# Re: Re: Summary A

```>To Timothy van der Linden
>
>(I trimed things a bit.)

I don't mind, if I forgot something I've my older letters.

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>Fourtunately it would have a fixed aim toward Sol.  Unfortunately everything
>in the solar system tumbles.  So I expect we'll have to move a big mas to a
>usable orbut and then stablize it (and possibly gyro stablize part of it).
> The launchers could be mounted on that and the fuel processors and storage
>reserved set up on it.  (You prep the fuel before you leave, and leave enough
>extra for the next ship in.)

As said before, even if the launcher is 100 metres in length it still may be
difficult. The best thing we could do is search for a big asteroid which has
no own-rotation and is in a far orbit from it's sun (and thus moves not much
during a few months).

>> >I'm not clear on the requirment for the launcher.  Hopefully it won't need
>to
>> >be that long.  I don't think we'ld need speed that high because then the
>ship
>> >would get to far away from the launcher before it got that fast.  I think
>> >beam presision is the main limitation, but I haven't work on it.
>
>> This length is not only needed to accelerate but also to
>> aim accurately.
>
>You need a 100 km coil to aim 1/4 light year or less?

Lets see:

d=the diametre of the accelerator tube
l=length of the accelerator

maximum angle of deviation: Tan(theta)=d/l
maximum deviation after 1/4ly : 1/4 ly * Tan(theta) = 1/4 ly * d/l

using d=0.1, l=1E5, 1 ly=9.46E15 m

deviation = 0.25*9.46E15*0.01/1E5=2.4E9 m

This deviation is too much, so even a longer pipe should be needed, or a
smaller diametre, but the latter has a limit since it needs to exhaust a
minimum amount of mass per second.
Maybe I've forgotten something, but I don't see what it could be, maybe a
torroidal accelerator is better after all.

>> Yes, but the size of it is much bigger (1E18 times?)
>> than needed for a few billion atoms per second.
>> It's not the same as adding simple cannons together,
>> since the particles will start to interact and desturb
>> the same fields that accelerate them.
>
>Then package every E18th set of particals into a fuel packet canister.

That's like extending a rifle to shoot an big asteroid instead of a bullet
(that's only 1E10). I'm not pointing to the extra energy needed, but just to
the fact that things cannot be enlarged without changing completely.

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>> I don't know why I came with this before: They would probably have some
>> small space cruisers that would be the space equivalent of todays
>> jet-fighters. In these cruisers they could just blank the window (if it has
>> one) and fly in a simulated landscape.----
>
>Thats a little involved. I'm not sure if it would work.  Certainly ground ops
>training is out, but that might get you trained enough to operate the
>flyiers.

What do you mean by ground ops? Riding vehicles should be easier to simulate
since there would be no difficult g-forces to simulate. If you mean hands on
field work then indeed it may be a bit more difficult, but a single
generation crew would have to become used to that too after being out for 5
to 10 years.

>>>Same in the ship.
>>
>> No, the ship would have much less resources (ores and
>> machinery).
>
>The ship would have identical machinery (it would have to carry it eiather
>way), I'm not really sure of the extra ore would make a big difference.

I was assuming they could extend=build new tools when they arrived (eg.
large, low-tech equipment like steel-rollers)

>> I don't understand what you mean: Do you see any
>> public problems with hibernation itself or not?
>
>Starngly I've never heard much public upset at the idea.

I think that is because so far no one has been recovered after being freezed
in, most people think that it is impossible to revive a person either
because of religious and/or technical reasons.
Of course there may be other methods of hibernation that are less drastic,
although probably all methods mean that people should be in a deep coma. I
wonder if the media likes the idea of killing people just so far that they
are continiously on the stairway to heaven.

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>>>Not really, they are just big structural elements.  That should be pretty
>>>easy to build from local supplies.
>
>>Is that true? I always thought that it needed special bolts an
>>nuts etc.
>
>There are not that hard to build compared to the high tech parts.

OK, I see that. But is it that difficult to extend the equipment from making
bolts with a precision of 1/1000 mm to making a micro chip?

Tim

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