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starship-design: RE: New Starship Classes


Gee, we've already covered most of those points! Sorry, but I suppose it is
unrealistic of me to expect everyone to go and read all of the archives when
they join the group...<G>

You raised quite a few points, some of which I will save for the actual
description of Pathfinder and Caravan. What I will do is summarize briefly
as best as I can remember some of the earlier "discussions" about your

> -----Original Message-----
> From: Christoph Kulmann [mailto:guderiak@hotmail.com]
> Sent: Sunday, April 19, 1998 12:15 PM
> To: lparker@cacaphony.net
> Cc: starship-design@lists.uoregon.edu
> Subject: New Starship Classes
> It's a good idea, but I strongly disagree with your proposed
> crew of 10
> - 20 specialists.
> First of all, even a relatively small ship would still need
> decades for
> a two-way mission to a neighbouring star system.

I am making different assumptions as to propulsion systems. I am assuming
constant acceleration at 10 m/sec (1G). Such a trip will take only
marginally longer than the difference in light years (in real-time) and
considerably less in ship board time.

> The second objection is just an innocent question: What should
> Pathfinder do? Just monitor an alien star system? A robot
> probe could do
> the same job - and much, much cheaper. Especially if you
> consider that
> most of our neighbouring stars won't show any signs of life, I think
> it's wiser to send unmanned probes first.

Umm, I think it was the general consensus that anything that a robot probe
could discover, we will be able to observe directly from Earth by that time.
A ship (of any class) would only be sent after it was determined there was
adequate reason to send one. Exactly which type of ship would depend upon
what we thought was at the other end.

> To send an Explorer class ship would only be justified if
> something very
> special is found by one of the Pathfinders:
Which is precisely why I think we need more than one class. It is not going
to be immediately apparent that an Explorer class ship is justified in every
system we decide to go to. An Explorer is an all purpose vessel with a large
crew capable of dealing with every aspect of EXPLORING a new system
thoroughly. It would primarily be targeted at systems in which we already
expect to establish a permanent manned presence. It would be responsible for
preparing the way for colonization.

A Pathfinder is more of a survey ship, it would be sent to systems which for
some reason we don't get a clear indication of habitable planets or perhaps
no indication of habitable planets. As you point out the search for aliens
and alien artifacts is important and it would be terribly irresponsible of
us to assume that they would only be found in oxygen/water environments.
Contrariwise, an Explorer mission to such a null environment would be
extremely wasteful of time, money and resources as you point out.

> 1. A small and relatively fast interstellar probe (WITHOUT any human
> crew!!) could be launched within our own lifetime (well, at least
> mine...). If they are designed for a one-way mission and
> equipped with
> high-resolution cameras and powerful senders, multiple star
> systems could be screaned simultanously. So we will have
> plenty of data
> to imagine what is "out yonder". If there is sufficient
> public demand,
> this could be achieved by a combined international effort.

A robot, even an AI robot is only as good as its programming. It won't
recognize an alien artifact if it is crawling across the ship's hull. (If it
could, we would already know what it looked like and wouldn't need to send
the ship!)

> 2. If one of the three conditions mentioned above is met, we
> can start

This was an earlier discussion. Most of what you say here is valid and has
already been covered. I am working on a timeline that covers the
interplanetary infrastructure necessary to support this mission. The web
page containing the timeline draft was previously posted to the group. I
haven't worked on it lately, but I will repost the address this weekend.

Everyone in the group realizes that 2050 is highly unlikely, barring
miraculous breakthroughs, but we had to have some point to aim for and the
founding members picked 2050 for good reasons. (Okay, Kelly, David? Someone
else want to take up this one?)
> 3. Now to your Caravan ... more than one ship - I
> think, four ... Solar System wide community, with several
> billion people living and working outside Earth: on Mars, the Asteroids,
> Ganymed, etc.
> In other words, we need an economic basis approaching
> something like a stellar civilization (Type II in Kardashev's
> model). To
> be honest, this will take at least one or two MILLENNIA to achieve.

Exploration is a little like math, you cna't move on to the next level until
you've already done some of the next level and you will never really
complete the previous level until you are fully into the next level. We
can't wait until we are a Type II to start doing Type II things or we will
never get to be a Type II .... Incidentally, we are net yet a Type I, maybe
Type 0.80!

> But then, a very simple question arises: Why bother with a class of
> ships which will only be launched in an era as distant as the Roman
> Empire??????

Although I understand your reasoning, I disagree with it. I don't believe it
will take that long.

> Don't you agree that engineers of the 4th Millennium will
> have much more
> sophisticated technologies from which to build a starship?

Sure I do, I can also build one heck of catamaran in my backyard. Should the
Polynesians have waited until I came along to explore the Pacific?

> --------------------------------------------------
> I hope my arguments don't cause any disillusionment for
> anyone. But as
> far as starship design is concerned, I think it is important
> to stick to
> the ground and don't make steps too fast. From the first time I found
> your LIT-pages I was fascinated by your concepts because they are
> reasonable - they don't move too far into the realm of
> Science Fiction.

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

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

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

> Your idea of different ship classes is a good one - but I think it is
> really wiser to send unmanned, small and relatively cheap Pathfinder
> probes first and let them do the remote sensing. Parallel to this we
> could refine the design of the Explorer class, which could be
> send out once an alien world raises our special curiosity.


The ICAN II mission serves as the basis of this design. For those who
haven't already familiarized themselves with the basics of the ICAN II
mission, it is  a Solar Lens satellite delivered to orbit past Pluto by a
vehicle powered by an Antiproton Catalyzed Microfission/Fusion (ACMF)
engine. This engine does not provide as much impulse as a pure fusion
engine, but we don't know how to build a pure fusion engine and probably
won't for at least fifty years.

In the interim, I think this engine can be developed to utilize Lithium in
one of the low neutron fusion reactions which will also increase thrust by
approximately 100 percent. A ship built around three or four of these
engines designed for constant acceleration should be possible within fifty
years. Of course, such a design would require considerably more than the
current or forecasted production of antiprotons, but I am being optimistic

The constraints of the ICAN mission envisioned a payload mass of 100 tons.
After some research, I have determined that 100 tons is the LOWER limit for
a Pathfinder mission. Explorer requires much, much more than that. Kelly's
proposal for Explorer is well thought out and very comprehensive, but will
take longer and cost a lot more.

Pathfinder is a way of getting there sooner and cheaper when we don't need
(or want) a full scale mission. Explorer fits in perfectly as a follow on
mission if we find a reason to go back.

As I have time (don't hold your breath, I work for a living) I will post the
Pathfinder mission definition.