HOW can you get continuous 1G thrust?  Even
with the Explorers and Fuel/Sail carrying about 400 times their weight in fuel
they would burn out after only 3-4 months of 1 G accel.  How do you expect to
just so much more power out of your fusionish drive system?



>
>> The second objection is just an innocent question: What should
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>> Pathfinder do? Just monitor an alien star system? A robot
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>> probe could do
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>> the same job - and much, much cheaper. Especially if you
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>> consider that
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>> most of our neighbouring stars won't show any signs of life, I think
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>> it's wiser to send unmanned probes first.
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>
>
>Umm, I think it was the general consensus that anything that a robot probe
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>could discover, we will be able to observe directly from Earth by that time.
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>A ship (of any class) would only be sent after it was determined there was
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>adequate reason to send one. Exactly which type of ship would depend upon
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>what we thought was at the other end.
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>>
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>> To send an Explorer class ship would only be justified if
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>> something very
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>> special is found by one of the Pathfinders:
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>>
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>Which is precisely why I think we need more than one class. It is not going
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>to be immediately apparent that an Explorer class ship is justified in every
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>system we decide to go to. An Explorer is an all purpose vessel with a large
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>crew capable of dealing with every aspect of EXPLORING a new system
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>thoroughly. It would primarily be targeted at systems in which we already
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>expect to establish a permanent manned presence. It would be responsible for
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>preparing the way for colonization.
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>
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>A Pathfinder is more of a survey ship, it would be sent to systems which for
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>some reason we don't get a clear indication of habitable planets or perhaps
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>no indication of habitable planets. As you point out the search for aliens
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>and alien artifacts is important and it would be terribly irresponsible of
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>us to assume that they would only be found in oxygen/water environments.
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>Contrariwise, an Explorer mission to such a null environment would be
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>extremely wasteful of time, money and resources as you point out.

My assumption for Explorer was that a smaller ship couldn't really do a
detailed study of the starsystms.  Given the extream lengths of missions
(decades) sending a mission, carrying back the data, and then using it to plan
the next mission, would just take to damb long.  If you were that patent, you
arn't interested enough to launch the mission.  Yould just wait a few more
decades for the tech to improve.

So Explore was designed big enough so one flight could de a good job of
detailed survay of all the planets, moons, a sample of the asterods and such,
and still have the resources to get everyone back.  For that even with better
automation, is probably a 700 personish crew requirement.


>> 1. A small and relatively fast interstellar probe (WITHOUT any human
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>> crew!!) could be launched within our own lifetime (well, at least
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>> mine...). If they are designed for a one-way mission and
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>> equipped with
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>> high-resolution cameras and powerful senders, multiple star
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>> systems could be screaned simultanously. So we will have
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>> plenty of data
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>> to imagine what is "out yonder". If there is sufficient
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>> public demand,
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>> this could be achieved by a combined international effort.
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>
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>A robot, even an AI robot is only as good as its programming. It won't
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>recognize an alien artifact if it is crawling across the ship's hull. (If it
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>could, we would already know what it looked like and wouldn't need to send
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>the ship!)
>

The robot probes mihgt not be able to bring back much more data then large
telescope from Here, but they'ld be far more expensive, and slower.


>>
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>> 2. If one of the three conditions mentioned above is met, we
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>> can start
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>This was an earlier discussion. Most of what you say here is valid and has
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>already been covered. I am working on a timeline that covers the
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>interplanetary infrastructure necessary to support this mission. The web
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>page containing the timeline draft was previously posted to the group. I
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>haven't worked on it lately, but I will repost the address this weekend.
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>
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>Everyone in the group realizes that 2050 is highly unlikely, barring
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>miraculous breakthroughs, but we had to have some point to aim for and the
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>founding members picked 2050 for good reasons. (Okay, Kelly, David? Someone
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>else want to take up this one?)

Any farther in the future then 2050 and we couldn't clearly guess what kind of
technology we'ld have to work with.  (Even physics mihgt be changing.)  So
we'ld be reduced to debating science fiction senerios about what kind of warp
drives, or hyperspace tricks might be developed.

Also, any then 2050 and we'ld clearly not have the space infastructure to do a
mission on this scale.




>> 3. Now to your Caravan ... more than one ship - I
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>> think, four ... Solar System wide community, with several
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>> billion people living and working outside Earth: on Mars, the Asteroids,
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>> Ganymed, etc.
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>> In other words, we need an economic basis approaching
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>> something like a stellar civilization (Type II in Kardashev's
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>> model). To
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>> be honest, this will take at least one or two MILLENNIA to achieve.

Construction and such of the Explorer and Fuel/Sail craft wouldn't be that
expensive, probably in the tens of billions of dollars, certainly not more
then a couple hundred billion.  The killer is the launcher or microwave
emmiter satelights.  They need to be on such a huge scale you'ld need self
replicating robotic construction systems to go forth and eat a fewthousand
(100 thousand) asteroids and fill the skies with microwave systems.  Other
wise the projects dead, and you wait for the next technology wave to simplify
things.

You don't need to wait for Type-I or type-II civilization status.




>Exploration is a little like math, you cna't move on to the next level until
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>you've already done some of the next level and you will never really
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>complete the previous level until you are fully into the next level. We
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>can't wait until we are a Type II to start doing Type II things or we will
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>never get to be a Type II .... Incidentally, we are net yet a Type I, maybe
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>Type 0.80!
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>
>
>>
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>> But then, a very simple question arises: Why bother with a class of
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>> ships which will only be launched in an era as distant as the Roman
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>> Empire??????
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>
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>Although I understand your reasoning, I disagree with it. I don't believe it
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>will take that long.
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>
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>> Don't you agree that engineers of the 4th Millennium will
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>> have much more
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>> sophisticated technologies from which to build a starship?
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Engineers of the late 21st century would.  Add a century or two and even the
physics bags of tricks will get radically different.  Zero point energy?
Hyperdrive? What?


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>Sure I do, I can also build one heck of catamaran in my backyard. Should the
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>Polynesians have waited until I came along to explore the Pacific?
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>
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>>
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>> --------------------------------------------------
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>>
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>> I hope my arguments don't cause any disillusionment for
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>> anyone. But as
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>> far as starship design is concerned, I think it is important
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>> to stick to
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>> the ground and don't make steps too fast. From the first time I found
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>> your LIT-pages I was fascinated by your concepts because they are
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>> reasonable - they don't move too far into the realm of
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>> Science Fiction.

Thanks.


>I think you will find that most of us are firmly rooted in reality. Much as
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>we might fantasize, the actual concepts defined here are typically rooted in
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>fact, not fiction.

Agreed.


>> But if you plan interstellar colonization before have gathered any
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>> experience with interstellar travel at all - Well, you will
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>> inevitably run into problems...

Actually the idea of interstellar colonization was a sore spot.  Some really
wanted to go that route, others figured any colony would be to small to be
self suficent, and intersteller distences are to expensive to support a
colony.  Also their didn't seem to be any real need.

Actually, why anyone would pay for these missions was also a sore spot.  Why
not just explore the solar system and ignore the stars until you can do it
cheaper and faster?  We couldn't really answer that, but for the purpose of
the exersize we assumed their was a reason.


>Which brings us back to Pathfinder. Pathfinder is doable with only
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>(relatively)modest increases in propulsion. It does not require exorbitant
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>commitments to build compared to Explorer or Caravan and makes a logical
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>choice for a first step to the stars.

I have serious qualms about that statement.  Your drive system dosn't seem to
have any real performance edge over my fusion concepts (fusion produces only
so much power per pound of fuel) but your expecting orders of magnitude better
performance.



>> Your idea of different ship classes is a good one - but I think it is
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>> really wiser to send unmanned, small and relatively cheap Pathfinder
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>> probes first and let them do the remote sensing. Parallel to this we
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>> could refine the design of the Explorer class, which could be
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>> send out once an alien world raises our special curiosity.
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>
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>SNEAK PREVIEW
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>
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>The ICAN II mission serves as the basis of this design. For those who
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>haven't already familiarized themselves with the basics of the ICAN II
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>mission, it is  a Solar Lens satellite delivered to orbit past Pluto by a
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>vehicle powered by an Antiproton Catalyzed Microfission/Fusion (ACMF)
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>engine. This engine does not provide as much impulse as a pure fusion
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>engine, but we don't know how to build a pure fusion engine and probably
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>won't for at least fifty years.

Actually NASA and hte Air Force are considering funding experiments to build
crude ones now.  Fusion motors are far easier then fusion reactors.



>In the interim, I think this engine can be developed to utilize Lithium in
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>one of the low neutron fusion reactions which will also increase thrust by
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>approximately 100 percent. A ship built around three or four of these
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>engines designed for constant acceleration should be possible within fifty
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>years. Of course, such a design would require considerably more than the
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>current or forecasted production of antiprotons, but I am being optimistic
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>here.
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>
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>The constraints of the ICAN mission envisioned a payload mass of 100 tons.
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>After some research, I have determined that 100 tons is the LOWER limit for
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>a Pathfinder mission. Explorer requires much, much more than that. Kelly's
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>proposal for Explorer is well thought out and very comprehensive, but will
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>take longer and cost a lot more.

Thanks.

It depends on how expensive the anti-protons are.  ;)




>Pathfinder is a way of getting there sooner and cheaper when we don't need
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>(or want) a full scale mission. Explorer fits in perfectly as a follow on
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>mission if we find a reason to go back.
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>
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>As I have time (don't hold your breath, I work for a living) I will post the
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>Pathfinder mission definition.
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>
>
>Lee


Kelly