Re: starship-design: One way (again...)

[Zenon Kulpa <zkulpa@zmit1.ippt.gov.pl>]

> From: Kelly St <KellySt@aol.com>
> 
> In a message dated 12/11/97 6:55:35 AM, zkulpa@zmit1.ippt.gov.pl wrote:
> 
> >> From: Kelly St <KellySt@aol.com>
> >> 
> >> In a message dated 12/8/97 3:24:52 PM, you wrote:

> >0ne-way: 
> >    flight there (10 yrs);
> >  + sustained stay for the rest of the crew (natural) life
> >    (with life expectancy in space of 70 yrs, age at start 30yrs,
> >     and flight time 10 yrs, this phase will last 30yrs at most);
> >  = 40 yrs;
> >Two-way:
> >    flight there (20 yrs);
> >  + sustained stay for the exploration phase (5 yrs);
> >  + flight back (20 yrs);
> >  = 45 yrs.
> >may actually be in favor of the one-way mission.
> >Not speaking about the fact that those who return from
> >the two-way mission will land on Earth five years
> >after their life expectancy...
> 
> Only because your assuming a fairly short life expectance. With the high 
> risk environment of a mission like that, that might be justifiable, 
> but for planing purposes you'ld have to assume longer.
> 
Why I should?
But even assuming 80 yrs (which would be stretching things a bit),
the numbers above do not change significantly
(it would be 50yrs for one-way and 45yrs for two way).


> >Hence, the two-way mission will need approximately the same
> >amount (and duration needs) of the equipment.
> >But two-way will be much more demanding from the fuel/engine
> >point of view (as Isaac correctly remarked, not simply two times
> >more, but possibly orders of magnitude more).
> 
> This makes no sence. If your assuming the same total fuel ration on the 
> ship for a one or two way mission. You need the same total thrust from 
> the engines (but of course on the return leg you can stand dropout with 
> less mission impact). So how could the demands on the engines be 
> orders of magnitude more, or realisticly even twice as much? 
> At most the engines firing time is twice as much, 
>
Ask Isaac, he is more competent in these matters than me.


> but thats separated by years to do check out and servicing.
> 
But what about "shell life"?
Also, for check out and servicing you will need spare parts 
(for engines, they may be quite huge!) and manufacturing capablity,
which you may as well spend for durable one-way mission habitat
building and maintenance instead.


> >Hence, which would cost more - still REMAINS DEBATABLE.
> >
> >Note also that in order to not became a suicide mission,
> >the two-way mission plan must ALSO be capable to safely change it
> >into one-way at target when the return flight becomes impossible
> >for some quite probable reasons (engine failure, problems
> >with fuel mining at target, etc.).
> 
> That would be desirable, but increasing the service life by more then 50%
>
Huh?
As I have calculated at the beginning, the time durability
for one-way and two-way missions is comparable, certainly 
not so much different as by 50%.


> would probably require MAJOR scale up in the ship systems and crew, which
> would probably be untenable. Contingencies for those problems that allow 
> a return would need to be factored in, or a possible rescue mission (i.e.
> diverting the next ship that could have been planed to be launched to 
> another star).
> 
Rescue mission? After you received the mayday signal (4yrs)
and been able to arrive with the rescue ship (+20 yrs, see above)
they will be long dead without the one-way capability!


> >> No, we would not go somewhere just to go to an outpost. In itself, 
> >> an outpost isn't a goal or a reason for going somewhere. 
> >> At best its a tool to allow you to do something there.  
> >> At worst its a stunt.  (Been there, done that, took
> >> our bows, and went home.)  
> >>
> >Ahh, but the above applies even stronger to the two-way mission
> >(especially the "and went home" part ;-)).
> 
> I don't follow that statement.  It sounds like your saying if we have no
> reason to go somewhere (or go back to) then stay there perminently?
> 
Huh?
Now I do not understand what you are speaking about...

Let me recapitulate:
You said in the above that an outpost building would be only a stunt,
and the you preceeded to defina a stunt as "(Been there, done that, 
took our bows, and went home.)". Now I remarked, that with that
"and went home" part your definition of "stunt" applies as well 
(or even better) to a two-way mission.
Which I then summed up with the sentence:
> >
> >Hence, from this point of view one-way and two-way seem equivalent...
> >
which sentence you seemingly overlooked.

Got it this time?


> >> If your assuming a maned outpost, it would be a strong incentive to 
> >> cancel the first mission.  I.E. to prevent being forced to eather: 
> >> send a retriaval expidition to bring them back, or to take the heat
> >> for leaving them to die for some Apollo like stunt.
> >>     ^^^^^^^^^^^^^^^^^^^
> >>
> >You again with that "leaving them to die" rhetoric...
> >And "leaving them to die" back on Earth is so much better?
> 
> Yes, obviously, for reasons I've stated several times, including above.
> 
Huh? 
What is so more sweet with dying on Earth rather than somewhere else?


> >Or "leaving them to die" during the long and quite boring 
> >return flight (of old age/sickness or in a catastrophic accident,
> >much more probable during the return flight due to engine wear)?
> 
> The return flight would certainly be no more boring then being parked 
> in the target system.  Eaither way you still stuck in the ship with 
> no where to go. But at least your going back somewhere at the end.
> 
In order to be stuck on Earth, and nowhere to go?  ;-)

I understand that one may be bored to stay all his life
on just this tiny and crowded planet.
So I understand he may wish to go to the stars and explore
and then (when lazy of old age) at least observe at close ranges
other planets (and another star).
But I do not understand why going from these very interesting 
circumstances back to that boring and crowded planet can
he call as so desirable "going back somewhere"?


> >Yes, before undertaking an insterstellar mission we must be
> >already a very spacefaring civilization - in fact I have repeated
> >this several times in our discussions in the past (and in the next
> >paragraph of my previous letter too, see below).
> >However, going interstellar will be the logical and ncessary
> >NEXT step to become really spacefaring, not merely in-system-faring...
> >We all agree that interstellar travel is orders of magnitude
> >harder than in-system, hence being able to launch a starship
> >will certainly signify that we are much more spacefaring
> >than before.
> 
> But, within the technical limits of the designs were coming up with. There
> are no practical benifits, and some significal costs) to launching such a
> mission. So launching it can't be considered important for the survival of
> the civilization, in the sence of the quoted comment. I.E. It does not 
> offer the potential to increse resorces andmaerial, or ranges, 
> accessable to human civilization.  
> 
Posibly not from point of view of current times.
For us now a "survival of civilization" priority task 
is certainly to settle our system, NOT going to the stars.
But when the system will be settled (and becoming crowded,
or some nearby star is detected to be probably going
supernova in say, a thousand years, or so...)
the start of interstellar travel will be a must too.


> >> >Without opening a real big frontier in space, the humanity will
> >> >decline even faster and earlier than we may expect.
> >> >The symptoms are already quite visible.
> >> 
> >> I'm not sure what your talking about as symptoms, 
> >>
> >One example - a prominent member of the interstellar travel
> >discussion list so strongly opposed to even considering 
> >one-way missions as a discussion option!    ;-(
> 
> Because they have significant increased costs political, social, and ,
> economic and have no corresponding advantage. (and their is the moral 
> issue involved.)
> 
I know, Kelly, that you are probably totally immune to arguments
in this particular area, since despite a mountain of arguments
(and even name-calling at times ;-) you are still stubbornly repeating
the same old buzzwords. But there are many pepople that differ
with you on this issue and are eager to go to a one-way mission.
As the old Roman rule says, the willing is not harmed.
If there are people eager to go to stars that have no
need to and see no meaning in travelling back dangerously 
tens of years only to be put into grave here, 
there is NO moral issue in letting them go. Period.


> >> Personally I think interest in space will perk up when space does do.
> >> things. At the moments its effects have been quite underwelming given 
> >> the levels of effort. A more productive space program, should gain 
> >> more interest and approval.
> >> 
> >Possibly, let us hope so.
> >But without a vision and exploration spirit in plenty,
> >there will be NO "more productive space program",
> >or even any space program.
> >
> >Agreed?
> 
> Not really. Most of the growth in space systems and programs, especially 
> up to the scale needed for a project like this, would have to come from
> commercial interests, not from exploration, political, or scientific
> interests. Such interests are making serious moves toward space, but have 
> to dismantal governmently roadblocks and sanctions. I'm not sure if you'ld
> consider that "...a vision and exploration spirit in plenty.."?
> 
Certainly, dismantling all that "governmently roadblocks and sanctions",
requires "...a vision and exploration spirit in plenty"
(we there in Poland should know...).
But of course, commercial interests are not a goal, they are a means
(many there in the U.S. might have forgotten that  ;-).
The goal is civilization survival (not exactly, but near...).
But to connect this goal, one's individual "sense of life",
and the "going to space" proposed means, one certainly
needs "...a vision and exploration spirit in plenty".
Do you think a stock broker arrives some day, between
assesing ups and downs of toadys market indicators,
at the overwhelming urge to go to stars, just by himself?   ;-)

-- Zenon