[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Engineering Newsletter

Hi guys, a few web pages you might be interested in.

 Zenon suggested nanotech and A.I. might be a pre req for star travel.  He
also suggested for more info about significance of nanotech for space
exploration.  See the Molecular Manufacturing Shortcut Group page at:



For serious info on planing space flights, check out:
Originally created as an internal JPL training document, the Basics of
Spaceflight is comprehensive, medium level overview of a wide range of
topics related to construction and operation of planetary spacecraft.

The material is supposed to be extremely well written and unlike many NASA
outreach and educational materials, has not been digested down to the
5th grade level.


Larry Klaes
Editor of SETIQuest Magazine recomends


It is still under construction, but its trying to let you explore how a
starship will interact while approaching light speed.  It can be found at


under the link cship.



ReplyTo: Timothy
Subject   : Plasma mirror

>>> I don't think refocussing is necessary, the mirror itself can
>>> be just a flat mirror so the reflected beam is nothing 
>>> different than the beam from Earth.
>>That would mean the catcher sail on the ship would be the same size as the
>>reflector mirror.  That would mean it would get more push forward from the
>>dirrect beam from earth, than push back from the reflected beam from the

>Hmm, yes, but there seems to have a similar problem with 
>the plasma mirror.

Not really, Since the ring sail & catcher mirror are in the same place
(attached to the ship) the ring sial would be geting the same energy (no
energy drop due to r^2 losses.)

>But I've found a solution:

     A /    \ B        Two mirrors A and B at a perpendicular angle
 / ||          || \
   ||          ||
   ||          ||
   ||          /\
   \/        Beam from Earth
 Beam to Earth

> This design makes the total mirror about 3 times bigger.
>The beam from Earth should be directed mainly on mirror B 
> so that the beam to the Earth (or from TC) is reflected 
>mainly from A. The final result is that there are two beams
> next to each other, one is going up the other is
>going down.

Whats the advantage?  Also you seem to asume the that the power beam will be
as small as the miror?  It sould be thousands of miles across.

>>Assuming of course the mirror flies sideway slightly so it isn't in
>>the ships shaddow all the way to Tau.  Of course if its off to one side you
>>have to turn it so its reflections tracks the ship, so your back to the
>>tracking problem.

>With this new design the biggest tracking problem is removed. Furthermore
>the Asimov always has to follow the beam just as in the acceleration phase.

I don't understand what your going for.

>>Also without the anchor on the ship it will tend to flutter and
>>shift off course due to slight variations in beam, ISM, mirror reflectvity,
>>seperation torque, etc..  This of course ignores the fact the sail isn't
>>rigid, and will tend to crumple once its free of the ship.   
>>> Of course the mirror has it's own "gyro-system" it can 
>>> compensate slight movements by using a small side 
>>> reflectors.  The same principle would be used when the 
>>> Asimov is accelerated by a beam. 
>With enough accuracy to hit the retro sail at a distence of light years?

>>10 ly, 30 ly does it really matter? The minimum is 10 ly for >> any kind of
>> beam-propulsion system. I wonder if an extra 20 ly makes that much


ReplyTo   : Timothy
Subject   : nanoAI

>>We still have no drive idea that could get a bit or small ship to Tau C.

>We have ideas, the biggest problem is the enormous amounts 
>of fuel that are needed. Lets say we use a
>take-all-fuel-with-you system. For matter&anti-matter fuel
> the ratio fuel:ship would be about 20:1 for small ships 1E4 >1E5 kg this
may be acceptable but for ships 1E8 or 1E9 kg 
>its a completly different story.

Your taking hundreds of tons of antimatter!  That is a stagering amount to
manufacture, or even hold on to!

>>We've added the relyability problems of the AI and Nano systems to the
>>project.  After all, programs can crash, and nano's are made of complex
>>molecules that might break down in the high radiation in transite.
>>they get there in tact, what do we tel them to use for resources in a
>>we don't know anything about?

>Indeed things can go wrong and will go wrong. So will things happen on a
>ship like the Asimov, only then people are endangered.
>High radiation as a cause of error can easely be prevented by
>sufficient shielding.

People are mentally much more adaptable and relyable than any current
Nano/A.I. systems.

>We know that there will be asteroids and planets there. This 
>means that all the basic materials should be present, so our
>mini factories have to find them an use them.

Thats a big job if your the size of a virus.


>>We also have extended the time of the project to un sustainable levels.
>> Figure a quarter century after launch before a returning beam from Tau C.
>>announces the decel system is compleated.  Then a quarter century after
>>(50 years from the launch of the first nano ship), a beam from your
>>announces you've started exploration.  If the projects going to take that
>>long you might as well wait untill you have a better drive system.

>Supposing a significant better system is possible within 50 
> extra years, I think its worth the waiting.

So will the backers.  So the nano idea won't be launched, and the idea isn't

>>For that matter. If the A.I's are good enough to build the decel gear.  You
>>might as well have them do the exploration and skip the human ship.

>That is something completly different discussion: Why do we 
>want to go there anyway. I was having a discussion with Nick
> Tosh about that, until his connection broke down. I can tell
> you, that I don't know why we want to go there so soon 
>If you have an answer I'd like to know...

As I remember the idea of LIT was to see if we could think of some way we
could build a starship in 2050 with probable technology of the day.  Tau C
was selected as a target to focus the groups attention on.

>For the AI and nano, if they will be as unreliable and 
> unadvanced as you think, my guess is that the time isn't right 
>for flying to TC anyway: If anything, and I mean anything goes >wrong in a
system that uses 1E17 Watts you are lost! It's not >like you can cut the
power any time you like. What I wrote 
>about overheating is just a small example of the problems 
>that go with these power streams. (And as far as I'm >concerned that problem
isn't solved yet)

Agreed. I remember a demo where a steelwool pad was throw in a radar beam.
 It burned away in secounds.  Very impresive!  Especially to someone who
might be thinking of riding such a beam for a couple decades.