Re: starship-design: my $0.02 (finally)

["L. Clayton Parker" <lparker@cacaphony.net>]

Zenon,

> This seems a reasonable requirement.
> Though, at the target you may still require something like
> spinning habitat to provide (pseudo)gravity for stay in the system.
> Unless you plan to build from the start a base 
> on some massive enough planet.
> 
> > More would be better, who knows what might come up.
> > 
> Not unless you plan some hibernation or "unburdening" environment
> for most of the crew.

I was simply allowing for emergency needs, not expecting that they would
sustain high-g accelerations for any considerable length of time. For
instance, there have been several proposals for gravity assisted manuevers
during the initial acceleration (or deceleration) phase in which having the
availability of additional thrust for a short length of time would
substantially alter the final velocity.

> > 2) On board reaction mass must be either sufficient for the ROUNDTRIP
or
> > easily replaceable with on board resources. Don't forget a safety
margin
> > here also.
> > 
> Concerning ROUNDTRIP - I disagree. 
> I am appending my letter from some time ago addressing this issue
> in case you heve missed it.
> WARNING: I do not want to start again my standard quarrel
> with Kelly here. Just to state my view...
>

You and Kelly have a standard quarrel? How nice! <G>

> 
> > 3) Engineering of the all systems (command, control, communications,
> > environmental and propulsion) should be sufficiently simple to permit
> > repairs and maintenance by the crew during the mission, or self repair
> > ability should be built in (preferably both).
> > 
> Agreed.
> However, I think that will be possoble only with considerable
> advances in AI and nanotechnology.

Ummm, some of this is even simpler than that. For example, do you honestly
think we can send a starship out with off the shelf light bulbs with only a
750 hour lifespan?

> 
> > 4) The propulsion system must be rugged enough to withstand continuous
> > operation without major overhaul or replacement for a period equal to
at
> > least two and a half to three times the duration of the voyage. (Note
that
> > this almost automatically excludes most current technologies.)
> > 
> Agreed.
> Note also that the roundtrip requirement would DOUBLE (at least!)
> the problem here.

That is why I chose two and a half to three times the duration of the
VOYAGE, a LARGE safety margin.

> > 5) Manned exploratory missions must be roundtrip, colonization missions
can
> > be considered one way for purposes of design. But the mass of a colony
> > ship will be corespondingly greater requiring an even more robust
design.
> > 
> See below: One-way has lesser requirements than 
> both roundtrip and colonization,
> and differs from colonization mission in ONLY ONE aspect:
> reproduction is switched off (so to speak).

I KNOW this point has been discussed before, but I simply think it is
impractical (not to mention immoral and unethical) to send our brightest
people out on what amounts to a suicide mission...now for robot probes this
is more than adequate. I would expect that ANY system we send a manned
exploration team to would already have been visited by at least one robot
probe to determine if it was even worth a second look.

> I think that the best way of investigating different options
> is my old idea of formulating a "design space": a structured
> list of possible options with crosslinks describing
> interdependencies of choices in different slots in the structure.
> See archives of the list (or ask me to forward some relevant
> messages).

I agree with the concept of design space, it is substantially the same
thing on a broader scale than what I had been saying. I have seen most of
the discussions, I have been following this list for several years even
though I am not a frequent contributor.

I deleted the remainder for brevity...

I do not necessarily disagree with what you say with the following
provisos:

1)	One way implies NO RETURN. Establishment of a long term base with
EVENTUAL return, resupply or additional personnel is not the same thing.

2)	Send robotic Pathfinders FIRST. No "one way" manned missions to systems
that do not have a hope of eventual settlement or offer some other
overpowering reason to establish a permanent manned presence.

3)	It makes more sense to establish our base(s) in the new system in space
first, then on the planetary bodies. We spent four and half million years
trying to get off of this planet, what's your hurry? In other words, the
industry that you assume to be in place in our outer solar system would in
reality be the first settlers of the new system. Given human behavior, I
suspect that it makes more sense that way anyway.

4)	Under these conditions, procreation within the limits of the life
support system is not only possible, it might even be desirable. You need
to look at this from a "human" perspective as well as scientific and
engineering.

So to review, a "one way" mission to set up an initial outpost either in
orbit or upon one or more satellites (not planets) with the eventual
promise of additional personnel and resupply as well as a chance of
rotation back to Sol, with the purpose of eventually settling the new
system and its planet(s) is reasonable.

A mission that is "one way" in the sense that there will be no hope of
return, resupply, relief, etc., is impractical and indefensible.

Lee Parker