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In a message dated 03/19/00 05:16:58 Mountain Standard Time, 
johnbean@ebard.com writes:

<< Subj:     Re: starship-design: HIGHLY OPTIMIZED TOLERANCE
 Date:  03/19/00 05:16:58 Mountain Standard Time
 From:  johnbean@ebard.com (John Bean)
 Sender:    owner-starship-design@lists.uoregon.edu
 Reply-to:  johnbean@ebard.com (John Bean)
 To:    starship-design@lists.uoregon.edu
 Ben Franchuk <bfranchuk@jetnet.ab.ca> wrote:
 >I disagree -- you have to carry a boot strap able system.
 >All that stuff could fit in a large space craft the catch is it is not
 >to have small systems and you may have to reduce operating perimeters.
 >Take solid state logic... A portable chip processing plant could
 >be table top size, but may have to use 2 inch wafers, be limited to 64kb
 >x 1
 >dynamic ram,16 bit processors ,or smaller and only produce 256 chips a
 I don't know if I agree with the make-everything-myself idea when it comes
 to really complicated processes that are really expensive such as chip
 making. At some point you need to repair/replace the "table top wafer fab"
 and the technology to do that would have to be carried. Then that
 technology needs to be repaired so you need the technology to do that. This
 goes on forever with each iteration adding weight, complexity and cost.
 Also making chips is not as simple as a wafer lab according to the guys who
 are making custom chips for me. The process is big by nature, requires lots
 of energy, lots of chemicals and consumables, very skilled people and
 ultra-high tech ultra expensive equipment. These guys snicker or drool
 whenever you talk about a small or inexpensive or easy prototype machine
 like you are discussing.
 Even if you could create this machine and have it weigh 100 pounds with 100
 pounds of support stuff, excluding consumables, and 100 pounds of spare
 parts and equipment it becomes really heavy and would cost millions of
 dollars. I don't know how to figure out the weight of the person to operate
 this or the supplies he needs. This also ignores the toxicity of some of
 the processes.
 A better suggestion may be to design a "generic" logic module using modern
 technology. I'm not suggesting a few gates on a board as in the 80s I am
 suggesting a 32 Bit ARM processor, a DSP, 160k of program flash, 8Mbits of
 data flash, 12k of RAM, a USB port, an IRDA port, some A/D channels, some
 D/A channels, somer general purpose IO pins. This could be built on a 2x3
 board that uses very low current (50ma with both CPU and DSP cooking at
 22/80 mips) at 3.0 volts using available (off the shelf) technology for $20
 a board in medium volumes at about 2 oz a board.
 In place of your 300 lbs of machine you could carry 2400 spares for $48000.
 Considering a desk-top fab will probably cost Millions, which excludes the
 packaging and testing equipment also required.
 The real difference is that you have to get used to the concept that in
 some things, such as modern electronics, you are often better off to throw
 a bunch of parts at a simple task than to make something custom.
 If you need to interface a full keyboard use one of these boards and also
 use one to interface to a single switch. The idea is to have so many of
 them that it just doesn't matter. If the initial design used this approach
 there would be thousands of these boards in a starship spread through
 critical (life-support) and non-crital (personal entertainment) systems.
 Take some multiplier of these as spares and you would be covered for many
 Since many of the boards will be used for different types of tasks a
 particular failure on one part of the board would not prevent the board
 from being used in another location. For instance if an AD failed switch
 that board to some task that doesn't use the ADs and take the one from the
 task that didn't use the AD. This provides some redundancy without even
 reaching into the spares.
 This approach can be applied to other technology issues also. For instance
 only use two kinds of displays, a big one and a small one, and make sure
 the big one can do the job of the small one. Then carry spares, mostly of
 the big ones.
 Another way to extend the mission duration is to send supply ships ahead,
 or send them faster from behind with some replacement stuff. Since "stuff"
 doesn't need gravity or environmental controls or oxygen or food or water
 it can be moved much faster and much cheaper than we can move people.
 Although re-supply may be distasteful to "pure" starship travel the
 reallity is that even here on earth it was, and is, considered normal.
 Aircraft carriers and submarines and space stations do it, the only
 difference is distance.
 Considering FTL isn't going to happen soon, if ever, it is probably safe to
 assume that we would go pretty slow in a colony ship. If a supply ship can
 go 1.5 times faster at 8 months we send one with the first resupply
 reaching us at the 1 year point. Assuming engines will keep getting better
 perhaps the next supply ship is launched at 18 months and reaches us in 2
 years. Radio will still be effective so we can provide them with a shopping
 list even if it is taking weeks or months for it to reach earth.
 Personally I don't think we will be going to reach the stars soon. However,
 I think starting to travel is critical to our survival just like setting
 out in doughouts was to most early sea fareing nations. I think that our
 travelers, now in space for 15 years, will be stuned when some kid pulls up
 in his dads Mach5 with his FTL Quantum drive with the Window's logo on it
 and says "haven't you heard, Bill Gates bought NASA, now everyone has an
 Intel FTL drive in their family car. Other than having to turn it back on
 every hour and the occasional warping into a star it works great"

Has anyone thought about the development in organic computer technology that 
is being worked in labs?  Computer circuits that are self repairing.  Kind of 
a combination between neural nets and processors.  They've already put a tiny 
chip into a cell, with the terribly slow rate that space advancements are 
doing (at least the manned ones), this technology could be up and running 
before we ever leave for the nearest star.  That way, you don't have to make 
chips with equipment and such, you can grow them.  They would also presumably 
last longer than silicon as well as grow and work better.  Just a thought.

Mike Pfeifer