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Re: For Consideration

Tim says in response to Brian:
> As long as the fuel is prelaunced there is no problem, but you were
> suggesting to use the fuel as shielding. If you planned using that fuel for
> deceleration, it could not work because there isn't an engine that can stop 
> it.

only true for internally powered engines, an externally powered MARS 
design, would be able to carry enough reaction Mass (I hope) to overcome 
both the photonic thrust, and slow the ship at 1 G (10 m/s^2)

Now Brian says
> >Of course, using Kevin Houston's maser idea would be divine and with it we 
> >could accelerate/declerate the whole way.  But I just don't see how he is 
> >going to keep a maser beam on a starship that is 11.8 ly away.  Or is it 
> >11.9 or even 12.2 ly.  I can't find a single pair of sources that agree on 
> >how far away Tau Ceti is!

there is in existence today, a laser interferometer gyroscope, that by 
all accounts is accurate to within one wavelength of light.  assuming you 
are using something at 580 nanometers, this translates into only 680 
Kilometers divergence after 12.0 lightyears.  If the maser antenna is 
wider by that radius, (ie, if the maser beam is 1000 Km in radius, the 
antenna should be 1680 km in radius) or, if the maser beam is wider than 
the antenna (just switch the above numbers,) then either the beam will 
allway rest upon the antenna (in the first case), or the antenna wil 
allways be within the beam (in the second case)

However, Since you missed much of the discussion between the newsletter 
dying (how that listserver coming Dave?) and the time you joined, I will 
re-iterate the main monkey-wrench in the system.  Before I do so, let me 
re-state the main Idea.

By accelerating the Reaction Mass (RM) to near light speed, we could 
increase it's momentum endlessly (by approaching the speed of light ever 
closer) thus allowing less RM to escape out the back of the ship.  by 
using the maser antenna as a "sail", and retro-reflecting most of the 
energy, we could accelerate away from earth at a nice 1 G (and since the 
exhaust speed would be C (photons) the RM would be zero.  at the 
turn-around point, instead of reflecting the maser beam, we would convert 
it to electricity, and accelerate RM in the direction of TC.  But there 
wont be enough energy to overcome the momentum imparted by the photons 
absorbed, to raise the exhaust speed up to .9996 C.  Thus our mass costs 
will go up.  instead of accelerating a small amount of RM to Near-light 
speed, we will have to accelerate a larger amount to some lower speed 
(perhaps .75 or .8 C)  I would love to tell everyone that I had solved 
this little mystery, but alas, I have been very busy with school-work.

To Dave, 
Re handedness.

While you are correct, in that proteins and sugars come in left and right 
handed forms, the choice is not completely arbitrary.  We use Left-handed 
Proteins, and right-handed Sugars,  (from now on, it's RH and LH) but 
anything that uses carbon and oxygen will use some kind of sugar. and 
unfortunately, RH sugar is the most thermodynamically stable.  Thus if 
the Alien bugs use Sugar at all, they will have figured out how to handle 
RH glucose.  as for proteins, This does appear to be an arbitrary choice 
made by life early in it's developement.  It may be that protiens _must_ 
be LH if Sugars are RH, or it may be something different, However, even 
if the bugs couldn't digest our proteins, we would not like them eating 
our glucose and reproduceing ad infinitum.  because if they can't eat us, 
it's a sure bet that our immune system would be completely stymied.

on anti-biotics, Kelly is right.  all my Bio-Chem Books show that 
Anti-biotics attacks certain specific Key reactions that all life must 
use.  For example, Sulfa drugs attack the Flavin pathway.  Thus unless 
the bugs are supplied with the component, they cannot survive (unless 
they have a mutant enzyme which can distinguish between the proper flavin 
precursor and the sulfa drug.  This is what I meant by the evolutionary 
age of the life being important.  We carry many genes within us that are 
deactivated.  Some of them are very old, from the days when we were 
fish.  (fetuses have gills at one point)  the same is true of bacteria, 
they have genes that code for long surpassed chemical weapons.
Like this:
Bacteria A developes weapon.
Bacteria B developes defense to that weapon
Bacteria C-Z die for not having the defense,
Bacteria B thrives and al future bacteria have the defense gene
Bacteria A stops making the weapon, because it is no longer effective.

The weapons get better and better, and the more of them your ancestors 
were exposed to, the better your chance of fending off an attack by an 
alien bug.  A good SF book on this is "The War against the Chtorr" by 
David Gerald  it's a book, not about an invasion, but about an 
infestation.  and the aliens are trying to Chtorraform our planet to suit 
themselves.  but their evolution is much older than ours, so all thier 
bugs learned how to master penicillin millenia ago (and any other 
anti-biotic we could come up with) plus all the Chtoran life-forms have 
chemical weapons and defenses that earth life had never seen before.
the long and the short of it is. we are losing. and the human race has to 
figure out how to survive in a world that is changing around us.

anyway, gotta go now.

Kevin Houston