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

> From: "L. Clayton Parker" <lparker@cacaphony.net>
> Since most of the discussion so far has revolved around specific
> technologies for GETTING THERE, I thought some consideration of general
> engineering design philosophies might be in order. Here are just a few of
> the key things to consider:
> 1) Minimum acceleration of 10 m/sec - Anything less would take too long to
> get there and expose the crew to a host of side effects. This simplifies
> design of the ship and eliminates the need for spinning habitat rings etc.
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.

> 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...

> 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).
However, I think that will be possoble only with considerable
advances in AI and nanotechnology.

> 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.)
Note also that the roundtrip requirement would DOUBLE (at least!)
the problem here.

> 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).

> These are just some of the things that need to be considered prior to
> selecting a propulsion technology or method. Some methods are just plain
> impractical because they would never last through the trip, others fail to
> meet additional requirements. If I have duplicated previous conversations,
> please excuse this but I think it is more important at this date to define
> requirements before examining the technologies current or hypothesized that
> might fulfill them. If anybody has any additional thoughts or comments
> regarding things they think may be important in defining engineering
> requirements please feel free to post them.
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

Here goes a copy of my letter on mission types:

> From zkulpa@ippt.gov.pl Wed Dec  4 22:04:02 1996
> To: starship-design@lists.uoregon.edu
> Subject: Re: starship-design: Mission structure
> There was some discussion on the mission types rather long ago
> (mostly, my quarrel with Kelly on one-way missions  :-).
> I want to sum up briefly my opinion in this matter:
> - Note that the prerequsite for starting the interstellar
>   mission is prior start of the COLONIZATION OF THE SOLAR SYSTEM -
>   i.e., at least establishment of permanent, ALMOST self-sustaining
>   bases on the Moon and Mars, possibly some small space bases/colonies,
>   routine interplanetary manned trips, at least, say, within
>   the orbit of Jupiter, asteroid mining facilities and factories. 
>   Without this, construction in space of the huge starship, 
>   capable of sustaining significant crew
>   without constant resupply for tens of years, as well as
>   the solar-system-wide supporting propulsion system
>   (huge orbiting masers/lasers, etc.) is simply not possible.
>   Hence, the technology for building significantly large
>   self-sustaining manned bases in space will be available
>   at the time, that is, building of the space colony or
>   long-duration self-sustaining base in another star system
>   will be quite feasible and much easier than we may think today.
> - However, building somewhere. light-years away, a really
>   independent colony starting new permanent human habitat there
>   seems still a huge undertaking for me. I think, to establish
>   something of the sort will require a whole flotilla of starships
>   and tens of years of construction of all necessary infrastructure,
>   possibly including terraforming of some planet.
> - Therefore, a much more realistic solution for me is
>   establishing a LONG-DURATION OUTPOST BASE.
>   That is, it calls for a so-called ONE-WAY mission.
>   What is a difference, from the point of view of the crew,
>   between the one-way mission and the colonization mission?
>   There is a SINGLE difference: there is NO PROCRERATION
>   on the one-way mission. Only this, nothing more!
>   Hence, from technical point of view, the one-way mission
>   is simpler and requires much smaller resources, becoming
>   feasible in the "early colonization of the solar system" 
>   conditions outlined above. Technically, the one-way mission:
>   -- can have much smaller crew (as the questions of genetic diversity
>      and all sociotechnical specialization variety are absent);
>   -- requires no provisions for rearing and educating children,
>      which include additional crew, much more elaborate
>      environmental control, education facilities, much more
>      storage (or on-board industry) for all things for 
>      children and young;
>   -- the outpost does not have to be indefinitely sustainable -
>      it would suffice to stay operational till the longest
>      possible natural life of the crew, which means some 50+ years
>      only, certainly less than 100.
> - The outpost may be later transformed into a permanent colony,
>   if the conditions in the target system show to be good enough
>   and the technological advances within the solar system during 
>   the time of the trip and initial exploration phase (this means 
>   some 20 years of Earth time...) will allow for sending follow-up
>   starships with enough resources to establish a colony.
> So, I think that the course of events will be like this:
> - robotic "pathfinder" probe (testing the starship technology
>   and preliminary assessing of the conditions for subsequent stages);
> - one-way outpost construction mission;
> - possible follow-up colonization expeditions.
> -- Zenon

-- Zenon