Re: RE: RE: starship-design: FTL travel

[KellySt@aol.com]

In a message dated 4/20/00 8:29:57 PM, lparker@cacaphony.net writes:

>In a message dated Thursday, April 20, 2000 5:48 PM, KellySt@aol.com writes:
>>
>> In a message dated 4/19/00 8:48:13 PM, lparker@cacaphony.net writes:
>>
>> >> Unless your building something huge its a wast of time.
>> >
>> >Nope, you can prefab small too.
>>
>> Can doesn't mean its a good idea.
>>
>
>Huh? Why not? Or should I point out that you have your economies of scale
>reversed? It is easier, cheaper and more profitable to mass produce a small
>object than a large one. Who ever heard of mass producing the Titanic?

Or biulding a titanic in segments to be assembled in the feild.  Prefabing 
little segments of a statin to be assembled in orbit means lots more seams to 
leak.  Besides its not like your likely to have a lot of things in the 
station that you'l have lots of copies of.  So mass productin is a bit 
dificult.

>> Chose the best system for the project not the project to
>> promote your agenda.
>>  Dson't think like a advocate.  You couldn't possible mine,
>> smelt, and
>> manufacture most of what you'ld need - certainly not for less
>> launch mass
>> then a reasonably sized station.   Why do we NEED industry in
>> orbit?  If the
>> answer is you feel industry in orbit is important, go to
>> jail, do not collect
>> $200.  You need to bepractical and profitable.  Launching the
>> material from
>> earth for initial projects would be far more cost effective
>> and safe.  Most
>> you couldn't make in space anyway.  At least you exercise the
>> launcher and
>> save some serious bucks.
>
>Whose promoting an agenda? <G>
>
>Seriously, though; you might get away with building interplanetary probes
>in
>pieces and assembling them in orbit, but as long as it is done that way
>you
>are promoting large heavy lift, expensive to launch boosters. On the other
>hand a permanent manufacturing presence in orbit would require LOTS of
>small, efficient, cheap launches to maintain.

No because the infastructure to build the probes and early stations is much 
larger and heavier then years worth of probes and statins would be.  
Expensive launch is much less of a problem since the bulk of the cost of a 
good reusable is building the craft and keeping up its facilities and such.  
So if you quadruple the launch rate the total cost goes up far far less.  In 
some cases hardly at all.  Just fuel and wear.  With DC-x they found if you 
launched 3 times a week or three times a year you had to keep most of the 
same people on in similar pay rates.  Spare parts and such ae a pretty low in 
comparison, and ofcourse the cost to develop and build the craft are divided 
over the total number of flights.

>Second, an interplanetary craft might max out at only a few hundred tons,
>hundreds of times smaller than an interstellar probe. Add up the launch
>cost
>of oh, say a 10,000 ton probe if every piece is lifted to orbit from Earth
>on Titans and Arianes. What fraction of the PLANETARY Gross Product is
>that?

If your lifting 10,000 tons you can cut lift costs dramatically.  Cut costs 
to 1/100th that of a titan or such and the total lift cost would be 
$2,000,000,000  About the cost of 1 year of shuttle launches (under 200 tons 
possible lift).

Shows you how bad current launchers are.  In theory the lift costs could be 
cut even another factor of ten or 100.

Now obviously your not going to want to lift millions to hundreds of millions 
of tons for a big starship if you could get it cheaper in space.  But you 
wouldn't want to life a thousand ton steel mill to make 40 tons of steel.


>Third, what do you want to see, a repeat of Apollo? Okay lets spend ten
>trillion dollars to put a man on the third planet of Alpha Centauri and
>then
>go home and quit? Not me.
>
>I want to see a thriving orbital industry sending hundreds of ships out
>to
>mine asteroids, ferry goods to and from orbital installations, the moon
>and
>the planets. Research stations all over the solar system, inhabited stations
>all over the place. In short lots and LOTS of experienced orbital know
>how.

Then you don't want the interstellar or any exploration missions, you want a 
earth side market for your space based industry.  Without that it will all 
blow away to dust like NASA after Apollo.  Doesn't mater how much stuff you 
put up there.  If its up there for no real general pourpose, It'll be 
abandoned.


>Anything can be manufactured in space. Many things can be manufactured
>BETTER. I have a get out of jail card and I think space is the equivalent
>of
>Boardwalk and Park Place with hotels...very profitable.

Good idea, but a different conversation.  Space tourism could easily dwarf 
anything we're talking about.  It would nessisarily keep any manufacturing 
facilities going.  (How many factories moved to Cancun, or Jamaca?)  But they 
would feed a HUGE launch industry and provide launch infastructure to drool 
for, as well as residence facilities for research and consructin platforms to 
house their staffs on.

>> Asteroids an't thought to be solid.  Best bet is sticky ruble piles.
>
>Some are, some aren't. Depends on what they are made of. Some are thought
>to
>be rubble piles, some are thought to be solid. For mining purposes the
>rubble pile actually works better. The slag form the smelting operation
>can
>then be fused together to make large structures. The University of Minnesota
>has a good class on this.
>
>>
>> I though congress changed that law last year?
>
>The law has nothing to do with Congress, it is the FAA that has to change
>it. I could be wrong, but I don't think they have actually done so yet.
>It
>was one of the major reasons Kistler Aerospace took there project to
>Australia and it did have some influence on SeaLaunch as well.

Congress has to change the law and when they found Kistler was being forced 
off shore they did (I'm pretty sure).


>> Oh, folks are also working on the space planes themselves.
>
>Lots and lots of folks are working on space planes! Mostly they are after
>the X-Prize. Some actually intend to make money at this.

Space access is the most interesting.  ;)

>Lee


Kelly