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RE: starship-design: RE: New Starship Classes

> -----Original Message-----
> From: Kelly St [mailto:KellySt@aol.com]
> Sent: Thursday, April 23, 1998 10:46 PM
> To: lparker@cacaphony.net; starship-design@lists.uoregon.edu
> Subject: Re: starship-design: RE: New Starship Classes

> 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?

It isn't so much a matter of HOW I expect to get continuous 1G thrust as a
matter of defining what is necessary to make the mission possible. I ruled
out centripetal force artificial gravity schemes as being unworkable in the
long run, which leaves only continuous acceleration. This coupled with the
need to make the flight times as short as possible produces an optimum
flight profile of 1G continuous acceleration.

I am not so sure that fusion motors are capable of this, just that it is
necessary. Any advance that makes ACMF motors more efficient will probably
also apply to any other type of fusion system to some degree. I don't really
care if it is ACMF or fuel sail or something else.
> 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.

Again, I am being somewhat more optimisitic about what can be accomplished
by robotic/AI systems with humans near by to provide backup. As an example,
return to the question of finding alien artifacts, it would be enormously
difficult to program a robot to recognize an alien artifact that we
ourselves have never seen. What we can do however, is program a set of
boundary conditions that would trigger an alarm to bring a human
teleoperator into the loop. Such a system would not work over interstellar
distances of course, but if the operator is in the same planetary system
within a few light minutes, it is capable of expanding our reach enormously.

> 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.

My point exactly, of course we have been over this before...

> 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.

Thank you, not being one of the founding members, I had never heard the
reasons for the selection of criteria. They make sense.

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

Kelly is glossing over the truth here. After LOTS of discussion, we couldn't
find ANY reason to go period. Unfortunately, our purpose here was to design
a way to get there. Kind of shot ourselves in the foot.

Actually, I prefer to think of it more like the parable of the man and the

We will go because it is there.

> I have serious qualms about that statement.  Your drive
> system doesn'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.

See above. I expect orders of magnitude improvement from any system before
we can go....

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

The engine I described is the one the Air Force is funding.

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

For both our sakes I hope they become very plentiful and cheap...