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Re: Re: starship-design: Re: Re: debate

In a message dated 12/11/97 12:39:11 AM, kuo@bit.csc.lsu.edu wrote:

>Kelly St wrote:
>>In a message dated 12/9/97 11:55:52 AM, kuo@bit.csc.lsu.edu wrote:
>>>>>>Beyond that plannig on such systems in the next 50 years is highly
>>>>>>conservative even by the standrads of commercial investors.
>>>>>Commercial investors take amazing risks all the time.  They need to
>>>>>do so in order to make their overall profits.  That is the nature
>>>>>of investment.  Given the current profitability of the stock market
>>>>>compared to bonds, I would have thought that obvious.
>>>>Commercial investors never take amazing risks.  Their entire focus
>>>>is to avoid amazing risks.
>>>Untrue.  They regularly invest large sums of money on speculations
>>>which may fail, and when it's other people's money it can make big
>>>news when the bet fails.
>>All investments are risks.  "amazing risks" suggests an unusually high risk
>They are unusually high, in that the average middle income investor
>can not afford to take them.

Do you have any idea how risky most high yeild stock the "average middle
income investor" is flocking to know are?  The risks of total loss are rated
at approching that.

>Bill Gates is extremely paranoid and cutthroat in his business
>practices because he's seen first hand how volatile the computer
>industry is and how no one is assured to stay on top.  He's well
>aware that a single slip up could be all it takes to permanently
>cripple a computer company, like IBM or Apple.

As a nit, IBM or Apple spent years to decades shooting themselves in the foot
with arrogent attitudes before it caught up with them.

>>>I have great confidence that for interstellar travel something on
>>>the level of a theoretical anti-matter rocket or less will remain
>>>the best we can hope for in the next millenia.  The physics of
>>>relativity and conservation of energy strongly suggest this.
>>The physics of relativity and conservation of energy have only been
>>in the last century.
>Conservation of energy has been around for longer than that, and the
>physics of relativity did not invalidate most of the predictions
>made by classical mechanics.

Actually E=mC^2 did violate classical conservation of energy, since no one
ever thought matter and energy were convertable.  No doubt similar
'corrections' in our assumptions are ahead of us.

>What relativity did was it explained a lot of phenomena which didn't
>quite fit classical mechanics.
>The critical difference between classical mechanics and general
>relativity is that there were a lot of natural phenomena which
>didn't fit classical mechanics, and there are NO phenomena (natural
>or manmade) which don't fit general relativity.  We might observe
>some phenomena which don't, but we've pushed the bounds to near
>light velocities and haven't found anything inconsistent with it yet.

Actually physisc is full of unexplain phenominon and unexplored energies and
and conditions.  Masy we don't even have the equipment to look at yet.

>>They are not the end of physics research, nore are they likely to
>>be the ultimate form of power or rocket physics.
>I disagree.  I think general relativity and conservation of energy
>will stand forever as limiting factors to technology.  The degree
>to which we understand the motion of heavenly bodies is fundamentally
>different from any period in history, because with general relativity
>we acquired for the first time the ability to explain _all_ observed
>The principle of conservation of energy is a principle which has
>less direct predictive power, but it's one which has stood the
>test of time despite changes in our understanding of physics.
>>Research into
>>newer physics, capable of far greater power, performance, etc (zero point
>>energy, inertia/mass damping, etc) has progressed to the degree that NASA is
>>funding some conferences and studies on them.
>We will always look for ways around what we know, and research into
>zero point energy and cold fusion is very inexpensive to conduct.
>That doesn't mean there's any credibility to any of it.

True, but their was no credibility to relativity until it was tested.

>>So I would estimate that the odds that current physics (like
>>the physics of relativity and conservation of energy, or mass
>>conversion rockets) will not be greatly surpassed in the next
>>century, are about nil (assuming no colapse of civilization).
>If you honestly think so, then why do you care at all about this
>starship design list's concept?  According to your thinking, there
>is no chance that anything we come up with will be anything even
>remotely like what would be worth sending to the stars.

True, in the same way the lunar systems designed by the british interplanetary
society most of a century ago, or those designed by VonBraun in the '50's,
bore little relation to to the apollo systems.  But it did show you could go
to the moon with those technologies.

>The predictive power of general relativity is simply too much
>better than what came before, and too heavily tested and confirmed
>by hostile scientists, to put it on the same level as what came

  :)   Chavanist.  All ages think they found the ultimate truths, all are
superceeded by their  succesors.

>>>Huh?  Advantage over what?  A dispersed phased array system can't
>>>be adapted to longer range without significant modification.  What
>>>_can_ be done is to increase it's efficiency by bunching it up
>>>together as tightly as possible, ideally shoulder-to-shoulder.
>>>The only thing you gain by dispersing them over a wide area is...
>>>you don't gain anything, actually.  At every range, the beam
>>>produced by the tightly bunched up array is superior to the
>>>beam produced by the widely dispersed array.
>>You gain increased range due to the larger virtual lens from the array.
>NO YOU DO NOT!!!!!!!!
>The larger virtual lens size is exactly counteracted by the reduced
>efficiency.  In other words, if you get a spot which is 1/10 the
>area, it will also have 1/10 the beam energy.  You haven't gained
>OTOH, you have _lost_ 9/10's of the theoretical optimum beam (the
>optimum beam is if the elements are bunched up shoulder to shoulder).
>Kelly, try and comprehend this one fact, if nothing else.  The
>widely spaced array gains you NOTHING.

Thats was countered by oter on this board.  To put it blutly.  You need that
size to focus at long ranges.  If you can't focus the beam, it dosn't matter
how much of it you transmit.

>>>>>The possible reuse of the lasers is particularly notable if it is
>>>>>reused in a single mission (e.g. sequencially launching multiple
>>>>>modules which provide deceleration fuel).
>>>>>However, the possible reuse of lasers for marketable power generation
>>>>>is, IMO, dubious.  First, there has to be a market for that amount
>>>>>of power.  
>>>>Presumably for large scale industrial operations in space, such as non
>>>>earth asteropid work and transport.  But agreed, this is speculative.
>>>The only serious use for them I can imagine is for laser powered
>>>rocket transport.  Assuming nuclear reactors remain expensive and/or
>>>fission materials remain restricted, laser powered rockets offer
>>>great potential savings in rocket costs.
>>>For any sort of heavy industrial work where it's worth putting a
>>>high power refinery on site, it's also worth putting its power
>>>source on site.  Beamed power really only offers a potential
>>>advantage in cases where the power is only needed a small fraction
>>>of the time (which is the case for rockets).
>>Since the refineries and propulsion platforms would need to relocate around
>>asteroidal space, being able to buy a couple months powe without shipping a
>>power plant to the site could make a lot of economic sence.
>These refineries are likely to mass a lot more than their power
>source, so if it's worth moving the refinery on site, it's not
>much of a marginal cost to bring its power source along as well.
>(The alternative is moving the asteroid to a refinery, which is
>an example of rocket power--which I already describe as a valid
>potential use for beamed power, if nuclear rockets are restricted.)

Actually in space this isn't a factor for a lot of types of refineries.  I.E.
you use power, but little physical equipment, but thats geting off topic.

>    _____     Isaac Kuo